The sustainable sourcing of novel bioactive compounds from natural sources is crucial to the success of the pharmaceutical,food,and cosmetics industries.Iris bucharica Foster(syn.Juno bucharica(Foster)Vved.)is a promi...The sustainable sourcing of novel bioactive compounds from natural sources is crucial to the success of the pharmaceutical,food,and cosmetics industries.Iris bucharica Foster(syn.Juno bucharica(Foster)Vved.)is a promising source of novel bioactive molecules,particularly phenolic compounds,which are renowned for their antioxidant properties.In this study,we developed a reliable HPLC-UV-DAD method to identify and quantify phenolic compounds in the leaves and bulbs of I.bucharica,establishing the first set of quality control markers for this species.A total of 21 phenolic compounds were identified in the leaves,with flavonoids isoorientin,guaijaverin,hyperoside,and cosmosiin,the isoflavonoid biochanin A,and the simple phenolic ferulic acid being the most prominent.In comparison,14 compounds were identified in the bulbs,primarily isoflavonoids,including tectoridin and germanaism B,and flavonoid apigenin.The leaves extracts exhibited significant antioxidant activity,whereas the anti-allergic and anti-inflammatory effects were mild.These findings highlight I.bucharica as a sustainable source of bioactive compounds with potential industrial applications.However,further studies are needed to evaluate bioavailability and in vivo efficacy,as well as to optimise extraction methods to realize its industrial potential fully.展开更多
Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its...Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.展开更多
Achillea species are known for their healing properties since ancient times.There is extensive literature on their pharmacological action due to their bioactive compounds.The present study aimed to investigate the ant...Achillea species are known for their healing properties since ancient times.There is extensive literature on their pharmacological action due to their bioactive compounds.The present study aimed to investigate the antioxidant and antimicrobial effects of hydroalcoholic extracts from the inflorescences and leaves of the species Achillea crithmifolia Waldst.and Kit.,A.grandifolia Friv.and A.millefolium L.The phytochemical profiles of all extracts were evaluated both by NMR spectroscopy and LC-MS analysis,and the results were consistent with the spectrophotometrically determined total phenolic(TP:125.42-191.98 mg/g)and total flavonoid(TF:47.34-180.02 mg/g)contents.All the extracts were tested for their antioxidant activity using DPPH and ABTS•+radical scavenging assay,as well as ferrous ion chelating ability and reducing power tests.All the extracts showed moderate antioxidant activity,compared to the reference substance BHT.Additionally,the antibacterial activity of the extracts was evaluated against major food-borne pathogens,showing moderate antimicrobial effects.展开更多
Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples w...Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples were collected from 10 provinces in China,and six SPAs(three parent SPAs and their three transformation products)were analyzed.The concentrations of6SPAs(the sum of six target compounds)ranged from 15.4 to 3210 ng/g(geometric mean(GM):169 ng/g).The highest concentration of6SPAswas found in Sichuan Province(GM:349 ng/g),which was approximately 4 times higher than that in Hubei Province(81.6 ng/g)(p<0.05).The concentrations of butylated hydroxytoluene(BHT),2,2'-methylene bis(4-methyl-6–tert-butylphenol)(AO2246),2,6-di–tert–butyl–1,4-benzoquinone(BHT-Q),2,6-di–tert–butyl–4-(hydroxymethyl)phenol(BHT-OH),and ∑_(p)-SPAs were substantially higher in dust from urban areas than rural areas(p<0.05).AO2246 concentration in dust from homes(GM:0.400 ng/g)was about 4 times higher than that in workplaces(0.116 ng/g)(p<0.01).Significantly higherp-SPAs concentrations were found in dust from homes(GM:17.5 ng/g)than workplaces(11.4 ng/g)(p<0.01).The estimated daily intakes(EDIs)of ∑_(6)SPAs exposed through dust ingestion were 0.582,0.342,0.197,0.076,and 0.080 ng/kg bw/day in different age groups,and exposed through dermal contact was 0.358,0.252,0.174,0.167,and 0.177 ng/kg bw/day.EDIs showed that the exposure risks of SPAs decreased with age.This is the first work to determine SPAs in dust from10 provinces in China and investigate the spatial distribution of SPAs in those regions.展开更多
Silica gel column chromatography(CC),Sephadex LH-20 CC and high performance liquid chromatography(HPLC)were used to study the chemical constituents of the fruits of the medicine-food plant Rubus idaeus Linnaeus.A new ...Silica gel column chromatography(CC),Sephadex LH-20 CC and high performance liquid chromatography(HPLC)were used to study the chemical constituents of the fruits of the medicine-food plant Rubus idaeus Linnaeus.A new tetrahydrogenated naphthol syringic acid ester,named rubusnolicester(1),two new phenolic glycoside derivatives,4-chloro-2,6-dimethoxylphenol-1-O-β-D-glucopyranoside(2)and salicylic acid-2-O-(6'-O-acetyl)-β-D-glucopyranoside(3),together with one known salicylic acid glycoside derivative(4)and three known flavonoids derivatives(5~7),were isolated.Their structures were elucidated by HRESI-MS,NMR spectroscopy,and a comparison of optical rotation(OR).Compounds 1~7 were evaluated the inhibitory activities against the nitric oxide(NO)production induced by lipopolysaccharide(LPS)in mouse macrophage RAW264.7 cells in vitro.Compound 1 exhibited inhibitory effect with the IC50 value of(12.28±1.25)μmol/L.展开更多
Salvia miltiorrhiza(S.miltiorrhiza)represents a crucial component of traditional Chinese medicine,demonstrating effects on blood circulation activation and stasis removal,and has been widely utilized in asthma treatme...Salvia miltiorrhiza(S.miltiorrhiza)represents a crucial component of traditional Chinese medicine,demonstrating effects on blood circulation activation and stasis removal,and has been widely utilized in asthma treatment.This study isolated a novel phenolic acid(S1)from S.miltiorrhiza and investigated its anti-asthmatic activity and underlying mechanisms for the first time.An allergic asthma(AA)model was established using ovalbumin(OVA).The mechanism of S1's effects on AA was investigated using multi-factor joint analysis,flow cytometry,and co-culture systems to facilitate clinical asthma treatment.S1(10 or 20 mg·kg-1)was administered daily to mice with OVA-induced AA(OVA-AA)during days 21-25.The study examined airway responsiveness,lung damage,inflammation,and levels of immunoglobulin E(IgE),PGD2,interleukins(IL-4,5,10,13,17A),tumor necrosis factorα(TNF-α),GM-CSF,CXCL1,CCL11,and mMCP-1.Additionally,mast cell(MC)activation and degranulation were explored,along with T helper type 17(Th17)/Treg immune cells and TLR4 pathway biomarkers.The antagonistic activity of that specific antagonist of TLR4(TAK-242)(1μmol·L^(-1)),a specific TLR4 blocker,against S1(10μmol·L^(-1))was examined in co-cultured 16 HBE cells and bone marrow-derived cells(BMDCs)or splenic lymphocytes(SLs)induced with LPS(1μg·mL^(-1))to elucidate the TLR4 pathway's mediating role.S1 demonstrated reduced airway responsiveness,lung damage,and inflammation,with downregulation of IgE,PGD2,interleukins,TNF-α,GM-CSF,CXCL1,CCL11,and mMCP-1.It also impeded MC activation and degranulation,upregulated IL^(-1)0,and influenced Th17/Treg immune cell transformation following OVA challenge.Furthermore,S1 inhibited the TLR4 pathway in OVA-AA mice,and TLR4 antagonism enhanced S1's positive effects.Analysis using an OVA-AA mouse model demonstrated that S1 alleviates AA clinical symptoms,restores lung function,and inhibits airway response.S1's therapeutic effects occur through regulation of Th17/Treg immune cells and inflammation,attributable at least partially to the TLR4 pathway.This study provides molecular justification for S1 in AA treatment.展开更多
