In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different...In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different peanut varieties to the inoculation with A. flavus has not been investigated and might be useful for breed- ing resistant peanut cultivars. In this study, peanut varieties resistant or susceptible to aflatoxin accumulation caused by A. flavus were selected to compare the synthe- sis differences of the four main stilbenes （resveratrol, ε-viniferin, 6-viniferin and pterostilbene） and the activities of their resistant enzymes （PAL, POD, PPO）, and explore the relationship between stilbene synthesis and resistance to aflatoxin accu- mulation. The results indicated that the synthesis speed of stilbenes was related to the resistance to aflatoxin accumulation in peanuts seeds. The total content of the four stilbenes reached the highest value of 47.37 μg/g in the resistant cultivars （Qian huasheng 3） after inoculation by A. flavus （54 times of the control） on the 3nd day, while the total content of stilbenes in susceptible cultivars （Huayu 22） was 5.5 μg/g. The content of stilbenes and the activities of their resistant enzymes from the resistant cultivars were both higher than from the susceptible one. The four peanut varieties with relative higher stilbene contents and lower disease index and aflatoxin content were selected by using the stilbene content. Very significant negative corre- lation, with correlation coefficients （r） of -0.789, -0.851 and -0.850, was observed between the stilbene content with disease index, the content of aflatoxin B1 and the total content of aflatoxins, respectively. Therefore, the study suggested that the total content of stilbene compounds might serve as an important chemical index in peanut seeds after inoculation with A. flavus on the 3nd day, during screening and breeding of peanut varieties resistant to aflatoxin accumulation.展开更多
Three new prenylated stilbenes, named as cajanusins A-C(1-3), and one new natural product cajanusin D(4), along with six known derivatives(5-10) were isolated from the leaves of Cajanus cajan. Their structures were fu...Three new prenylated stilbenes, named as cajanusins A-C(1-3), and one new natural product cajanusin D(4), along with six known derivatives(5-10) were isolated from the leaves of Cajanus cajan. Their structures were fully elucidated by means of extensive spectroscopic methods and comparison with data in the reported literatures. The new compounds of 1 and 2 were evaluated for in vitro cytotoxic activities against a panel of human cancer cell lines.展开更多
Alzheimer’s disease is one of the most frequent neurodegenerative diseases.This pathology is characterized by protein aggregates,mainly constituted by amyloid peptide and tau,leading to neuronal death and cognitive i...Alzheimer’s disease is one of the most frequent neurodegenerative diseases.This pathology is characterized by protein aggregates,mainly constituted by amyloid peptide and tau,leading to neuronal death and cognitive impairments.Drugs currently proposed to treat this pathology do not prevent neurodegenerative processes and are mainly symptomatic therapies.However,stilbenes presenting multiple pharmacological effects could be good potential therapeutic candidates.The aim of this review is to gather the more significant papers among the broad literature on this topic,concerning the beneficial effects of stilbenes (resveratrol derivatives) in animal models of Alzheimer’s disease.Indeed,numerous studies focus on cellular models,but an in vivo approach remains of primary importance since in animals (mice or rats,generally),bioavailability and metabolism are taken into account,which is not the case in in vitro studies.Furthermore,examination of memory ability is feasible in animal models,which strengthens the relevance of a compound with a view to future therapy in humans.This paper is addressed to any researcher who needs to study untested natural stilbenes or who wants to experiment the most effective natural stilbenes in largest animals or in humans.This review shows that resveratrol,the reference polyphenol,is largely studied and seems to have interesting properties on amyloid plaques,and cognitive impairment.However,some resveratrol derivatives such as gnetin C,trans-piceid,or astringin have never been tested on animals.Furthermore,pterostilbene is of particular interest,by its improvement of cognitive disorders and its neuroprotective role.It could be relevant to evaluate this molecule in clinical trials.展开更多
Two new dimeric stilbenes, named gnetifolin L and gnetifolin O, were isolated from the alcoholic extract of lianas of Gnetum montanum. Their structures were elucidated mainly on the basis of spectroscopic data includi...Two new dimeric stilbenes, named gnetifolin L and gnetifolin O, were isolated from the alcoholic extract of lianas of Gnetum montanum. Their structures were elucidated mainly on the basis of spectroscopic data including 2D-NMR studies on peracetate derivatives.展开更多
