Penentuan Kondisi Terbaik Ekstraksi Antioksidan dari Gambir Menggunakan Metode Permukaan Respon

Abstract

Extract of Uncaria gambier contains phenolic compounds that have function as an antioxidants. Antioxidant content depends on the extraction conditions. To obtain high antioxidant activity of the phenolic compounds, the optimization process was carried out using response surface methodology (RSM) with three variables namely the ratio of solvent (ethyl acetat : ethanol), the ratio of sample : solvent and time of extraction with the antioxidant activity DPPH (IC50) as response. Optimization result showed a quadratic polynomial regression equation of Y = 137.25 + 5.18 (R.solvent) + 24.75 (R.sample) + 11.53 (Time of.extrac) + 6.17 (R.solvent x sample) + 3.14 (Rsolvent x Time of.extrac) + 13.79 (R.sample x Time of.extrac) – 5.44 (R.solvent2) – 15.33 (R.sample2) – 5.42 (Time of.extrac2). The optimum response was achieved at the solvent ratio of ethyl acetat : ethanol = 0,37 : 0,55, ratio of sample : solvent = 1:2 and time of extraction 20 hours. Validation result revealed that the predicted value (IC50 = 82.89 mg/mL) of this model was reasonably close to the experimental result (IC50 = 82,735 ± 0,362 mg/mL). Visual characterization of the extracts indicated that the extracts have different colour in each treatment, depending on the ratio of the solvent used.