The mutagenicities of alkaloids and N-nitrosoguvacoline from betel quid

In Taiwan, betel quid is a natural masticatory, which is composed of fresh green areca fruit, Piper betle and slaked lime paste. Areca fruit contains some alkaloids, of which arecoline is the major one. N-Nitrosoguvacoline (NG), one of the N-nitrosation products of arecoline, is the only one N-nitrosamine found in Taiwanese betel quid chewing saliva. The mutagenic studies in Ames Salmonella microsome test showed that crude alkaloid extracts of areca fruit and arecoline were active in Salmonella typhimurium TA100, and NG was weakly active in TA98 and TA100. The activities in both arecoline and NG decreased further in the presence of rat liver S9 mix. Nitrite was significantly consumed during the N-nitrosation of arecoline and sodium nitrite at acidic condition (pH 3), whereas the formation of NG was favored at neutral condition (pH 7). Crude phenolic extracts of leaf and inflorescence of Piper betle inhibited the formation of NG by blocking the nitrite. However, a high amount of crude phenolic extracts of areca fruit enhanced the formation of NG.