Zerumbone Cytotoxicity Assay

The effect of zerumbone on tumor cell viability was assessed by using the XTT: (sodium 3′-[1-(phenylaminocarbonyl)- 3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate) cell proliferation kit (Roche Applied Science, Indianapolis, IN) as described previously.25 (link) Briefly, cells (3 × 10⁴/mL) were seeded in 96-well plates and grown overnight. The next day, the medium was aspirated and cells were exposed to different concentrations of zerumbone for 7 h. Next, the zerumbone was aspirated and the wells were rinsed and replenished with fresh medium. After a further 48 h of culture, XTT labeling mixture was added to the cells and incubated for another 4 h. The resulting formazan product was then spectrophotometrically quantified (490 nm) by using an enzyme-linked immunosorbent assay (ELISA) plate reader (Perkin Elmer, Waltham, MA). Results are expressed as percent cell viability for each concentration of zerumbone with respect to untreated controls (0.1% DMSO in medium).