Phytochemical And Bioactivity Studies Of Strobilanthes Crispus L
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Date
2012-01
Authors
Koay, Yen Chin
Journal Title
Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
Phytochemical investigation of the hexane, dichloromethane and methanol extracts of the leaves of Strobilanthes crispus has led to the isolation of nine compounds, comprising 1-heptacosanol (c-1), lignoceric acid (c-2) and stigmasterol (c-3) from the hexane extract, a mixture of four esters of β-amyrin (c-4), taraxerone (c-5), taraxerol (c-6) and a mixture of two esters of taraxerol (c-7) from the dichloromethane extract, as well as 4-acetyl-2,7-dihydroxy-1,4,8-triphenyloctane-3,5-dione (c-8) and stigmasterol 3-O-β-D-glucopyranoside (c-9) from the methanol extract. Structures of compounds c-1 to c-9 were elucidated with the aid of chromatographic and spectroscopic techniques. Compound c-3 has previously been reported from the leaves of S. crispus, however, the rest of the compounds were isolated for the first time from this plant. The dichloromethane and methanol leaf extracts, together with the isolated compounds were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, and Gram-negative bacteria: Klebsiella pneumoniae, Escherichia coli and Salmonella typhimurium, using micro-dilution assay. The majority of the samples tested indicated promising inhibitory activities against Staphylococcus aureus and Bacillus subtilis (7.8-62.5 μg mL-1), while appreciable activity was observed against Salmonella typhimurium and Escherichia coli (31.0-125.0 μg mL-1). Compound c-8, a rare natural occurring compound, exhibited the strongest inhibitory effect against both Gram-positive and Gram-negative bacteria, with low MIC values (between 7.8 and 62.5 μg mL-1). In the acetylcholinesterase enzyme inhibitory test, the dichloromethane extract showed activity (85.0%) against acetylcholinesterase with an IC50 value of 46.0 μg mL-1 at the concentration of 100.0 μg mL-1.
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Keywords
Phytochemical and bioactivity studies , of Strobilanthes crispus L