Stilbenes are natural phenolic compounds which function as antimicrobial phytoalexins in plants and affect human health as cardioprotective, antibaceteria, antioxidative and antineoplastic agents. In this review, the ...Stilbenes are natural phenolic compounds which function as antimicrobial phytoalexins in plants and affect human health as cardioprotective, antibaceteria, antioxidative and antineoplastic agents. In this review, the progresses of study on relevant enzymes, genes, and regulation mechanism in biosynthesis pathway of stilbenes are described. Here we introduce a holistic and systematic method of researching relevant enzymes, genes and other regulatory factors in biosynthesis pathway of stilbenes—Systems biology. The application of knowledge of relative enzymes, genes and regulation mechanisms in stilbenes biosynthesis in metabolic engineering which is used as a tool of improving the disease resistance of plants and health caring quality of crops is also discussed.展开更多
Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AI...Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AIEgens are needed.Stilbene,though structurally suitable,lacks visible luminescence.Here,we report a minimally modified stilbene-based AIEgen-4-dipropylamino-4'-cyano-bridged stilbene(DpCBS[7])-that exhibits fluorescence solvatochromism and efficient AIE across a broad polarity range in the visible region.DpCBS[7]exhibits low quantum yields(Φ_(fl)=0.010.04)in solvents from nonpolar n-hexane to polar dimethyl sulfoxide,with large Stokes shifts,viscosity-sensitive luminescence,and highly efficient solid-state luminescence(Φ_(fl)=0.70).To elucidate its dual solvatochromic and AiE behavior,femtosecond transient absorption spectroscopy was conducted.In solution,DpCBS[7]displays transient absorption with lifetimes of 21 ps(toluene)and 56 ps(acetonitrile)at 293 K,indicating ultrafast nonradiative decay leading to low Φ_(fl).Arrhenius analysis over the temperature range of 263-313 K revealed activation energies(ΔE_(a))of 9.90kJ/mol in toluene and 12.8 kJ/mol in acetonitrile for the S_(1)→S_(0) decay of DpCBS[7].The ΔE_(a) values show no clear systematic dependence on solvent polarity.In contrast,pre-exponential factor A remains consistently high regardless of solvent polarity,indicating that the striking photophysical response is governed primarily by the pre-exponential factor rather than by modulation of the activation energy.These findings highlight the fundamental importance of tailoring the distribution function through structural modification as a robust strategy to control AiE characteristics.展开更多
Objective To investigate the neuroprotective effects of four stilbenes, namely cajaninstilbene acid （CSA）, Iongistyline A, Iongistyline C, and cajanolactone A, isolated from the leaves of Cajanus cajan. Methods Neur...Objective To investigate the neuroprotective effects of four stilbenes, namely cajaninstilbene acid （CSA）, Iongistyline A, Iongistyline C, and cajanolactone A, isolated from the leaves of Cajanus cajan. Methods Neuroprotective effects of the four stilbenes were evaluated using rat pheochromocytoma cell line （PC12 cells） damage models induced by corticosterone （Cort） or glutamate. In order to elaborate whether the neuroprotective effects of stilbenes are related to anti-oxidant properties, both oxidant and anti-oxidant parameters were measured. Results The results of MTT assay and LDH release assay demonstrated that the four stilbenes possessed neuroprotective effects. Moreover, the treatment on PC12 cells with Cort or glutamate （Glu） could significantly increase the levels of ROS and MDA with decreasing the activities of SOD and CAT. However, the four tested stilbenes could significantly alleviate such situation by dropping out the levels of ROS and MDA, as well as enhancing the activities of SOD and CAT. Conclusion These results provide a scientific basis for further studies to explore the potential neuroprotective effects on neurodegenerative diseases.展开更多
Two new stllbenes with two Isoprenoid groups, namely artostllbenes A （compound 1） and B （compound 2）, were Isolated from the stems of Arfocarpus chama Buch.-Ham. by repeated column chromatography. The＆ structures...Two new stllbenes with two Isoprenoid groups, namely artostllbenes A （compound 1） and B （compound 2）, were Isolated from the stems of Arfocarpus chama Buch.-Ham. by repeated column chromatography. The＆ structures were elucldated as （E）-4-[2-（7-meth-xy-2-2-d-methy-6-（3-methy-but-2-eny-）-2H-1-benz-pyran-5-y-）v-ny-]benzene-1- 2-dlol （compound 1） and （Z）-4-[2-（7-meth-xy-2-2-dimethy--6-（3-methy-but-2-eny-）-2H-1-benz-pyran-5-y-）v-ny-]ben- zene-l,2-dlol （compound 2） by spectroscopic methods, mainly by 1D-, 2D-NMR and MS spectra. Compounds 1 and 2 are two cls- and trans-lsomers and compound 2 is the flrst cis-stllbene isolated from Moraceous plants.展开更多
