Objective: To isolate and evaluate the cytotoxic activity of different actinomycetes species isolated from the Red Sea coast in Sharm el-Sheikh, Egypt.Methods: Forty actinomycetes strains were isolated from different ...Objective: To isolate and evaluate the cytotoxic activity of different actinomycetes species isolated from the Red Sea coast in Sharm el-Sheikh, Egypt.Methods: Forty actinomycetes strains were isolated from different sediments and seawater samples collected from the Red Sea coast in Egypt. Actinomycetes were recognized by morphological and microscopic examinations. Cell viability and cytotoxicity induced by the crude extracts on breast cancer cell lines MDA-MB-231 were assessed using methylene blue assay. The strains with promising cytotoxic activity were identified by sequencing and amplifying the 16 S r RNA genes. The antibacterial activities of the crude extracts were performed using Kirby–Bauer disc diffusion method.Results: The results indicated that five ethyl acetate extracts exhibited cytotoxicity towards breast cancer cell lines MDA-MB-231. The highest cytotoxic activity was found for the ethyl acetate extracts of EGY2 and EGY39. The isolate EGY3 was identified as a new Streptomyces species, while the actinomycete EGY22 was found to be a member of the genus Nocardiopsis sp. The crude extract of the isolate EGY8 showed slightly high antimicrobial activity against different test microorganisms.Conclusions: The results of the present study reveal that marine sediments of the Red Sea are a potent source of novel species of actinomycetes. The isolates may be useful in discovery of novel bioactive compounds and an important step in the development of microbial natural product research.展开更多
Zingiber rubens Roxb., and Zingiber zerumbet (L.) Smith were collected respectively from Nghe An, Province and Ha Tinh, Province,Vietnam. The root essential oils were obtained by water distillation and analyzed by Gas...Zingiber rubens Roxb., and Zingiber zerumbet (L.) Smith were collected respectively from Nghe An, Province and Ha Tinh, Province,Vietnam. The root essential oils were obtained by water distillation and analyzed by Gas chromatography (GC) and Gas chromatography coupled with Mass spectrometry (GC-MS). The most abundant components of Z. rubens were (Z)-citral (30.1%), camphene (9.7%), β-phellandrene (7.5%) and 1,8-cineole (7.0%) and zingiberene (5.3%). The main oil constituents of Z. zerumbet were (Z)-citral (26.1%), camphene (16.3%), sabinene (14.6%), zingiberene (7.2%) and lavandulyl acetate (6.7%). This species has low zerumbone (1.2%) content.展开更多
Background:Triphala extract is a well known medicinal herbal formula which is usually prescribed by Thai traditional doctors to adjust the physiological functions of the body.Previous studies have reported that Tripha...Background:Triphala extract is a well known medicinal herbal formula which is usually prescribed by Thai traditional doctors to adjust the physiological functions of the body.Previous studies have reported that Triphala has antioxidant,anti-inflammatory,antihypercholesterolemia and anticancer properties.Though this herbal recipe is commonly used in Thailand,its human safety,especially in the oral form,has not been studied.We therefore conducted a clinical trial(Phase I).Objective:This study evaluated the safety of administering the aqueous extract of Triphala to healthy volunteers at 2500 mg/d.Design,setting,participants and interventions:An open-label,single-arm trial was conducted at Chulabhorn International College of Medicine,Thammasat University,Pathum Thani,Thailand,between July 2017 and July 2018.The study enrolled 10 male and 10 female healthy volunteers;all were given Triphala(water extract;five capsules of 500 mg each)orally,once a day,at bedtime,for four consecutive weeks.Main outcome measures:Signs and symptoms,physical examinations,hematology and blood chemistry were assessed at the beginning of the trial and every week thereafter,for four consecutive weeks.After finishing the trial,on day 28,all volunteers were invited to a follow-up session on day 35 to evaluate the safety of the herbal recipe using the same measurements.Results:At the oral dose of 2500 mg/d,Triphala had no serious adverse effects in healthy volunteers.Moreover,it was found to have significantly improved the volunteers’high-density lipoprotein cholesterol(HDL-C)levels on day 35 and also reduced their blood sugar levels on days 14 and 35.Conclusions:We conclude that aqueous extract of Triphala is safe for healthy volunteers and that it elevates HDL-C levels and lowers blood sugar.Further clinical study should investigate its effects on HDL-C and blood sugar levels among the dyslipidemic and prediabetic groups.Trial registration:This trial was registered in the Thai Clinical Trial Registry with the identifier TCTR20180423002.展开更多
In vitro antimicrobial activity of the dichloromethane and methanol extracts of Piper sarmentosum leaves, fruits, stems, and the essential oil obtained from the fresh leaves together with their constituents were inves...In vitro antimicrobial activity of the dichloromethane and methanol extracts of Piper sarmentosum leaves, fruits, stems, and the essential oil obtained from the fresh leaves together with their constituents were investigated against two rice pathogenic fungi： Rhizoctonia solani （sheath blight causal agent） and Bipolaris oryzae （brown spot causal agent）, and two rice pathogenic bacteria： Xanthomonas oryzae pv. oryzae （Xoo） （bacterial leaf blight causal agent） and pv. oryzicola （Xoc） （bacterial leaf streak causal agent）. Among them, the dichloromethane extracts of the leaves and fruits, and the essential oil showed significantly high potential anti-rice microbial activity. Based on bioassay-guided fractionation of the dichloromethane leave and fruit extracts, myristicin, sarmentine, brachystamide B, brachyamide B, and piperonal were isolated. Moreover, the major constituent of its oil was also myristicin. Myristicin and brachyamide B revealed the highest potent inhibition against R. solani and B. oryzae （half maximal inhibitory concentration （IC5o） of 0.69 and 0.12 mmol L-I）, respectively. Moreover, brachyamide B and piperonal displayed most antibacterial activity against Xoo （MIC/MBC 7.62/1.90 mmol L-1） and Xoc （MIC/MBC 2.59/20.75 mmol L-1）, respectively. Additionally, the essential oil also exhibited the antimicrobial activity against all tested rice pathogenic bacteria and fungi. These compounds and the oil were first evaluated for anti-rice pathogenic microbial activity.展开更多
From the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves, isomahanine (1) and mahanine (2) were isolated that showed antibacterial activity towards Flavobacterium columnare and Streptococcus iniae which ca...From the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves, isomahanine (1) and mahanine (2) were isolated that showed antibacterial activity towards Flavobacterium columnare and Streptococcus iniae which caused columnaris disease and streptococcosis respectively. Isomahanine was found to have the strongest activity against F. columnare (isolate ALM-00-173) and S. iniae (isolate LA94-426) based on 24-h 50% inhibition concentration (IC50) and minimum inhibition concentration (MIC). Although compound (7), a nicotinamide isolated from Amyris texana had the lowest MIC (2.8 ± 0 mg/L) of any of the test compounds against F. columnare, the 24-h IC50 of 14.8 ± 0.6 mg/L was higher than that of isomahanine and subsequently the 24-h IC50 RDC values for (7) were almost a magnitude of order higher than those obtained for isomahanine. Isomahanine also had the strongest activity against S. iniae, with a 24-h IC50 of 1.3 ± 0.1 mg/L and MIC of 3.5 ± 0 mg/L, respectively.展开更多