Chrysanthemum morifolium Ramat.is an important industrial crop with a high medicinal value,whose capitulum consists of ray and disc florets containing numerous bioactive components,such as flavonoids and phenolic acid...Chrysanthemum morifolium Ramat.is an important industrial crop with a high medicinal value,whose capitulum consists of ray and disc florets containing numerous bioactive components,such as flavonoids and phenolic acids.However,the distribution and accumulations of the bioactive metabolites in florets of Chrysanthemum morifolium were unclear.Herein,the ray and disc florets of Chrysanthemum morifolium were separated for comparing the bioactive metabolites.The contents of phenolic compounds and antioxidant activities were significantly different between the two florets.The metabolomic analysis identified 203 and 241 differential metabolites between ray and disc florets at two flowering stages.The derivatives of quercetin,isorhamnetin,tricin,and caffeoylquinic acid were enriched in the disc florets,while apigenin,kaempferol,acacetin,and their glycosides mainly accumulated in the ray florets.Besides,the results of transcriptome and qRT-PCR suggested that the F3H,F3'H,and FLS genes highly expressed in disc florets,while the FNS gene was well expressed in ray florets,which explained the different distribution of phenolic compounds between ray and disc florets.Furthermore,the expression of CmCYC2 genes was found to be significantly related to the distribution of flavones by correlation analysis.It was proved by the luciferase reporter assay that CmCYC2a and CmCYC2d factors could bind and activate the CmFNS promoter to regulate the flavones biosynthesis in ray florets.These results revealed the significant difference of metabolite contents and gene expression profile between ray and disc floret in Chrysanthemum morifolium and demonstrated that the quality of Chrysanthemum morifolium‘Hangju'was closely relevant to its flower morphology.展开更多
Phenolic resin-based porous composites are the promising thermal protection materials for aerospace applications.The high-temperature evolution of microstructure due to the decomposition of the resin also presents gre...Phenolic resin-based porous composites are the promising thermal protection materials for aerospace applications.The high-temperature evolution of microstructure due to the decomposition of the resin also presents great challenges to predict the internal heat and mass transport behaviors.This work investigates the effects of microstructural characteristics such as the number of pores,size distribution,pore-throats size and volume fraction on the permeation behaviors of fluid in the needle-punched short-cut fiber reinforced silicon phenolic resin-based porous composites.The specimens are prepared by the sol-gel method and the atmospheric pressure drying process and the pyrolysis experiment are conducted at 400℃and 800℃.Then,a scanning electron microscope and a Nano-CT computer tomography are applied to obtain the surface morphologies and the interior slice images of the specimens.The AVIZO software is employed to accurately extract and analyze the pore structural model and simulated calculate the absolute permeability.It is found that the small pores develop gradually during pyrolysis due to the resin decomposition and the quartz fibers rearrangement,resulting in an increase in number of large pores.Nonetheless,the equivalent radii of most pores are less than 1μm.Very few pores possess a large radius over 5μm.However,the volume fraction of these large pores exceeds 99%.In addition,with the pore size growing,the connectivity between these pores is enhanced,immediately causing an increase in number and size of the pore-throats.Larger pore and more pore-throats would add the unblocked flow channels for the fluid passing,reducing flow resistance.The seepage simulation also confirms that the absolute permeability gains significant increase after pyrolysis in all directions.For example,the absolute permeability of the pyrolyzed sample is 9.0×10^(-13)m^(2) in X direction,which is an order of magnitude greater than that of the unpyrolyzed sample.This study provides important insights for understanding the high-temperature evolution at of microstructure and the permeation behavior of fluid in porous thermal protection materials.展开更多
The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results sho...The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results showed that the mica improved the thermal properties of the composites,the thermal expansion coefficient decreased,and the liquid phase formation caused the composites to shrink and increase the density.The flexural strength of mica surface modified composites not only increased to 78.64MPa after thermal treatment at 800-1200℃,but reached 83.02 MPa after high temperature treatment at1400℃.The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo_(2)C and MoB,and the improvement of the shear strength of the composites by the mica.The shear strength of MBm5-2 at room temperature reached 33.08 MPa,indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.展开更多
Moringa oleifera Lam.is a Moringa genus in the Moringaceae family that is high in nutrients and has a wide range of applications.Phenolic compounds are widely found in plants and have various health benefits for the h...Moringa oleifera Lam.is a Moringa genus in the Moringaceae family that is high in nutrients and has a wide range of applications.Phenolic compounds are widely found in plants and have various health benefits for the human body.With its high content and wide variety of phenolic compounds,M.oleifera Lam.has been widely studied for its health benefits.The phenolic compounds in M.oleifera Lam.(MOPCs)can be a potential source of functional food ingredients in pharmaceutical and industrial applications.Numerous studies have shown that MOPCs have antioxidant,anti-obesity,anti-diabetic,and antibacterial effects.Although the research on MOPCs has been gradually increasing,the extraction,isolation,identification,biological activities,and comprehensive application of MOPCs need a more systematic summary and generalization.Therefore,this paper reviews the isolation and extraction methods,structure identification,biological activities,and comprehensive applications to provide a further reference for the research and application of MOPCs.展开更多