Twenty five samples of 4,4'-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, aceto...Twenty five samples of 4,4'-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, acetonitrile and ethanol, in which 242 experimental data were recorded. The effects of substituents and solvents on the energy of their UV absorption max wavelengths were discussed. The research results showed: the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was mainly affected by their intramolecular structure (substituent effect) in a given solvent, that is, the energy is dominated by both of excited-state substituent parameter o-~c and polar substituent constant crp. While their energy was dominated by the substituent effect and solvent effect in different kinds of solvents. An equation quantifying the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was developed. In addition, it is found that the n-octanol/water partition coefficient (logP) is more effective than the solvatochromic dye (ET(30)) in scaling the solvent effect. The equation employed the parameter logP has a better correlation and more specific physical meaning. Further, the energies of UV absorption max wavelengths of some reported compounds were predicted by the obtained equation, which are in agreement with their experimental values.展开更多
A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig...A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig-Horner reaction and a rearrangement in the presence of t-BuOK in toluene under mild conditions. This approach could be readily applied to a facile synthesis of biologically important natural products, resveratrol and its derivatives, such as trimethoxystilbenes 1 （Z） and 2 （E）.展开更多
A base-catalyzed ring-opening of 1-benzylisochromans 1 firstly produced 2-alkenylstilbenes 2, which then underwent a mild acid-catalyzed intramolecular cyclization to furnish 1,2-disubstituted indenes 3 in high yields...A base-catalyzed ring-opening of 1-benzylisochromans 1 firstly produced 2-alkenylstilbenes 2, which then underwent a mild acid-catalyzed intramolecular cyclization to furnish 1,2-disubstituted indenes 3 in high yields. Subsequently, a base-catalyzed isomerization of the 1,2-disubstituted indenes 3 afforded the more stable 2,3-disubstituted indenes 4 in almost quantitative yields.展开更多
A sensitive and specific reversed-phase high performance liquid chromatography （RP-HPLC） method was established for the simultaneous quantitative determination of eight active components, two stilbenes （resveratrol...A sensitive and specific reversed-phase high performance liquid chromatography （RP-HPLC） method was established for the simultaneous quantitative determination of eight active components, two stilbenes （resveratrol, polydatin） and six flavonoids （rutin, quercilrin, quercetin, luteotin, isoorientin, kaempferol）, in Polygonum multiflorum Thunb. The chromatographic separation was performed on a Kromasil C18 column （250 mm^4.6 mm, 5 ~tm）, and gradient elution was carried out with water-methanol as the mobile phase at a flow rate of 1 mL/min. Stilbenes and flavonoids were respectively detected at 320 nm and 350 nm with DAD. The correlation coefficients of all the calibration curves were found to be higher than 0.9995. The average recoveries were ranged from 96.8% to 102.5% with RSD less than 4.8% for these components. RP-HPLC was validated to be a robust method for the quantitative determination of active components in Polygonum multiflorum Thunb, and it could be used in the quality control of this traditional medicine.展开更多
Immature embryos, mature embryos and embryogenic calli of 6 rice (Oryza sativa L.) materials were transformed with particle bombardment. The plasmids pSSVstl and pVE5+ were used, both containing the phytoalexin gene f...Immature embryos, mature embryos and embryogenic calli of 6 rice (Oryza sativa L.) materials were transformed with particle bombardment. The plasmids pSSVstl and pVE5+ were used, both containing the phytoalexin gene from grapevine coding for stilbene synthase, but driven by 35S and its own promoter respectively. Through resistance selection for G418 (100 to 150 mg/L) or hygromycin (50 mg/L), 54 independent transgenic plants were isolated and further assessed by PCR, Southern blot and Dot blot analyses. The transgenic plants and their progenies were tested for resistance to blast ( Pyricularia oryzae ) and bacterial blight of rice ( Xanthomonas oryzae ). Preliminary results indicated that the stilbene synthase gene could enhance the resistance of transgenic plants and their progenies to both pathogens.展开更多
Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The presen...Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The present study aims to evaluate the effects of tetrahydroxy stilbene glucoside （TSG）, the extract from herbal medicine Polygoni Multiflori, on cognitive impairment and the over-expression of hippocampal amyloid precursor protein （APP） induced by chronic exposure to Al in rats. Methods Rats were treated with 0.3% aluminum chloride （AlCl3） prepared in the drinking water for 90 d. AlCl3-treated animals were then randomly assigned to receive vehicle, TSG （4 g/kg）, or Vitamin E （VE; 40 mg/kg） treatment for 5 months. VE served as a positive control. The effect of TSG was evaluated by passive avoidance task, and APP expression was evaluated by Western blotting. Results Following exposure to AlCl3 for 90 d, animals displayed a striking decrease （〉80%） in step-through latency in the passive avoidance task and a significant increase in the expression of APP in the hippocampus. Both TSG and VE significantly ameliorated the performance impairment in the passive avoidance task, and suppressed the over-expression of APP. Moreover, the effects of TSG, but not of VE, were in a time-dependent manner. Conclusion TSG may possess therapeutic effects against Alzheimer’s disease.展开更多