The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pat...The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pathogenic effects on Zinnia elegans and Hydrangea macrophylla plants had been identified as Nigrospora spherica by molecular techniques. The mosquito adulticidal constituent in the culture filtrate was identified as phomalactone by spectroscopic techniques. Laboratory bioassays showed that phomalactone had larvicidal activity against permethrin susceptible and resistant Aedes aegypti larvae and topical adulticide activities on permethrin susceptible and resistant Aedes aegypti and Anopheles quadrimaculatus mosquitoes. Phomalactone was effective as a topical adulticide against the standard Orlando reference strain of Ae. aegypti with an LD50 of 0.64 μg/org. Activity against An. quadrimaculatus was 0.20 μg/org.展开更多
Objective: To investigate the effects of the leaf ethanolic extract of Pseuderanthemum palatiferum(PPE) and its isolated phytochemicals, stigmasterol and sitosterol-3-O-b-Dglucopyranoside, against a-amylase and a-gluc...Objective: To investigate the effects of the leaf ethanolic extract of Pseuderanthemum palatiferum(PPE) and its isolated phytochemicals, stigmasterol and sitosterol-3-O-b-Dglucopyranoside, against a-amylase and a-glucosidase enzyme activities both in vitro and in vivo.Methods: A concentration of maltose, which is a product released in a-amylase-catalyzing reaction, was used as an index of in vitro a-amylase activity. Meanwhile, in vitro a-glucosidase enzyme activity was indicated by the amount of liberated p-nitrophenol in a-glucosidase-catalyzing reaction. In vivo a-amylase and a-glucosidase enzyme activities were evaluated in the normal rats by using oral starch tolerance test and oral sucrose tolerance test, respectively.Results: PPE exerted a concentration-dependent inhibitory action against both aamylase and a-glucosidase in vitro with the IC_(50) values of(11.79 ± 8.10) mg/m L and(1.00 ± 0.11) mg/m L, respectively. Stigmasterol and sitosterol-3-O-b-D-glucopyranoside also exerted an in vitro a-amylase inhibition with the IC_(50) values of(59.41 ± 8.22) mg/m L and(111.19 ± 9.02) mg/m L, respectively. However, these phytochemicals did not produce a concentration-dependent inhibition against in vitro a-glucosidase activity. PPE and its isolated phytochemicals significantly decreased the blood glucose levels at t = 30 min in the oral starch tolerance test. From the sucrose tolerance test, only PPE but not its isolated phytochemicals significantly caused a depletion in the blood glucose levels at t = 30 min Conclusions: These results indicate an inhibitory action against carbohydrate-digesting enzymes as the anti-diabetic mechanism of action of PPE. Nonetheless, further clinical study is required to justify its role in the treatment of diabetes.展开更多
In vitro biological activities including anti-phytopathogenic fungi, antibacterial, antifeedant and herbicidal activities of the extracts from the heartwoods of Mansonia gagei Drumm. were evaluated. The dichlorometha...In vitro biological activities including anti-phytopathogenic fungi, antibacterial, antifeedant and herbicidal activities of the extracts from the heartwoods of Mansonia gagei Drumm. were evaluated. The dichloromethane （DCM） extract displayed antifungal activity against four plant pathogenic fungi （Altemaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora parasitica） higher than the methanolic （MeOH） extract. The separation of the DCM extract using bioassay guided antifungal activity against P. parasiUca led to the isolation of mansorins A, B, and C, mansonones C, E, G and H. Among isolated compounds, mansonone E displayed the highest antifungal activity against P. parasitica, followed by mansonone C, mansorin B and mansonone G. This potent compound revealed the same minimum inhibitory concentrations （MIC） of 31 μg mL-1 against C. gloeosporioides and P. parasitica, and minimum fungicidal concentration （MFC） of 31 and 125 μg mL-1, respectively. Moreover, mansonone E exhibited highly significant antibacterial activity against both Xanthomonas oryzae pv. oryzae （Xoo） and X. oryzae pv. oryzicola （Xoc） with MIC and minimum bactericidal concentration （MBC） as 7.8 and 〉500μg mL-1, respectively. This compound furthermore could inhibit the feed of Spodoptera litura with 45.9% antifeedant and significantly herbicidal activity reduced the shoot and root growth of Brassica chinensis, Oryza sativa, Mimosa pigra and Echinochlooa crus-galli. Mansonone E has potential as a new natural pesticide for agricultural plant pathogen management.展开更多
Objective:To investigate the cytotoxic activity and molecular mechanism(s)of two Thai noni juice(TNJ)products ethanolic extracts against cholangiocarcinoma(CCA)cell lines and non-cancerous cells,and to explore phenoli...Objective:To investigate the cytotoxic activity and molecular mechanism(s)of two Thai noni juice(TNJ)products ethanolic extracts against cholangiocarcinoma(CCA)cell lines and non-cancerous cells,and to explore phenolic acid compositions of TNJ products.Methods:Phenolic acid profiles of TNJ Chiangrai(TNJ-Cr)and TNJ Buasri(TNJ-Bs)ethanolic extracts were determined by HPLC.The cytotoxicity of TNJ ethanolic extracts on cancer and non-cancerous cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and trypan blue assays.Mechanism(s)underlying the anti-CCA activity of TNJ ethanolic extracts were determined by cell cycle,apoptosis,and reactive oxygen species(ROS)generation assays.The expression levels of proteins involved in apoptosis and ERK signaling were evaluated by Western blot analysis.Results:Phenolic acid profiles of both TNJ ethanolic extracts showed that the p-hydroxybenzoic,vanillic,and protocatechuic acids were the major phenolic acids in TNJ products.Cytotoxicity assays revealed that the TNJ-Cr and TNJ-Bs ethanolic extracts reduced viability of CCA cell lines through induction of apoptosis by up-regulation of p53 and Bax proapoptotic proteins.Both TNJ ethanolic extracts promoted ROS generation by activating the ERK1/2 signaling in well-differentiated CCA cells KKU-213B.Meanwhile,TNJ ethanolic extracts did not induce ROS production in poorly differentiated CCA cells KKU-100.Both TNJ ethanolic extracts showed no toxicity to human peripheral blood mononuclear cells.Conclusions:TNJ ethanolic extracts could inhibit CCA cell proliferation by inducing ROS generation and apoptosis and may be applicable for combination therapies in CCA treatment.展开更多
