Many drugs used in the therapeutic regimen for various ailments undergo metabolism via cytochrome P450 1A2 (CYP1A2), so the agents or conditions altering the expression and/or activity of this enzyme play a significant role in therapeutic efficacy/failure of its substrates. Though curcumin is reported to be an inhibitor of CYP1A2, influence of curcumin on the pharmacokinetics of CYP1A2 probe phenacetin in rats has not yet been published to the best of our knowledge. Hence an attempt has been made to investigate the same. Two groups of wistar albino rats were taken, of which, one group received curcumin at 400 mg kg -1 , per os (PO) followed by phenacetin (150 mg kg -1 , PO) and the other received only phenacetin. Plasma concentrations of phenacetin, a known CYP1A2 substrate and its metabolite paracetamol were determined by high performance liquid chromatography. Based on plasma concentrations, the pharmacokinetic parameters were determined by compartmental methods. Curcumin pretreatment significantly (P \ 0.05) decreased peak plasma concentration (C max ) of phenacetin in rats. None of the other pharmacokinetic parameters of either phenacetin or paracetamol were affected. To conclude, curcumin pretreatment decreases C max of phenacetin but has no role on the disposition kinetics of either phenacetin or its metabolite paracetamol in rats. This implies that single dose of curcumin has no effect on CYP1A2 mediated metabolism in rats.

Ion transport enzymes may play an important role in T cell activation. This study investigates the role of turmeric and its individual components, turmerin-and curcumin-on Ca 2+ and Na/K + adenosine triphosphatases (ATPase) in the course of T cell activation.Concanavalin A (Con A) stimulated human blood mononuclear T cell proliferation paradigm was investigated for 3, 5 and 7 day periods with different concentrations of turmeric, curcumin and turmerin. Con A-stimulated cells treated with turmeric (250, 50, 5 µg/ml) for 3 and 5 days inhibited ATPase levels when compared to base levels obtained by cells in media alone. At day 7, there was a 3-fold increase for Ca 2+ATPase levels and a 2-fold increase for Na/K + ATPase. Curcumin (250, 50, 5 µg/ml) showed the same pattern for ATPase activity as turmeric at 3 and 5 days with a 2-fold increase at day 7. Turmerin (2500, 1250, 250, 25 ng/ml) for Na/K + ATPase activity showed an increase at day 3, a decrease on day 5, and a 2-fold increase on day 7. Ca 2+ ATPase activity in the presence of turmerin showed an increase in ATPase levels at day 3 (except at 2500ng/ml where it decreased) and a decrease in day 5(except at 25 ng/ml where it increased). Turmeric and curcumin generally inhibitedATPase and Na/K + ATPases in early (day 3) and intermediate (day 5) stages of mitogen stimulation. However, the effect after 7 days incubation for turmeric, curcumin and turmerin showed a marked increase up to three fold.