Characterization of the Omija ( Schisandra chinensis) Extract and Its Effects on the Bovine Sperm Vitality and Oxidative Profile during In Vitro Storage

Schisandra chinensis is a woody vine native to China, Korea, and Russia, which has been used as a traditional herbal remedy to treat male infertility. As very little information is available concerning its effects on ejaculated spermatozoa, the aim of this study was to investigate the chemical, antioxidant, and antibacterial properties of the S. chinensis berry (Omija) extract followed by an assessment of its in vitro effects on bovine sperm function and oxidative balance. Phytochemical components of the Omija extract were determined by high performance liquid chromatography. The content of polyphenols, flavonoids, and carotenoids was assessed by spectrophotometric protocols. Antioxidant characteristics of the Omija extract were determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and molybdenum-reducing antioxidant power (MRAP) assays. The disc diffusion method and determination of the minimal inhibitory concentration were applied to study the antibacterial properties of Schisandra. Thirty semen samples were exposed to different concentrations of Omija (1, 5, 10, 25, 50, and 75 µg/mL) for 0, 2, and 24 h. Sperm motility, mitochondrial activity, and superoxide and reactive oxygen species production, as well as total antioxidant capacity and oxidative damage to proteins and lipids were determined. Our data reveal that the Omija extract, particularly at a concentration range within 5-50 µg/mL, exhibited dose-dependent motion-promoting and metabolism-enhancing properties, accompanied by significant antioxidant effects. We may conclude that the biomolecules present in the Omija extract such as schisandrins and phenolic molecules offer protection to critical sperm structures against oxidative insults and/or possible bacterial contamination, leading to a higher preservation of mammalian sperm viability and functional activity.