UJI AKTIVITAS ANTIOKSIDAN PENANGKAP RADIKAL SENYAWA FLAVONOID DAUN KEPEL (Stelechocarpus burahol Bl. Hool f. & Th)

Daun Kepel ( Stelechocarpus burahol (Bl.) Hook f. & Th.) is a plant have some biological activities and traditionally medicine for uretic acid and diuretic. Kepel leaves has content of flavonoid and polyphenol that make antioxidant activity. Making a simplisia extract of kepel arranged by infundation using ethanol solutes, which then is concentrated unit obtaining solid extracts. Antioxidant is a compound that has ability to inhibit oxidation process or block free radical, so an atom that has no combined electron (radical) bunch to another radical until stable. Antioxidant activity is determined by DPPH method and is measured using UV-Vis spectrophotometer until obtaining the proportion of EC50. EC50 is defined as an effective concentration essence that can decrease 50% of absorption compared to control solution of DPPH.the result of this research obtained that EC50 proportion of ethanol extract 27,6133 µg/ml, and EC50 proportion of rutin 5,8447 µg/ml (in ethanol). It can say antioxidant activity ethanol extract is more few from rutin. Keywords: Antioxidant, DPPH method, free radical, Stelechocerpus burahol (Bl.) Hook f. & Th.