Therapeutic potential of eucommia in chronic metabolic diseases: phytochemical basis, pharmacological actions, and molecular mechanisms

Chronic metabolic diseases, mainly including obesity, diabetes mellitus, hyperlipidemia, and metabolic dysfunction-associated steatotic liver disease, are characterized by disorders of glucose and lipid metabolism, abnormal energy homeostasis, chronic low-grade inflammation, and multi-organ dysfunction. With the increasing global burden of these diseases, natural medicines and medicine–food homology resources with potential metabolic regulatory properties have attracted growing attention, although their long-term efficacy and safety require further investigation. Eucommia ulmoides Oliver (Eucommiaceae), hereafter referred to as Eucommia, is a traditional tonic herb in China and has long been used to tonify the liver and kidney and strengthen bones and muscles. Its medicinal bark (Eucommia Cortex), leaves (Eucommia Folium), flowers, and seeds contain diverse bioactive constituents, including iridoids, phenolic acids, flavonoids, lignans, terpenoids, and polysaccharides. Preclinical studies suggest that Eucommia and its bioactive constituents may exert beneficial effects on metabolic abnormalities through several potential mechanisms, including the regulation of fatty acid oxidation, lipid synthesis, insulin resistance, gut microbiota and microbial metabolites, bile acid metabolism, oxidative stress, inflammation, and autophagy, as well as potential protective effects on metabolism-related organs. However, these findings require further validation in human studies. This narrative review summarizes the phytochemical basis, reported pharmacological activities, and proposed molecular mechanisms of Eucommia in chronic metabolic diseases, and discusses the potential of its Folium as a renewable complementary resource, while critically considering the limitations of current evidence regarding clinical efficacy, long-term safety, and environmental and economic sustainability.