Recent Advances in 10-Hydroxy-2-Decenoic Acid (10-HDA): Biosynthesis, Biological Functions, and Regulatory Mechanisms...

Royal jelly (RJ) is a highly valued bee-derived functional food and natural health product, in which 10-hydroxy-2-decenoic acid (10-HDA) represents the most characteristic lipid component. As a unique fatty acid found exclusively in RJ, 10-HDA serves not only as a key marker for product authenticity, freshness, and quality evaluation but also as a major contributor to the biological activities of RJ, including immunomodulatory, metabolic regulatory, antimicrobial, anti-inflammatory, antitumor, and dermatological effects. Given its nutritional and quality-related importance, and because most previous reviews have focused primarily on the biological activities or compositional characteristics of 10-HDA, current knowledge regarding its biosynthesis, secretion, and regulatory mechanisms in worker mandibular glands has not yet been systematically organized and summarized. Understanding these processes is essential for explaining the biological origin of 10-HDA accumulation in RJ and for developing strategies to improve 10-HDA yield, royal jelly quality, and production standardization. This review summarizes current knowledge on the physicochemical properties and health-related functions of 10-HDA and further integrates recent advances in its endogenous biosynthesis and regulatory mechanisms. Particular emphasis is placed on the proposed three-step biosynthetic pathway, beginning with stearic acid and proceeding through cytochrome P450-mediated ω-hydroxylation, successive β-oxidation, and terminal dehydrogenation. We also discuss how 10-HDA production is shaped by worker developmental stage, glandular maturation, genetic background, dietary nutrients, botanical origin, endocrine signals, and apicultural management practices. By linking the biological origin of 10-HDA with its functional properties and quality-determining role in RJ, this review provides an integrated framework for understanding the formation of 10-HDA-rich royal jelly. By linking the biological origin, functional properties, and quality-determining role of 10-HDA in RJ, this review provides an integrated framework for understanding 10-HDA-rich royal jelly. It also identifies key gaps in biosynthetic validation, secretion mechanisms, and regulatory networks, offering guidance for RJ quality standardization, production optimization, and functional food development.