Caffeine-derived N-nitroso compounds. V. Carcinogenicity of mononitrosocaffeidine and dinitrosocaffeidine in bd-ix rats.

Mononitrosocaffeidine (MNC) and dinitrosocaffeidine (DNC) are new N-nitroso compounds obtained from in vitro nitrosation of caffeidine, a hydrolysis product of caffeine present in a typically made and widely consumed tea from Kashmir (India), a high incidence area of esophageal and stomach cancer. The chemical synthesis, in vitro metabolic studies and mutagenicity of the compounds has been previously reported. DNC, a nitrosamide is highly mutagenic both with and without metabolic activation whereas MNC, like several other aromatic asymmetric nitrosamines, does not exhibit genotoxic or mutagenic properties.

Detection of methylating activity due to nitrosamide in some nitrosated Nigerian foodstuffs.

Popular vegetables, condiments and some Nigerian staple foods were evaluated for their relative methylating potential due to nitrosamide formation following nitrosation under standardized conditions. Methylating activity of nitrosated foodstuffs, expressed as N-nitroso-N-methylurea equivalents, was determined by gas chromatography-thermal energy analysis. In positive samples (detection limit 10 microgram/kg) methylating activity detected was in the range of 50-1200 microgram/kg, the highest activity being found in Telfairia occidentalis (ugwu).

Tobacco-specific nitrosamines in some Nigerian cigarettes.

Ten popular brands of cigarettes on the Nigerian market were analyzed for tobacco-specific nitrosamines (TSNA) in tobacco and in mainstream smoke, as well as nitrate in tobacco. TSNA was analyzed using a gas chromatography/thermal energy analyzer (GC-TEA), while nitrate was determined spectrophotometrically as nitrite following on-line reduction with copper, diozatization with sulfanilamide and coupling with N-(1-naphthyl) ethylene diamine to form an azo dye. In mainstream smoke, the concentration of NNN, NAB/NAT and NNK were respectively, between 8 and 90 ng, 10 and 65 ng, and between 15 and 72 ng/cigarette.

Nitrosatable amines and nitrosamide formation in natural stimulants: Cola acuminata, C. nitida and Garcinia cola.

Three varieties of kola nut, Cola acuminata, C. nitida and Garcinia cola, of Nigerian origin, were analysed for their content of primary and secondary amines, and assessed for their relative methylating potential due to nitrosamide formation. Primary and secondary amines were determined as benzene sulfonamides by gas chromatography/thermal energy analysis (GC/TEA).

Nitrosation of Nigerian medicinal plant preparations under 'chemical' and 'simulated' gastric conditions.

Preparations of some tropical plants of medicinal importance, collected from the savannah vegetational belt of Nigeria, were nitrosated and analysed for volatile N-nitrosamines formed under chemical and simulated gastric conditions. N-Nitrosamines were determined on a Thermal Energy Analyser following gas chromatographic separation. Mean concentrations of N-nitrosodimethylamine (NDMA) in the range of 7 to 58 ppb and N-nitrosodiethylamine (NDEA) in the range of 23 to 26 ppb were formed in 31 and 7%, respectively, of the preparations using artificial gastric juice (simulated gastric condition).