New cytotoxic obacunone-type limonoid and others constituents from the stem bark of Carapa procera DC (Meliaceae)

Abstract

The phytochemical study of the CH₂Cl₂- MeOH (1:1, v/v) extract of the stem bark of Carapa procera DC (Meliaceae) led to the isolation and characterisation of a new natural limonoid 7β-obacunol (6), along with seven known compounds. Their structures were elucidated by spectroscopic means, including 1 D and 2 D NMR, HRESI-MS and by comparison with published data. The cytotoxicity of compounds 1-6 was assessed in vitro by the WST-1 assay on human lung adenocarcinoma A549 and Raw 264.7 mouse macrophage cell lines. Results suggested that obacunone (3) exhibited the most potent cytotoxic effect against A549 and Raw 264.7 cells with respective IC₅₀ values of 25.24 µM and 29.14 µM, while the new natural limonoid 7β-obacunol (6) exhibited 32.75 µM and 39.19 µM, respectively on both cell lines. Therefore, limonoid derivatives might be promising sources of natural bioactive metabolites against cancer.

Graphical Abstract

Keywords:

• Meliaceae
• Carapa procera
• triterpenoids
• limonoids
• cytotoxicity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are grateful to acknowledge the SNF (Swiss National Foundation) for providing financial support to RM and JPD through the respective project N° IZSEZ0_177640/1 and IZSEZO_180383/1. RM also thanks the DAAD (German Academic Service Exchange) for the award of three months research stay at the University of Hohenheim through the Research Stay for University Academics and scientists Programme (Funding ID: 57314019).