Objective:To investigate the effect of combination treatments of cisplatin and KK4 and ICG15042 peanut testa extracts against cholangiocarcinoma cells in vitro.Methods:The growth inhibition,cell cycle arrest and apopt...Objective:To investigate the effect of combination treatments of cisplatin and KK4 and ICG15042 peanut testa extracts against cholangiocarcinoma cells in vitro.Methods:The growth inhibition,cell cycle arrest and apoptosis of cholangiocarcinoma cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis,respectively.The levels of proteins involved in apoptosis were assessed using Western blotting assays.The caspase activity was assessed using a colorimetric caspase activity assay.Results:Cisplatin and peanut(KK4 and ICG15042)testa extracts inhibited the growth of cholangiocarcinoma cell lines(KKUM214 and KKU-100 cells)in a dose-and time-dependent manner.The combination treatments reduced cell viability and induced apoptosis of cholangiocarcinoma cells more efficiently than singledrug treatments.Cancer cell death synergistically mediated by cisplatin and peanut testa extracts was observed in KKU-M214 cells(combination index<1.0)but not in KKU-100 cells(combination index>1.0).The combination treatments also increased the subG1 population and caused KKU-M214 cell cycle arrest at S and G2/M phases,which were the combined effects of cisplatin(S phase arrest)and peanut testa extracts(G2/M phase arrest).In addition,p ERK1/2,Ac-H3,Bcl-2 and proteins related to apoptosis,including Bax and caspases 3,8,9,exhibited enhanced expression in KKUM214 cells.The combination treatments caused down-regulation of p53,whereas the expression of p21 was fairly constant when compared with cisplatin single drug treatment.Conclusions:Peanut testa extracts in combination with cisplatin synergistically reduce cell viability and induce apoptosis through stimulation of caspases 3,8 and 9 in KKU-M214 cells.展开更多
The chemistry of essential obtained from the leaves of Senna podocarpa (Guill. Et Perr.) Lock from Nigeria is being reported. The hydrodistilled oil was analyzed by gas chromatography-flame ionization detector (GC-FID...The chemistry of essential obtained from the leaves of Senna podocarpa (Guill. Et Perr.) Lock from Nigeria is being reported. The hydrodistilled oil was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) techniques. The main constituents of the oil were 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl) ester phthalate (26.6%) and β-elemene (27.9%). There were significant amounts of caryophyllene oxide (7.3%) and urs-12-en-24-oic acid, 3-oxo-methyl ester (5.5%). The antimicrobial activity of the essential oil was evaluated against a panel of seven bacteria and two fungal strain using agar diffusion and broth microdilution methods. Results had shown that the oil exhibited moderate to strong antimicrobial activity against the tested microorganisms. The activity zones of inhibition (ZI) ranged between 10.0 ± 0.2 mm and 28.3 ± 2.9 mm while the minimum inhibitory concentrations (MIC) ranged between 0.3 mg/mL 5.0 mg/mL, respectively. The chemical constituents and antimicrobial activity of the essential oil of Senna podocarpa were being reported for the first time.展开更多
In the present investigation, we studied new essential oil contents and compositions of three individual plants from Cupressaceae family cultivated in Vietnam. The air-dried plants were hydrodistilled and the oils ana...In the present investigation, we studied new essential oil contents and compositions of three individual plants from Cupressaceae family cultivated in Vietnam. The air-dried plants were hydrodistilled and the oils analysed by Gas chromatography (GC) and Gas chromatography couples with Mass spectrometry (GC-MS). The components were identified by comparison of their retention indices on HP-5 MS capillary column with literature reference and MS pattern with authentic library’s collection. a-Pinene (36.0%), α-cedrol (18.3%) and thujopsene (5.7%) were the main constituents of Cupressus tonkiensis Silba. Monoterpenes were the quantitative significant compounds of Sabina chinensis (L.) Antoine. These are bornyl acetate (19.5%), sabinene (17.3%) and a-pinene (15.8%). Moreover, the main compounds of Thuja orientalis L., were identified as a-pinene (34.1%), α-cedrol (16.5%), β-caryophyllene (5.4%) and β-selinene (5.2%). The chemotaxonomy implication of these results was also discussed.展开更多
Essential oils obtained from hydrodistillation of three medicinal plants grown in Vietnam were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). The monoterpene hydrocarbons, α-pin...Essential oils obtained from hydrodistillation of three medicinal plants grown in Vietnam were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). The monoterpene hydrocarbons, α-pinene (50.2%), β-pinene (23.6%) and limonene (5.3%) were the most abundant constituents of the rhizome oil of Zingiber collinsii Mood & Theilade (Zingiberaceae). The main compounds of the stem oil of Croton kongensis Gagnep., (Euphorbiaceae) were benzyl benzoate (12.7%), β-selinene (9.8%), bulnesol (8.0%) and 5,6,7,8-tetrahydroquinoxaline (7.4%). The leaf oil of Goniothalamus albiflous Ban., consisted mainly of α-pinene (26.2%), caryophyllene oxide (10.6%) and 1,8-cineole (9.7%). The composition of the oils of Zingiber collinsii and Croton kongensis was being reported for the first time.展开更多
The chemical composition of the essential oil obtained by hydrodistillation from the leaves of Phyllanthus reticulatus Poiret (Euphorbiaceae) growing in Nigeria has been studied. The constituents of the oil were analy...The chemical composition of the essential oil obtained by hydrodistillation from the leaves of Phyllanthus reticulatus Poiret (Euphorbiaceae) growing in Nigeria has been studied. The constituents of the oil were analyzed by means of gas chromatography (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Monoterpenes (64.9%) were the dominant class of compounds, followed by sesquiterpenes (23.0%). The major constituents were α-pinene (6.0%), sabinene (7.6%), β-pinene (18.1%), linalool (6.9%) and camphor (7.7%), among the monoterpenes, and β-caryophyllene (11.9%) and germacrene D (8.6%) among the sesquiterpenes. This is the first report on the volatile constituents of Phyllanthus reticulatus.展开更多
Columnaris (caused by Flavobacterium columnare) is one of the most common bacterial diseases affecting the pond-raised channel catfish (Ictalurus punctatus) in the southeastern United States of America resulting in an...Columnaris (caused by Flavobacterium columnare) is one of the most common bacterial diseases affecting the pond-raised channel catfish (Ictalurus punctatus) in the southeastern United States of America resulting in annual losses of millions of dollars. As part of our continuing effort to discover environmentally benign compounds for the control of columnaris disease, acyl derivatives of phloroglucinol were synthesized and tested against F. columnare using a rapid bioassay. Among the analogs that were tested, diacyl analogs showed very high antibacterial activity against F. columnare in the laboratory bioassay. Diisovaleryl and diisobutyryl analogs were found to have the strongest activity against F. columnare (isolate ALM-00-173) based on 24-h 50% inhibitory concentration (IC50) and minimum inhibitory concentration (MIC). Diisovaleryl and diisobutyryl analogs had IC50 values 0.82 mg/L and 0.80 mg/L, respectively, whereas the drug control florfenicol had an IC50 value of 0.81 mg/L. Diisovaleryl and diisobutyryl analogs also had 24-h relative-to- drug-control IC50 values around 1.0 indicating activities similar to florfenicol, which is included in medicated feed and is one of the current management approach for columnaris.展开更多
Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to...Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological samples.Docosanol and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88%cyanopropy)aryl-polysiloxane employed as the stationary phase.The ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 min.The GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance criteria.The docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R^(2)>0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were>93.2%and>95.8%,respectively.The validated method was successfully applied to analyze ex vivo human cadaver skin permeation samples.On applying Abreva®cream tube and Abreva®cream pump,the amount of docosanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,respectively.Accordingly,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control tool.This method can be used for routine analysis as a costeffective alternative to other techniques.展开更多
In this paper, compounds identified in the essential oils obtained by hydrodistillation of the leaves of Cinnamomum glaucescens (Nees) Hand.-Mazz and Cinnamomum verum J.S. Presl (Lauraceae family) of Vietnam origin ar...In this paper, compounds identified in the essential oils obtained by hydrodistillation of the leaves of Cinnamomum glaucescens (Nees) Hand.-Mazz and Cinnamomum verum J.S. Presl (Lauraceae family) of Vietnam origin are reported. The chemical analyses were performed using gas chromatography-flame ionisation detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The significant compounds of C. glaucescens were geraniol (36.2%) and terpinen-4-ol (19.7%). On the other hand, C. verum comprised of linalool (22.0%) and bicyclogermacrene (11.2%). The present results may represent new chemotypes of the essential oils of C. verum and C. glaucescens.展开更多
Brachiaria eruciformis (sm.) Griseb, locally known as “signal grass”, is a common weed in lawns and turfs in Mississippi, USA. During late spring and early summer months, leaves of B. eruciformis are infected with a...Brachiaria eruciformis (sm.) Griseb, locally known as “signal grass”, is a common weed in lawns and turfs in Mississippi, USA. During late spring and early summer months, leaves of B. eruciformis are infected with a fungus causing necrosis. The infected leaves ultimately turn brown and wither. As part of our search for potential new natural product-based agrochemicals, we studied this plant pathogen in order to investigate phytotoxic and fungitoxic metabolites produced by the fungus. The causative fungus was isolated from an infected leaf of B. eruciformis, cultured in potato dextrose agar plates and identified via molecular techniques as Pyricularia grisea. A phytotoxic compound was isolated from Czapek-Dox broth liquid culture medium and identified as pyrichalasin H by spectroscopic techniques. Pyrichalasin H was toxic to the fungal plant pathogen Colletotrichum fragariae in a TLC bioautography assay and phytotoxic to two monocot and one dicot plants. This is the first report of antifungal activity of pyrichalasin H against phytopathogens. Pyrichalasin H isolated from Pyricularia grisea, a pathogen infecting B. eruciformis (signal grass) was shown to be phytotoxic and fungicidal to Colletotrichum fragariae.展开更多
Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fung...Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fungal and bacterial pathogens. These pathogens can cause significant quantitative and qualitative losses from harvest to consumption during the handling and storage processes. Chemical fungicides are commonly used but are likely to leave residues on the produce, rendering short shelf-life produce, such as berries, unsuitable for human consumption. Identifying eco-friendly methods to control post-harvest disease is, therefore, of utmost importance. The presence of antifungal constituents in the roots of Poncirus trifoliata extracts was detected by thin layer chromatography-based bioautography. The active constituents were isolated and identified by bioautography assay-guided fractionation using flash chromatography followed by spectroscopic techniques. In this study, xanthoxyletin, demethylsuberosin, dentatin, nordentatin, ponfolin, and clausarin were isolated from the root extracts. The antifungal activity of these compounds was moderate to weak compared to the commercial fungicide captan. This study reports the isolation and identification of natural compounds from Poncirus trifoliata that exhibited antifungal activity against Colletotrichum fragariae and Botrytis cinerea, two major post-harvest pathogens.展开更多
Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes ...Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes has increased the importance for the search for novel mosquito control agents. Natural products, particularly plant and microbe derived secondary metabolites, are good sources in the search for such compounds. Ammi visnaga (Lam.) Lamarck is a plant in the Apiaceae family native to North Africa, Europe, and Asia. In the search for environmentally benign and effective insecticides as part of an ongoing joint effort between the USDA (US Department of Agriculture) and the DWFP (Deployed War Fighter Protection) program sponsored by the Department of Defense, we have investigated ethyl acetate extract of A. visnaga seeds. Two furanochromones, khellin and visnagin that exhibited larvicide activity against Aedes aegypti mosquito larvae were isolated from the ethyl acetate extract of the seeds by bioassay-guided fractionation. This is the first report of mosquito larvicidal activity of khellin and visnagin.展开更多
基金Supported by the Egyptian Science and Technology Development fund(STDF)(Grant No.4930)
文摘Objective: To isolate and evaluate the cytotoxic activity of different actinomycetes species isolated from the Red Sea coast in Sharm el-Sheikh, Egypt.Methods: Forty actinomycetes strains were isolated from different sediments and seawater samples collected from the Red Sea coast in Egypt. Actinomycetes were recognized by morphological and microscopic examinations. Cell viability and cytotoxicity induced by the crude extracts on breast cancer cell lines MDA-MB-231 were assessed using methylene blue assay. The strains with promising cytotoxic activity were identified by sequencing and amplifying the 16 S r RNA genes. The antibacterial activities of the crude extracts were performed using Kirby–Bauer disc diffusion method.Results: The results indicated that five ethyl acetate extracts exhibited cytotoxicity towards breast cancer cell lines MDA-MB-231. The highest cytotoxic activity was found for the ethyl acetate extracts of EGY2 and EGY39. The isolate EGY3 was identified as a new Streptomyces species, while the actinomycete EGY22 was found to be a member of the genus Nocardiopsis sp. The crude extract of the isolate EGY8 showed slightly high antimicrobial activity against different test microorganisms.Conclusions: The results of the present study reveal that marine sediments of the Red Sea are a potent source of novel species of actinomycetes. The isolates may be useful in discovery of novel bioactive compounds and an important step in the development of microbial natural product research.