Grapevine(Vitis vinifera L.)is one of the main crops worldwide,and ultraviolet-B(UV-B,280-315 nm)radiation is emerging as a promising technical tool to enhance secondary metabolites that can contribute to the quality ...Grapevine(Vitis vinifera L.)is one of the main crops worldwide,and ultraviolet-B(UV-B,280-315 nm)radiation is emerging as a promising technical tool to enhance secondary metabolites that can contribute to the quality and health-promoting properties of both grapes and the resulting wines.However,few studies have assessed the effectiveness of UV-B supplements under field conditions.Here,we compared the effects of two different field UV-B treatments(a single supplement applied at pre-harvest,and a double supplement applied at both veraison and pre-harvest)on the phenolic composition of Tempranillo grape skins and the resulting wines.The double supplement induced stronger changes than the single supplement,with responses being more pronounced in grape skins than in wines.In skins,UV-B supplements significantly increased flavonols,phenolic acids,and flavanols,consistent with previous reports highlighting flavonols as the most reliable UV-B-responsive compounds in grape skins.In wines,the clearest responses were increases in anthocyanins and color intensity.Overall,UV-B supplements improved grape and wine quality,although skin responses were only partially transmitted to the wines.Moreover,wine responses were more unpredictable than skin responses,likely reflecting not only the UV-B-induced changes in grape skins but also the complex chemical interactions among phenolic compounds(and also with other metabolites)during vinification.Further experimentation,particularly in the long term,is required to optimize the application of UV-B supplements as a viticultural and enological practice.展开更多
Advanced glycation end products(AGEs),a group of complex compounds generated by nonenzymatic interactions between amino acids,proteins and reducing sugars or lipids,accumulate in vivo and activate various signaling pa...Advanced glycation end products(AGEs),a group of complex compounds generated by nonenzymatic interactions between amino acids,proteins and reducing sugars or lipids,accumulate in vivo and activate various signaling pathways closely related to the occurrence of various chronic metabolic diseases.This study aims to explore the structure-activity relationship between phenolic acids with different structure and affecting the AGEs generation,and to provide data support for AGEs control.Phenolic acids(4-hydroxybenzoic,protocatechuic,gallic,p-coumaric,caffeic,ferulic and sinapic acids)were employed to indicate the AGEs formation condition in Maillard reaction performed in the glucose-lysine model system.Three 1,2-dicarbonyl compounds were reacted with phenolic acids and then tested by liquid chromatography-mass spectrometry.The results showed that N^(ε)-carboxy-methyl-lysine(CML),N^(ε)-carboxy-ethyl-lysine(CEL),and pyrraline formation inhibited by phenolic acids varied from(8.7±2.5)%to(33.2±2.5)%,(10.5±0.8)%to(57.1±3.2)%and(1.3±0.3)%to(23.3±0.8)%,respectively.The p-coumaric acid has no inhibitory effect on CML and CEL formation.Gallic acid shows the best inhibitory effect on CML formation due to its strong antioxidant activity.Sinapic acid showed the best glyoxal(GO)trapping rate and thus had the stronger inhibitory effect on CML formation.Ferulic acid can react with mono-,di-,and tri-methylglyoxal(MGO)to form adduct products,showing the best MGO scavenging rate and a good inhibitory effect on CEL formation.The main role of phenolic acid is an antioxidant agent to inhibit pyrraline formation.The glucose itself or ammonia-induced degradation and Amadori rearrangement products oxidation were lowered by protocatechuic,gallic and caffeic acids due to their antioxidant activities to form AGEs,while AGEs inhibited by ferulic and sinapic acids were mainly dependent on their trapping ability on 1,2-dicarbonyl compounds.展开更多
In thermal protection structures,controlling and optimizing the surface roughness of carbon/phenolic(C/Ph)composites can effectively improve thermal protection performance and ensure the safe operation of carriers in ...In thermal protection structures,controlling and optimizing the surface roughness of carbon/phenolic(C/Ph)composites can effectively improve thermal protection performance and ensure the safe operation of carriers in high-temperature environments.This paper introduces a machine learning(ML)framework to forecast the surface roughness of carbon-phenolic composites under various thermal conditions by employing an ML algorithm derived from historical experimental datasets.Firstly,ablation experiments and collection of surface roughness height data of C/Ph composites under different thermal environments were conducted in an electric arc wind tunnel.Then,an ML model based on Ridge regression is developed for surface roughness prediction.The model involves incorporating feature engineering to choose the most concise and pertinent features,as well as developing an ML model.The ML model considers thermal environment parameters and feature screened by feature engineering as inputs,and predicts the surface height as the output.The results demonstrate that the suggested ML framework effectively anticipates the surface shape and associated surface roughness parameters in various heat flow conditions.Compared with the conventional 3D confocal microscope scanning,the method can obtain the surface topography information of the same area in a much shorter time,thus significantly saving time and cost.展开更多
Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacia...Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical,tribological,electromagnetic interference(EMI)shielding and thermal conductivity properties of carbon fiber/phenolic resin composites.Specially,array carbon nanotubes can deep into the resin matrix,effectively hindering crack extension,and constructing an electrically and thermally conductive network.Compared with the carbon fiber/phenolic composites,the tensile strength and modulus of elasticity(163.86±9.60 MPa,5.06±0.25 GPa)of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09%and 22.22%.The average friction coefficient and wear rate(0.20±0.02,1.11×10^(-13)±0.13×10^(-13)m^(3)N^(−1)m^(−1))were reduced by 39.39%and 74.31%.EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness,diffusion coefficient(0.39±0.003 mm^(2)/s)and thermal conductivity(0.54±0.004 W/(m K))were enhanced by up to 14.37%and 50.42%.This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure,proposes the reinforcement mechanism of array carbon nanotubes,and opens up the prospect of carbon fiber/phenolic composites for electronic applications.展开更多
