Nat Prod Sci.  2025 Mar;31(1):24-31. 10.20307/nps.2025.31.1.24.

15-Methylhexadecanoic Acid and Other Chemical Constituents from Calliandra calothyrsus (Meisn) (Fabaceae) with Their Antibacterial Activities

• Tenkeu AC
• Mabou FD
• Botezatu AVD
• Tamokou JdD
• Takongmo GM
• Tomasi S
• Voutquenne-Nazabadioko L
• Dinica RM
• Tsopmo A
• Ngnokam D

• KMID: 2566710
• DOI: http://doi.org/10.20307/nps.2025.31.1.24

Abstract

A chemical study of the methanol extract from the leaves of Calliandra calothyrsus led to the isolation of nine compounds including, 15-methylhexadecanoic acid (1), isolated for the first time from this plant, kaempferol (2), quercetin-3-O-α-L-rhamnopyranoside (3), kaempferol-3-O-α-L-rhamnopyranoside (4), quercetin-3-O-β-D-galactopyranoside (hyperin) (5), polifoliosid (6), D-pinitol (7), quercetin (8), rhamnetin-3-O-β-D-xylopyranoside (9). New derivatives, namely tributyronitrilequercetin-3-O-α-L-rhamnopyranoside (10), tetrabutyronitrilequercetin-3-O--L-rhamnopyranoside (11) were obtained upon alkylation of compound 3 with 4-bromobutyronitrile. Structures of isolated compounds and semi-synthetic derivatives were assigned by 1D and 2D NMR analysis and mass spectrometry. The extracts and the isolated compounds were evaluated for their antibacterial activities. The EtOAc extract was highly active against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus. For pure compounds, the best MIC (8 µg/mL) was obtained with quercetin-3-O-β-D-galactopyranoside (5) against Enterococcus faecalis and quercetin (8) against Pseudomonas aeruginosa. The alkylation of compound 3 enhanced its antimicrobial activities by up to 4-fold depending on the species.

Keyword

Calliandra calothyrsus (Meisn); Fabaceae; 15-Methylhexadecanoic acid; Antibacterial activity