Isolation, Structure Elucidation and Antibacterial activity of Secondary Metabolites from Fungal Phyllosticta capitalensis

Fungal Phyllosticta capitalensis is reported to produce secondary metabolites with important bioactivities, i.e., antibacterial and antioxidant. This is the first time that the fungal P. capitalensis has been isolated from Andrographis paniculata twigs. Secondary metabolites isolation from the extract of the fungus P. capitalensis was performed using several techniques of chromatography, i.e., vacuum liquid chromatography and column chromatography, to obtain two pure compounds (1 and 2). Both compounds were determined for their structures using analyzing data of spectroscopy of NMR and FT-IR. Based on the analysis, compounds 1 and 2 were ergosterol and ergosterol peroxide, respectively. Both steroids were evaluated for their bioactivities following agar dilution method for antibacterial activity. Compound 2 was more active against three bacterial strains than compound 1. Based on the structure-activity relationship, presence of peroxide in C-5 and C-8 increases the bioactivity of ergosterol derivatives. Interestingly, herein, ergosterol peroxide (2) is firstly reported f from fungal P. capitalensis.