Nitrosation products from the plant Ephedra altissima and their potential endogenous formation.

The plant species Ephedra is commonly used in both folk medicine and for the preparation of health teas. Nitrosation of a tea made from Ephedra altissima yielded N-nitrosoephedrine (NEP), N-nitrosopseudoephedrine (NPEP), N-nitrosoproline (NPRO), N-nitrosomethylbenzylamine (NMBA), trace quantities of 2 unidentified non-volatile nitrosamines and the new nitroso compound 2-(N-nitroso-N-methylamino)propiophenone (NMAP). Incubation of a tea extract at 37 degrees C and pH 2.0 under conditions simulating the normal fasting stomach with a constant nitrite concentration (25 microM) for 1 h produced NEP, NPEP, NMAP and NPRO. The synthesis and preliminary results for the mutagenic effect of NMAP on the reversion of Salmonella typhimurium strains TA100 and TA1535 in the Ames test are reported.