Aqueous extracts of black tea ( Camellia sinensis) enhanced human sperm functions in vitro

Abstract

Black tea, produced by drying and crushing of Camellia sinensis leaves, thereby enhancing oxidation. It contains phytochemicals with antioxidant capacity and might improve male reproductive function by scavenging free radicals. This study aims to investigate the effects of black tea on human sperm in vitro. Semen samples were collected with informed consent after 3-5 days of abstinence from 59 donors at the University of the Western Cape, Bellville, South Africa. After liquefaction, baseline semen analysis was conducted to determine the sperm quality according to WHO (2010) criteria and classified as normozoospermic (n=40) and non-normozoospermic (n=19). Semen was washed with human tubular fluid medium supplemented with 1% bovine serum albumin (HTF-BSA; 1:5), centrifuged (300 xg; 10 min) and exposed to aqueous extract of black tea (0, 0.4, 4, 40 and 405 μg/ml) for 1h at 37ºC. Thereafter, sperm parameters such as motility, vitality, mitochondrial membrane potential (MMP), intracellular reactive oxygen species (ROS) production, capacitation and acrosome reaction were analyzed. Sperm vitality (p<0.01), and MMP (p<0.01) was higher in the black tea treated groups compared to the control, while a reduction in ROS production (p<0.01) and acrosome reaction (p<0.01) was observed in both groups. However, no effect was observed on sperm motility (p>0.05) at any concentration used. Our study shows for the first time the beneficial effect of black tea on human sperm function in vitro, which may be attributed to its antioxidant capacity.