AKTIVITAS ANTIOKSIDAN, TOTAL FENOL, FLAVONOID, KAROTENOID BARI BERBAGAI EKSTRAK BIJI KACANG MERAH (PHASEOLUS VULGARIS L.) DAN ISOLASI SENYAWA ANTIOKSIDAN

• Main Author: Puspanegara, Girinanda
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/64774
• Institution: Institut Teknologi Bandung

One of the causes of humans' disease is free radicals. Humans are exposed free radicals from air pollution, and those contained in food. Diseases caused by free radicals are cancer and cardiovascular disease. To prevent and cure the diseases caused by free radicals, antioxidant intake is needed. Red kidney bean (Phaseolus vulgaris L.) seed, that is consumed as food, contains some antioxidant compounds, such as phenols and flavonoids. The objectives of this research are to analyze antioxidant activity of various extracts of red kidney bean by DPPH method, determine IC50, total phenolic, total flavonoid, and carotenoid content of each extract, analyze correlation between total phenolic content, total flavonoid content, total carotenoid content and DPPH scavenging activity, and isolate antioxidant compound from red kidney bean seed. Crude drug was extracted by reflux method using three different solvents with increasing polarity, which are n-hexane, ethyl acetate, and ethanol. For each extract, monitoring by thin layer chromatography (TLC), DPPH (2,2-dipheny1-1-picrylhydrazil) scavenging activity, IC50 determination, total phenolic, flavonoid and carotenoid content were performed. Ethanol extract was fractionated by vacuum liquid chromatography (VLC). Fraction was subfractionated by classic column chromatography. Subfraction purity was performed using TLC with three mobile phases with different polarity. Antioxidant compound was characterized using specific spot visualizer, UV-visible spectrophotometry and two dimensional paper chromatography. Crude drug of red kidney bean seed contained flavonoid, phenol, quinone, saponin, steroid-triterpenoid, and terpenoid groups. Ethanol extract of red kidney bean seed (density of 1% extract 0.81 g/mL) showed the highest DPPH scavenging activity (45.33%), with DPPH scavenging IC50 225,9 ppm, total phenolic content 1.50 g GAE/100 g, total flavonoid content 1.63 g QE/100 g, total carotenoid 0.28 g BET/100 g. DPPH scavenging activity of ethanol extract was significantly different with ethyl acetate and n-hexane extract (p < 0.05). Antioxidant compound G was isolated from ethanol extract. Antioxidant activity of ethanol extract of red kidney bean seed was higher than and significantly different with that of ethyl acetate and n-hexane extract. Total phenolic, flavonoid, carotenoid content in ethanol extract of red kidney bean seed had no significant correlation with DPPH scavenging activity. Antioxidant compound G that was isolated from ethanol extract was expected to be flavonc aglycone that had free OH group in C7, without free OH in C5.