Green tea (Camellia sinensis) aqueous extract improved human spermatozoa functions in vitro

Background: Idiopathic causes of infertility is associated with oxidative stress. Antioxidants are known to scavenge the excessive production of reactive oxygen species (ROS). Green tea (Camellia sinensis) contains polyphenols that enhance its antioxidant potential. Aim: This study focused on the impact of aqueous green tea extract on normozoospermic human spermatozoa. Setting: Department of Medical Biosciences, University of the Western Cape (UWC), South Africa. Methods: Semen samples obtained using masturbation method following three to five days of sexual abstinence from consenting men (n = 59) at the University of the Western Cape (UWC) were liquefied and analysed. Normozoospermic samples were selected according to the World Health Organization (WHO) 5th guideline. Thereafter, semen samples (7.5 × 106 /mL) were washed in human tubular fluid (HTF; 10 min at 300 ×g) and exposed to aqueous extracts of green tea (0 μg/mL, 0.4 μg/mL, 4 μg/mL, 40 μg/mL, 405 μg/mL) for 1 h with various sperm parameters analyzed. Human tubular fluid supplemented with bovine serum albumin (HTF-BSA; 10%) served as control. Results: Sperm motility, reactive oxygen species production, across some reaction and deoxyribonucleic acid (DNA) fragmentation decreased significantly, particularly at the highest concentration (405 μg/mL; p 0.001). A substantial increase in the percentage of viable spermatozoa and those with intact mitochondrial membrane potential (MMP) were observed (p 0.001). Conclusion: Aqueous extract of green tea prolonged sperm viability and MMP while reducing sperm intracellular ROS production, capacitation and across some reaction and DNA fragmentation, and may be attributed to its antioxidant potential. However, a high concentration of the extract appears to be detrimental to the functioning of human spermatozoa.