Study on phytochemical and pharmacological activities of four Rhododendron plants endemic to Northeast China

Rhododendron micranthum Turcz., Rhododendron capitatum Maxim., Rhododendron dauricum L. and Rhododendron schlippenbachii Maxim. are four species of Rhododendron with the same geographical distribution, mainly distributed in the northeast of China and abundant in sources. This paper is the first comprehensive review on the chemical composition and pharmacological activities of these four species. The review, showed 323 compounds including terpenoids, flavonoids, coumarins, lignans, and volatile components were found in the four plants, and these four plants of Rhododendron not only had many chemical constituents of novel structures but also possessed extensive pharmacological effects, such as insecticide, analgesic, antibacterial, antitumor and so on. These research papers and literatures about the four plants were carried out using resources including classic books about Chinese herbal medicine, Flora Reipublicae Popularis Sinicae, and scientific databases including Web of Science, Sci-Finder, CNKI, Pubmed, etc. In recent years, our research group has engaged in the study of chemical composition and pharmacological activities of Rhododendron plants. The terpenes and volatile components isolated from Rhododendron plants contributed greatly to insecticidal activity. Therefore, it is of great significance to review researches of the four endemic resource-rich Rhododendron plants to help make full use of them especially on plant-derived insecticide. This comprehensive review will be significant for the discovery of new bioactive compounds from the above four endemic plants and will be informative for researchers seeking for new pharmacological activity of the four species.