Phytochemical screening and antioxidant and antimicrobial activities of crude extracts of different filamentous fungi.

Abstract

Five filamentous fungal strains that grew in different whey-based media under submerged fermentation were investigated for antioxidant properties and phytochemicals. Phytochemical analysis revealed the presence of alkaloids, tannin, flavonoids, glycosides, phenols, saponins, and terpenes in the crude intra- and extracellular ethyl acetate extracts of different strains. All fungal extracts exhibited effective antioxidant activities in terms of TPC, TFC, DPPH, FRAP, ABTS, reducing power, and metal chelating capacity. The activities of intracellular extracts were higher than the extracellular metabolites. Fermentation media with sugar and salt supplementation significantly influenced antioxidant production. Aspergillus niger in glucose-supplemented whey medium was found to exhibit the highest antioxidant properties. The antimicrobial activity of A. niger and Penicillium expansum extracts by microtiter plate assay showed a promising result against some pathogenic bacterial strains. Chromatographic analysis of the fungal extracts revealed the presence of chlorogenic acid, trans-cinnamic acid, ferulic acid quercetin, myricetin, kaempferol, and catechin which are known for their antioxidant properties. Accumulation of nutrients in fungal biomass under constraint environment produces secondary metabolites which has demonstrated efficacy towards alleviation of several degenerative diseases. The antioxidative enriched phytochemicals present in these five different fungal strains will provide a breakthrough in the utilisation of whey as inexpensive source of substrate for the growth of these fungi. Moreover, phytochemicals could be utilized as therapeutic agents in a cost-effective and environmentally friendly manner.