Bioactive natural products predominantly derived from Chinese herbal medicines for diminished ovarian reserve: mechanistic insights into ovarian protection.

Diminished ovarian reserve (DOR) is characterized by a reduction in oocyte quantity and quality and involves complex, interconnected pathological mechanisms. This review systematically evaluates bioactive natural products, predominantly derived from Chinese herbal medicines, using a mechanism-first framework, while considering their chemical scaffolds and botanical sources as complementary descriptors. Current evidence indicates that these compounds exert ovarian-protective effects through coordinated regulation of oxidative stress, inflammatory responses, DNA-damage repair and cellular senescence, apoptosis-related signaling, ferroptosis, and autophagy-mitophagy homeostasis. Across granulosa-cell systems and animal models of chemotherapy-induced ovarian injury, irradiation, accelerated aging, and reproductive aging, representative compounds have demonstrated beneficial effects on endocrine function, follicular preservation, mitochondrial homeostasis, oocyte quality, and fertility-related outcomes. Their capacity to modulate multiple interacting pathways may be particularly valuable for DOR, given its multifactorial pathogenesis. Emerging findings further suggest that the effects of apoptosis-, autophagy-, and growth-related signaling are dependent on cell type, pathway status, dose, timing, and disease stage, highlighting restoration of ovarian homeostasis as a central therapeutic principle. Although further studies incorporating rigorous causal validation, ovarian pharmacokinetic characterization, and standardized experimental design are warranted, the available evidence supports these natural products as promising candidates for mechanistic investigation and future therapeutic development in DOR.