Traditional uses, phytochemistry, and pharmacology of Ailanthus altissima (Mill.) Swingle bark: A comprehensive review

Ethnopharmacological relevance: The dried bark of Ailanthus altissima (Mill.) Swingle (BAA), commonly designated as "Chunpi" in Chinese, is extensively used as a common traditional medicine in China, Korea, and India. It has been used to treat multiple ailments, including asthma, epilepsy, spermatorrhea, bleeding, and ophthalmic diseases, for thousands of years. Aim of the review: To present a comprehensive and constructive review on the phytochemistry, pharmacology, pharmacokinetics, traditional uses, quality control, and toxicology of BAA; to aid the assessment of the therapeutic potential of BAA; to guide researchers working on the development of novel therapeutic agents. Materials and methods: Information related to BAA (from 1960 to 2020) was retrieved from a wide variety of electronic databases, such as PubMed, Web of Science, China Knowledge Resource Integrated Database, ScienceDirect, SciFinder, and Google Scholar. Additional information and materials were acquired from Chinese Medicine Monographs, the 2020 edition of the Chinese Pharmacopoeia, and several web sources, such as the official website of The Plant List and Flora of China. Additionally, perspectives for future investigations and applications of BAA were extensively explored. Results: Approximately 221 chemical compounds, including alkaloids, quassinoids, phenylpropanoids, triterpenoids, volatile oils, and other compounds, have been isolated and characterized from BAA; among these, the quassinoid ailanthone is the most typical. The crude extracts and active compounds of BAA have been reported to exert a wide range of pharmacological activities, such as antitumor, anti-inflammatory, antiviral, herbicidal, and insecticidal activities. Although BAA is safe when administered at a conventional dose, at higher doses, it exhibits toxicity due to the presence of quassinoids. Thus, more studies are required to evaluate the efficacy and safety of BAA. Conclusion: Modern pharmacological studies have revealed that BAA, as a valuable medicinal resource, possesses the potential to treat a wide variety of ailments, especially, cancer and gastrointestinal inflammation. These studies present a wide range of perspectives for the development of new drugs related to BAA. However, only a few traditional uses are associated with the reported pharmacological activities of BAA and have been confirmed by preclinical and clinical studies. Moreover, the pharmacokinetics, toxicology, and quality control of BAA should be considered indispensable research topics.