Isolation and secondary metabolites identification of endophytic fungi from plants in the Beibu Gulf
Objective The endophytic fungi of three medicinal plants in the Beibu Gulf were studied,and the secondary metabolites of Spegazzinia sp.MDCW-573 from Lygodium microphyllum(Cav.)R.Br.were also investigated.Methods The endophytic fungi Lygodium microphyllum(Cav.)R.Br.,Melastoma candidum D.Don and Alternanthera sessilis(L.)R.Br.ex DC.were isolated by the ten-fold dilution method.The secondary metabolites of Spegazzinia sp.MDCW-573 from Lygodium microphyllum(Cav.)R.Br.were isolated and purified.The structures were identified by NMR,MS and ECD methods.The antioxidant activity of the compounds was detected by the DPPH method,and the antibacterial activity was tested by the micro-double dilution method.Results A total of 171 strains of endophytic fungi were isolated from these three plants.Three isocoumarin compounds were isolated from the secondary metabolites of Spegazzinia sp.MDCW-573,among which compound 1 was a new compound.Compounds 1 and 3 displayed antibacterial activitiesagainst MRSA with the same MIC value of 128 μg/mL.The MIC of compound 1 against Staphylococcus aureus was 128 μg/mL.Conclusion Compounds 1~3 were isolated from the secondary metabolites of Spegazzinia sp.for the first time.Compound 1 is a new compound,and compounds 1 and 3 showed antibacterial activity.
Beibu Gulf of GuangxiEndophytic fungiSpegazzinia sp.Secondary metabolites