文摘Zingiber rubens Roxb., and Zingiber zerumbet (L.) Smith were collected respectively from Nghe An, Province and Ha Tinh, Province,Vietnam. The root essential oils were obtained by water distillation and analyzed by Gas chromatography (GC) and Gas chromatography coupled with Mass spectrometry (GC-MS). The most abundant components of Z. rubens were (Z)-citral (30.1%), camphene (9.7%), β-phellandrene (7.5%) and 1,8-cineole (7.0%) and zingiberene (5.3%). The main oil constituents of Z. zerumbet were (Z)-citral (26.1%), camphene (16.3%), sabinene (14.6%), zingiberene (7.2%) and lavandulyl acetate (6.7%). This species has low zerumbone (1.2%) content.
基金the Thai Traditional Medical Knowledge Fund for its research grant.
文摘Background:Triphala extract is a well known medicinal herbal formula which is usually prescribed by Thai traditional doctors to adjust the physiological functions of the body.Previous studies have reported that Triphala has antioxidant,anti-inflammatory,antihypercholesterolemia and anticancer properties.Though this herbal recipe is commonly used in Thailand,its human safety,especially in the oral form,has not been studied.We therefore conducted a clinical trial(Phase I).Objective:This study evaluated the safety of administering the aqueous extract of Triphala to healthy volunteers at 2500 mg/d.Design,setting,participants and interventions:An open-label,single-arm trial was conducted at Chulabhorn International College of Medicine,Thammasat University,Pathum Thani,Thailand,between July 2017 and July 2018.The study enrolled 10 male and 10 female healthy volunteers;all were given Triphala(water extract;five capsules of 500 mg each)orally,once a day,at bedtime,for four consecutive weeks.Main outcome measures:Signs and symptoms,physical examinations,hematology and blood chemistry were assessed at the beginning of the trial and every week thereafter,for four consecutive weeks.After finishing the trial,on day 28,all volunteers were invited to a follow-up session on day 35 to evaluate the safety of the herbal recipe using the same measurements.Results:At the oral dose of 2500 mg/d,Triphala had no serious adverse effects in healthy volunteers.Moreover,it was found to have significantly improved the volunteers’high-density lipoprotein cholesterol(HDL-C)levels on day 35 and also reduced their blood sugar levels on days 14 and 35.Conclusions:We conclude that aqueous extract of Triphala is safe for healthy volunteers and that it elevates HDL-C levels and lowers blood sugar.Further clinical study should investigate its effects on HDL-C and blood sugar levels among the dyslipidemic and prediabetic groups.Trial registration:This trial was registered in the Thai Clinical Trial Registry with the identifier TCTR20180423002.
基金supported by a grant from the 90th Anniversary of Chulalongkorn University Fund,Thailand(Ratchadaphiseksomphot Endowment Fund,F31GSES13)
文摘In vitro antimicrobial activity of the dichloromethane and methanol extracts of Piper sarmentosum leaves, fruits, stems, and the essential oil obtained from the fresh leaves together with their constituents were investigated against two rice pathogenic fungi： Rhizoctonia solani （sheath blight causal agent） and Bipolaris oryzae （brown spot causal agent）, and two rice pathogenic bacteria： Xanthomonas oryzae pv. oryzae （Xoo） （bacterial leaf blight causal agent） and pv. oryzicola （Xoc） （bacterial leaf streak causal agent）. Among them, the dichloromethane extracts of the leaves and fruits, and the essential oil showed significantly high potential anti-rice microbial activity. Based on bioassay-guided fractionation of the dichloromethane leave and fruit extracts, myristicin, sarmentine, brachystamide B, brachyamide B, and piperonal were isolated. Moreover, the major constituent of its oil was also myristicin. Myristicin and brachyamide B revealed the highest potent inhibition against R. solani and B. oryzae （half maximal inhibitory concentration （IC5o） of 0.69 and 0.12 mmol L-I）, respectively. Moreover, brachyamide B and piperonal displayed most antibacterial activity against Xoo （MIC/MBC 7.62/1.90 mmol L-1） and Xoc （MIC/MBC 2.59/20.75 mmol L-1）, respectively. Additionally, the essential oil also exhibited the antimicrobial activity against all tested rice pathogenic bacteria and fungi. These compounds and the oil were first evaluated for anti-rice pathogenic microbial activity.
