Four new oleanane-type triterpene glycosides, proceraosides A-D (1-4), were isolated from the seeds of Albizia procera. Their structures were established by extensive NMR experiments and chemical methods. Compounds 1-3 comprised acacic acid as the aglycon and a monoterpenic carboxylic acid linked to a monoterpene quinovoside as the acyl moiety at C-21. The common oligosaccharide moiety linked to C-28 in 1-3 was determined as alpha-l-arabino- furanosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->3)]-alpha-L-rhamnopyranosy l- (1-->2)-beta-D-glucopyranosyl ester. These compounds differed in the C-3-linked sugar unit or in the configuration of C-6' of the inner monoterpene moiety in the C-21-linked acyl unit. Compound 4 was established as the 16-deoxy analogue of 1.

Four new oleanane-type triterpene glycosides, pithedulosides H-K (1-4), were isolated from the seeds of Pithecellobium dulce. Their structures were established by extensive NMR experiments and chemical methods. Compounds 1-3 comprised acacic acid as the aglycon and either monoterpene carboxylic acid and its xyloside or monoterpene carboxylic acid as the acyl moiety at C-21. The oligosaccharide moieties linked to C-3 and C-28 were determined as alpha-L-arabinopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1 -->6)- [beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosyl and alpha-L-arabinofuranosyl-(1-->4)-[beta-D-glucopyranosyl-(1-->3)]-alpha- rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl ester, respectively. Compound 4 was established as an echinocystic acid 3-O-glycoside having the same sugar sequences as 1-3. Also obtained in this investigation was the known compound 5, which was identified as echinocystic acid 3-O-beta-D-xylopyranosyl- (1-->2)-alpha-L-arabinopyranosyl-(1-->6)-[beta-D-glucopyranosyl-(1 -->2)]- beta-D-glucopyranoside.

The antiulcer effect of aqueous extracts of the leaves of the neem tree was investigated in rats exposed to 2-h cold-restraint stress or given ethanol orally for 1 h. Extracts were administered in doses of 10, 40, or 160 mg leaf/kg body weight, either as single- or five-dose pretreatment regimens. Neem dose-dependently reduced gastric ulcer severity in rats subjected to stress and also decreased ethanol provoked gastric mucosal damage. The extract appeared to prevent mast cell degranulation and to increase the amount of adherent gastric mucus in stressed animals. These effects may explain, at least in part, the mode of the antiulcer action of neem.

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