Two new stilbene glycosides (1 and 2), together with nine known compounds (3-11), were isolated from the water extract of Polygonum multiflorum Thunb. The structures of the new compounds were elucidated by their c...Two new stilbene glycosides (1 and 2), together with nine known compounds (3-11), were isolated from the water extract of Polygonum multiflorum Thunb. The structures of the new compounds were elucidated by their chemical properties and spectroscopic analyses, including extensive 2D NMR experiments. Compound 2 showed strong DNA cleavage activity, and compounds 1, 2 and 10 (2, 3, 4′, 5_tetrahydroxy_ trans _stilbene_2_O_β_ D _glucopyranoside) exhibited significant inhibition of lipid peroxidation.展开更多
Functionalized benzylic zinc halides reacted with benzaldehydes in the presence of Lewis acid Me3SiCl giving high yields of trans-stilbenes under the catalysis of Co(PPh3)3Cl.
Biosynthesis of peanut stilbenes, including resveratrol as the secondary metabolites, could be enhanced by subjecting the kernels to germination and wound-stress. Investigations of the bio-elicited peanut sprout powde...Biosynthesis of peanut stilbenes, including resveratrol as the secondary metabolites, could be enhanced by subjecting the kernels to germination and wound-stress. Investigations of the bio-elicited peanut sprout powder (BPSP) addressed on characterization of the comprising stilbenes and effectiveness in longevity extension deserves intensive research. In this study, peanut kernels were subjected to germination and wound-stress in preparation of BPSP. The methanol extracts of BPSP were medium pressure liquid chromatographic (MPLC) fractionated and semi-preparative HPLC recovered and followed by instrumental identification and biological activity determinations of the isolated stilbenes. In longevity experiments, 16 female 11-mon-old BALB/c mice and both genders of 12-mon-old ICR mice were daily fed with BPSP supplemented diets at doses of 0, 0.1 and 0.5 g BPSP/kg bw for 750 and 762 days, respectively. Based on chemical characterization, enriched quantity of stilbenes in the BPSP up to ca. 1% (w/w) was detected. Two new stilbene compounds, namely, 4, 5’-dihydroxy-6’’-hydroxymethyl, 6’’-methylpyrano [2’’, 3’’: 3’, 4’] stilbene and 3, 4, 5’-trihydroxy-6’’, 6’’-dimethylpyrano [2’’, 3’’: 3’, 4’]stilbene along with 5 known stilbenes were isolated. The 7 stilbenes exhibited potent antioxidative and antiglycative activities and varied with structure-activity nature. Based on the resultant survival curves and average lifespans of both mouse models, basal diets supplemented with BPSP are effective to extend mouse longevity by a dose dependent manner. It is of merit to demonstrate that peanut kernels as a potent producer could be bio-elicited to biosynthesize a broad spectrum of bioactive stilbenes to prepare BPSP which is effective to extend mouse longevity as science-evidenced by the two long-term animal experiments.展开更多
基金Supported by Natural Science Foundation of Hainan Province(809034)National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032012025)~~
文摘In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different peanut varieties to the inoculation with A. flavus has not been investigated and might be useful for breed- ing resistant peanut cultivars. In this study, peanut varieties resistant or susceptible to aflatoxin accumulation caused by A. flavus were selected to compare the synthe- sis differences of the four main stilbenes （resveratrol, ε-viniferin, 6-viniferin and pterostilbene） and the activities of their resistant enzymes （PAL, POD, PPO）, and explore the relationship between stilbene synthesis and resistance to aflatoxin accu- mulation. The results indicated that the synthesis speed of stilbenes was related to the resistance to aflatoxin accumulation in peanuts seeds. The total content of the four stilbenes reached the highest value of 47.37 μg/g in the resistant cultivars （Qian huasheng 3） after inoculation by A. flavus （54 times of the control） on the 3nd day, while the total content of stilbenes in susceptible cultivars （Huayu 22） was 5.5 μg/g. The content of stilbenes and the activities of their resistant enzymes from the resistant cultivars were both higher than from the susceptible one. The four peanut varieties with relative higher stilbene contents and lower disease index and aflatoxin content were selected by using the stilbene content. Very significant negative corre- lation, with correlation coefficients （r） of -0.789, -0.851 and -0.850, was observed between the stilbene content with disease index, the content of aflatoxin B1 and the total content of aflatoxins, respectively. Therefore, the study suggested that the total content of stilbene compounds might serve as an important chemical index in peanut seeds after inoculation with A. flavus on the 3nd day, during screening and breeding of peanut varieties resistant to aflatoxin accumulation.
