INFLUENCE OF EXTRACTING SOLVENTS ON ITS ANTIOXIDANT PROPERTIES OF BAWANG DAYAK (ELEUTHERINE PALMIFOLIA L. MERR)

摘要

Bawang dayak (Eleutherine palmifolia L. Merr) is an indigenous plant in Borneo, Indonesia, traditionally used by Dayak tribes to treat degenerative diseases such as diabetes mellitus and cancer. In this study, 2.5 gram of sample powdered was extracted using 100 ml of deionized water, methanol in various concentrations (30%, 50%, 70%, 90%, and 100% v/v), absolute ethanol, acetone, and ethyl acetate at 40oC for 6 h. The antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC) of the freeze-dried E. palmifolia extracts were investigated using various in vitro assays. The extract obtained by 70% methanol in deionized water showed the strongest antioxidant activity (IC50 39.06±2.33 μg/mL) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, while absolute acetone extract showed the weakest antioxidant activity (IC50 235.90±2.12 μg/mL). Aqueous methanol (70% methanol) also was most effective in extracting polyphenol (phenolic content of 20.05±0.06 mg gallic acid equivalent/g of dry sample weight and flavonoid content of 15.03±0.11 mg quercetin equivalent/g of dry sample weight), while absolute ethanol, acetone, ethyl acetate and water were less effective in extracting polyphenol. The highest extraction yield was obtained by using water (21.40±0.04 %). These results suggest that E. palmifolia is a potential source of natural antioxidant for food and dietary applications with a potential to reduce oxidative stress.