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An experimental model is described to evaluate drug action, medicinal formulations or vegetable extracts on gastrointestinal transit. Test compounds are administered to 4 mice, 30 minutes before beginning the bioessay to assure the absorption. Immediately before the essay, a per os barium sulfate solution is given and serial radiographies are taken every 30 minutes. Observing the progress of the radiopaque substance in the gastrointestinal tract, it is possible to evaluate the action of different compounds among them or with respect to a control group. This method has advantages on some others already described, since it is bloodless, reproducible, reliable and economic. These characteristics allow their regular use to detect compounds that evidence a promissory pharmacological activity. [ABSTRACT FROM AUTHOR]

Centaurea solstitialis is a plant with antiulcerous properties. To isolate and identificate bioactive compounds responsible for the gastroprotective activity, phytochemist bioguided studies were carried out in flavonoids related with this pharmacological activity. A methanolic fraction, obtained from dried heads of the plant, was extracted with ethyl acetate previous hydrolysis with hydrochloric acid. Ethyl acetate fraction was chromatografhied in thin layer on plates of silica gel and the bands, that comigrated with authentic standards of quercetin (Rf = 0.80) and kaempferol (Rf = 0.89), became purified by HPLC, getting the isolating of the two flavonoids. The compounds were recovered and identified by mass spectrometry. Quantitative essays allowed to determine that the heads of the plant contain 0.63 and 1.47 mg of quercetin and kaempferol per gram of dry matter respectively. [ABSTRACT FROM AUTHOR]

Human beings and animals, specially canine and feline, are the species in which Diabetes mellitus has been more frequently diagnosed. Due to the need of finding alternative sources of hypoglycemic drugs and in order to get new drugs with this property, the effect of the aqueous extract of heads of Verbesina encelioides (Ve) was studied on glycemia levels in common mice and in transitory hyperglycemic once. In both assays animals were unfed for 15 hours. The different groups of common mice received an oral doses of 2, 3 and 4 g of aqueous extract of Ve per kg weight. After 6 hours glycemia was determined. The control group only received the vehicle. The glycemia levels in animals treated with 2 and 3 g/kg were significantly smaller to those of the control group (P<0.01). The 4 g/kg dose was lethal for all mice. The effect of the administration of 2 g Ve per kg weight on mice was evaluated. After 30 minutes, each mouse received an oral dose of 3 g of glucose per kg of weight, to become transitory hyperglycemic mice. The control group only received the vehicle and glucose. Glycemia was determined 1, 2, 3 and 4 hours after glucose was administered. These values were related to the basal glycemia levels. The differences between glycemia and basal values was significantly smaller in the group treated than in the group control (P<0.01). [ABSTRACT FROM AUTHOR]

A certain number of prostaglandins (PGs.) and synthetic analogs protect the gastrointestinal mucosa against noxious agents. To study the participation of endogenous PGs. on the cytoprotection that produce Centaurea solstitialis L., Compositae (n.y. Abrepuno) extracts, indomethacin as blocking agent of the PGs. synthesis was used. Residues of methanolic and chloroformic extracts of flowers of the plant with excipients mixture Tween 80 (T 80) and Carboxymethyl cellulose (CMC), were administered by gastric catheter to female mice inmediately before subjecting them to stress by water immersion. A 5 mice group was administered T 80 + CMC (a). Another 4 groups, of equal number of animals, were treated with methanolic (b,c) and chloroformic (d,e) extracts. Groups a, c and e, received a subcutaneous dosis of indometacin (5 mg/kg) each, 1 hour before the bioassay. Four and a half hours later, the animals were sacrified. The stomachs were removed and insufflated with formol at 10% and they were sumerged for 24 hours in this solution, afterwards they were opened by the major curvature, to observe lessions. The stomachs were phtographied and the ulcering area (mm2) was determined by means of an image analyzer. Percentages of inhibition (PI) produced by the extracts in groups b, c, d and e compared with the control group a, were calculated. The PI were 100%; 98.13%; 91.89% and 48.74% for the groups b, c, d and e, respectively. The difference found between the groups d and e (p < 0.05) would implicate an important partial participation of the PGs. in the cytoprotector mechanism of action of the chloroformic extract. Meanwhile, flavonoids, among them kaempferol, present in the methanolic extracts of the plant, showed a moderate effect which would complement with the effects of other components of this fraction, and would allow to state the posibility of a mechanism of action independent of PGs. [ABSTRACT FROM AUTHOR]

Residues aqueous, methanolic and chloroformic extracts of Centaurea solstitialis L. Compositae flowers, commonly known as Abrepuño, were resuspended with an excipient mixture of Tween 80 (T80) and Carboxymethyl cellulose (CMC) and administered through a gastric catheter to female Wistar rats in order to study the citoprotective properties of the plant on ulcers caused by stress due to immersion in water. The essay were carried out by administering T80 + CMC to a group of five rats as control. Other four groups, of equal number of animals, were treated with aqueous (a), methanolic (b), methanolic-chloroformic (1:1) (c) and chloroformic residues, all of them resuspended in a mixture of T80 + CMC. Prevention to ulcers in a, c and d groups was 100%, whereas a 78% was reached in group b (p < 0.05). The methanolic and chloroformic extracts, which contain flavonoid and sesquiterpene lactones respectively, would be responsible for the citoprotective effects shown by these results. [ABSTRACT FROM AUTHOR]

The effects of a partially purified aqueous extract of Solanum malacoxylon (SM) leaves and of an SM extract incubated with ruminal fluid (RF) prior to administration on intestinal phosphate and calcium absorption in rachitic rats were compared with 1α, 25-dihydroxy-vitamin D[1α,25-(OH)-D] using a duodenal loop in situ method. The time course responses elicited by both extracts were qualitatively similar to that of 1α, 25-(OH)-D. However, a single dose of SMRF was significantly more effective in stimulatingP absorption than an equivalent dose of SM. Part of this difference can be accounted for by incomplete saturation of the phosphate transport system with the level of SM employed. Treatment with rumen potentiated the effects of SM onCa absorption to a lesser extent. Extraction of SMRF with nonpolar organic solvents and purification of the lipid extract by chromatography on Silica Gel G thin-layer plates and on Sephadex LH-20 columns yield two fractions which promote intestinalP absorption. The bioactive fraction eluting first from the Sephadex LH-20 column migrates similarly as 1α,25-(OH)-D. The greater effectiveness of SMRF extracts on intestinal phosphate and calcium absorption may be tentatively attributed to the release of 1α,25-(OH)-D from the corresponding glycoside, shown previously to be present in SM, and to steroid modification during incubation with rumen. [ABSTRACT FROM AUTHOR]

The erythrocytes of rats treated with 1,25-dihydroxycholecalciferol or 1,25-dihydroxycholecalciferol glycoside showed decreased levels of 2,3-diphosphoglycerate. The same result has been obtained in vitro, indicating a direct effect of the sterol on the red cell. The glycoside is less active than the free sterol in vivo and more active in vitro. The decreased levels of diphosphoglycerate induced tissue hypoxia as shown by a higher plasma lactate/pyruvate ratio and a three fold increase in plasma erythropoietin concentration. [ABSTRACT FROM AUTHOR]