Ameliorative effect of black tea on nicotine induced cardiovascular pathogenesis in rat

Abstract

Regarding the role of nicotine in the development of cardiovascular complications of smoking, we investigated whether black tea has a modulatory effect on cardiovascular pathogenesis of nicotine in rat. Animals were randomized to control, tea, nicotine and tea plus nicotine groups. Test groups received black tea brewed (adding 400 ml boiling water to 10 g Lipton black tea for 5 min) orally alone or with nicotine 2 mg/kg/day, s.c. separately or combined for four weeks. On 28th day, lipids profile of blood and also malondialdehyde (MDA) level, glutathione peroxidase (GPx) activity and total antioxidant capacity (TAC) of heart tissue were measured. Nicotine administration caused a significant increase in total cholesterol, TG and HDL-C and also atherogenic index of plasma (log TG/HDL-C). Moreover, nicotine increased MDA level of heart. Black tea alone increased the antioxidant capacity of heart tissue without significant effect on lipid profile and MDA levels. Concomitant use of black tea and nicotine significantly attenuated the hyperlipidemic and atherogenic effects of nicotine but was unable to attenuate the MDA. Our findings suggest that black tea consumption reduces hyperlipidemia and atherogenesis as two cardiovascular risk factors and complications of nicotine, in rat. If these results can be extrapolated to human, smokers who daily drink black tea may be less at risk of cardiovascular disease.

Keywords: atherogenic index; black tea; blood lipids; heart; nicotine; total antioxidant capacity.

Table 1. Plasma lipid levels in different animal groups of study

Figure 1. Atherogenic index of plasma in different groups. Values are means ± SEM. n= 12, CTL: control, T: black tea, N: nicotine, N+T: nicotine+black tea, HDL-C: high-density lipoprotein, TG: triglyceride. **P < 0.01 versus CTL and N+T groups

Figure 2. Total antioxidant capacity (TAC) of heart tissue. Values are means ± SEM. n= 6-7, CTL: control, T: black tea, N: nicotine, N+T: nicotine+black tea, *P < 0.05 compared with CTL. ▼P < 0.01 compared with nicotine group

Figure 3. Glutathione peroxidase (GPx) activity of heart tissue. Values are means ± SEM. n= 6-7, CTL: control, T: black tea, N: nicotine, N+T: nicotine+black tea

Figure 4. Malondialdehyde (MDA) levels of heart tissue. Values are means ± SEM. n= 6-7, CTL: control, T: black tea, N: nicotine, N+T: nicotine+black tea, *P < 0.05 compared with CTL group