Antioxidant activity of endophytic fungi from stem bark of Jambu nasi-nasi (Syzygium zeylanicum) and its host extracts

Jambu nasi-nasi (Syzygium zeylanicum) has a long ethnobotanical history and is a promising candidate to obtain secondary metabolites with high biological activity from its endophytic fungi. The content of secondary metabolites of this genus has various biological activities such as antioxidants. There was a continuous and urgent need for researchers to find new antioxidant compounds with potential bioactive compounds. This study aimed to compare the antioxidant activity of endophytic fungi from the stem bark of S. zeylanicum with the antioxidant activity of the host plant organs. Isolation of endophytic fungi was carried out by sterilizing the surface of the plant organs and then growing them on PDA medium. Endophytic fungi extraction using ethyl acetate solvent by growing fungal spores into PDB medium and incubating for 30 days. Ethyl acetate extract from isolated endophytic fungi was investigated for antioxidant activity using the 1,1diphenyl-2-picryl hydrazyl (DPPH) method. Endophytic fungi isolated from the stem bark obtained 2 isolates, namely MB1 and MB2. The results of the antioxidant test in reducing DPPH free radicals obtained the Inhibitory concentration (IC50) of ethyl acetate extract for MB1 isolates of 28.58 µg/ml and MB2 isolates of 17,44 µg/ml. Both isolates were categorized as having very strong antioxidant activity. While the stem bark of the host plant has an antioxidant activity of 128,64 µg/ml with a medium category. Based on the results of the study, it can be concluded that the ethyl acetate extract of endophytic fungi has stronger antioxidant activity than the host plant.