Symplocos: From Phytochemistry and Structure-Activity Relationships to Mechanism-based Therapeutic Values – A Review

Abstract: The genus Symplocos (the family Symplocaceae) has long been used in traditional medicine for treating inflammatory, metabolic, and hepatic disorders. Recent pharmacological evidence supports these uses, yet no integrated evaluation of its chemistry, biological mechanisms, and Structure-activity Relationships (SAR) has been conducted. The current study provides an insightful review of the structural diversity, pharmacological actions, and SAR of Symplocos species, emphasizing their therapeutic importance and potential involvement in integrative medicine. Information was methodologically gathered from the English scientific databases, including Scopus, Web of Science, Google Scholar, and ScienceDirect, up to September 2025. The most significant keyword that was utilized alone or in combination to find references was “Symplocos”. A total of 236 compounds have been summarized, the majority of which are triterpenoids, triterpenoid saponins, phenolics, flavonoids, and lignans. Numerous in vitro and in vivo pharmacological results were documented, including cytotoxic, antioxidant, anti-inflammatory, antidiabetic, antinociceptive, antidepressant, hepatoprotective, renoprotective, and reproductive hormonal activities. Mechanistically, these actions involved the regulation of the PI3K/Akt, MAPK, and NF-κB pathways, the enhancement of GSH, SOD, and CAT activities, and the RORγt-Th17 inhibition in metabolic and autoimmune models. From the SAR analysis, glycosylation and other substitution patterns remarkably affected bioactivity and selectivity. Symplocos species are a rich reservoir of bioactive molecules with clearly defined mechanistic and structural determinants. Their proven pharmacological properties provide a scientific basis for the development of mechanism-based natural therapies.