MINT PREVENTS SHAMMA-INDUCED CARCINOGENESIS IN HAMSTER-CHEEK POUCH

Shamma, a complex mixture of powdered tobacco, slaked lime, ash, oils, spices and other additives, has been linked to oral cancer in Saudi A rabia. Shamma varies in colour and odour due to the nature of the addi tives which characterize different brands, Using the Ames Salmonella a ssay, a chloroform extract of a brand named 'white shamma' (WSH) was f ound to be mutagenic, while that of a brand called 'brown shamma' (BSH ), which is known to contain mint as a flavouring agent, was found to be nonmutagenic. Using HPLC, a mutagenic and a non-mutagenic fraction were isolated from the extract of BSH, The nonmutagenic fraction of BS H was found to neutralize the genotoxic effect of the mutagenic fracti on when the two were recombined, A chloroform extract of mint showing no mutagenic activity in the Ames assay effectively inhibited the muta genicity of carcinogens/mutagens like benzo[a]pyrene, aflatoxin B-1, m ethylmethane sulfonate and extract of WSH, A carcinogenicity assay des igned to test the effects of WSH and BSH in the hamster cheek pouch mo del showed that the former was tumorigenic, while the latter was not. However, when crushed leaves of mint were mixed with powdered WSH (in 1:1 proportion), the tumorigenic effect of the latter was abolished. T hese data strongly suggested that mint has a chemopreventive effect ag ainst shamma-induced carcinogenesis, which could be due to its antimut agenic properties.