KARAKTERISASI SENYAWA FENOLIK DARI BIJI BUAH RAMBUTAN (Nephelium lappaceum L.)

Abstract

Rambutan seeds are one of the waste produced from rambutan that is potential to be used in the food and pharmaceutical fields because it is rich in nutrients and secondary metabolites. This research was carried out to characterize phenolic compounds from the ethyl acetate fraction by using chromatographic methods, phytochemical tests, and ¹H-NMR analysis. The isolate was obtained as white powder with 6.2 mg and gave positive sign for phenolic by phytochemical test. ¹H-NMR spectrum data (CD₃OD, 500 MHz) showed the chemical shift characteristic of coumarin compounds at δ_H (ppm): 7.82 (1H, d, J= 8.3 Hz), 7.39 (1H, d, J= 7.55 Hz), 6.73 (1H, d, J= 8.05 Hz), and 5.61 (1H, d, J= 7.55 Hz), an anomeric proton at δ_H 4.8-5 ppm, the characteristics of the methyl group of L-rhamnose sugar at δ_H 1.29 ppm and other sugar protons at δ_H 3-4 ppm. Based on the ¹H-NMR analysis and comparison with literature, a phenolic compound obtained from rambutan (Nephelium lappaceum L.) seeds is                            7-O-β-L-rhamnose-8-hydroxycoumarin or 8-O-β-L-rhamnose-7-hydroxycoumarin.