Uvaol is a 6-6-6-6-6 pentacyclic ursane type dihydroxy triterpenoid. It is present in various plants such as Plumeria rubra, Olea europaea, Nerium oleander and Malus domestica. One step conversion of ursolic acid, a 6-6-6-6-6 pentacyclic triterpenic acid having an identical triterpenoid backbone, to uvaol has also been reported. A variety of pharmaceutical properties, including antimicrobial, hepatoprotective, anti-inflammatory, anti-tumour, anti-cancer, cardiovascular effects and healing of cutaneous wounds etc. have been reported. In this review, various plant sources of uvaol and its pharmaceutical properties have been reported.

Erythrodiol, is a naturally abundant biologically active triterpenoid. It is the biosynthetic precurso r of pentacyclic oleanae-type triterpenic acids in plants. This is a dihydroxy triterpenoid having beta-amyrin type fused pentacyclic (6-6-6-6-6) carbon skeleton Herein, we have reviewed the various plant resources of this oleanane-type triterpenoid erythrodiol. Various pharamacological activities of erythrodiol have also been discussed.