[Triterpenoid constituents in fruits of Psidum guajava].

The chemical constituents from the fruit of Psidium guajava were investigated. Nine triterpenoids, ursolic acid (1), 1beta, 3beta-dihydroxyurs-12-en-28-oic acid (2), 2alpha,3beta-dihydroxyurs-12-en-28-oic acid (3), 3beta,19alpha-dihydroxyurs-12en-28-oic acid (4), 19a-hydroxylurs-12-en-28-oic acid-3-O-alpha-L-arabinopyranoside (5), 3beta, 23-dihydroxy urs-12-en-28-oic acid (6), 3beta, 19alpha, 23beta-tri-hydroxylurs-12-en-28-oic acid (7), 2alpha, 3beta,19alpha, 23beta-tetrahydroxyurs-12-en-28-oic acid (8), 3alpha,19alpha,23,24-tetrahydroxyurs -12-en-28-oic acid (9) were isolated by means of chromatography, and their structures were elucidated on the basis of MS, H NMR, 13C-NMR spectra. Compounds 2, 5-9 were isolated from this plant for the first time.