Isolasi dan Identifikasi Golongan Senyawa Flavonoida dari Kulit Batang Cemara Angin (Casuarina cunninghamiana Miq.)

Abstract

The isolation and identification of flavonoid compounds from the bark of Casuarina cunninghamiana Miq. have been carried out through several stages, beginning with maceration extraction using methanol as the solvent, followed by partitioning with ethyl acetate and n-hexane. The ethyl acetate extract was then evaporated and analyzed using Thin Layer Chromatography (TLC) to determine the optimal solvent system. Compound isolation was performed using column chromatography with silica gel as the stationary phase and a mixture of chloroform:ethyl acetate (90:10; 80:20; 70:30; 60:40; 50:50; 40:60; 30:70; 20:80; 10:90 v/v) as the mobile phase.The isolated compound was obtained as a yellow orange amorphous solid weighing 5.5 mg, with an Rf value of 0.53 using chloroform:ethyl acetate (30:70 v/v) as the eluent. Based on UV-Visible spectrophotometric analysis in acetone solvent, two major absorption peaks were observed at maximum wavelengths (λmax) of 282 nm (band II) and 315 nm (band I). The FT-IR spectrum showed the presence of hydroxyl (–OH), ketone carbonyl (C=O), aromatic C=C, C-H, C-O, C-O-C, and sp² C-H groups at absorption bands of 3427.08 cm⁻¹, 1695.21 cm⁻¹, 1581.63 cm⁻¹, 1381.03 cm⁻¹, 1284.59 cm⁻¹, 1124.50 cm⁻¹, and 704.02 cm⁻¹. Meanwhile, the ¹H-NMR data showed meta-coupled aromatic doublet proton signals of H-6 (δ 6.9321–6.9279 ppm) and H-8 (δ 6.9561–6.9598 ppm), a doublet of doublet at δ 7.60–7.72 ppm corresponding to H-2′, H-5′, H-3′, and H-6′, and a singlet signal at δ 7.03 ppm corresponding to the H-3 position, which is characteristic of flavones. Overall, the spectroscopic data indicate that the isolated compound belongs to the flavonoid group, specifically a flavone.