A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has si...A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has significantly improved oxidation resistance.When the addition amount of Ti_(3)SiC_(2)is 75%,the carbonization volume shrinkage rate of the composite after aerobic static combustion is only 5.95%.At the same time,the LAR and MAR after 30 seconds of oxyacetylene ablation under a heat flux density of 1.5 MW/m2 are 0.0307 mm/s and 0.0149 g/s,respectively.The compressive strength after aerobic static combustion at 1000℃is up to 20.43%of that before aerobic static combustion,which is 1.99 times that of the unfilled material,significantly improving the high-temperature mechanical properties of the composite.展开更多
The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramib...The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.展开更多
A phytochemical investigation on the stems and rhizomes of Sinomenium acutum led to the isolation of 19 compounds, including three phenanthrenes, six anthraquinones, and ten phenolic derivatives. The structures of the...A phytochemical investigation on the stems and rhizomes of Sinomenium acutum led to the isolation of 19 compounds, including three phenanthrenes, six anthraquinones, and ten phenolic derivatives. The structures of the isolated compounds were elucidated by analysis of the MS and NMR spectroscopic data and comparison with the literature. Compounds 1 and 2 are two new natural products, and their 1H and 13C NMR spectral data were fully assigned for the first time, with the help of2D NMR. All of the isolates were obtained from genus Sinomenium for the first time and the phenanthrene and anthraquinone are the structure type first reported from this genus plants.展开更多
Three new phenolic glycosides, named as equisetumoside A (3-methoxy-11,12-dihydroxy-phenylhexane-9- one-4-O-beta -D-glucopyranoside), equisetumoside B (3-methoxy-4,11-dihydroxy-phenylhexane-9-one12-O-beta -D-glucopyra...Three new phenolic glycosides, named as equisetumoside A (3-methoxy-11,12-dihydroxy-phenylhexane-9- one-4-O-beta -D-glucopyranoside), equisetumoside B (3-methoxy-4,11-dihydroxy-phenylhexane-9-one12-O-beta -D-glucopyranoside) and equisetumoside C ( cis-ferulic acid potassium salt 4-O-beta -D-glucopyranoside) were isolated from the water-soluble extract of fertile sprouts of Equisetum, arvense L. (Equisetaceae), together with uridine, inosine, 2'-deoxyinosine, 2'-deoxycytidine, tryptophan, thymidine, 5-carboxy-2'-deoxyuridine, coniferin, and kaempferol 3-O-beta -D-sophoroside-7-O-beta -D-glucopyranoside. Their structures were elucidated by spectroscopic analysis and chemical transformation.展开更多
A reverse-phase HPLC method was developed for the simultaneous separation and determination of five bioactive phenolic acids,yunnaneic acid E,rosmarinic acid,lithospermic acid,salvianolic acid B and salvianolic acid A...A reverse-phase HPLC method was developed for the simultaneous separation and determination of five bioactive phenolic acids,yunnaneic acid E,rosmarinic acid,lithospermic acid,salvianolic acid B and salvianolic acid A in eight different samples of Salvia yunnanensis collected in Yunnan Province.For comparison,the sample of Salvia miltiorrhiza was included. All the samples were extracted for 60 min with 50%methanol in an ultrasonic bath.The optimal separation was achieved on a YMC-Pack Pro C18 column,with a gradient of 0.1%（v/v） phosphoric acid and acetonitrile,at a flow rate of 1.0 mL/min and at a detection wavelength of 280 nm.The separation was obtained within 65 min for five bioactive phenolic acids.All calibration curves showed good linearity（r^2〉0.999） within test ranges.The relative standard deviation of the method was less than 5%for intra- and inter-day assays.The mean recovery of the method was in the range from 97%to 104%,with RSD less than 5%.This assay was successfully applied to the quantitative determination of five bioactive phenolic acids in nine resource samples. The results showed that the developed HPLC assay was suitable for the quality control of S.yunnanensis and it can be used to differentiate S.yunnanensis from S.miltiorrhiza.展开更多
Phenolic inhibitors were preliminarily isolated from the normal and abortive litchi (Litchi chinensis Sonn.) ovules with a series of solvents, and then separated and purified by thin-layer chromatography (TLC), furthe...Phenolic inhibitors were preliminarily isolated from the normal and abortive litchi (Litchi chinensis Sonn.) ovules with a series of solvents, and then separated and purified by thin-layer chromatography (TLC), further isolated and identified with GC-MS, and finally checked with standards. p-Hydroxybenzoic acid (p-HBA) was isolated and identified from litchi ovules in this experiment for the first time. Determination of its biological activity showed that p-HBA was a very strong growth inhibitory substance. In abortive ovules, p-HBA content and IAA oxidase activity were much higher; IAA content was much lower than those in normal ovules (P<0.01). It is suggested that p-HBA may be involved in the regulation of litchi embryo development; high content of p-HBA may accelerate IAA oxidation and affect the balance of growth promoting and inhibitory substances, causing embryo abortion.展开更多
基金supported by grants from the National Science and Technology Council(NSTC),Taiwan(NSTC 114-2320-B-037-020-MY3,113-2320-B-037-023,and 112-2320-B-037-012 granted to M.K.,113-2321-B-255-001,113-2321-B-182-003,112-2321-B-182-003,112-2321-B-255-001,111-2320-B-255-006-MY3,and 111-2321-B-255-001 granted to T.L.H.)Kaohsiung Medical University Research Foundation[KMU-Q113011 awarded to M.K.and KMU-M114020 awarded to B.H.C.]NSYSU-KMU joint research project(NSYSU-KMU-114-P16)awarded to M.K.
文摘The sustainable sourcing of novel bioactive compounds from natural sources is crucial to the success of the pharmaceutical,food,and cosmetics industries.Iris bucharica Foster(syn.Juno bucharica(Foster)Vved.)is a promising source of novel bioactive molecules,particularly phenolic compounds,which are renowned for their antioxidant properties.In this study,we developed a reliable HPLC-UV-DAD method to identify and quantify phenolic compounds in the leaves and bulbs of I.bucharica,establishing the first set of quality control markers for this species.A total of 21 phenolic compounds were identified in the leaves,with flavonoids isoorientin,guaijaverin,hyperoside,and cosmosiin,the isoflavonoid biochanin A,and the simple phenolic ferulic acid being the most prominent.In comparison,14 compounds were identified in the bulbs,primarily isoflavonoids,including tectoridin and germanaism B,and flavonoid apigenin.The leaves extracts exhibited significant antioxidant activity,whereas the anti-allergic and anti-inflammatory effects were mild.These findings highlight I.bucharica as a sustainable source of bioactive compounds with potential industrial applications.However,further studies are needed to evaluate bioavailability and in vivo efficacy,as well as to optimise extraction methods to realize its industrial potential fully.
