Infertility affects about 25% of couples worldwide, and oxidative stress (OS) is linked to its idiopathic etiology. Green, black, white,
and oolong teas are produced from Camellia sinensis, depending on their oxidation level, and contain antioxidant properties that
may enhance male reproductive functions. The study aimed to investigate the effects of black tea aqueous extract on human sperm
functions in vitro. Semen samples were collected from donors, liquefied, analyzed, and divided into normal (n=40) and abnormal
(n=19) groups using the World Health Organization 2010 criteria. Samples were washed and incubated with black tea aqueous
extracts (0, 0.4, 4, 40, 405 μg/ml) for 1 hr and analyzed. Along with a considerable decrease in intracellular reactive oxygen species
(ROS) production, DNA-fragmented spermatozoa, and acrosome reaction, the percentage of sperm vitality and intact mitochondrial membrane potential (MMP) increased (p<0:05). Furthermore, compared to the normal group, a substantial increase in the
percentage of acrosome reaction, ROS production, and percentage of spermatozoa with fragmented DNA, while a reduction in the
percentage of intact MMP and sperm vitality, was noted in the abnormal group (p<0:05). Compared to the controls, there was no
significant change in motility between the normal and abnormal groups (p>0:05). Black tea’s antioxidant activity, caffeine
concentration, or both may have contributed to its improvement in human sperm function in vitro.