Leaves of jambu air (Syzygium samarangense L.) has been used by local residents as medicine for various diseases caused by free radical agents in human's body. This study aims to find a new source of antioxidants from medicinal plants and their endophytic fungi Syzygium samarangense leaves was fractionated by maceration method using gradient solvent i.e. n-hexane, ethyl acetate, and methanol. The antioxidant activity of the leaf fractions was determined using 1,1diphenyl-2-picryl hydrazyl

more »

... method. The chemical compound was isolated from active fraction by chromatographic techniques and their chemical structure was identified using spectroscopy techniques. The endophytic fungi was isolated from S. samarangense leaves and continued to cultivation in potato-dextrose broth (PDB) medium for four weeks. The medium was extracted using ethyl acetate and determined its antioxidant activity. Fungi's isolate with highest activity was analyzed to identify its molecular. Ethyl acetate fraction of S. samarangense leaves showed highest antioxidant activity. Spectroscopy analysis result concluded the isolated compound is 5,7-dihydroxy-6,8-dimethyl flavanone. Four endophytic fungi had been isolated form S. samarangense leaves. Antioxidant activity test showed that ethyl acetate extract of endophytic fungi BJA-1 has the highest value. Molecular identification of BJA-1 shows high homology with Lasiodiplodia venezuelensis strain CBS 129753.