Investigating effects of aqueous root extract of Mondia whitei on sperm functionality
Introduction: Mondia whitei commonly known as "White Ginger" is a highly acclaimed medicinal plant that is extensively used across Africa. M. whitei is used as treatment for sexual dysfunction and is considered to be an aphrodisiac by traditional medicine practitioners. Yet, scientific evidence to support these claims are minimal and those that are published possess ambiguity. To date, only one study reporting the in vitro effect of the aqueous rhizome extract of M. whitei on human sperm motility is available. Therefore, the aim of the study was to determine the in vitro effects of M. whitei in human sperm functions. Materials and Methods: Roots of Mondia whitei obtained from the tropical Kakamega rain forest, located in the Western Province of Kenya, were cleaned and chopped into smaller segments. These pieces were ovendried at 25℃ for 3 days and milled to form a powdery substance which was infused with hot (about 70℃) distilled water for 1 hour. After cooling and filtration, the extract was frozen at -20℃ and subsequently freeze-dried. The dried extract was then stored at 4℃ in a closed container until experimentation. A total of 60 semen samples were collected: 28 of them represented healthy sperm donors and 32 infertile patients. Among these subjects, oligozoospermic and asthenozoospermic semen samples were identified and analysed separately. Sperm were washed using human tubular fluid medium supplemented with bovine serum albumin (HTF-BSA) and incubated for 1 hour at 37℃ with different concentrations of M. whitei (0.0185, 0.185, 1.85, 18.5 and 185 μg/ml). A sample without M. whitei served as control. Sperm cell motility, vitality, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), capacitation, acrosome reaction and DNA fragmentation were assessed. Results: Total motility and the percentage of sperm with intact MMP showed significant dose-dependent increases in both groups (patient and donor), while, the percentages of progressively motile sperm only revealed significant increases in the patient group. Besides, the percentage of ROS-positive spermatozoa showed significant trend towards higher concentrations in the patient group only. Conversely, a trend towards reduced sperm DNA-fragmentation could be observed in the patient, but not the donor group. Similar tendencies were noted in oligozoospermic and asthenozoospermic, but not for normozoospermic subjects. Yet, sperm vitality, capacitation, acrosome reaction and kinematic parameters were not affected. Conclusions: Phytochemicals present in M. whitei root extract maintains spermatozoa total motility, progressive motility and intact-MMP and DNA integrity. However, at therapeutic concentration (<1.85 μg/ml) it does not trigger sperm intrinsic superoxide production nor increase ROS by causing oxidative stress, that leads to DNA fragmentation.