Isolasi Dan Identifikasi Golongan Senyawa Flavonoida dari Kulit Batang Rambai (Baccaurea motleyana Müll. Arg)

Abstract

Flavonoid compounds were successfully isolated from rambai (Baccaurea motleyana) stem bark through maceration-methanol extraction, followed by partition extraction using ethyl acetate and n-hexane solvents. The result was an extract in the ethyl acetate phase, which was then evaporated. The concentrated ethyl acetate extract was initially characterized by TLC, then purified via gradient column chromatography (silica gel; chloroform-ethyl acetate 90:10→10:90). The fourth fraction of the column results was then purified using Preparative TLC with a chloroform:ethyl acetate (20:80) solvent system. The isolate obtained was a brownish-yellow amorphous solid (4.8 mg) with an Rf value of 0.64 on TLC using a chloroform:ethyl acetate (20:80) solvent system. Further characterization was carried out using UV-Vis spectrophotometry technique showing 2 bands, namely the first band with a wavelength of 340 nm with an absorbance of 0.2278 and band II with a wavelength of 281 nm with an absorbance of 0.2564. Infrared spectrophotometer analysis (FT-IR) with the results obtained the presence of functional groups O-H Stretching with a frequency (in cm⁻¹) 3448.72 cm-1, C-H sp3 Stretching with a frequency (in cm⁻¹) 2924.09 cm-1, C=O ketone Stretching with a frequency (in cm⁻¹) 1660.71 cm-1, C=C aromatic Stretching with a frequency (in cm⁻¹) 1616.35 cm-1, C-H sp3 Bending with a frequency (in cm⁻¹) 1440.83 cm-1, C-O Stretching with a frequency (in cm⁻¹) 1296.16 cm-1, C-H sp2 Bending out-of-plane with a wavelength of 873.59 cm-1. The 1H-NMR spectrum identified a characteristic H-3 proton signal at a chemical shift of δ 6.55 ppm for the flavone compound. Spectroscopic data concluded that the isolated compound belongs to the flavone group, which is a subclass of flavonoids.