文摘From the ethyl acetate extract of Murraya koenegii (Rutaceae) leaves, isomahanine (1) and mahanine (2) were isolated that showed antibacterial activity towards Flavobacterium columnare and Streptococcus iniae which caused columnaris disease and streptococcosis respectively. Isomahanine was found to have the strongest activity against F. columnare (isolate ALM-00-173) and S. iniae (isolate LA94-426) based on 24-h 50% inhibition concentration (IC50) and minimum inhibition concentration (MIC). Although compound (7), a nicotinamide isolated from Amyris texana had the lowest MIC (2.8 ± 0 mg/L) of any of the test compounds against F. columnare, the 24-h IC50 of 14.8 ± 0.6 mg/L was higher than that of isomahanine and subsequently the 24-h IC50 RDC values for (7) were almost a magnitude of order higher than those obtained for isomahanine. Isomahanine also had the strongest activity against S. iniae, with a 24-h IC50 of 1.3 ± 0.1 mg/L and MIC of 3.5 ± 0 mg/L, respectively.
文摘The culture filtrate of a plant pathogenic fungus that infected Zinnia elegans and Hydrangea macrophylla was investigated for mosquitocidal constituents by bioassay guided isolation. The fungus responsible for the pathogenic effects on Zinnia elegans and Hydrangea macrophylla plants had been identified as Nigrospora spherica by molecular techniques. The mosquito adulticidal constituent in the culture filtrate was identified as phomalactone by spectroscopic techniques. Laboratory bioassays showed that phomalactone had larvicidal activity against permethrin susceptible and resistant Aedes aegypti larvae and topical adulticide activities on permethrin susceptible and resistant Aedes aegypti and Anopheles quadrimaculatus mosquitoes. Phomalactone was effective as a topical adulticide against the standard Orlando reference strain of Ae. aegypti with an LD50 of 0.64 μg/org. Activity against An. quadrimaculatus was 0.20 μg/org.
基金Supported by Mahasarakham University research grant(Grant No.5805028/2558,fiscal year 2015)
文摘Objective: To investigate the effects of the leaf ethanolic extract of Pseuderanthemum palatiferum(PPE) and its isolated phytochemicals, stigmasterol and sitosterol-3-O-b-Dglucopyranoside, against a-amylase and a-glucosidase enzyme activities both in vitro and in vivo.Methods: A concentration of maltose, which is a product released in a-amylase-catalyzing reaction, was used as an index of in vitro a-amylase activity. Meanwhile, in vitro a-glucosidase enzyme activity was indicated by the amount of liberated p-nitrophenol in a-glucosidase-catalyzing reaction. In vivo a-amylase and a-glucosidase enzyme activities were evaluated in the normal rats by using oral starch tolerance test and oral sucrose tolerance test, respectively.Results: PPE exerted a concentration-dependent inhibitory action against both aamylase and a-glucosidase in vitro with the IC_(50) values of(11.79 ± 8.10) mg/m L and(1.00 ± 0.11) mg/m L, respectively. Stigmasterol and sitosterol-3-O-b-D-glucopyranoside also exerted an in vitro a-amylase inhibition with the IC_(50) values of(59.41 ± 8.22) mg/m L and(111.19 ± 9.02) mg/m L, respectively. However, these phytochemicals did not produce a concentration-dependent inhibition against in vitro a-glucosidase activity. PPE and its isolated phytochemicals significantly decreased the blood glucose levels at t = 30 min in the oral starch tolerance test. From the sucrose tolerance test, only PPE but not its isolated phytochemicals significantly caused a depletion in the blood glucose levels at t = 30 min Conclusions: These results indicate an inhibitory action against carbohydrate-digesting enzymes as the anti-diabetic mechanism of action of PPE. Nonetheless, further clinical study is required to justify its role in the treatment of diabetes.
基金the office of the Higher Education Commission,Thailand for supporting grant fund under the program Strategic Scholarships for Frontier Research Network for the Ph D Program Thai Doctoral degree for this research (77/2551)the 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund,GCUGR11244525026D24)
文摘In vitro biological activities including anti-phytopathogenic fungi, antibacterial, antifeedant and herbicidal activities of the extracts from the heartwoods of Mansonia gagei Drumm. were evaluated. The dichloromethane （DCM） extract displayed antifungal activity against four plant pathogenic fungi （Altemaria porri, Colletotrichum gloeosporioides, Fusarium oxysporum and Phytophthora parasitica） higher than the methanolic （MeOH） extract. The separation of the DCM extract using bioassay guided antifungal activity against P. parasiUca led to the isolation of mansorins A, B, and C, mansonones C, E, G and H. Among isolated compounds, mansonone E displayed the highest antifungal activity against P. parasitica, followed by mansonone C, mansorin B and mansonone G. This potent compound revealed the same minimum inhibitory concentrations （MIC） of 31 μg mL-1 against C. gloeosporioides and P. parasitica, and minimum fungicidal concentration （MFC） of 31 and 125 μg mL-1, respectively. Moreover, mansonone E exhibited highly significant antibacterial activity against both Xanthomonas oryzae pv. oryzae （Xoo） and X. oryzae pv. oryzicola （Xoc） with MIC and minimum bactericidal concentration （MBC） as 7.8 and 〉500μg mL-1, respectively. This compound furthermore could inhibit the feed of Spodoptera litura with 45.9% antifeedant and significantly herbicidal activity reduced the shoot and root growth of Brassica chinensis, Oryza sativa, Mimosa pigra and Echinochlooa crus-galli. Mansonone E has potential as a new natural pesticide for agricultural plant pathogen management.
基金This work was supported by the National Research Council of Thailand through Khon Kaen University,granted number 592302 and 601702.
文摘Objective:To investigate the cytotoxic activity and molecular mechanism(s)of two Thai noni juice(TNJ)products ethanolic extracts against cholangiocarcinoma(CCA)cell lines and non-cancerous cells,and to explore phenolic acid compositions of TNJ products.Methods:Phenolic acid profiles of TNJ Chiangrai(TNJ-Cr)and TNJ Buasri(TNJ-Bs)ethanolic extracts were determined by HPLC.The cytotoxicity of TNJ ethanolic extracts on cancer and non-cancerous cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and trypan blue assays.Mechanism(s)underlying the anti-CCA activity of TNJ ethanolic extracts were determined by cell cycle,apoptosis,and reactive oxygen species(ROS)generation assays.The expression levels of proteins involved in apoptosis and ERK signaling were evaluated by Western blot analysis.Results:Phenolic acid profiles of both TNJ ethanolic extracts showed that the p-hydroxybenzoic,vanillic,and protocatechuic acids were the major phenolic acids in TNJ products.Cytotoxicity assays revealed that the TNJ-Cr and TNJ-Bs ethanolic extracts reduced viability of CCA cell lines through induction of apoptosis by up-regulation of p53 and Bax proapoptotic proteins.Both TNJ ethanolic extracts promoted ROS generation by activating the ERK1/2 signaling in well-differentiated CCA cells KKU-213B.Meanwhile,TNJ ethanolic extracts did not induce ROS production in poorly differentiated CCA cells KKU-100.Both TNJ ethanolic extracts showed no toxicity to human peripheral blood mononuclear cells.Conclusions:TNJ ethanolic extracts could inhibit CCA cell proliferation by inducing ROS generation and apoptosis and may be applicable for combination therapies in CCA treatment.
