PRODUCTION OF BIOACTIVE COMPOUNDS WITH ANTIOXIDANT AND ANTIMICROBIAL POTENTIALS BY ENDOPHYTIC FUNGI FROM RED GRAPE (Vitis vinifera L.) FRUIT PEEL AND SEED

Abstract

Grapes (Vitis vinifera L.) are among the most widely consumed fruits for its asociated health benefits. Endophytic fungi are groups of fungi with very specific ecosystem inside plant tissues and produces varieties of secondary metabolites with medicinal and nutraceutical applications. The present study was undertaken to investigate production of bioactive extracts with antioxidant and antimicrobial potentials activities of endopytic fungi from red grape peel and seed. The antioxidant activity was conducted based on determination of phenolic content, 1,1-diphenyl-2-picrylhydrazyl and hydrogen peroxide free radical scavenging activities. The antimicrobial activity test was conducted based on disc diffusion and broth dilution methods.The result of macro and microscopic characteristics of the endophytic fungal isolates from red grape seed and skin demonstrated the presence of fungal genera including Peniophora sp, Acremonium sp and Chaetomium sp. Chaetomium sp extract has presented significantly the highest phenolic content (11.05mg/ml), and 1,1-diphenyl-2-picrylhydrazyl(87.50%) from red grape seed isolate; phenolic content (9.59mg/ml) and the highest 1,1-diphenyl-2-picrylhydrazyl (89.10%) from red grape fruit skin isolate. Significantly, the highest hydrogen peroxide free radical scavenging activity, HPSA (92.56% &89.14 %) were recorded for Peniophora and Acremonium spp isolates respectively. The highest concentration of the crude extracts (200mg/ml) presented the strongest antibacterial activity with maximum zone of inhibition (31.83mm) for Acremonium sp extract from red grape fruit skin isolate against S. aureus. The maximum zone of inhibition 48.83mm was recorded for Peniophora sp extract of red grape seed isolate against A. versicolor. The endophytic fungal extract presented the strongest antibacterial activity with minimal inhibitory concentration (2.34mg/ml) and corresponding minimum bactericidal concentration (2.34mg/ml) for Acremonium sp(spp) extract from both red grape seed and fruit skin isolates against S. aureus. The strongest antifungal activity with minimal inhibitory concentration(0.78mg/ml) and corresponding minimumfungicidal concentration (0.78mg/ml) was recorded for Peniophora sp extract from red grape seed isolate against A. versicolor. Chaetomium and Acremonium spp strains from red grape seed and peel can be recommended for the production of natural antioxidant compounds. The identified antimicrobial activities suggest the possibility of developing a novel, useful biopesticide based on Chaetomium and Acremonium spp strains for antibacterial drug and Peniophora sp as well as Acremonium and Chaetomium spp strains for antifungal production if strengthened with further studies.