Kapasitas Stabilisasi Radikal Bebas dan Kelasi Ion Metal Ekstrak Air Daun Vernonia amygdalina Del.

The medicinal plant of Vernonia amygdalina known as “Daun Afrika” is an original plant of Afrika. The plant is used for healing malaria, diabetes, digestion disorder, and sexually transmitted diseases. The objectives of the study were to evaluate the antioxidant potency of “Daun Afrika” water extracts including phenolic compound contents, the capacities of stabilizing free radicals by transferring hydrogen atoms, and chelating metal ions by transferring electrons at varied extract concentrations. The Extraction process of bioactive compounds used infusion method with hot water 90oC for 30 minutes. Determination of antioxidant properties of extracts including phenolic compound contents with Folin-Ciocalteu method, free radical stabilization capacities using DPPH (1,1-Diphenyl-2picrylhydrazyl) free radical scavenging method, and metal ions chelation using ferrous ions chelation method. The result showed that water extracts of “Daun Afrika” at a concentration of 0.1-0.5% had phenolic compounds of 18,81-69.89 μg EAG/ml, DPPH free radical scavenging capacities about 20,99-41,98% and ferrous ions chelation activity of 8,28-40,71%. The water extract of “Daun Afrika” had less potential as a source of natural antioxidant for stabilizing free radicals but it was very effective to chelate metal ions prooxidant