Chemical Constituents and Biological Activities of Strobilanthes crispus L.

Abstract

Phytochemical investigation of Strobilanthes crispus has led to the isolation of 1-heptacosanol (1),
\ntetracosanoic acid (2), stigmasterol (3) from the hexane extract, a mixture of four C20-C24 fatty acid esters of �-
\namyrin (4), taraxerol (5), taraxerone (6), a mixture of two C22 and C24 fatty acid esters of taraxerol (7) from the
\ndichloromethane extract, 4-acetyl-2,7-dihydroxy-1,4,8-triphenyloctane-3,5-dione (8) and stigmasterol �-Dglucopyranoside
\n(9) from the methanol extract. The dichloromethane and methanol crude extracts together with
\nthe isolated compounds (4-9) were tested for antibacterial activity using the determination of minimum
\ninhibitory concentration assay and acetylcholinesterase inhibitory activity using the micro-plate assay. The
\nmajority of the samples tested indicated good activity against the Gram-positive bacteria (7.8�125.0 μg/mL),
\nand moderate to weak activity against the Gram-negative bacteria (31.0�250.0 μg/mL) employed. Moderate to
\nweak activity was observed against acetylcholinesterase. Compound (8) showed excellent antibacterial activity
\nagainst Bacillus subtilis and Staphylococcus aureus, with MIC values of 15.6 and 7.8 μg/mL, respectively, and
\nsignificant activity against Escherichia coli and Salmonella typhimurium, with MIC values of 62.5 and 31.0
\nμg/mL, respectively. Compound (8) also showed the highest acetylcholinesterase inhibitory activity, with an IC50
\nvalue of 31.0 μg/mL. This is the first report describing the antibacterial and acetylcholinesterase inhibitory
\nactivities of S. crispus on the basis of the isolated constituents. This research work has provided scientific proof
\nof the traditional medicinal use of the leaves of S. crispus.