The experiment of activity and stability of antioxidant extracted from Senduduk (Melastoma malabathricum L) leaves at various conditions of concentration, pH values, and temperatures

Melastoma Malabathricum L. (Senduduk) is a type of weed that serves as an antibacterial, antioxidant, anti-inflammatory, anti-cancer, anti-hepatoxic, anti-diabetic and antiseptic to kill or prevent the growth of microorganisms. The purpose of this study is to obtain antioxidant extracts from Senduduk leaves and to test its antioxidants stability in various temperatures and pH. Senduduk leaves are extracted by macerating them with 95% ethanol solvent for 72 hours, and then the solvent is evaporated using a vacuum evaporator at 40 °C. In this experiment, DPPH (1,1-diphenyl-2-pikrihidazil 1,1-diphenyl-2-pikrihidazil) method is used to test the antioxidant activity. Based on this experiment, the extract yield produced from Senduduk leaves was 10.40% (w/w). The results show that the extracts experience an ability to inhibit DPPH free radical formation by 91.734% at 100 ppm concentration. It is known that the antioxidant from the extract of Senduduk leaves is stable at pH 3-5 and at temperature of 70 °C. The IC50 (Inhibition Concentration) value is 55.432 ppm, which proves that the antioxidant properties of the leaves extracts can be classified as strong antioxidant.