The pentacyclic triterpenes, in particular ursolic acid and oleanolic acid
and their derivatives, exist abundantly in the plant kingdom, where they
are well known for their anti-inflammatory, antitumour and antimicrobial
Using a degenerate primer designed from triterpene synthase sequences, we
have isolated a new gene from the medicinal plantArtemisia annua. The
predicted protein is highly similar to b-amyrin synthases (EC 5.4.99.–),
sharing amino acid sequence identities of up to 86%.
An oxidosqualene cyclase cDNA, LcIMS1, was isolated from cultured cells of Luffa cylindrica Roem. by heterologous hybridization with cDNA of Glycyrrhiza glabra b-amyrin synthase. Expression of LcIMS1 in yeast lacking endogenous oxidosqualene cyclase activity resulted in the accumulation of isomultiﬂorenol, a triterpene. This is consistent with LcIMS1 encoding isomultiﬂorenol synthase, an oxidosqualene cyclase involved in bryonolic acid biosynthesis in cultured Luffa cells.
Oleanane-type triterpene is one of the most widespread triterpenes found in
plants, together with the lupane type, and these two types often occur
together in the same plant. Bruguiera gymnorrhiza(L.) Lamk. and Rhizo-phora stylosaGriff. (Rhizophoraceae) are known to produce both types of