Sterculia and Brachychiton: a comprehensive overview on their ethnopharmacology, biological activities, phytochemistry and the role of their gummy exudates in drug delivery

Objectives Sterculia and Brachychiton are two related genera (Malvaceae) containing more than 300 species. Most of these species are ornamental trees that are native to Australia and widely cultivated in many countries. Different members of the two genera were used by various cultures for medicinal and economical purposes. This review sheds light on the medicinal values and chemical composition of various species of these two genera. Key findings Sterculia and Brachychiton species were used traditionally for the treatment of gastrointestinal disorders, microbial infection, skin diseases, inflammation and many other conditions. The seeds of various species were roasted and eaten by many traditional tribes. Plants from the two genera revealed their anti‐inflammatory, antioxidant, antimicrobial, antidiabetic, antiulcer, insecticidal and analgesic activity. These activities may be attributed to the presence of a wide range of secondary metabolites as flavonoids, phenolic acids, coumarins, terpenoids particularly sesquiterpenes and triterpenes in addition to sterols and fatty acids. Moreover, the gummy exudates obtained from some members of these genera played an important role in different pharmaceutical dosage forms and drug‐delivery systems. Conclusions More research is recommended on other species of Sterculia and Brachychiton to discover new molecular entities with potential biological and economic values.