Antibacterial and cytotoxic activities of undescribed cassiaric acid and other constituents from Cassia arereh stem barks

Abstract

A new lupane-type triterpene, 2α,3β-dihydroxylupan-29-oic acid (1), and one new ceramide derivative: (2S*,2'R*,3S*,4R*,5R*,7'E,11E,12'E,20E)-N-[2'-hydroxyoctadeca-6,11-dienoyl]-2-aminohexacosa-11,20-diene-1,3,4,5-tetrol (2) were isolated from the ethyl acetate fraction obtained from the methanol extract of the stem barks of Cassia arereh together with seven known compounds. Their structures were characterized using two-dimensional NMR, mass spectrometry, and compared with reported data. To date, this is the first report of the isolation of a multiple double bonds sphingolipid type (2) from this genus. The ethyl acetate extract and selected isolates were examined for antimicrobial and cytotoxic activities in vitro. Betulinaldehyde (5) has shown to be active against all bacterial strains whereas, cassiaric acid (1) and betulinic acid (6) have demonstrated to be moderately active. In addition, cassiaric acid (1) showed the best cytotoxic result against HeLa and MCF-7 cell lines tested with IC₅₀ 75.00 µM, while lupeol (3) and betulinic acid (6) displayed weak cytotoxicity at 100.00 µM.

Graphical Abstract

Keywords:

• Cassia arereh
• Fabaceae
• cassiaric acid
• lupane triterpenoid derivative
• cassiaramide
• sphingolipid
• antimicrobial and cytotoxicity

Acknowledgements

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. We are indebted to Dr Mamoalosi Selepe and Adetola Adewole for NMR and technical assistance and to Mr Victor Nana (National Herbarium of Cameroon) for the botanical identification.

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The study was partly funded by the South African Medical Research Council Self-Initiated Research (SAMRC), grant number: A1A979, and the National Research Foundation Thuthuka (grant No. 113980).