Sri Atun, Sri Handayani, Luthfi Fitri Frindryani
The aims of this study are to identify and to analyze antioxidant activity of bioactive compounds in ethanol extract of temukunci (Boesenbergia rotunda) rhizome. This research method was carried out by maceration of 3 kg dryed powder of B. rotunda in ethanol. The extract was concentrated using a vacuum evaporator. White crystals obtained from ethanol extract further recrystallized to produce as much as 80 mg of pure compound. Identification of pure compound was obtained using UV-Vis, IR, and 1H-NMR. The antioxidant activity of ethanol extracts, pure compounds, and ascorbic acid (positive control) were obtained using DPPH (2,2-diphenyl-1-picrylhydrazyl) method. The UV-Vis spectra showed λmax 287.40 and 214.20 nm, the IR spectra showed absorption C=C aromatic group at 1571.66 cm-1, C=O carbonyl at 1639.37 cm-1 and CO at 1153.35 cm-1. 1H-NMR spectra showed a group monosubtituted benzene, benzene tetrasubstituted, proton of hydroxyl group, proton of methoxyl group, one proton oxyalkyl, and two protons alkyl. The spectroscopic data showed the compound is pinostrobin (5-hydroxy-7-metoxyiflavanone). The antioxidant activity (IC50) of the ethanol extracts from B. rotunda rhizome, pinostrobin, and ascorbic acid (positive control) were 92.6; 62.84; and 3.7 μg/mL repectively. The study showed that the ethanol extract of B. rotunda rhizome and bioactive compounds have high antioxidant activity, but their activity lower than ascorbic acid. © 2017 Author(s).
Departmen of Chemistry Education, Faculty Mathematics and Natural Science, Universitas Negeri Yogyakarta, Indonesia, Jl. Colombo No. 1, Depok, Sleman, Yogyakarta, 55281, Indonesia
