PRODUCTION OF BIOACTIVE EXTRACTS WITH ANTIOXIDANT AND ANTIMICROBIAL POTENTIALS OF ENDOPHYTIC FUNGI FROM GARLIC (Allium sativum L.) AND LEEK (Alllium ampeloprasum var. porrum)

Abstract

Bioactive natural compounds isolated from fungal endophytes have been playing a promising role in the search for novel drugs and becoming an inspiring source for researchers due to their enormous structure diversity and complexity. Therefore, the present study was undertaken to assess antioxidant and antimicrobial activities of endophytic fungi from garlic bulbs and leek leaves. The study involved garlic (Allium sativum) bulb and leek (Alllium Ampeloprasum var. porrum) leaf samples collection. The garlic bulb and leek samples were surface sterilized before used as endophytic fungal culture. Fungal culturing and identifications of genera were made according to fungal identification manual. Then, the crude endophytic fungal extracts were prepared using methanol as a solvent. The antioxidant activity was conducted based on the quantification of phenolic content, DPPH and hydrogen peroxide scavenging activities. The antimicrobial activity test was tested based on disc diffusion method for determination of diameter of inhibition zone, and broth dilution method for determination of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC). Alternaria sp extract from leek leaf isolate has presented significantly the highest phenolic content (11.50mgGAE/mg) and DPPH (17.32%) followed by Fusarium sp with phenolic content (10.02mgGAE/mg) and DPPH (15.12%). Significantly, the highest hydrogen peroxide free radical scavenging activity, HPSA (57.51%) was recorded for Penicillium sp extract followed by Trichoderma sp extract with HPSA content (30.40%). The highest concentration of the crude extracts (200mg/ml) presented the strongest antibacterial activity with maximum zone of inhibition (24.93mm) was recorded for Fusarium sp extract from leek leaf isolate against E. coli. The maximum zone of inhibition 33.60mm was recorded for Trichoderma sp extract from garlic bulb isolate against A. versicolor whilst the minimum zone of inhibition diameter (14.37mm) was recorded for Cladosporium sp extract against A.niger. The endophytic fungal extract presented the strongest antibacterial activity with MIC (0.78mg/ml) and corresponding MBC (0.78mg/ml) for Fusarium sp extract from leek leaf isolate against both S. aureus and E. coli. The strongest antifungal activity with MIC (0.78mg/ml) and corresponding MFC (0.78mg/ml) was recorded for Trichoderm sp extract of garlic isolate against A. versicolor. It can be concluded from the result of the present study that the leek fungal extracts had better antibacterial activity while the garlic fungal extracts had superior antioxidant and antifungal activities