Macro-, micro-, and trace element distributions in areca nut, husk, and soil of northeast India.

In areca nut and husk, 14 elements (As, Ca, Cd, Cl, Co, Cu, K, Mg, Mn, Na, Rb, Sb, and Zn) were determined, while 34 elements including rare earth elements were detected in the corresponding soil samples using instrumental neutron activation analysis and atomic absorption spectrometry methods, whereas the concentration levels of Hg in tested samples are negligible, perhaps, below the detection limits. No rare earth elements were detected in edible areca nut. The concentration levels of various essential elements and heavy elements such as As, Cd, and Cu present in areca nut are within the permissible levels, whereas Pb content is relatively higher than FAO/WHO's permissible levels. The order of bioaccumulation index for heavy metals in areca nut was Cd > Sb > Cu > Zn ≥ Mn ≥ Co > Pb ≥ As. Bioaccumulation index values are indicating that areca palm may not be able to accumulate other heavy elements in the edible areca nut, except for Cd. On the basis of pollution indices, Northeast Indian soil may be relatively unpolluted.

Genetic and epigenetic instability induced by betel quid associated chemicals.

Over the years, betel quid chewing and tobacco use have attracted considerable interest as they are implicated as the most likely causative risk factors of oral and esophageal cancers. Although areca nut use and betel quid chewing may lead to apoptosis, chronic exposure to areca nut and slaked lime may promote pre-malignant and malignant transformation of oral cells. The putative mutagenic and carcinogenic mechanisms may involve endogenous nitrosation of areca and tobacco alkaloids as well as the presence of direct alkylating agents in betel quid and smokeless tobacco. Metabolic activation of carcinogenic N-nitrosamines by phase-I enzymes is required not only to elicit the genotoxicity via the reactive intermediates but also to potentiate the mutagenicity with the sporadic alkylations of nucleotide bases, resulting in the formation of diverse DNA adducts. Persistent DNA adducts provides the impetus for genetic and epigenetic lesions. The genetic and epigenetic factors cumulatively influence the development and progression of disorders such as cancer. Accumulation of numerous genetic and epigenetic aberrations due to long-term betel quid (with or without tobacco) chewing and tobacco use culminates into the development of head and neck cancers. We review recent evidence that supports putative mechanisms for mutagenicity and carcinogenicity of betel quid chewing along with tobacco (smoking and smokeless) use. The detailed molecular mechanisms of the extent of accumulation and patterns of genetic alterations, indicative of the prior exposure to carcinogens and alkylating agents because of BQ chewing and tobacco use, have not yet been elucidated.

Determination of Multi Elements in Tobacco Plant of Northeast India by Neutron Activation Analysis and Atomic Absorption Spectrometry.

Even when cultivated in uncontaminated soils, tobacco plant has higher propensity to extract and accumulate trace elements. The concentrations (mass fractions) of essential elements (K, Ca, Mg, Na, Cl, Mn, Fe, Cu, and Zn) and 28 non-essential elements in tobacco plant (leaves, stem, and root) of Northeast India and their respective soils were quantitatively measured. Hg mass fraction in all samples analyzed were found to be < 10 mg/kg. The heavy element mass fractions of tobacco are weakly correlated to different soil parameters. The bioconcentration factor values indicated that Cd (7) is selectively absorbed and translocated in the tobacco leaves compared to Zn (1.7), Cu (1.5), Ni (0.12), and Pb (0.1). Under acidic soil conditions, tobacco plant efficiently absorbed and translocated Cl- ion with great ease, whereas it may be a very low accumulator of rare-earth elements. The mass fractions of Mn, Cu, Sb, Cs, Rb, and Pb are very similar to the "reference plant," whereas significantly higher mass fractions of Al, Sc, Ti, Zr, Hf, Ta, Th, and U are present in the roots of tobacco plant relative to the "reference plant." Principal component analysis has revealed that Northeast Indian tobacco can be clearly differentiated from other varieties of tobaccos used in different countries because of their element profiles.