Analysis of secondary metabolites present in endophytic fungi from selected invasive plants as potent antioxidants and antibacterial agents

Abstract

Prosopis juliflora, Acacia auriculiformis, and Annona glabra are three of the well-established invasive plants in Sri Lanka. Symbiotic relationships of endophytic fungi with these plants may produce secondary metabolites with high medicinal values. Thus, this study was aimed at the identification of endophytic fungi and extracting secondary metabolites of fungi, with biological importance. Plant roots were collected from the Southern province and isolation of endophytic fungi was performed using standard procedures. Twelve endophytic fungi were isolated and identified. Five species (Penicillium sp1, Penicillium sp2, Aspergillus sp1, Aspergillus sp2, and Aspergillus sp3) were selected for further analysis. Qualitative phytochemical analysis of ethyl acetate crude extracts (scale up by batch culturing) of fungi showed the presence of alkaloids, phenols, tannins, terpenes, flavonoids, saponins, and sterols in all extracts. Quantitative analysis of total flavonoids and total phenolic content was also performed following standard protocols. The antioxidant capacity of extracts was investigated using DPPH and FRAP assay with ascorbic acid and FeSO4.7H2O as the standards respectively.