Isolation, characterisation and antibacterial activity of new compounds from methanolic extract of seeds of Caesalpinia crista L. (Caesalpinaceae).

Phytochemical study on the methanolic extract of Caesalpinia crista afforded two novel compounds, 2-hydroxytrideca-3,6-dienyl-pentanoate and octacosa-12,15-diene along with known compounds 3-O-methylellagic acid 3′O-α-rhamnopyranoside, β-sitosterol and sucrose. Compound 3-O-methylellagic acid 3′O-α-rhamnopyranoside is reported for the first time from the plant. Molecular structures, of isolated compounds, were elucidated by using the NMR spectroscopy in combination with IR and mass spectral data. All isolated compounds, extract and fractions were evaluated for in vitro antibacterial activity against various Gram-positive and Gram-negative bacterial strains and found to be significantly active against Staphylococcus aureus and methicillin-resistant S. aureus (minimum inhibitory concentration: 64–512 μg mL− 1).