Abstract
Introduction: Herbal medicines are popular, despite a lack of regulation and research into safety and efficacy [1]. Supplements marketed for fertility are prevalent, but most studies regarding sperm focus on motility, with little research regarding toxicity. This study aimed to characterise the biochemical changes that occur in sperm after in vitro exposure to three common herbal supplements; green tea extract (GTE), maca root and Korean ginseng.
Methods: 12 ejaculates from three Merino rams were collected for each supplement, and sperm incubated with 0, 0.1, 0.5, 1 or 5 mg/ml of GTE, Korean ginseng (Paanax ginseng) or maca root (Lepidium meyenii). Supplements were dissolved in DMSO and PBS with a final concentration of 1% DMSO in all samples. At 0.5, 3 and 6 h post-exposure, computer-assisted sperm analysis (CASA) and flow cytometry were used to assess motility, viability, acrosome reaction, membrane lipid disorder, mitochondrial superoxide production, intracellular reactive oxygen species (ROS) and DNA fragmentation.
Results: Treatment with each supplement induced acrosome reaction in treated cells (2.02%± 0.39 n=180 p < .001), but showed no difference in viability(73.3%±1.49 n=180 p > .05). There was increased mitochondrial superoxide production across all concentrations and time points for each sup-plement (9.72%± 0.79% n=180 p < .001), as well as membrane lipid disorder across all supplements (17.28%±0.85 n=180 p < .001). All concentrations of GTE, and 0.5, 1 and 5 mg/ml ginseng and maca increased DNA fragmentation (7.71% ± 0.39% n=180 p < .001). Intracellular ROSproduction increased with 0.1, 0.5 and 5 mg/ml GTE (7.42%±0.45% p < .001).
Conclusions: Despite the reported antioxidant activity of herbal supplements, the increase in mitochondrial superoxide production and DNA fragmentation suggests that exposure to these concentrations of ginseng, maca and GTE increased oxidative stress in sperm [2]. The higher membrane fluidity and reduced acrosome integrity suggests potential oestrogenic activity of herbal supplements, as oestrogen can induce capacitation-like changes[3]. Despite the popularity and perceived safety of herbal supplements, this research indicates they should be used with caution until their effects are further elucidated.