Pentacyclic triterpenoids from the leaves of Plumeria obtusa

Abstract Nine pentacyclic triterpenoids along with a coumarin have been isolated from the fresh, undried and uncrushed spring leaves of Plumeria obtusa . The new triterpenes obtusin and obtusilic acid have been characterized as the 24- E and 27- Z p -coumaric esters of the novel 3β,24-dihydroxyurs-12-en-28-oic acid and 3β,27-dihydroxyurs-12-en-30-oic acid, respectively, through chemical and spectral studies while the other eight compounds have been identified as known kaneroside, oleandrin, α-amyrin, neriucoumaric acid, isoneriucoumaric acid, alphitolic acid, oleanonic acid, methyl p - E -coumarate and scopoletin hitherto unreported from this source.