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A method was developed for the isolation and identification of phytosterols and fatty alcohols in jojoba oil. The method consists in the separation of these compounds from wax esters in the oil by means of an aluminum oxide column followed by further fractionation of the minor components by column chromatography on silica gel. The 4-demethylsterols, 4-methylsterols, triterpene alcohols (4,4-dimethylsterols), and fatty alcohols are identified by means of their gas chromatographic and mass spectrometric data. The present paper includes a method for the quantitation of the free sterols in jojoba oil. Keywords: Plant; alcohol; sterol; lipid; Simmondsia

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A high-pressure liquid chromatographic method for the determination of diuron and its metabolites in human urine and blood is presented. The synthesis of different metabolites and of a suitable internal standard is described and the structure of the compounds is determined by mass spectrometry and nuclear magnetic resonance spectroscopy. The method is applied to an overdose case.

The seed oils from fifteen hybrid Hibiscus varieties were analyzed for desmethyl sterol content to identify bioactive compounds that could promote the use of these oils for edible applications. Hibiscusis being developed as a new crop with edible and nutraceutical applications for the component tissues and tissue extracts. Previously, hybrid varieties were developed for ornamental purposes on the basis of flower morphology and color. Currently, the effects of selective breeding on seed oil components are of interest as these represent potential natural products with bioactive properties. In the present study, sterol structures were identified as the corresponding trimethyl silyl ether derivatives obtained from the unsaponifiable fraction of the seed oils. This material contained an average of 32 wt % sterols and exhibited a relative composition of sitosterol, 76.3%; campesterol, 10.3%; stigmasterol, 7.3%; 5-avenasterol, 4.4%; and cholesterol, 0.6%. The content of 5-avenasterol showed statistically significant variation among the hybrid varieties with a range of 1.2-5.8%.

Background and purpose: Acute intraperitoneal (i.p.) administration of cholecystokinin (CCK) is known to induce a significant, but short-lasting, reduction in food intake, followed by recovery within hours. Therefore, we had covalently coupled CCK to a 10 kDa polyethylene glycol and showed that this conjugate, PEG-CCK 9 , produced a significantly longer anorectic effect than unmodified CCK 9 . The present study assessed the dose-dependency of this response and the effect of two selective CCK 1 receptor antagonists, with different abilities to cross the blood-brain barrier (BBB), on PEG-CCK 9 -induced anorexia. Experimental approach: Food intake was measured, for up to 23 h, after i.p. administration of different doses (2, 4, 8, 16 and 32 mg kg À1 ) of CCK 9 or PEG-CCK 9 in male Wistar rats. Devazepide (100 mg kg À1 ), which penetrates the BBB or 2-NAP (3 mg kg À1 ), which does not cross the BBB, were coadministered i.p. with PEG-CCK 9 (6 mg kg À1 ) and food intake was monitored. Key results: In PEG-CCK 9 -treated rats, a clear dose-dependency was seen for both the duration and initial intensity of the anorexia whereas, for CCK 9 , only the initial intensity was dose-dependent. Intraperitoneal administration of devazepide or 2-NAP, injected immediately prior to PEG-CCK 9 , completely abolished the anorectic effect of PEG-CCK 9 . Conclusions and implications: The duration of the anorexia for PEG-CCK 9 was dose-dependent, suggesting that PEGylation of CCK 9 increases its circulation time. Both devazepide and 2-NAP completely abolished the anorectic effect of i.p. PEG-CCK 9 indicating that its anorectic effect was solely due to stimulation of peripheral CCK 1 receptors.

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Simmondsin, a glycoside extracted from jojoba meal (Simmondsia chinensis), causes a reduction in food intake after oral administration. To investigate the mechanism by which simmondsin reduces food intake, fasted and free-feeding rats were given simmondsin-supplemented food and simultaneously injected with devazepide, a specific antagonist of peripheral-type cholecystokinin receptors (CCKA receptors). In free-feeding rats, supplementation of food with 0.5% simmondsin caused a reduction in food intake of +/- 40% in the period of 4 h following food presentation. Intraperitoneal injection of 100 micrograms devazepide/kg body weight prevented this effect. In rats fasted for 20 h, the food intake in the 30 min after presentation of food supplemented with 0.15% or 0.50% simmondsin was reduced in a dose-related manner; this was also inhibited by simultaneous application of devazepide. It is suggested that peripheral CCKA receptors are involved in the effect of simmondsin on food intake. However, a direct effect of simmondsin on CCKA receptors has been excluded, since simmondsin was unable to cause contraction of the guinea-pig gallbladder in vitro.