Synthesis, antibacterial and antimutagenic activity of zerumbone-bicarbonyl analogues.

Synthesis of new zerumbone-bicarbonyl analogues by SeO oxidation is reported. Selective oxidation of methyl at C-13 to an aldehyde and a ketone with exo-cyclic double bond between C-13 and C-6 in zerumbone has been recognized. Both these compounds have an additional conjugated-carbonyl-functionality. They exhibited significantly higher antimutagenic activity than zerumbone against Salmonella tester strains. They are more active against Gram positive bacteria than Gram negative bacteria; however zerumbone showed highest activity against E. coli, whereas its derivatives were least effective against E. coli.