基金supported by the National Natural Science Foundation of China(Nos.81773602 and 81502949)the Natural Science Foundation of Guangdong Province(Nos.2016A030313149 and 2016A020217015)+3 种基金the Innovative Team Project of GZUCM(No.2016KYTD04)Pearl River Science and Technology New Star Fund of Guangzhou(No.201605120849569)Guangdong Special Support Program(No.2017TQ04R599)the Foundation of Key Laboratory of Plant Resources Conservation and Sustainable Utilization,South China Botanical Garden,Chinese Academy of Sciences
文摘Three new prenylated stilbenes, named as cajanusins A-C(1-3), and one new natural product cajanusin D(4), along with six known derivatives(5-10) were isolated from the leaves of Cajanus cajan. Their structures were fully elucidated by means of extensive spectroscopic methods and comparison with data in the reported literatures. The new compounds of 1 and 2 were evaluated for in vitro cytotoxic activities against a panel of human cancer cell lines.
文摘Alzheimer’s disease is one of the most frequent neurodegenerative diseases.This pathology is characterized by protein aggregates,mainly constituted by amyloid peptide and tau,leading to neuronal death and cognitive impairments.Drugs currently proposed to treat this pathology do not prevent neurodegenerative processes and are mainly symptomatic therapies.However,stilbenes presenting multiple pharmacological effects could be good potential therapeutic candidates.The aim of this review is to gather the more significant papers among the broad literature on this topic,concerning the beneficial effects of stilbenes (resveratrol derivatives) in animal models of Alzheimer’s disease.Indeed,numerous studies focus on cellular models,but an in vivo approach remains of primary importance since in animals (mice or rats,generally),bioavailability and metabolism are taken into account,which is not the case in in vitro studies.Furthermore,examination of memory ability is feasible in animal models,which strengthens the relevance of a compound with a view to future therapy in humans.This paper is addressed to any researcher who needs to study untested natural stilbenes or who wants to experiment the most effective natural stilbenes in largest animals or in humans.This review shows that resveratrol,the reference polyphenol,is largely studied and seems to have interesting properties on amyloid plaques,and cognitive impairment.However,some resveratrol derivatives such as gnetin C,trans-piceid,or astringin have never been tested on animals.Furthermore,pterostilbene is of particular interest,by its improvement of cognitive disorders and its neuroprotective role.It could be relevant to evaluate this molecule in clinical trials.
文摘Two new dimeric stilbenes, named gnetifolin L and gnetifolin O, were isolated from the alcoholic extract of lianas of Gnetum montanum. Their structures were elucidated mainly on the basis of spectroscopic data including 2D-NMR studies on peracetate derivatives.
文摘Stilbenes are natural phenolic compounds which function as antimicrobial phytoalexins in plants and affect human health as cardioprotective, antibaceteria, antioxidative and antineoplastic agents. In this review, the progresses of study on relevant enzymes, genes, and regulation mechanism in biosynthesis pathway of stilbenes are described. Here we introduce a holistic and systematic method of researching relevant enzymes, genes and other regulatory factors in biosynthesis pathway of stilbenes—Systems biology. The application of knowledge of relative enzymes, genes and regulation mechanisms in stilbenes biosynthesis in metabolic engineering which is used as a tool of improving the disease resistance of plants and health caring quality of crops is also discussed.