基金supported by the Thailand Research Fund for providing financial support through the Senior Research Scholar Project of Prof.Dr.Sanun Jogloy(Project no.RTA6180002)partially supported by the National Research Council of Thailand through Khon Kaen University,Thailand
文摘Objective:To investigate the effect of combination treatments of cisplatin and KK4 and ICG15042 peanut testa extracts against cholangiocarcinoma cells in vitro.Methods:The growth inhibition,cell cycle arrest and apoptosis of cholangiocarcinoma cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis,respectively.The levels of proteins involved in apoptosis were assessed using Western blotting assays.The caspase activity was assessed using a colorimetric caspase activity assay.Results:Cisplatin and peanut(KK4 and ICG15042)testa extracts inhibited the growth of cholangiocarcinoma cell lines(KKUM214 and KKU-100 cells)in a dose-and time-dependent manner.The combination treatments reduced cell viability and induced apoptosis of cholangiocarcinoma cells more efficiently than singledrug treatments.Cancer cell death synergistically mediated by cisplatin and peanut testa extracts was observed in KKU-M214 cells(combination index<1.0)but not in KKU-100 cells(combination index>1.0).The combination treatments also increased the subG1 population and caused KKU-M214 cell cycle arrest at S and G2/M phases,which were the combined effects of cisplatin(S phase arrest)and peanut testa extracts(G2/M phase arrest).In addition,p ERK1/2,Ac-H3,Bcl-2 and proteins related to apoptosis,including Bax and caspases 3,8,9,exhibited enhanced expression in KKUM214 cells.The combination treatments caused down-regulation of p53,whereas the expression of p21 was fairly constant when compared with cisplatin single drug treatment.Conclusions:Peanut testa extracts in combination with cisplatin synergistically reduce cell viability and induce apoptosis through stimulation of caspases 3,8 and 9 in KKU-M214 cells.
文摘The chemistry of essential obtained from the leaves of Senna podocarpa (Guill. Et Perr.) Lock from Nigeria is being reported. The hydrodistilled oil was analyzed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) techniques. The main constituents of the oil were 1,2-benzenedicarboxylic acid, mono (2-ethylhexyl) ester phthalate (26.6%) and β-elemene (27.9%). There were significant amounts of caryophyllene oxide (7.3%) and urs-12-en-24-oic acid, 3-oxo-methyl ester (5.5%). The antimicrobial activity of the essential oil was evaluated against a panel of seven bacteria and two fungal strain using agar diffusion and broth microdilution methods. Results had shown that the oil exhibited moderate to strong antimicrobial activity against the tested microorganisms. The activity zones of inhibition (ZI) ranged between 10.0 ± 0.2 mm and 28.3 ± 2.9 mm while the minimum inhibitory concentrations (MIC) ranged between 0.3 mg/mL 5.0 mg/mL, respectively. The chemical constituents and antimicrobial activity of the essential oil of Senna podocarpa were being reported for the first time.
文摘In the present investigation, we studied new essential oil contents and compositions of three individual plants from Cupressaceae family cultivated in Vietnam. The air-dried plants were hydrodistilled and the oils analysed by Gas chromatography (GC) and Gas chromatography couples with Mass spectrometry (GC-MS). The components were identified by comparison of their retention indices on HP-5 MS capillary column with literature reference and MS pattern with authentic library’s collection. a-Pinene (36.0%), α-cedrol (18.3%) and thujopsene (5.7%) were the main constituents of Cupressus tonkiensis Silba. Monoterpenes were the quantitative significant compounds of Sabina chinensis (L.) Antoine. These are bornyl acetate (19.5%), sabinene (17.3%) and a-pinene (15.8%). Moreover, the main compounds of Thuja orientalis L., were identified as a-pinene (34.1%), α-cedrol (16.5%), β-caryophyllene (5.4%) and β-selinene (5.2%). The chemotaxonomy implication of these results was also discussed.
文摘Essential oils obtained from hydrodistillation of three medicinal plants grown in Vietnam were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC-MS). The monoterpene hydrocarbons, α-pinene (50.2%), β-pinene (23.6%) and limonene (5.3%) were the most abundant constituents of the rhizome oil of Zingiber collinsii Mood & Theilade (Zingiberaceae). The main compounds of the stem oil of Croton kongensis Gagnep., (Euphorbiaceae) were benzyl benzoate (12.7%), β-selinene (9.8%), bulnesol (8.0%) and 5,6,7,8-tetrahydroquinoxaline (7.4%). The leaf oil of Goniothalamus albiflous Ban., consisted mainly of α-pinene (26.2%), caryophyllene oxide (10.6%) and 1,8-cineole (9.7%). The composition of the oils of Zingiber collinsii and Croton kongensis was being reported for the first time.
文摘The chemical composition of the essential oil obtained by hydrodistillation from the leaves of Phyllanthus reticulatus Poiret (Euphorbiaceae) growing in Nigeria has been studied. The constituents of the oil were analyzed by means of gas chromatography (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Monoterpenes (64.9%) were the dominant class of compounds, followed by sesquiterpenes (23.0%). The major constituents were α-pinene (6.0%), sabinene (7.6%), β-pinene (18.1%), linalool (6.9%) and camphor (7.7%), among the monoterpenes, and β-caryophyllene (11.9%) and germacrene D (8.6%) among the sesquiterpenes. This is the first report on the volatile constituents of Phyllanthus reticulatus.
