Isolasi dan Identifikasi Golongan Senyawa Flavonoida Dari Buah Jambu Leci (Psidium cattelainum Sabine)

Abstract

Flavonoid compounds were isolated and identified from the fruit of the guava (Psidium Cattleianum Sabine). The isolation process involved methanol solvent maceration extraction until a negative FeCl3% was obtained. This was followed by partition extraction of the concentrated ethyl acetate extract using n-hexane as the solvent. Isolation testing was conducted using thin-layer chromatography (TLC) and column chromatography. Thin-layer chromatography tested the concentrated methanol extract, while column chromatography was utilized to separate the components within the extract mixture. The eluent ratios in this chromatography employed chloroform:ethyl acetate (90:10; 80:20; 70:30; 60:40) v/v as the mobile phase and silica gel as the stationary phase. Preparative chromatography was carried out using chloroform:methanol (20:80) v/v as the eluent, resulting in several fractions. The resulting fractions underwent repeated TLC testing to identify those with the same Rf values. Fractions with identical Rf values in the range of 266-355 nm were purified, yielding 5 mg of an amorphous yellow substance with a final Rf value of 0.70 after preparative chromatography. UV-Vis spectroscopy analysis with methanol solvent revealed two absorption peaks at wavelengths (λmax) of 350 nm and 280 nm. The FT-IR spectrum indicated the presence of O-H, C-H sp3 stretching, C=O ketone, C=C aromatic, C-H sp3 bending, C-O-C, and C-H sp2 bending out-of-plane at 3427.51; 2958.80; 1728.22; 1602.85; 1382.96; 1280.73; and 742.59 cm⁻¹, respectively. The 1H-NMR spectrum showed the presence of protons H-2' and H-6', H-3' and H-5', H-6, H-8, and CH3 from 3-OCH3. Based on the data analysis, the results of the isolation suggest that the isolated compound is a flavonoid of the flavonol class."