基金the“Pioneer”and“Leading Goose”R&D Program of Zhejiang(No.2023C01072)the Institute of Zhejiang University-Quzhou for their financial support。
文摘Poly(phenylene oxide)(PPO)exhibits excellent dielectric properties,making it an ideal substrate for high-frequency,high-speed copper-clad laminates.The phenolic hydroxyl group at the end of PPO plays a key role in its reactivity.Accurately quantifying the phenolic hydroxyl content in PPO is essential but challenging.In this study,we proposed a method for measuring the phenolic hydroxyl content of PPO using differential UV absorption spectroscopy.In alkaline solutions,the phenolic hydroxyl in PPO completely ionizes to form phenoxide ions,leading to a significant increase in UV absorbance at approximately 250 and 300 nm.Notably,the differential UV absorbance at approximately 300 nm was directly proportional to the phenolic hydroxyl concentration.Using 2,6-dimethylphenol as a standard,a calibration curve was established to relate the phenolic hydroxyl concentration to differential UV absorbance at approximately 300 nm,providing a precise and straightforward method for phenolic hydroxyl quantification in PPO with distinct advantages over conventional techniques.
基金supported by the Serbian Ministry of Education,Science and Technological Development(Agreements No.451-03-136/2025-03/200122 and 451-03-136/2025-03/200378).
文摘Achillea species are known for their healing properties since ancient times.There is extensive literature on their pharmacological action due to their bioactive compounds.The present study aimed to investigate the antioxidant and antimicrobial effects of hydroalcoholic extracts from the inflorescences and leaves of the species Achillea crithmifolia Waldst.and Kit.,A.grandifolia Friv.and A.millefolium L.The phytochemical profiles of all extracts were evaluated both by NMR spectroscopy and LC-MS analysis,and the results were consistent with the spectrophotometrically determined total phenolic(TP:125.42-191.98 mg/g)and total flavonoid(TF:47.34-180.02 mg/g)contents.All the extracts were tested for their antioxidant activity using DPPH and ABTS•+radical scavenging assay,as well as ferrous ion chelating ability and reducing power tests.All the extracts showed moderate antioxidant activity,compared to the reference substance BHT.Additionally,the antibacterial activity of the extracts was evaluated against major food-borne pathogens,showing moderate antimicrobial effects.
基金supported by the National Key Research and Development Program of China(No.2023YFC3706602)the National Natural Science Foundation of China(Nos.22225605 and 22193051)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0750200).
文摘Synthetic phenolic antioxidants(SPAs)are widely used in diverse industries due to their exceptional antioxidant characteristics.However,human exposure to SPAs may cause health problems.In this study,226 dust samples were collected from 10 provinces in China,and six SPAs(three parent SPAs and their three transformation products)were analyzed.The concentrations of6SPAs(the sum of six target compounds)ranged from 15.4 to 3210 ng/g(geometric mean(GM):169 ng/g).The highest concentration of6SPAswas found in Sichuan Province(GM:349 ng/g),which was approximately 4 times higher than that in Hubei Province(81.6 ng/g)(p<0.05).The concentrations of butylated hydroxytoluene(BHT),2,2'-methylene bis(4-methyl-6–tert-butylphenol)(AO2246),2,6-di–tert–butyl–1,4-benzoquinone(BHT-Q),2,6-di–tert–butyl–4-(hydroxymethyl)phenol(BHT-OH),and ∑_(p)-SPAs were substantially higher in dust from urban areas than rural areas(p<0.05).AO2246 concentration in dust from homes(GM:0.400 ng/g)was about 4 times higher than that in workplaces(0.116 ng/g)(p<0.01).Significantly higherp-SPAs concentrations were found in dust from homes(GM:17.5 ng/g)than workplaces(11.4 ng/g)(p<0.01).The estimated daily intakes(EDIs)of ∑_(6)SPAs exposed through dust ingestion were 0.582,0.342,0.197,0.076,and 0.080 ng/kg bw/day in different age groups,and exposed through dermal contact was 0.358,0.252,0.174,0.167,and 0.177 ng/kg bw/day.EDIs showed that the exposure risks of SPAs decreased with age.This is the first work to determine SPAs in dust from10 provinces in China and investigate the spatial distribution of SPAs in those regions.
文摘Silica gel column chromatography(CC),Sephadex LH-20 CC and high performance liquid chromatography(HPLC)were used to study the chemical constituents of the fruits of the medicine-food plant Rubus idaeus Linnaeus.A new tetrahydrogenated naphthol syringic acid ester,named rubusnolicester(1),two new phenolic glycoside derivatives,4-chloro-2,6-dimethoxylphenol-1-O-β-D-glucopyranoside(2)and salicylic acid-2-O-(6'-O-acetyl)-β-D-glucopyranoside(3),together with one known salicylic acid glycoside derivative(4)and three known flavonoids derivatives(5~7),were isolated.Their structures were elucidated by HRESI-MS,NMR spectroscopy,and a comparison of optical rotation(OR).Compounds 1~7 were evaluated the inhibitory activities against the nitric oxide(NO)production induced by lipopolysaccharide(LPS)in mouse macrophage RAW264.7 cells in vitro.Compound 1 exhibited inhibitory effect with the IC50 value of(12.28±1.25)μmol/L.
