Isolasi dan Identifikasi Golongan Senyawa Flavonoida dari Kulit Batang Kesambi (Schleichera oleasa (Lour.) Oken)

Abstract

The isolation and identification of flavonoid compounds from the stem bark of kesambi (Schleichera oleosa (Lour.) Oken) were carried out through several stages. The research process began with maceration extraction using methanol as the solvent, followed by liquid–liquid partition extraction using ethyl acetate and n- hexane to obtain the ethyl acetate fraction, which was subsequently concentrated. The concentrated ethyl acetate extract was analyzed by thin-layer chromatography (TLC) and further separated using column chromatography with silica gel as the stationary phase and ethyl acetate as the mobile phase in various ratios (90:10; 80:20; 70:30; 60:40; 50:50; 40:60; 30:70; 20:80; 10:90, v/v). The third fraction was further purified by preparative TLC using chloroform–ethyl acetate (10:90 v/v) as the mobile phase. The isolated compound was obtained as a brownish amorphous solid with a mass of 6 mg and an Rf value of 0.55 using chloroform–ethyl acetate (10:90 v/v) as the eluent. Further analysis of the isolated compound by UV–Visible spectrophotometry showed two absorption maxima at wavelengths of 320 nm and 260 nm. Infrared (FT-IR) spectroscopic analysis indicated the presence of O–H stretching vibrations at 3425.58 cm⁻¹, C=O (ketone) stretching vibrations at 1639.59 cm⁻¹, and C–O stretching vibrations at 1259.52 cm⁻¹. The ¹H-NMR spectrum identified the H-2 proton at a chemical shift of 8.54 ppm, which is characteristic of an isoflavone structure. Based on the spectroscopic data, the isolated compound was identified as an isoflavone.