Determination and assay validation of the bioactive sesquiterpene lactone xanthatin isolated from Xanthium cavanillesii using capillary electrophoresis.

This study describes the development and validation of a method for quantification of the antiulcer experimental drug xanthatin in tablets by capillary electrophoresis (CE). Solid oral dosage forms based on xanthatin were designed and assayed on rats. A CE methodology was developed; the parameters evaluated were: background electrolyte composition, concentration and pH, applied voltage and sample preparation. The method was validated in terms of range of linearity, limits of detection (LOD) and quantification (LOQ), accuracy, precision and selectivity and then applied to the pharmaceutical dosage forms. Xanthatin determination was carried out in less than 3 min with a 20 mM sodium tetraborate buffer, pH 9.20. Drug concentration per tablet found was 2.97 +/- 0.2 mg. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, LOD and LOQ were 7.6 and 26 microg mL(-1) respectively. For accuracy evaluation a recovery test was performed, the values being better than 98.6%. With respect to precision, the results obtained were better than 1.02 RSD% (repeatability) and 1.54% (intermediate precision). After the manufacturing process the resulting tablets were biologically active. The methodology developed is useful, simple and rapid for xanthatin determination in tablets.

Antiinflammatory activity from aerial parts of Baccharis medullosa, Baccharis rufescens and Laennecia sophiifolia in mice.

The antiinflammatory activities of ten organic extracts from the aerial parts of Baccharis medullosa DC., Baccharis rufescens S. and Laennecia sophiifolia (Kunth) G. L. Nesom were investigated in mice subjected to carrageenan induced paw oedema. Intraperitoneally administered organic extracts given at doses equivalent to 80 mg/kg of material inhibited the acute phases of inflammation in this model. Our results indicate that the most effective extracts were: n-hexane (I) from B. medullosa, acetone (V) and chloroform (VII) from L. sophiifolia, and acetone (VIII) and chloroform (X) from B. rufescens. All exerted the strongest effect at 5 h after injection of the phlogistic agent.

Diterpenes from Laennecia sophiifolia.

From the aerial parts of Laennecia sophiifolia (Kunth) G.L. Nesom, a neo-clerodane and an acyclic furano diterpene were isolated, along with four known compounds, 2beta-hydroxyhardwickiic acid, hawtriwaic acid, apigenin, and beta-sitosterol. Their structures were established as 12-epi-bacchotricuneatin A and (2E,6E)-9-(3-furyl)-6-methyl-2-(4-methylpent-3-enyl)-nona-2,6-dienoic acid, by analysis of spectral evidence. The absolute structure of 12-epi-bacchotricuneatin A was determined by a circular dichroism spectral comparison with that of bacchotricuneatin A.

Growth-inhibitory activities of benzofuran and chromene derivatives toward Tenebrio molitor.

Growth-inhibitory activities of selected natural benzofurans (4-9), trans-cinnamic acid derivatives (10-13), chromene compounds (14 and 16), and some semisynthetic derivatives were determined in last instar larvae of Tenebrio molitor via topical administration in Me2CO. The most inhibitory of the tested compounds were 3-gamma, gamma-dimethylallyl-p-coumaric acid (10) and the benzofuran derivative 12-(p-cumaroyloxy)-tremetone (5), the former compound acting on the pupae and the latter on the last instar larvae. Several developmental deficiencies were observed, and some structure-activity relationships are discussed.