Antioxidant Activity Test Of Kepel Leaf Extract Gel Preparation (Stelechocarpus Burahol) With Variations Of Carbopol 940 Concentration Using The Dpph Method

Abstract

Kepel leaves (Stelechocarpus burahol) have the potential as a source of natural antioxidants. This study aims to determine the effect of variations in Carbopol 940 concentration on the physical quality, stability, and antioxidant activity of kepel leaf extract gel. The extract was obtained through maceration using 96% ethanol and formulated into a gel with variations in Carbopol 940 concentrations of 1%, 1.5%, and 2%. Evaluations included organoleptic, homogeneity, pH, spreadability, adhesiveness, viscosity, physical stability using a cycling test, and antioxidant activity using the DPPH method. Data were analyzed using SPSS. The results of the kepel leaf extract study showed very strong antioxidant activity with an IC50 value of 10.14 ± 0.89 ppm. All gel formulas met the physical quality requirements of the preparation. Increasing the concentration of Carbopol 940 decreased the pH value and spreadability, but increased the viscosity. The formula containing 1.5% Carbopol 940 showed the best physical characteristics and stability. The antioxidant activity of the gel preparation showed IC50 values ​​of 226.61 ± 7.68 ppm (F1); 230.96 ± 3.11 ppm (FII); and 241.56 ± 4.66 ppm (FIII), respectively, where the entire formula was classified as a very weak antioxidant.