Four Higher Fungal Secondary Metabolites And Their Biological Activities

Higher fungi are rich in resources and contain novel secondary metabolites with remarkable biological activit ies.They are a treasure trove in the search for lead compounds of new drugs or pesticides.With the development of modern science and technology,the study of higher fungi has received more and more attention,and the bioactive compounds have great potential and promising prospects in the screening of drug lead compounds.The investigated four higher fungi were Phellinus robustas,Trametes pubescens,Rhodophyllus rhodopolius and Xylaria longipes.34 compounds,including two new skeleton ones,were isolated from the above mentiond four species by silica gel,reversed-phase(RP),and Sephadex LH-20 column chromatograph yies.Their structures were established on the basis of extensive spectroscopic analysis including 1D,2D NMR spec troscopy,MS,UV and IR spectroscopic methods,as well as ECD chemical calculations.The type of isolated compounds includes new skeleton sesquiterpenes,steroids,benzene ring derivatives,fatty acids,as well as other small molecules.From the ethyl acet ate extracts of the fruiting body of Phellinus robustas,ten compounds were isolated and identified as phellinus A(1),phellinus B(2),(22E,24R)-5?,8?-epidiox y-ergosta-6,22-diene-3?-ol(3),(22E,24R)-5?,8?-epidiox y-ergosta-6,9(11),22-trien-3?-ol(4),(22E,24R)-ergosta-5,7,22-trien-3?-ol(5),(22E,24R)-ergosta-7,22-diene-3?-ol(6),vanillin(7),dibutyl phthalate(8),ethyl palmitate(9),9(Z),12(Z)-octadecanedioenoic acid(10).Compounds 1-2 are two sesquiterpenes with novel 5/6 bicyclic skeleton.The activity test results showed that the ethanolic extract of its fruiting bodies exhibited weak antitumor activity against HL-60 cells,SMMC-7721 cells,and A-549 cells with IC ₅₀ values of19.36,27.58,17.08?g/m L,respectively.The ethyl acetate extract of its fruiting body showed some scavenging activity against DPPH,ABTS,and hydrox yl radicals with IC ₅₀ values of 0.471,0.085 and 2.407 mg/m L,respectively.Compound 3 has strong scav enging effect on hydrox yl radical,with an IC₅₀ value of 0.355 mg/m L,which is better than the positive control Vc.From the ethyl acetate extracts of the fermentation broth of Trametes pubescens,ten compounds were isolated and identified as 2(S)-3'-hydrox ybutan-2'-yl-2-hydrox ypropanoate(11),3-hydrox ybutan-2-yl acetate(12),?-sitosterol(13),ergosta-7,22-dien-3?-yl linoleate(14),9(Z),12(Z)-octadecanedienic acid(15),succinic acid(16),methyl stearate(17),(E)-heptadecane-9-enoic acid(18),palmitic acid(19),2,3-butanediol(20).The ethyl acetate extract of its fermentation broth had certain scavenging activities on DPPH,ABTS and hydrox yl radical,and the IC ₅₀ values were2.532,1.386 and 3.946 mg/m L,respectively.Compound 11 showed strong DPPH scavenging effect and better than the positive control Vc with an IC₅₀value of 0.009 mg/m L.Compounds 15?16?17?18 had good scavenging activity against hydrox yl radical,and the IC ₅₀ values were 0.235,0.266,0.038 and 0.735 mg/m L,respectively,which was better than the positive control Vc.The ethyl acetate extract from the fermentation broth of thrombopora villosa had good antibacterial activity against Staphylococcus aureus,methicillin resistant Staphylococcus aureus(MRSA)and Escherichia coli.The minimum inhibitory concentration(MIC)values were3.125,0.781 and 1.562 mg/m L and the minimum bactericidal concentration(MBC)values were 6.25,1.561 and 3.125 mg/m L,respectively.The MIC values of compounds 15 and 17 on Staphylococcus aureus were 0.538 and1.012 mg/m L,MBC values were 1.075 and 2.025 mg/m L,respectively.The inhibition rates of compounds 15 and 17 on MRSA were 19.41%and 82.72%respectively.From the ethyl acetate extracts of the fermentation broth of Rhodophyllus rhodopolius,ten compounds were isolated and identified as 2-hydrox ypropionic acid(21),methyl linoleate(22),oleic acid(23),9(Z),12(Z)-octadecanedioenoic acid(24),p-hydrox yphen ylethanol(25),ethyl 4-hydrox yphen ylacetate(26),palmitic acid(27),(22E,24R)-5?,8?-epidiox y-ergosta-6,22-diene-3?-ol(28),stigmasterol(29),?-sitosterol(30).The ethyl acetate extract of its fermentation broth had moderate scavenging activities on DPPH,ABTS and hydrox yl radical,and the IC ₅₀values were 2.054,4.851and 0.203 mg/m L,respectively.From the ethyl acetate extracts of the fermentation broth of Xylaria longipes,four compounds were isolated and identified as dibutyl phthalate(31),methyl stearate(32),(3R,4R)-3,4-dihydrox y-3-methyl-pentan-2-one(33),(3?S,4?R)-3?,4?-dihydrox y-3?-methyl-pentan-2?-one(34).The ethyl acetate extract of its fermentation broth had weak scavenging activities against DPPH,ABTS and hydrox yl radical,and the IC ₅₀ values were 0.535,0.671 and 40.692 mg/m L,respectively.