Isolasi dan Identifikasi Golongan Senyawa Flavonoida Serta Uji Aktivitas Antibakteri dari Kulit Batang Penda Emas (Xanthostemon Chrysanthus (F.Muell.) Benth.)

Abstract

The flavonoid compound had been isolated from stem bark of golden penda (Xanthostemon chrysanthus (F.Muell.) Benth.). Isolation was carried out by maceration extraction method with methanol and methanol extract was re-extracted with ethyl acetate repeatedly until negative to FeCl3 5%. Ethyl acetate extract was concentrated and reconstituted with methanol and partitioned with n-hexane until the n-heksane layer was clear. The methanol extract was analyzed by thin layer chromatography and separated by column chromatography with a stationary phase of silica gel and mobile phase of eluent chloroform : methanol (90:10; 80:20; 70:30; 60:40) v/v. The compound obtained from fraction 81-104 was purified by preparative thin layer chromatography to produce yellow amorphous solid of 6 mg with Rf = 0,35 using chloroform : ethyl acetate (30:70) v/v as eluent and Rf = 0,53 using eluent chloroform : methanol (80:20) v/v. Based on the analysis of UV-Vis spectrum with methanol solvent which showed wavelength (λmax) 313 and 280 nm. FT-IR spectrum showed the presence of OH, stretching sp3 C-H, C=O ketone, C=C aromatic, bending sp3 C-H, C-O, C-O-C and C-H sp² bending out-of-plane. The Proton Nucleus Magnetic Resonance Spectrum ( 1H-NMR) showed the presence of H-2’, H-6’, H-3’, H-5’, H-8, H-2, H-3, OH, CH2 from 7-OCH2CH3, CH3 from 7-OCH2 CH3 and CH3 from 6- CH3 protons. Based on the interpretation of spectroscopy data shows that the isolated compound is dihydroflavonol group. It was found that total flavonoids from the stem bark of golden penda were strong against Gram-positive and negative bacteria at concentration 25,50 and 75mm and moderate against bacteria at concentration 10 mg/mL. Evidenced by the clear zone produced against Staphylococcus aureus bacteria of 10,3; 11,0; 12,7; and 16,4 mm. Likewise with the resulting clear zone against Escherichia coli bacteria of 8,6; 12,4; 14,2; and 15 mm.