ISOLATION OF AN ANTIOXIDANT COMPOUND FROM ETHYL ACETATE EXTRACT OF KERSEN (MUNTINGIA CALABURA L.) LEAVES

• Main Author: Nur Rizkiyati, Halimah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/45489
• Institution: Institut Teknologi Bandung

Free radicals are reactive compounds that have unpaired electrons, can oxidize proteins, fats, even DNA of cells and initiate degenerative diseases. Excessive amount of free radicals in the body can also cause cell damage and even cell death. Antioxidants are compounds that can inhibit the oxidation reaction by donating electrons and change free radicals into non-radical compounds. Based on several studies, the plant of kersen (Muntingia calabura L.) is known to have antioxidant activities. In addition, people used the leaves to treat various diseases. This study aimed to determine IC50 of DPPH (2,2-diphenyl-1- picrylhydrazyl) scavenging activity, total phenolics, total flavonoids, and total carotenoids of each extracts, to test the correlation of total phenolics, total flavonoids and total carotenoids against IC50 DPPH scavenging activity and to isolate the antioxidant compounds from the leaves extract. Crude drug of the leaves was extracted by reflux using three solvents with increasing polarity, i.e. n-hexane, ethyl acetate and ethanol. All extract were monitored by thin layer chromatography (TLC). IC50 of DPPH scavenging activity, total phenolics, flavonoids, and carotenoids content of each extract were determined by ultraviolet-visible spectrophotometry, as well as their correlation with IC50 of DPPH scavenging activity. The ethyl acetate extract was fractionated by column chromatography, continued with subfractionated of fraction 40-53 using TLC preparative. The subfraction was purified and tested for its purity by TLC, followed by characterization of isolate. Crude drug of the leaves contained flavonoids, quinones, phenolic compound, alkaloids, tannins, and steroids/triterpenoids. The ethanol extract of the leaves showed the highest antioxidant activity with the lowest IC50of 0.38 µg/mL, the highest phenolic total of 18.07 g GAE/100 g and the highest flavonoid total of 6.40 g QE/100 g. The n-hexane extract had the highest carotenoid total of 4.59 g BE/100 g. All extracts have high antioxidant activity by DPPH method, with significant negative correlation to total phenolics and flavonoids content (p<0.01). Phenolic and flavonoid compounds were the major contributor in antioxidant activity of the leaves. An isolated antioxidant compound H was presumed to be a flavanone aglycone having free OH groups in C-5 and C-7.