基金supported in part by MEXT/JSPS KAK-ENHI grants 23H02036(G.K.)JP23H04631,JP23K26670,JP23H03833,JP24K01471,JP24K01515(K.M.)+8 种基金JP23K01977,JP23K20039,JP25K01678(K.O.)24K08341(S.S.)Toyota Riken Scholar(K.M.)the Yoshida Aca-demic and Educational Promotion Foundation(K.M.)the Environment Research and Technology Development Fund(grant number 3RA-2502)of the Environmental Restoration and Conservation Agency provided by Ministry of the Environment of Japan(K.M.)Kyushu University Platform of Inter-/Transdisciplinary Energy Research(Q-PIT)Module-Research Program(K.M.)Kyushu University Integrated Initiative for Designing Future Society(K.M.)JST SPRING,Grant Number JPMJSP2180(T.T.)Network Joint Research Center for Materials and Devices(20253036)(K.I.)The Creative Research Encouragement Award,School of Materials and Chemical Technology,Institute of Science Tokyo(G.K.)。
文摘Aggregation-induced emission luminogens(AIEgens)are typically largeπ-conjugated molecules,but their low affinity and noninvasiveness toward analytes limit practical applications.To address this,smaller,more planar AIEgens are needed.Stilbene,though structurally suitable,lacks visible luminescence.Here,we report a minimally modified stilbene-based AIEgen-4-dipropylamino-4'-cyano-bridged stilbene(DpCBS[7])-that exhibits fluorescence solvatochromism and efficient AIE across a broad polarity range in the visible region.DpCBS[7]exhibits low quantum yields(Φ_(fl)=0.010.04)in solvents from nonpolar n-hexane to polar dimethyl sulfoxide,with large Stokes shifts,viscosity-sensitive luminescence,and highly efficient solid-state luminescence(Φ_(fl)=0.70).To elucidate its dual solvatochromic and AiE behavior,femtosecond transient absorption spectroscopy was conducted.In solution,DpCBS[7]displays transient absorption with lifetimes of 21 ps(toluene)and 56 ps(acetonitrile)at 293 K,indicating ultrafast nonradiative decay leading to low Φ_(fl).Arrhenius analysis over the temperature range of 263-313 K revealed activation energies(ΔE_(a))of 9.90kJ/mol in toluene and 12.8 kJ/mol in acetonitrile for the S_(1)→S_(0) decay of DpCBS[7].The ΔE_(a) values show no clear systematic dependence on solvent polarity.In contrast,pre-exponential factor A remains consistently high regardless of solvent polarity,indicating that the striking photophysical response is governed primarily by the pre-exponential factor rather than by modulation of the activation energy.These findings highlight the fundamental importance of tailoring the distribution function through structural modification as a robust strategy to control AiE characteristics.
基金International Science and Technology Cooperation of China(2011DFA32730,1108)National Science and Technology Major Project(2012ZX09301002-001)
文摘Objective To investigate the neuroprotective effects of four stilbenes, namely cajaninstilbene acid （CSA）, Iongistyline A, Iongistyline C, and cajanolactone A, isolated from the leaves of Cajanus cajan. Methods Neuroprotective effects of the four stilbenes were evaluated using rat pheochromocytoma cell line （PC12 cells） damage models induced by corticosterone （Cort） or glutamate. In order to elaborate whether the neuroprotective effects of stilbenes are related to anti-oxidant properties, both oxidant and anti-oxidant parameters were measured. Results The results of MTT assay and LDH release assay demonstrated that the four stilbenes possessed neuroprotective effects. Moreover, the treatment on PC12 cells with Cort or glutamate （Glu） could significantly increase the levels of ROS and MDA with decreasing the activities of SOD and CAT. However, the four tested stilbenes could significantly alleviate such situation by dropping out the levels of ROS and MDA, as well as enhancing the activities of SOD and CAT. Conclusion These results provide a scientific basis for further studies to explore the potential neuroprotective effects on neurodegenerative diseases.
基金Supported by the National Natural Science Foundation of China （30572247） and Shanghai Municipal Education Commission （04YQHB009）.
