[Examination of original plant of Jamaica quassia extract, a natural bittering agent, based on composition of the constituents].

Jamaica quassia extract is a natural bittering agent used as a food additive in Japan. The main constituents of the extract have already been reported to be quassin and neoquassin. In this study, the differences in composition of the constituents among four Jamaican quassia extract products were analyzed by LC/MS. The results showed that the four products have similar compositions of their minor constituents, as well as their main constituents. We isolated four of the minor constituents that were commonly included in the four products, and identified them as 11-dihydro-12-norneoquassin, canthin-6-one, 4-methoxy-1-vinyl-beta-carboline and 4,9-dimethoxy-1-vinyl-beta-carboline. The List of Existing Food Additives in Japan mentions that Jamaica quassia (Picrasma excelsa) is the original plant from which Jamaica quassia extract is produced. However, we presume that Jamaica quassia extract may actually be made from appropriate plants other than Picrasma excelsa, since P. excelsa is listed as an endangered species by the International Union for Conservation of Nature and Natural Resources. We prepared hot water extracts from two other species of plants, Quassia amara (American quassia, Surinam quassia) and P. quassioides ('Nigaki' in Japanese), and investigated their constituents by LC/MS. The results showed that the compositions of the constituents in the Jamaica quassia extract products resembled those in the extract derived from Q. amara. These findings suggest that Jamaica quassia extract products are probably made from Q. amara.

Promoting potential of a Jamaica quassia extract in a rat medium-term hepatocarcinogenesis bioassay.

Jamaica quassia extract (JQE), a natural bittering agent, was investigated for hepatocarcinogenesis-promoting potential using a medium-term liver bioassay system. F344 male rats were given a single intraperitoneal injection of diethylnitrosamine (200mg/kg body weight) and then starting 2 weeks later, received JQE in the diet at concentrations of 500, 5000 or 30,000 ppm for 6 weeks. Animals for tumor promotion (+) and (-) controls were fed 500 ppm sodium phenobarbital (PB) and basal diet, respectively during the promotion phase in this model. All animals were subjected to two-thirds partial hepatectomy at week 3 and killed at week 8. As with the PB-promoted case, both numbers and areas of glutathione S-transferase placental form-positive liver cell foci were significantly increased by JQE at 30,000 ppm, with non-significant increases evident at 5000 ppm. The results thus indicate that JQE at high dose has promoting potential for rat hepatocarcinogenesis.

Quassinoids from Picrasma crenata.

From woods of Picrasma crenata, a new stereoisomer dihydronorneoquassin was obtained together with others well knowns dihydronorneoquassin, parain, alpha-neoquassin, beta-neoquassin and quassin. The structures were determined by spectroscopic data and chemical evidence.