Amelioration by black tea extract of sodium fluoride induced hemolysis of human red blood cell corpuscles

The ameliorative effect of black tea extract on sodium fluoride (NaF) induced hemolysis was studied in vitro. Venous blood samples from twenty healthy, 25-30-year-old, well-nourished male donors residing in a nonfluorotic area of Ahmedabad, India, were collected in EDTA vials for the preparation of red blood cell (RBC) suspensions in normal saline. When 2.0 mL of RBC suspensions were treated for 4 hr at 37 degrees C with 0.05-0.5 mL of 4 mg NaF/mL in normal saline (50-500 Ng NaF/mL in a final normal saline volume of 4.0 mL), they exhibited a significant dose-dependent increase in hemolysis. Addition of black tea extract (100 mu g/mL in final 4.0 mL volume) to the RBC suspensions did not significantly affect hemolysis. However, concurrent addition of 0.5 mL of NaF (500 mu g/mL in final 4.0-mL volume) and 0.025-1.0 mL of black tea extract (2.5-100 mu g/mL in final volume) caused a significant reduction in the percent hemolysis with maximum amelioration occurring at 40 Ng extract/mL. The higher concentrations of tea extract (50-100 mu g/mL) did not produce further amelioration, but the percent hemolysis remained significantly lower than that of the NaF treated RBC suspensions.