Combretumlignan, a new cyclolignan and others constituents with antibacterial activity from Combretum zenkeri (combretaceae).

A previously undescribed cyclolignan, named Combretumlignan 1, was isolated from the methanolic extract of the twigs of Combretum zenkeri together with fifteen known compounds. Their structures were determined by a comprehensive analysis of their spectroscopic data in comparison with those published in the literature. The extract, fractions and compounds 1, 4 and 5 were evaluated against six Gram-negative and one Gram-positive bacteria strains. The methanol crude extract of twigs of this plant showed good antibacterial activities with MIC values of 31.2 and 62.5 μg/mL against Staphylococcus aureus and Salmonella enterica respectively. The ethyl acetate fraction showed strong antibacterial activity (MIC = 7.8 μg/mL) against Salmonella typhimurium 19430 while the crude extract and the n-hexane fraction exhibited significant activity (MIC = 31.2 μg/mL) against Staphylococcus aureus 12600 for crude extract, and against Salmonella typhimuriummurium 19430 and Pseudomonas aeruginosa HM801 for the n-hexane fraction. All the tested compounds inhibited the growth of the seven bacterial strains tested with MICs ranging from 3.9─125 µg/mL. Hexadecyl ferulate 5 displayed the best activity with a MIC value of 3.9 μg/mL against Salmonella typhimurium 19430. Compound 1 showed moderate activity against Salmonella typhimurium 19430 and Escherichia coli with MIC values of 62.5 μg/mL and 31.2 µg/mL, respectively.