文摘Two new stllbenes with two Isoprenoid groups, namely artostllbenes A （compound 1） and B （compound 2）, were Isolated from the stems of Arfocarpus chama Buch.-Ham. by repeated column chromatography. The＆ structures were elucldated as （E）-4-[2-（7-meth-xy-2-2-d-methy-6-（3-methy-but-2-eny-）-2H-1-benz-pyran-5-y-）v-ny-]benzene-1- 2-dlol （compound 1） and （Z）-4-[2-（7-meth-xy-2-2-dimethy--6-（3-methy-but-2-eny-）-2H-1-benz-pyran-5-y-）v-ny-]ben- zene-l,2-dlol （compound 2） by spectroscopic methods, mainly by 1D-, 2D-NMR and MS spectra. Compounds 1 and 2 are two cls- and trans-lsomers and compound 2 is the flrst cis-stllbene isolated from Moraceous plants.
基金financially supported by the National Natural Science Foundation of China (21072053 & 20772028) the Scientific Research Fund of Hunan Provincial Education Department (10K025)
文摘Twenty five samples of 4,4'-disubstituted stilbene derivatives were synthesized, and their UV absorption max wavelengths were determined in over 10 kinds of solvents including cyclohexane, ether, chloroform, acetonitrile and ethanol, in which 242 experimental data were recorded. The effects of substituents and solvents on the energy of their UV absorption max wavelengths were discussed. The research results showed: the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was mainly affected by their intramolecular structure (substituent effect) in a given solvent, that is, the energy is dominated by both of excited-state substituent parameter o-~c and polar substituent constant crp. While their energy was dominated by the substituent effect and solvent effect in different kinds of solvents. An equation quantifying the energy of UV absorption max wavelengths of 4,4'-disubstituted stilbenes was developed. In addition, it is found that the n-octanol/water partition coefficient (logP) is more effective than the solvatochromic dye (ET(30)) in scaling the solvent effect. The equation employed the parameter logP has a better correlation and more specific physical meaning. Further, the energies of UV absorption max wavelengths of some reported compounds were predicted by the obtained equation, which are in agreement with their experimental values.
文摘A new and convenient synthetic method has been developed for the construction of stilbenes bearing electron-withdrawing group（s） by using benzils and arylmethyldiphenylphosphine oxides via sequences involving Wittig-Horner reaction and a rearrangement in the presence of t-BuOK in toluene under mild conditions. This approach could be readily applied to a facile synthesis of biologically important natural products, resveratrol and its derivatives, such as trimethoxystilbenes 1 （Z） and 2 （E）.
基金We are grateful to the National Natural Science Foundation of China （No. 20972048） for the financial support of this work
文摘A base-catalyzed ring-opening of 1-benzylisochromans 1 firstly produced 2-alkenylstilbenes 2, which then underwent a mild acid-catalyzed intramolecular cyclization to furnish 1,2-disubstituted indenes 3 in high yields. Subsequently, a base-catalyzed isomerization of the 1,2-disubstituted indenes 3 afforded the more stable 2,3-disubstituted indenes 4 in almost quantitative yields.
文摘A sensitive and specific reversed-phase high performance liquid chromatography （RP-HPLC） method was established for the simultaneous quantitative determination of eight active components, two stilbenes （resveratrol, polydatin） and six flavonoids （rutin, quercilrin, quercetin, luteotin, isoorientin, kaempferol）, in Polygonum multiflorum Thunb. The chromatographic separation was performed on a Kromasil C18 column （250 mm^4.6 mm, 5 ~tm）, and gradient elution was carried out with water-methanol as the mobile phase at a flow rate of 1 mL/min. Stilbenes and flavonoids were respectively detected at 320 nm and 350 nm with DAD. The correlation coefficients of all the calibration curves were found to be higher than 0.9995. The average recoveries were ranged from 96.8% to 102.5% with RSD less than 4.8% for these components. RP-HPLC was validated to be a robust method for the quantitative determination of active components in Polygonum multiflorum Thunb, and it could be used in the quality control of this traditional medicine.
文摘Immature embryos, mature embryos and embryogenic calli of 6 rice (Oryza sativa L.) materials were transformed with particle bombardment. The plasmids pSSVstl and pVE5+ were used, both containing the phytoalexin gene from grapevine coding for stilbene synthase, but driven by 35S and its own promoter respectively. Through resistance selection for G418 (100 to 150 mg/L) or hygromycin (50 mg/L), 54 independent transgenic plants were isolated and further assessed by PCR, Southern blot and Dot blot analyses. The transgenic plants and their progenies were tested for resistance to blast ( Pyricularia oryzae ) and bacterial blight of rice ( Xanthomonas oryzae ). Preliminary results indicated that the stilbene synthase gene could enhance the resistance of transgenic plants and their progenies to both pathogens.
