Isolation of a new β-carboline alkaloid from aerial parts of Triclisia sacleuxii and its antibacterial and cytotoxicity effects

Abstract

A new β-carboline alkaloid named sacleuximine A (1) together with known compounds palmatine (2), isotetrandrine (3), trans-N-feruloyltyramine (4), trans-N-caffeoyltyramine (5), yangambin (6), syringaresinol (7), sesamin (8), (+) epi-quercitol (9), 4-hydroxybenzaldehyde (10), β-sitosterol (11), quercetin 3-O-rutinoside (12) and myricetin 3-O-β-glucose (1→6) α-rhamnoside (13) have been isolated from methanol extract of Triclisia sacleuxii aerial parts. Compounds 1–10 were evaluated for their cytotoxicity against human adenocarcinoma (HeLa), human hepatocarcinoma (Hep3B) and human breast carcinoma (MCF-7) cells lines and also for antibacterial activities against both Gram-positive and Gram-negative bacteria. The cytotoxicity (IC₅₀) values ranged between 0.15 and 36.7 μM while the minimum inhibitory concentrations were found to be in the range of 3.9 and 125 μM, respectively. This is the first report of antibacterial compounds and the isolation of lignans together with a β-carboline alkaloid from T. sacleuxii.

Keywords:

• Triclisia sacleuxii
• Menispermaceae
• secondary metabolites
• cytotoxicity
• antibacterial
• aerial parts

Acknowledgments

This work was supported by the National Commission for Science, Technology and Innovation (NACOSTI) and Germany Academic Exchange Services (DAAD). The authors are grateful to Mr. Mutiso (Taxonomist) of Botany department, University of Nairobi for identification and collection of the plant materials and Mr. James Odhiambo of the School of Public Health, Maseno University for conducting the bioassay experiments. The Institute of Organic Chemistry, Johannes Gutenberg University at Mainz, Germany is acknowledged for the spectroscopic data.