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
Marine microorganisms have long been recognized as potential sources for drug discovery.Griseofulvin was one of the first antifungal natural products and has been used as an antifungal agent for decades.In this study,...Marine microorganisms have long been recognized as potential sources for drug discovery.Griseofulvin was one of the first antifungal natural products and has been used as an antifungal agent for decades.In this study,12 new griseofulvin derivatives[(±)-1-2,(+)-3,(±)-4,10-12,and 14-15]and two new griseofulvin natural products(9 and 16)together with six known analogues[(-)-3,5-8,and 13]were isolated from the mangrove-derived fungus Nigrospora sp.QQYB1 treated with 0.3%NaCl or 2%NaBr in rice solid medium.Their 2D structures and absolute configurations were established by extensive spectroscopic analysis(1D and 2D NMR,HRESIMS),ECD spectra,computational calculation,DP4+analysis,and X-ray single-crystal diffraction.Compounds 1-4 represent the first griseofulvin enantiomers with four absolute configurations(2S,6'S;2R,6'R;2S,6'R;2R,6'S),and compounds 9-12 represent the first successful production of brominated griseofulvin derivatives from fungi via the addition of NaBr to the culture medium.In the antifungal assays,compounds 6 and 9 demonstrated significant inhibitory activities against the fungi Colletotrichum truncatum,Microsporum gypseum,and Trichophyton mentagrophyte with inhibition zones varying between 28 and 41 mm(10μg/disc).The structure-activity relationship(SAR)was analyzed,which showed that substituents at C-6,C-7,C-6'and the positions of the carbonyl and double bond of griseofulvin derivatives significantly affected the antifungal activity.展开更多
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funded by the Guangdong Marine Economy Development Special Project(GDNRC[2022]35,GDNRC[2023]39)the National Natural Science Foundation of China(U20A2001,42276114).
文摘Marine microorganisms have long been recognized as potential sources for drug discovery.Griseofulvin was one of the first antifungal natural products and has been used as an antifungal agent for decades.In this study,12 new griseofulvin derivatives[(±)-1-2,(+)-3,(±)-4,10-12,and 14-15]and two new griseofulvin natural products(9 and 16)together with six known analogues[(-)-3,5-8,and 13]were isolated from the mangrove-derived fungus Nigrospora sp.QQYB1 treated with 0.3%NaCl or 2%NaBr in rice solid medium.Their 2D structures and absolute configurations were established by extensive spectroscopic analysis(1D and 2D NMR,HRESIMS),ECD spectra,computational calculation,DP4+analysis,and X-ray single-crystal diffraction.Compounds 1-4 represent the first griseofulvin enantiomers with four absolute configurations(2S,6'S;2R,6'R;2S,6'R;2R,6'S),and compounds 9-12 represent the first successful production of brominated griseofulvin derivatives from fungi via the addition of NaBr to the culture medium.In the antifungal assays,compounds 6 and 9 demonstrated significant inhibitory activities against the fungi Colletotrichum truncatum,Microsporum gypseum,and Trichophyton mentagrophyte with inhibition zones varying between 28 and 41 mm(10μg/disc).The structure-activity relationship(SAR)was analyzed,which showed that substituents at C-6,C-7,C-6'and the positions of the carbonyl and double bond of griseofulvin derivatives significantly affected the antifungal activity.
