Effects of medicinal herb tea on the smoking cessation and reducing smoking withdrawal symptoms.

Medicinal herbs (21 species) were screened for the antioxidant activity and nicotine degradation activity (NDA) in vitro. Eleven of them with higher antioxidant activity and NDA were selected for preparation of the medicinal herb tea (MHT) and the effects of MHT on smoking cessation and reducing smoking withdrawal symptoms were evaluated in 100 male human smokers. Among these medicinal herbs, Eugenia aromaticum and Astragalus membranaceus Bunge showed the highest antioxidant activity (IC50 of 30.0 microg/mL) and NDA (1.81), respectively. MHT showed relatively high antioxidant activity (IC50 of 50.6 microg/mL) and NDA (1.23). The urinary cotinine level, a metabolite of nicotine, increased in the first 2 weeks and greatly decreased from the 2nd to 4th week in the MHT taking group, which indicates that MHT accelerates the conversion of nicotine into cotinine. Human groups taking MHT for 4 weeks underwent reduced smoking withdrawal symptoms compared to the non-MHT taking subjects, and 38% of subjects taking MHT succeeded in smoking cessation, while only 12% of non-MHT taking subjects succeeded in quitting smoking.