According to a recent report by the WHO, 50–80 million people suffer with infertility. Amongst these populations, male counterparts account for 20–50% of infertility cases. The aetiology of infertility in men includes many factors such as psychological issues, lifestyle and environmental factors, hormonal disorders and chromosomal abnormalities. The pathophysiology of these aetiologies may be initiated by a local inflammatory reaction increasing reactive oxygen species (ROS) production, which can negatively affect the male reproductive system by altering the hypothalamic–pituitary–gonadotropin axis (HPG axis). Alteration of the HPG axis may affect testicular steroidogenesis, spermatogenesis, the Leydig cells and Sertoli cells, leading to poor semen quality. The prevalence of male infertility underscores the need for a thorough scientific investigation to identify treatable or reversible factors using plant adjuvants with antioxidative properties. Therefore, this review aims to provide an overview of the currently available knowledge on the aetiologies of male reproductive dysfunction, emphasising infertility risk factors, as well as elucidating the possible ways by which readily available alternatives, such as Moringa oleifera leaves, may mitigate male infertility by highlighting its role on the oxidative stress parameters, reproductive hormonal levels, testicular steroidogenesis and spermatogenesis, gene expression, weight and morphology of the testis and sperm parameters.

Leydig cells are essential for steroidogenesis and spermatogenesis. An imbalance in the production of reactive oxygen species (ROS) and the cellular antioxidant level brings about oxidative stress. Oxidative stress (OS) results in the dysfunction of Leydig cells, thereby impairing steroidogenesis, spermatogenesis, and ultimately, male infertility. To prevent Leydig cells from oxidative insults, there needs to be a balance between the ROS production and the cellular protective capacity of antioxidants. Evidence indicates that medicinal plants could improve Leydig cell function at specific concentrations under basal or OS conditions. The increased usage of medicinal plants has been considered a possible alternative treatment for male infertility. This review aims to provide an overview of the impact of oxidative stress on Leydig cells as well as the effects of various medicinal plant extracts on TM3 Leydig cells. The medicinal plants of interest include Aspalathus linearis, Camellia sinensis, Moringa oleifera, Morinda officinale, Taraxacum officinale, Trichilia emetica, Terminalia sambesiaca, Peltophorum africanum, Ximenia caffra, Serenoa repens, Zingiber officinale, Eugenia jambolana, and a combination of dandelion and fermented rooibos (CRS-10). According to the findings obtained from studies conducted on the evaluated medicinal plants, it can, therefore, be concluded that the medicinal plants maintain the antioxidant profile of Leydig cells under basal conditions and have protective or restorative effects following exposure to oxidative stress. The available data suggest that the protective role exhibited by the evaluated plants may be attributed to their antioxidant content. Additionally, the use of the optimal dosage or concentration of the extracts in the management of oxidative stress is of the utmost importance, and the measurement of their oxidation reduction potential is recommended.