Research progress on triterpenoids of Betula plants

The secondary metabolites of plants are important sources of natural drugs. Betula plants have abundant pharmacological value, complex mechanism and wide applications, which are closely related to the triterpenoids of theirs. Triterpenoids in Betula species are mainly divided into dammarane-type, ocotillol-type, oleanane-type, lupane-type and cycloaltunane-type. The extracts of Betula species have varieties of activities such as anti-tumor, anti-inflammatory, anti-oxidant, anti-bacterial, etc. And the biosynthetic pathways of triterpenoids after 2, 3-oxidosqualene are split into four branches of dammarenediol-Ⅱ, lupeol, cycloartenol and amyrin according to the different oxidosqualene cyclases. This review summarizes the chemical constituents, pharmacological activities and biosynthetic pathways of triterpenoids in Betula plants. It provides a reference for the research and development of new drugs and the production of these triterpenoids in microbial cell factories by synthetic biology methods.