Antioxidant effect of ethanolic extract of Piper betle Linn. (Paan) on erythrocytes from patients with HbE-beta thalassemia.

HbE-beta thalassemia is caused by an interaction between HbE and defective b globin gene of thalassemia. Repeated blood transfusions cause an iron overload, triggering an enhanced generation of free radicals. In the present study, the anti-oxidant property of ethanolic extract of the leaves of Piper betle Linn. (PB) was evaluated in the erythrocytes from patients with HbE-beta thalassemia. In patients with HbE-beta thalassemia (n = 30) and age- and sex-matched healthy individuals (n = 30), the baseline level of reactive oxygen species (ROS) and free radical scavenging activity in the erythrocytes was measured by flow cytometry using dihydrodichlorofluorescein diacetate (H2DCFDA), in terms of the geometric mean fluorescence channel (GMFC). The baseline generation of ROS was significantly higher in the erythrocytes from patients with HbE-beta thalassemia, as compared to healthy volunteers, the GMFC being 67.20 ± 4.64 vs. 23.03 ± 1.88 (p<0.001), which was effectively decreased by PB. Similarly, H2O2 (0.5-1.0 mM) induced a higher increase in the GMFC in the erythrocytes from patients with HbE-beta thalassemia, as compared to controls which was effectively reduced by PB. Taken together, PB showed promising anti-oxidant activity against the erythrocytes from patients with HbE-beta thalassemia.

Functionality of drug efflux pumps in antimonial resistant Leishmania donovani field isolates.

The recent upsurge of antimony (Sb) resistance is a major impediment to successful chemotherapy of visceral leishmaniasis (VL). Mechanisms involved in antimony resistance have demonstrated an upregulation of drug efflux pumps; however, the biological role drug efflux pumps in clinical isolates remains to be substantiated. Thus, in this study, the functionality of drug efflux pumps was measured in promastigotes and axenic amastigotes isolated from VL patients, who were either Sb-sensitive (AG83, 2001 and MC9) or resistant (NS2, 41 and GE1) using rhodamine123 as a substrate for multidrug resistant (MDR) pumps and calcein as a substrate for multidrug resistance-associated proteins (MRP) respectively; their specificity was confirmed using established blockers. Sb-resistant (Sb-R) isolates accumulated higher amounts of R123, as compared to Sb-sensitive (Sb-S) isolates. Verapamil, a MDR inhibitor failed to alter R123 accumulation, suggesting absence of classical MDR activity. In Sb-R isolates, both promastigotes and axenic amastigotes accumulated significantly lower amounts of calcein than Sb-S isolates and probenecid, an established pan MRP blocker, marginally increased calcein accumulation. Depletion of ATP dramatically increased calcein accumulation primarily in Sb-R isolates, indicating existence of a MRP-like pump, which was more active in Sb-R isolates. In conclusion, our data suggested that overfunctioning of a MRP-like pump contributed towards generation of Sb-R phenotype in L. donovani field isolates.