Heterophynone and methyl ester of Colic acid, two new compounds with antimicrobial activity from Cola heterophylla (Sterculiaceae)

The ethyl acetate fraction, the stem bark and the residual methanolic extracts from the leaves of Cola heterophylla (Sterculiaceae) led to the isolation of two new compounds: Heterophynone (1) and methyl ester of Colic acid (6), along with four known triterpenes: betulinic acid (2), oleanolic acid (3), ursolic acid (4) and chletric acid (5). Structures of compounds were established by different spectroscopic methods that included 1D and 2D NMR experiment. The antimicrobial activity of isolated compounds was evaluated against two yeasts, Candida Albicans NR 29456 and Candida Krusei 1415; and five Gram-positive bacterial, Salmonella enteric Serovar Muenchem, Salmonella enteric Serovar Thyphimurium, Staphylococcus aureus NR 46003, Staphylococcus aureus NR46374 and Pseudomonas aeruginosa HM 601). Among tested compounds, Heterophynone was found to be the most active with significant antimicrobial activity against Salmonella enteric Serovar Thyphimurium (MIC = 7.82 μg/mL and MBC = 62.5 μg/mL) and good activity against Candida Albicans NR 29456 (MIC = 62.5 μg/mL).