Use of plant-derived compounds for chilled gamete storage in felids and canids

Wild felids and canids play important roles in maintaining ecosystem stability and biodiversity, yet many species are threatened by habitat loss, climate change, urbanization, and poaching. Assisted reproductive technologies (ARTs) have therefore become valuable tools for wildlife conservation and genetic resource banking. However, prolonged storage and post-mortem deterioration remain major limitations affecting gamete quality and fertilizing ability. Oxidative stress is a major cause of gamete deterioration during chilled storage. During chilled storage, excessive reactive oxygen species (ROS) production can induce membrane damage, mitochondrial dysfunction, DNA fragmentation, apoptosis, and impaired fertilization capacity. Because endogenous antioxidant defenses progressively decline during chilled storage, supplementation with exogenous antioxidants has gained increasing attention for improving gamete survival during storage. This review summarizes the potential applications of plant-derived antioxidants in chilled storage of reproductive tissues and cells, focusing on chamuangone from Garcinia cowa Roxb. (Cha Muang), green tea polyphenols, and curcumin from Curcuma longa. These compounds have demonstrated beneficial effects on sperm motility, viability, membrane integrity, oocyte maturation, and fertilization-related biomarkers during chilled storage of feline and canine reproductive tissues. Antioxidant supplementation has also been associated with storage of IZUMO1 and integrin β5 expression together with reduced apoptosis-related markers such as cleaved caspase-3. Collectively, plant-derived antioxidants may improve short-term chilled storage of gamete through antioxidative, anti-apoptotic, and membrane-stabilizing mechanisms, highlighting their potential applications in reproductive biotechnology and conservation programs.