EFFECT OF CULTURE MEDIA AND CULTURE TIME ON ANTIOXIDANT AND ALPHA-GLUCOSIDASE INHIBITORY ACTIVITIES OF METHANOL EXTRACT FROM Graphis handelii MYCOBIONT

This study investigated the influence of culture media and culture time on the antioxidant and a-glucosidase inhibitory activities of the methanol extract obtained from the mycobiont of Graphis handelii. Different culture media, including MIX, PDA, and SAB4%, were employed to culture the mycobiont, and the biomass was harvested during different culture periods (4, 8, and 12 weeks). The resulting methanol extracts were evaluated for their free radical scavenging and alpha-glucosidase inhibitory activities. The results showed that all nine methanol extracts exhibited antioxidant capacity through DPPH scavenging in vitro assay. Among them, the extract derived from the mycobiont cultured in MIX medium for four weeks had the most vigorous activity, scavenging 86.52% DPPH at the concentration of 200 µg/mL, and its IC50 value was determined to be 107.10 ± 5.39 µg/mL. In contrast, all extracts showed weak or no α-glucosidase inhibitory activities. The findings showed that the culture medium composition impacts the production of antioxidant compounds in the mycobiont. This research holds significance for optimising cultivation conditions to maximise the biological potential of Graphis handelii mycobiont extracts, particularly for antioxidant activities.