Bioautography was employed as the screening method for purifying bioactive substances of the crude extract of Zingiber cassumunar Roxb. Purification procedures included silica gel 60 column chromatography, thin layer chromatography and medium pressure liquid chromatography. Identification of purified compounds was achieved by spectroscopic methods. Three phenylbutanoids were purified and identified as (E)-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl] cyclohex-1-ene (1), (E)-4-(3,4-dimethoxyphenyl)-but-3-en-1-ol (2) and (E)-4-(3,4-dimethoxyphenyl)-but-3-en-1-yl acetate (3). Compound 1 showed high antibacterial activity against Staphylococcus aureus and Escherichia coli with both MIC (16 µg/ml) and MBC (32 µg/ml). These were followed by the MIC values (32 µg/ml) and MBC values (128 µg/ml) for compounds 2 and 3 against the same microorganisms. These compounds revealed bacteriolytic effects on the assayed strains, causing evident damage on cell walls and membranes using SYTOX Green. The cytotoxicity activity of purified compounds was determined using MTT colorimetric assay against L929 and Vero cell lines. They showed weak cytotoxicity activity with IC50 values of 1263.42 to 2857.83 µg/ml and 1537.83 to 2698.45 µg/ml toward L929 and Vero cell lines, respectively.
Key words: Antibacterial activity, cytotoxicity activity, phenylbutanoids, Plai, Zingiber cassumunar Roxb.
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