Flavonoids from Achyrocline satureioides with relaxant effects on the smooth muscle of Guinea pig corpus cavernosum.

Ethanol extract of the aerial parts of Achyrocline satureioides (Lam.) DC. (Asteraceae) showed a significant, dose dependent, relaxant effect on the smooth muscle of corpus cavernosum strips, obtained from Guinea pig (65.5 +/- 4.1% of relaxation at the dose of 25.0 mg/ml). Bioassay guided fractionation of this extract furnished two flavonoids, quercetin and quercetin 3-methyl ether, with important vasorelaxing effects on the corpus cavernosum strips (79.8 +/- 8.4 and 66.0 +/- 4.8% of relaxation respectively at the dose of 0.075 mg/ml). Two methyl derivatives of quercetin obtained by synthesis, quercetin 3,7,3',4'-tetramethylether and quercetin 3,5,7,3',4'-pentamethylether, showed similar relaxant effects at the dose of 0.075 mg/ml (86.4 +/- 8.5 and 67.31 +/- 1.4% of relaxation respectively). The results show that the ethanol extract of A. satureioides and the assayed compounds exhibit significant vasorelaxing properties. Additionally, it is shown that the number of methyl groups in the quercetin nucleus has no significant influence on the effectiveness of these compounds.

Antinociceptive and antiinflammatory activities of Artemisia copa extracts.

The aqueous extract from aerial parts of Artemisia copa Phil. (Compositae), was evaluated for antinociceptive activity using writhing, formalin, and hot-plate tests in mice. A dose-related antinociceptive response was obtained in the writhing test at doses of 500 and 1000 mg/kg p.o. (percentage of inhibition 23.3 and 52.70, respectively). The extract also inhibited the second phase of formalin test (38.81%) and this effect was not antagonized by pretreatment with naloxone 5mg/kg i.p. Furthermore, no significant effect was obtained in the hot-plate test. Dichloromethane and ethanolic extracts, were analyzed for antiinflammatory activity with the carrageenan-induced paw edema in rats and the ear edema induced by 12-O-tetradecanoylphorbol-13 acetate (TPA) and arachidonic acid (AA) in mice. Both extracts showed antiinflammatory activity in the TPA (88 and 54%), and the ethanolic extract showed a 37% inhibition in AA test. No effects were seen at doses of 300 mg/kg p.o. and 100 mg/kg i.p. in the carrageenan test. The results obtained indicate that A. copa has analgesic and topical antiinflammatory activities that supports the folk medicinal use of the plant.

Argentinian plant extracts with relaxant effect on the smooth muscle of the corpus cavernosum of guinea pig.

Extracts of different polarity from Baccharis trimera, Haplopappus rigidus Huperzia saururus, Maytenus ilicifolia, Satureja parvifolia and Senecio eriophyton were tested for their relaxant activity on smooth muscle using L-phenylephrine precontracted strips of corpus cavernosum obtained from Guinea pigs. Highly significant and dose dependent results were obtained with the dichloromethane extracts of H. saururus (87% of relaxation at the dose of 10 mg/ml), S. parvifolia (95% of relaxation at 2.5 mg/ml) and S. eriophyton (94% of relaxation at 5 mg/ml). Similar effects were observed with the methanol extracts of H. saururus (88% of relaxation at 10 mg/ml) and S. parvifolia (84% of relaxation at 10 mg/ml). These results were comparable to those obtained with the dichloromethane and methanol extracts of the well known Mexican species Turnera diffusa. Moreover, the aqueous extract of H. rigidus and the aqueous and methanol extracts of S. eriophyton were highly effective in a dose dependent manner (more than 90% of relaxation at the dose of 10 mg/ml). Significant results, but with a lower overall relaxant activity (about 70% of relaxation at 10 mg/ml), could also be obtained with the aqueous extract of S. parvifolia and with the dichlormethane and methanol extracts of B. trimera and M. ilicifolia. The positive controls with Sildenafil citrate at doses ranging from 0.35 to 35 microg/ml yielded moderate effects (up to 46% of relaxation at 35 microg/ml). The effects observed in the present study seem to validate the folk medicinal use of the tested plants and open new ways in the search for natural products with vasodilatory effects.

Antinociceptive effect of the aqueous extract of Balbisia calycina.

The aqueous extract from the aerial parts of Balbisia calycina (Gris.) A.T. Hunziker et Ariza (Ledocarpaceae), was evaluated for antinociceptive activity using the abdominal constriction, hot plate and formalin tests. The extract was administered orally to male mice at doses of 200, 400 and 800 mg/kg. A dose-dependent antinociceptive effect of the extract was obtained with the abdominal constriction test at doses of 400 and 800 mg/kg. This antinociceptive effect was not reversed by pretreatment with naloxone. No significant response was obtained with the hot plate test. With the formalin test doses of 400 and 800 mg/kg had no significant effect during the first phase of the test (0-5 min), while with the dose of 800 mg/kg, a significant inhibition during the second phase (15-30 min) was observed. The phytochemical investigation of the aqueous extract of B. calycina revealed the presence of the flavonoids luteolin, avicularin and hyperoside. The possible involvement of these flavonoids (specially luteolin) in the antinociceptive action is discussed.