Clerodendrum inerme (L.) Gaertn.: a critical review on current progress in traditional uses, phytochemistry, pharmacological aspects and toxicity

Clerodendrum inerme (L.) Gaertn., commonly known as garden quinine, is a perennial shrub that belongs to the Lamiaceae family. It has been extensively used in various traditional medicinal practices to treat ailments such as rheumatic pain, arthritis, scrofulous, venereal disease, skin diseases, wounds, fever, cough, dysentery, and more. This review aims to critically examine a comprehensive compilation of recent research on C. inerme, encompassing its botanical characteristics, ethnomedical applications, phytochemicals, pharmacological activity, and toxicological data, in order to provide insights and inspiration for future research, promote further development, and facilitate the rational application of C. inerme. Nearly 95 chemical constituents belonging to different classes have been isolated from C. inerme, including diterpenoids, triterpenoids, steroids, flavonoids, phenolic glycosides, lignans, iridoid and megastigmane glycosides. Notably, diterpenoids, triterpenoids, steroids, and flavonoids are the main bioactive substances that have been extensively studied and demonstrated the most significant bioactivity. Pharmacological studies demonstrated that the extract of C. inerme exhibits a wide range of biological activities, such as antioxidant, antimicrobial, anticancer, antiinflammatory, insecticidal, antifeedant, neuroprotective, anti-motor tic, and so on, which are closely connected to its numerous ethnomedicinal applications. Nevertheless, some literature have reported the toxicity of C. inerme. Therefore, it is imperative to conduct further in-depth studies encompassing toxicology, as well as preclinical and clinical research, to ascertain the safety and efficacy of C. inerme for medicinal purposes.