Antibacterial and antimutagenic activities of novel zerumbone analogues.

Zerumbone, the key constituent of Zingiber zerumbet Smith, is a very important bioactive phytochemical.
Two new compounds viz. azazerumbone 1 and azazerumbone 2 were synthesised by ZnCl2-catalysed
Beckmann rearrangement of the zerumbone oxime. The structure elucidation of these analogues of
zerumbone was carried out by 1D (1H NMR and 13C NMR) and 2D-NMR (COSY, HSQC and NOESY) spectral
analysis. Studies on the antibacterial activity established that azazerumbone 2 had better activity than
zerumbone. Among the tested bacteria, Bacillus cereus was the most sensitive and Yersinia enterocolitica
was found to be the most resistant. These compounds exhibited strong protection against sodium azide
induced mutagenicity of Salmonella typhimurium strains TA 98 and TA 1531. Azazerumbone 2 showed
better antibacterial and antimutagenic activity than azazerumbone 1. The antibacterial and antimutagenic
activities exhibited by zerumbone and its analogues demonstrate their potential for use as nutraceuticals
and in food preservation.