基金supported by the National Natural Science Foundation of China(No.32200322)Henan Science and Technology Research and Development Plan Joint Fund(No.242301420082)+1 种基金Henan Province“Science and Technology Vice General”Three-Year Action Plan(2024-2026)Henan Postdoctoral Fund(No.HN2025059)。
文摘Salvia miltiorrhiza(S.miltiorrhiza)represents a crucial component of traditional Chinese medicine,demonstrating effects on blood circulation activation and stasis removal,and has been widely utilized in asthma treatment.This study isolated a novel phenolic acid(S1)from S.miltiorrhiza and investigated its anti-asthmatic activity and underlying mechanisms for the first time.An allergic asthma(AA)model was established using ovalbumin(OVA).The mechanism of S1's effects on AA was investigated using multi-factor joint analysis,flow cytometry,and co-culture systems to facilitate clinical asthma treatment.S1(10 or 20 mg·kg-1)was administered daily to mice with OVA-induced AA(OVA-AA)during days 21-25.The study examined airway responsiveness,lung damage,inflammation,and levels of immunoglobulin E(IgE),PGD2,interleukins(IL-4,5,10,13,17A),tumor necrosis factorα(TNF-α),GM-CSF,CXCL1,CCL11,and mMCP-1.Additionally,mast cell(MC)activation and degranulation were explored,along with T helper type 17(Th17)/Treg immune cells and TLR4 pathway biomarkers.The antagonistic activity of that specific antagonist of TLR4(TAK-242)(1μmol·L^(-1)),a specific TLR4 blocker,against S1(10μmol·L^(-1))was examined in co-cultured 16 HBE cells and bone marrow-derived cells(BMDCs)or splenic lymphocytes(SLs)induced with LPS(1μg·mL^(-1))to elucidate the TLR4 pathway's mediating role.S1 demonstrated reduced airway responsiveness,lung damage,and inflammation,with downregulation of IgE,PGD2,interleukins,TNF-α,GM-CSF,CXCL1,CCL11,and mMCP-1.It also impeded MC activation and degranulation,upregulated IL^(-1)0,and influenced Th17/Treg immune cell transformation following OVA challenge.Furthermore,S1 inhibited the TLR4 pathway in OVA-AA mice,and TLR4 antagonism enhanced S1's positive effects.Analysis using an OVA-AA mouse model demonstrated that S1 alleviates AA clinical symptoms,restores lung function,and inhibits airway response.S1's therapeutic effects occur through regulation of Th17/Treg immune cells and inflammation,attributable at least partially to the TLR4 pathway.This study provides molecular justification for S1 in AA treatment.
基金financially supported by grants from the National Natural Science Foundation of China(Grant No.81503180)the Opening Project of Zhejiang Provincial Key Laboratory of Resources Protection and Innovation of Traditional Chinese Medicine(Grant No.2021E10013)+1 种基金the Opening Project of NMPA Key Laboratory for Quality Research and Evaluation of Traditional Chinese Medicine(Grant No.AHYJ-KFKT-202101)the Earmarked fund for Jiangsu Agricultural Industry Technology System(Grant No.JATS[2022]460)。
文摘Chrysanthemum morifolium Ramat.is an important industrial crop with a high medicinal value,whose capitulum consists of ray and disc florets containing numerous bioactive components,such as flavonoids and phenolic acids.However,the distribution and accumulations of the bioactive metabolites in florets of Chrysanthemum morifolium were unclear.Herein,the ray and disc florets of Chrysanthemum morifolium were separated for comparing the bioactive metabolites.The contents of phenolic compounds and antioxidant activities were significantly different between the two florets.The metabolomic analysis identified 203 and 241 differential metabolites between ray and disc florets at two flowering stages.The derivatives of quercetin,isorhamnetin,tricin,and caffeoylquinic acid were enriched in the disc florets,while apigenin,kaempferol,acacetin,and their glycosides mainly accumulated in the ray florets.Besides,the results of transcriptome and qRT-PCR suggested that the F3H,F3'H,and FLS genes highly expressed in disc florets,while the FNS gene was well expressed in ray florets,which explained the different distribution of phenolic compounds between ray and disc florets.Furthermore,the expression of CmCYC2 genes was found to be significantly related to the distribution of flavones by correlation analysis.It was proved by the luciferase reporter assay that CmCYC2a and CmCYC2d factors could bind and activate the CmFNS promoter to regulate the flavones biosynthesis in ray florets.These results revealed the significant difference of metabolite contents and gene expression profile between ray and disc floret in Chrysanthemum morifolium and demonstrated that the quality of Chrysanthemum morifolium‘Hangju'was closely relevant to its flower morphology.
基金supported by the Projection of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(20FKSY23)。
文摘Phenolic resin-based porous composites are the promising thermal protection materials for aerospace applications.The high-temperature evolution of microstructure due to the decomposition of the resin also presents great challenges to predict the internal heat and mass transport behaviors.This work investigates the effects of microstructural characteristics such as the number of pores,size distribution,pore-throats size and volume fraction on the permeation behaviors of fluid in the needle-punched short-cut fiber reinforced silicon phenolic resin-based porous composites.The specimens are prepared by the sol-gel method and the atmospheric pressure drying process and the pyrolysis experiment are conducted at 400℃and 800℃.Then,a scanning electron microscope and a Nano-CT computer tomography are applied to obtain the surface morphologies and the interior slice images of the specimens.The AVIZO software is employed to accurately extract and analyze the pore structural model and simulated calculate the absolute permeability.It is found that the small pores develop gradually during pyrolysis due to the resin decomposition and the quartz fibers rearrangement,resulting in an increase in number of large pores.Nonetheless,the equivalent radii of most pores are less than 1μm.Very few pores possess a large radius over 5μm.However,the volume fraction of these large pores exceeds 99%.In addition,with the pore size growing,the connectivity between these pores is enhanced,immediately causing an increase in number and size of the pore-throats.Larger pore and more pore-throats would add the unblocked flow channels for the fluid passing,reducing flow resistance.The seepage simulation also confirms that the absolute permeability gains significant increase after pyrolysis in all directions.For example,the absolute permeability of the pyrolyzed sample is 9.0×10^(-13)m^(2) in X direction,which is an order of magnitude greater than that of the unpyrolyzed sample.This study provides important insights for understanding the high-temperature evolution at of microstructure and the permeation behavior of fluid in porous thermal protection materials.
基金Funded by the National Natural Science Foundation of China(Nos.52171045,52162013,and 51932006)。
文摘The surface of MoSi2-SiB6/phenolic resin matrix composites was modified by mica,and the thermal oxidation behavior of the composites and the mechanical properties of the pyrolysis products were studied.The results showed that the mica improved the thermal properties of the composites,the thermal expansion coefficient decreased,and the liquid phase formation caused the composites to shrink and increase the density.The flexural strength of mica surface modified composites not only increased to 78.64MPa after thermal treatment at 800-1200℃,but reached 83.02 MPa after high temperature treatment at1400℃.The improvement of the mechanical properties of the residual product benefits from the formation of high temperature ceramic phases such as Mo_(2)C and MoB,and the improvement of the shear strength of the composites by the mica.The shear strength of MBm5-2 at room temperature reached 33.08 MPa,indicating that the improvement of the interlayer properties of the composites further improved its mechanical properties.
