Antioxidant activity of the ethanolic extract from the bark of Chamaecyparis obtusa var. formosana
2008
Marimuthu, Palanisamy | Wu, Jilin | Chang, Hui-Ting | Chang, Shang-Tzen
BACKGROUND: Chamaecyparis obtusa var. formosana (Taiwan hinoki) is an endemic conifer in Taiwan and the purpose of this study is to evaluate the antioxidant activity of various fractions obtained from the bark of this plant material. The ethanolic extract of the bark was sequentially separated into three fractions, including n-hexane, ethyl acetate and ethanol soluble fractions, by liquid-liquid partition. Then the antioxidant activities of crude extract and three fractions along with 13 subfractions obtained from the ethyl acetate (EA) soluble fraction were tested for several antioxidant assays.RESULTS: The total phenolic content of the samples varied from 27.71 to 102.86 mg GAE g⁻¹ dry weight for fractions, and from 49.94 to 206.46 mg GAE g⁻¹ for subfractions (where GAE is milligrams of gallic acid per gram of extract). The Trolox equivalent antioxidant capacity (TEAC) ranged from 0.15 to 0.26 mmol L⁻¹ Trolox equivalents. The EA soluble fraction was found to be the best antioxidant-rich fraction in terms of DPPH and reducing power assays. With further data analysis it was found that there was a positive correlation between the total phenolic content of extracts and TEAC is R² = 0.61.CONCLUSION: Results from various antioxidant assays showed that the EA fraction possessed strong antioxidant activity. This would provide additional information about the antioxidant activity of bark extract of this plant species.
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