Uji Aktivitas Antioksidan Fraksi Etil Asetat dan Identifikasi Golongan Senyawa Flavonoida dari Kulit Buah Aren (Arenga Pinnata (Wurmb) Merr)

Abstract

Isolation and identification of flavonoid compounds from the skin of sugar palm fruit (Arenga pinnata (Wurb.) Merr) were carried out through maceration extraction using methanol solvent, followed by partition extraction using ethyl acetate and n-hexane. Separation was carried out by column chromatography using chloroform: ethyl acetate mobile phase through increasing polarity in stages. Fraction IV (vial 151–290) was purified by preparative TLC using n-hexane: ethyl acetate (30:70 v/v), producing a yellow amorphous solid of 13 mg with an Rf value of 0.60. The results of UV-Vis spectroscopy analysis showed two absorption peaks at wavelengths of 337 nm and 269 nm. The FT-IR spectrum showed the presence of hydroxyl groups (-OH), C=O ketone, C-H sp², and C-O. Analysis with (1H-NMR) showed the presence of typical protons of flavonoids of the flavone group, namely the H-3 proton at a shift of 0.5 - 0.8 and the presence of protons at positions, H-6, H-8, H-2', H-3', H-5', and H-6'. Based on the results of spectroscopic characterization, the compound was identified as a flavone group. The antioxidant activity test of the ethyl acetate fraction using the DPPH method obtained an IC50 of 69.43 ppm, indicating that the skin of the sugar palm fruit is able to ward off free radicals as a source of natural antioxidants.