基金supported by Major Project of Science and Technology Department of Yunnan Province(202002AA100005,202102AE090027-2)National Natural Science Foundation of China(82260703)+1 种基金Cassava Industrial Technology System of China(CARS11-YNTY)Yunnan Province Ten Thousand Plan Industrial Technology Talents Project(YNWR-CYJS-2020-010)。
文摘Moringa oleifera Lam.is a Moringa genus in the Moringaceae family that is high in nutrients and has a wide range of applications.Phenolic compounds are widely found in plants and have various health benefits for the human body.With its high content and wide variety of phenolic compounds,M.oleifera Lam.has been widely studied for its health benefits.The phenolic compounds in M.oleifera Lam.(MOPCs)can be a potential source of functional food ingredients in pharmaceutical and industrial applications.Numerous studies have shown that MOPCs have antioxidant,anti-obesity,anti-diabetic,and antibacterial effects.Although the research on MOPCs has been gradually increasing,the extraction,isolation,identification,biological activities,and comprehensive application of MOPCs need a more systematic summary and generalization.Therefore,this paper reviews the isolation and extraction methods,structure identification,biological activities,and comprehensive applications to provide a further reference for the research and application of MOPCs.
基金the project PID2023-150695NB-I00,funded by MCIU/AEI/10.13039/501100011033/FEDER,UEAdditional funding from the Agencia de Desarrollo Economico de La Rioja(ADER,Government of La Rioja)through the Project S-UV-STAINABLE Rioja(2022-I-IDI-00064)is also acknowledged.
文摘Grapevine(Vitis vinifera L.)is one of the main crops worldwide,and ultraviolet-B(UV-B,280-315 nm)radiation is emerging as a promising technical tool to enhance secondary metabolites that can contribute to the quality and health-promoting properties of both grapes and the resulting wines.However,few studies have assessed the effectiveness of UV-B supplements under field conditions.Here,we compared the effects of two different field UV-B treatments(a single supplement applied at pre-harvest,and a double supplement applied at both veraison and pre-harvest)on the phenolic composition of Tempranillo grape skins and the resulting wines.The double supplement induced stronger changes than the single supplement,with responses being more pronounced in grape skins than in wines.In skins,UV-B supplements significantly increased flavonols,phenolic acids,and flavanols,consistent with previous reports highlighting flavonols as the most reliable UV-B-responsive compounds in grape skins.In wines,the clearest responses were increases in anthocyanins and color intensity.Overall,UV-B supplements improved grape and wine quality,although skin responses were only partially transmitted to the wines.Moreover,wine responses were more unpredictable than skin responses,likely reflecting not only the UV-B-induced changes in grape skins but also the complex chemical interactions among phenolic compounds(and also with other metabolites)during vinification.Further experimentation,particularly in the long term,is required to optimize the application of UV-B supplements as a viticultural and enological practice.
基金supported by the National Natural Science Foundation of China(32472468 and 32001817)the Fundamental Research Program of Shanxi Province(202303021221123)+1 种基金the Youth Project of the Shanxi Fundamental Research Program(202203021222032)the Start-up Funds forScientific Research atNorth University of China(304-1101285714).
文摘Advanced glycation end products(AGEs),a group of complex compounds generated by nonenzymatic interactions between amino acids,proteins and reducing sugars or lipids,accumulate in vivo and activate various signaling pathways closely related to the occurrence of various chronic metabolic diseases.This study aims to explore the structure-activity relationship between phenolic acids with different structure and affecting the AGEs generation,and to provide data support for AGEs control.Phenolic acids(4-hydroxybenzoic,protocatechuic,gallic,p-coumaric,caffeic,ferulic and sinapic acids)were employed to indicate the AGEs formation condition in Maillard reaction performed in the glucose-lysine model system.Three 1,2-dicarbonyl compounds were reacted with phenolic acids and then tested by liquid chromatography-mass spectrometry.The results showed that N^(ε)-carboxy-methyl-lysine(CML),N^(ε)-carboxy-ethyl-lysine(CEL),and pyrraline formation inhibited by phenolic acids varied from(8.7±2.5)%to(33.2±2.5)%,(10.5±0.8)%to(57.1±3.2)%and(1.3±0.3)%to(23.3±0.8)%,respectively.The p-coumaric acid has no inhibitory effect on CML and CEL formation.Gallic acid shows the best inhibitory effect on CML formation due to its strong antioxidant activity.Sinapic acid showed the best glyoxal(GO)trapping rate and thus had the stronger inhibitory effect on CML formation.Ferulic acid can react with mono-,di-,and tri-methylglyoxal(MGO)to form adduct products,showing the best MGO scavenging rate and a good inhibitory effect on CEL formation.The main role of phenolic acid is an antioxidant agent to inhibit pyrraline formation.The glucose itself or ammonia-induced degradation and Amadori rearrangement products oxidation were lowered by protocatechuic,gallic and caffeic acids due to their antioxidant activities to form AGEs,while AGEs inhibited by ferulic and sinapic acids were mainly dependent on their trapping ability on 1,2-dicarbonyl compounds.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2241240,12172045,and 12221002).
文摘In thermal protection structures,controlling and optimizing the surface roughness of carbon/phenolic(C/Ph)composites can effectively improve thermal protection performance and ensure the safe operation of carriers in high-temperature environments.This paper introduces a machine learning(ML)framework to forecast the surface roughness of carbon-phenolic composites under various thermal conditions by employing an ML algorithm derived from historical experimental datasets.Firstly,ablation experiments and collection of surface roughness height data of C/Ph composites under different thermal environments were conducted in an electric arc wind tunnel.Then,an ML model based on Ridge regression is developed for surface roughness prediction.The model involves incorporating feature engineering to choose the most concise and pertinent features,as well as developing an ML model.The ML model considers thermal environment parameters and feature screened by feature engineering as inputs,and predicts the surface height as the output.The results demonstrate that the suggested ML framework effectively anticipates the surface shape and associated surface roughness parameters in various heat flow conditions.Compared with the conventional 3D confocal microscope scanning,the method can obtain the surface topography information of the same area in a much shorter time,thus significantly saving time and cost.
基金supported by the National Natural Science Foundation of China(No.51872232)the Key Scientific and Technological Innovation Research Team of Shaanxi Province(No.2022TD-31)the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04).
