Induction of tumours by Indian dietary constituents.

Fishes and vegetables are preserved by salting and sundrying; and later fried in oil and consumed. Such preparations have been found to contain polycyclic aromatic hydrocarbons, and are genotoxic and mutagenic. The potential carcinogenic effects of these and other dietary items have been studied by oral feeding to swiss mice at 100 mg/animal/day for 12 months; and observing upto two years. When so prepared and tested, chillies (Capsicum annum L.) produce adenocarcinomas in the abdomen in 35% of animals; Sundakkai (Solanum torvum), hepatic heamangiomas in 30%; Ribbon fish (Trichurus lepturus), squamous gastric carcinoma in 20%; cluster beans (Cyomopsis tetragonoloba), fat deposition throughout the abdomen. While whitebait fish (Stolephorus bataviensis) and seer fish (Scomberomorus commersonnii) have no effect. Fried mustard (Brassica juncea) causes severe necrosis of the liver (25%), but no tumours. Consumption of oil fried foods in high doses can lead to variety of deleterious biological effects. Raw cinnamon (Cinnamon zelanicum) is tumourigenic, inducing squamous pappillomas in some and poorly differentiated carcinomas in others.

Genotoxic effects of some foods & food components in Swiss mice.

A number of commonly consumed foods and food components in south India were screened for their genotoxic effects on Swiss mice. Salted, sundried and oil fried vegetables and fishes induced chromosomal aberrations, sperm head abnormalities and micronuclei production, which were comparable to the effect of the positive control viz., 20-methylcholanthrene. Spices like Cissus quadrangularis (an indigenous herb used in certain south Indian dishes) and pyrolysed cumin and aniseeds showed moderate effects. Calamus oil, widely used in pharmaceuticals was highly effective. All the three parameters of genotoxicity gave similar results.

Mutagenic activity of south Indian food items.

Dietary components and food dishes commonly consumed in South India were screened for their mutagenic activity. Kesari powder, calamus oil, palm drink, toddy and Kewra essence were found to be strongly mutagenic; garlic, palm oil, arrack, onion and pyrolysed portions of bread toast, chicory powder were weakly mutagenic, while tamarind and turmeric were not. Certain salted, sundried and oil fried food items were also mutagenic. Cissus quadrangularis was mutagenic, while 'decoctions' of cumin seeds, aniseeds and ginger were not. Several perfumes, essential oils and colouring agents, which are commonly used were also screened and many of them exhibited their mutagenic potential by inducing the 'reverse mutation' in Salmonella typhimurium tester strains.

Mutagenicity of nitrosated food items.

Several food items, commonly consumed in South India, after nitrite treatment under simulated gastric conditions were found to be mutagenic in Salmonella typhimurium tester strain TA 100. Dichloromethane extracts containing the volatile nitroso compounds and ethyl-acetate extracts with the non-volatile nitroso compounds of some of the food items exhibited mutagenicity.

Presence of polycyclic aromatic hydrocarbons in some South Indian food components.

South Indian food dishes, comprising several deep fried items have been proved to be mutagenic. Polycyclic aromatic hydrocarbons (PAHs) such as, benzo(a)pyrene, chrysene and dibenzanthracene, which are potent and proven carcinogens have been identified and quantified in several of the commonly consumed South Indian food dishes and food components. Most of the pyrolysed items contained PAHs in appreciable quantities. PAHs were detected in significant levels in salted, sundried and oil fried vegetables and fishes. Some of the raw and uncooked food components also revealed the presence of PAHs.