文摘Columnaris (caused by Flavobacterium columnare) is one of the most common bacterial diseases affecting the pond-raised channel catfish (Ictalurus punctatus) in the southeastern United States of America resulting in annual losses of millions of dollars. As part of our continuing effort to discover environmentally benign compounds for the control of columnaris disease, acyl derivatives of phloroglucinol were synthesized and tested against F. columnare using a rapid bioassay. Among the analogs that were tested, diacyl analogs showed very high antibacterial activity against F. columnare in the laboratory bioassay. Diisovaleryl and diisobutyryl analogs were found to have the strongest activity against F. columnare (isolate ALM-00-173) based on 24-h 50% inhibitory concentration (IC50) and minimum inhibitory concentration (MIC). Diisovaleryl and diisobutyryl analogs had IC50 values 0.82 mg/L and 0.80 mg/L, respectively, whereas the drug control florfenicol had an IC50 value of 0.81 mg/L. Diisovaleryl and diisobutyryl analogs also had 24-h relative-to- drug-control IC50 values around 1.0 indicating activities similar to florfenicol, which is included in medicated feed and is one of the current management approach for columnaris.
文摘Docosanol is the only US Food and Drug Administration(FDA)approved over-the-counter topical product for treating recurrent oral-facial herpes simplex labialis.Validated analytical methods for docosanol are required to demonstrate the bioequivalence of docosanol topical products.A gas chromatography/selected ion monitoring mode mass spectrometry(GC/SIM-MS)method was developed and validated for docosanol determination in biological samples.Docosanol and isopropyl palmitate(internal standard)were separated on a high-polarity GC capillary column with(88%cyanopropy)aryl-polysiloxane employed as the stationary phase.The ions of m/z 83 and 256 were selected to monitor docosanol and isopropyl palmitate,respectively;the total run time was 20 min.The GC/SIM-MS method was validated in accordance with US FDA guidelines,and the results met the US FDA acceptance criteria.The docosanol calibration standards were linear in the 100-10000 ng/mL concentration range(R^(2)>0.994).The recoveries for docosanol from the receptor fluid and skin homogenates were>93.2%and>95.8%,respectively.The validated method was successfully applied to analyze ex vivo human cadaver skin permeation samples.On applying Abreva®cream tube and Abreva®cream pump,the amount of docosanol that penetrated human cadaver skin at 48 h was 21.5±7.01 and 24.0±6.95 ng/mg,respectively.Accordingly,we concluded that the validated GC/SIM-MS was sensitive,specific,and suitable for quantifying docosanol as a quality control tool.This method can be used for routine analysis as a costeffective alternative to other techniques.
文摘In this paper, compounds identified in the essential oils obtained by hydrodistillation of the leaves of Cinnamomum glaucescens (Nees) Hand.-Mazz and Cinnamomum verum J.S. Presl (Lauraceae family) of Vietnam origin are reported. The chemical analyses were performed using gas chromatography-flame ionisation detector (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). The significant compounds of C. glaucescens were geraniol (36.2%) and terpinen-4-ol (19.7%). On the other hand, C. verum comprised of linalool (22.0%) and bicyclogermacrene (11.2%). The present results may represent new chemotypes of the essential oils of C. verum and C. glaucescens.
文摘Brachiaria eruciformis (sm.) Griseb, locally known as “signal grass”, is a common weed in lawns and turfs in Mississippi, USA. During late spring and early summer months, leaves of B. eruciformis are infected with a fungus causing necrosis. The infected leaves ultimately turn brown and wither. As part of our search for potential new natural product-based agrochemicals, we studied this plant pathogen in order to investigate phytotoxic and fungitoxic metabolites produced by the fungus. The causative fungus was isolated from an infected leaf of B. eruciformis, cultured in potato dextrose agar plates and identified via molecular techniques as Pyricularia grisea. A phytotoxic compound was isolated from Czapek-Dox broth liquid culture medium and identified as pyrichalasin H by spectroscopic techniques. Pyrichalasin H was toxic to the fungal plant pathogen Colletotrichum fragariae in a TLC bioautography assay and phytotoxic to two monocot and one dicot plants. This is the first report of antifungal activity of pyrichalasin H against phytopathogens. Pyrichalasin H isolated from Pyricularia grisea, a pathogen infecting B. eruciformis (signal grass) was shown to be phytotoxic and fungicidal to Colletotrichum fragariae.
文摘Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fungal and bacterial pathogens. These pathogens can cause significant quantitative and qualitative losses from harvest to consumption during the handling and storage processes. Chemical fungicides are commonly used but are likely to leave residues on the produce, rendering short shelf-life produce, such as berries, unsuitable for human consumption. Identifying eco-friendly methods to control post-harvest disease is, therefore, of utmost importance. The presence of antifungal constituents in the roots of Poncirus trifoliata extracts was detected by thin layer chromatography-based bioautography. The active constituents were isolated and identified by bioautography assay-guided fractionation using flash chromatography followed by spectroscopic techniques. In this study, xanthoxyletin, demethylsuberosin, dentatin, nordentatin, ponfolin, and clausarin were isolated from the root extracts. The antifungal activity of these compounds was moderate to weak compared to the commercial fungicide captan. This study reports the isolation and identification of natural compounds from Poncirus trifoliata that exhibited antifungal activity against Colletotrichum fragariae and Botrytis cinerea, two major post-harvest pathogens.
文摘Aedes aegypti mosquitoes are responsible for transmission of many viral diseases, such as Zika fever, dengue fever, yellow fever, and chikungunya. Emergence of resistance to currently used pesticides among mosquitoes has increased the importance for the search for novel mosquito control agents. Natural products, particularly plant and microbe derived secondary metabolites, are good sources in the search for such compounds. Ammi visnaga (Lam.) Lamarck is a plant in the Apiaceae family native to North Africa, Europe, and Asia. In the search for environmentally benign and effective insecticides as part of an ongoing joint effort between the USDA (US Department of Agriculture) and the DWFP (Deployed War Fighter Protection) program sponsored by the Department of Defense, we have investigated ethyl acetate extract of A. visnaga seeds. Two furanochromones, khellin and visnagin that exhibited larvicide activity against Aedes aegypti mosquito larvae were isolated from the ethyl acetate extract of the seeds by bioassay-guided fractionation. This is the first report of mosquito larvicidal activity of khellin and visnagin.