文摘Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical,tribological,electromagnetic interference(EMI)shielding and thermal conductivity properties of carbon fiber/phenolic resin composites.Specially,array carbon nanotubes can deep into the resin matrix,effectively hindering crack extension,and constructing an electrically and thermally conductive network.Compared with the carbon fiber/phenolic composites,the tensile strength and modulus of elasticity(163.86±9.60 MPa,5.06±0.25 GPa)of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09%and 22.22%.The average friction coefficient and wear rate(0.20±0.02,1.11×10^(-13)±0.13×10^(-13)m^(3)N^(−1)m^(−1))were reduced by 39.39%and 74.31%.EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness,diffusion coefficient(0.39±0.003 mm^(2)/s)and thermal conductivity(0.54±0.004 W/(m K))were enhanced by up to 14.37%and 50.42%.This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure,proposes the reinforcement mechanism of array carbon nanotubes,and opens up the prospect of carbon fiber/phenolic composites for electronic applications.
基金Funded by by the Wuhan Science and Technology Project(No.2024010702030141)。
文摘A Ti_(3)SiC_(2)-modified high-silica oxygen/phenolic aerogel composite with excellent oxidation resistance and high-temperature performance was prepared.The experimental results show that the obtained composite has significantly improved oxidation resistance.When the addition amount of Ti_(3)SiC_(2)is 75%,the carbonization volume shrinkage rate of the composite after aerobic static combustion is only 5.95%.At the same time,the LAR and MAR after 30 seconds of oxyacetylene ablation under a heat flux density of 1.5 MW/m2 are 0.0307 mm/s and 0.0149 g/s,respectively.The compressive strength after aerobic static combustion at 1000℃is up to 20.43%of that before aerobic static combustion,which is 1.99 times that of the unfilled material,significantly improving the high-temperature mechanical properties of the composite.
基金This research is supported by National Natural Science Foundation of China (No.30170764)
文摘The contents of seven different phenolic acids such as gallic acid, catechinic acid, pyrocatechol, caffeic acid, coumaric acid, ferulic acid and benzoic acid in the poplar leaves （Populus Simonii×Populus Pyramibalis c.v and Populus deltoids） suffocated by Methyl jasmonate （MeJA） and Methyl salicylate （MeSA） were monitored for analyzing their functions in interplant communications by using high-pressure liquid chromatography （HPLC）.The results showed that the contents of phenolic acids had obviously difference in leaves exposed to either MeSA or MeJA.When P.deltoides leaves exposed to MeJA or MeSA, the level of gallic acid, coumaric acid, caffeic acid, ferulic acid and benzoic acid was increased, gallic acid in leaves treated with MeJA comes to a peak at 24 h while to a peak at 12-d having leaves treated with MeSA.When P.Simonii ×P.Pyramibalis c.v leaves were exposed to MeJA or MeSA, the level of gallic acid, pyrocatechol and ferulic acid was increased; The catechinic acid and benzoic acid had a little drop; The caffeic acid and coumaric acid were undetected in both suffocated and control leaves.This changed pattern indicated that MeJA and MeSA can act as airborne signals to induce defense response of plants.
基金National Natural Sciences Foundation of Chin(NS FCGrant Nos.81222051 and 81473106)National Key Technology R&D Program"New Drug Innovation"of China(Gran No s.2012ZX09301002-002-002 and 2012ZX09304-005)
文摘A phytochemical investigation on the stems and rhizomes of Sinomenium acutum led to the isolation of 19 compounds, including three phenanthrenes, six anthraquinones, and ten phenolic derivatives. The structures of the isolated compounds were elucidated by analysis of the MS and NMR spectroscopic data and comparison with the literature. Compounds 1 and 2 are two new natural products, and their 1H and 13C NMR spectral data were fully assigned for the first time, with the help of2D NMR. All of the isolates were obtained from genus Sinomenium for the first time and the phenanthrene and anthraquinone are the structure type first reported from this genus plants.
文摘Three new phenolic glycosides, named as equisetumoside A (3-methoxy-11,12-dihydroxy-phenylhexane-9- one-4-O-beta -D-glucopyranoside), equisetumoside B (3-methoxy-4,11-dihydroxy-phenylhexane-9-one12-O-beta -D-glucopyranoside) and equisetumoside C ( cis-ferulic acid potassium salt 4-O-beta -D-glucopyranoside) were isolated from the water-soluble extract of fertile sprouts of Equisetum, arvense L. (Equisetaceae), together with uridine, inosine, 2'-deoxyinosine, 2'-deoxycytidine, tryptophan, thymidine, 5-carboxy-2'-deoxyuridine, coniferin, and kaempferol 3-O-beta -D-sophoroside-7-O-beta -D-glucopyranoside. Their structures were elucidated by spectroscopic analysis and chemical transformation.
基金National High-Tech R & D Program(863 Program, Grant No.2004AA2Z3342)
文摘A reverse-phase HPLC method was developed for the simultaneous separation and determination of five bioactive phenolic acids,yunnaneic acid E,rosmarinic acid,lithospermic acid,salvianolic acid B and salvianolic acid A in eight different samples of Salvia yunnanensis collected in Yunnan Province.For comparison,the sample of Salvia miltiorrhiza was included. All the samples were extracted for 60 min with 50%methanol in an ultrasonic bath.The optimal separation was achieved on a YMC-Pack Pro C18 column,with a gradient of 0.1%（v/v） phosphoric acid and acetonitrile,at a flow rate of 1.0 mL/min and at a detection wavelength of 280 nm.The separation was obtained within 65 min for five bioactive phenolic acids.All calibration curves showed good linearity（r^2〉0.999） within test ranges.The relative standard deviation of the method was less than 5%for intra- and inter-day assays.The mean recovery of the method was in the range from 97%to 104%,with RSD less than 5%.This assay was successfully applied to the quantitative determination of five bioactive phenolic acids in nine resource samples. The results showed that the developed HPLC assay was suitable for the quality control of S.yunnanensis and it can be used to differentiate S.yunnanensis from S.miltiorrhiza.
文摘Phenolic inhibitors were preliminarily isolated from the normal and abortive litchi (Litchi chinensis Sonn.) ovules with a series of solvents, and then separated and purified by thin-layer chromatography (TLC), further isolated and identified with GC-MS, and finally checked with standards. p-Hydroxybenzoic acid (p-HBA) was isolated and identified from litchi ovules in this experiment for the first time. Determination of its biological activity showed that p-HBA was a very strong growth inhibitory substance. In abortive ovules, p-HBA content and IAA oxidase activity were much higher; IAA content was much lower than those in normal ovules (P<0.01). It is suggested that p-HBA may be involved in the regulation of litchi embryo development; high content of p-HBA may accelerate IAA oxidation and affect the balance of growth promoting and inhibitory substances, causing embryo abortion.
