Antioxidant activity and chemical compositions of essential oil and ethanol extract of Chuanminshen violaceum

Abstract

The essential oil, ethanol extract and its solvent fractions, petroleum ether fraction (PEF), chloroform fraction (CF), ethyl acetate fraction (EAF), n-butanol fraction (BF), and aqueous fraction (AF), from Chuanminshen violaceum were measured for the evaluation of antioxidant activity. A qualitative analysis of the components of the essential oil and solvent fractions were then performed using gas chromatography–mass spectrometry (GC–MS). As a result, essential oil showed better antioxidant activity than ethanol extract and its solvent fractions. Among the solvent fractions, the EAF showed the strongest DPPH radical scavenging ability (0.185±0.008mg/mL) and reducing power while the CF showed the highest hydroxyl radical scavenging ability (0.307±0.011mg/mL). And both of them had high phenolic content (p<0.05) compared to other fractions. GC–MS analyses of the essential oil resulted in the identification of 30 compounds, representing 94.56% of the total oil. The major components were falcarinol (57.02%), 1,7-dimethyl-4-(1-methylethyl)-Spiro[4.5]dec-6-en-8-one (9.08%) and geranyl tiglate (7.54%). In addition, 53 constituents were identified in the fractions including the biological activity-containing compounds such as bergapten, ficusin, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-Pyran-4-one, and falcarinol. Consequently, the antioxidant activities of the essential oil and solvent fractions of ethanol extract are not only contributed by phenolics but also related to other constituents. Based on these results, the essential oil and fractions of ethanol extract from C. violaceum are promising sources of natural antioxidants.