基金supported by the Natural Science Foundation of Hunan Province, China (No.20227)
文摘Objective Excessive aluminum （Al） exposure impairs neurocognitive function in humans and animals. Epidemiologic studies have shown a potential linkage between chronic Al exposure and Alzheimer’s disease. The present study aims to evaluate the effects of tetrahydroxy stilbene glucoside （TSG）, the extract from herbal medicine Polygoni Multiflori, on cognitive impairment and the over-expression of hippocampal amyloid precursor protein （APP） induced by chronic exposure to Al in rats. Methods Rats were treated with 0.3% aluminum chloride （AlCl3） prepared in the drinking water for 90 d. AlCl3-treated animals were then randomly assigned to receive vehicle, TSG （4 g/kg）, or Vitamin E （VE; 40 mg/kg） treatment for 5 months. VE served as a positive control. The effect of TSG was evaluated by passive avoidance task, and APP expression was evaluated by Western blotting. Results Following exposure to AlCl3 for 90 d, animals displayed a striking decrease （〉80%） in step-through latency in the passive avoidance task and a significant increase in the expression of APP in the hippocampus. Both TSG and VE significantly ameliorated the performance impairment in the passive avoidance task, and suppressed the over-expression of APP. Moreover, the effects of TSG, but not of VE, were in a time-dependent manner. Conclusion TSG may possess therapeutic effects against Alzheimer’s disease.
文摘Two new stilbene glycosides (1 and 2), together with nine known compounds (3-11), were isolated from the water extract of Polygonum multiflorum Thunb. The structures of the new compounds were elucidated by their chemical properties and spectroscopic analyses, including extensive 2D NMR experiments. Compound 2 showed strong DNA cleavage activity, and compounds 1, 2 and 10 (2, 3, 4′, 5_tetrahydroxy_ trans _stilbene_2_O_β_ D _glucopyranoside) exhibited significant inhibition of lipid peroxidation.
基金This work was supported by the National Natural Science Foundation of China and the Northwest Normal University Science and Technology Devolopment Foundation of China.
文摘Functionalized benzylic zinc halides reacted with benzaldehydes in the presence of Lewis acid Me3SiCl giving high yields of trans-stilbenes under the catalysis of Co(PPh3)3Cl.
文摘Biosynthesis of peanut stilbenes, including resveratrol as the secondary metabolites, could be enhanced by subjecting the kernels to germination and wound-stress. Investigations of the bio-elicited peanut sprout powder (BPSP) addressed on characterization of the comprising stilbenes and effectiveness in longevity extension deserves intensive research. In this study, peanut kernels were subjected to germination and wound-stress in preparation of BPSP. The methanol extracts of BPSP were medium pressure liquid chromatographic (MPLC) fractionated and semi-preparative HPLC recovered and followed by instrumental identification and biological activity determinations of the isolated stilbenes. In longevity experiments, 16 female 11-mon-old BALB/c mice and both genders of 12-mon-old ICR mice were daily fed with BPSP supplemented diets at doses of 0, 0.1 and 0.5 g BPSP/kg bw for 750 and 762 days, respectively. Based on chemical characterization, enriched quantity of stilbenes in the BPSP up to ca. 1% (w/w) was detected. Two new stilbene compounds, namely, 4, 5’-dihydroxy-6’’-hydroxymethyl, 6’’-methylpyrano [2’’, 3’’: 3’, 4’] stilbene and 3, 4, 5’-trihydroxy-6’’, 6’’-dimethylpyrano [2’’, 3’’: 3’, 4’]stilbene along with 5 known stilbenes were isolated. The 7 stilbenes exhibited potent antioxidative and antiglycative activities and varied with structure-activity nature. Based on the resultant survival curves and average lifespans of both mouse models, basal diets supplemented with BPSP are effective to extend mouse longevity by a dose dependent manner. It is of merit to demonstrate that peanut kernels as a potent producer could be bio-elicited to biosynthesize a broad spectrum of bioactive stilbenes to prepare BPSP which is effective to extend mouse longevity as science-evidenced by the two long-term animal experiments.
