The antibacterial activity of vanillin derivative compounds

The aim this study is to perform synthetic compound of 9-(4-hydroxy-3-methoxyphenyl)-3,3,6,6-tetramethyl- 3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (1a) and 9-(3-ethoxy-4-hydroxyphenyl)-3,3,6,6-tetramethyl- 3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-dione (1b) (1,8-dioxo-hydroxanthene derivates) derivate from vanillin and to determine their antibacterial activity against various bacteria such as Staphylococcus epidermidis, Propionibacterium acnes, Staphylococcus epidermidis, Bacillus subtilis, Salmonella typhimurium, and Pseudomonas aeruginosa. Compound 1a and 1b were synthesized from dimedone and aromatic aldehyde (vanillin and ethyl vanillin) in the presence of concentrated sulfuric acid and ethanol as solvent. Their antibacterial activity was determined by well diffusion assay method with measuring zone of inhibition in mm. Two derivatives of 1,8-dioxo-octahydroxanthene (compound 1a and 1b) has been successfully synthesized. Compound 1b has very strong antibacterial activity against Staphylococcus epidermidis with inhibition zone 23,38 mm and compound 1a has medium antibacterial activity against P. acnes, S. epidermidis, B. subtilis, S. typhimurium, and P. aeruginosa. The susbtitution of the methoxy group attached to the aromatic aldehydes with an ethoxy group enhance the antibacterial activity of 1,8-dioxo-hydroxanthene compounds.