L. San Román
University of Salamanca
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Journal of Ethnopharmacology | 2002
Mario Francisco Guerrero; Pilar Puebla; Rosalía Carrón; M.L. Martín; L. Arteaga; L. San Román
The antihypertensive and vasodilator effects of ethanolic extracts prepared from Calea glomerata Klatt, Croton schiedeanus Schlecht, Curatella americana L., Lippia alba (Mill)n N.E.Br. and Lupinus amandus, which are medicinal plants used in Colombian folk medicine for the treatment of hypertension, were assayed both in SHR and Wistar rats and in rat isolated aortic rings. At a dose of 20 mg/kg, intravenous bolus administration of the ethanolic extracts, from C. schiedeanus, C. americana and L. amandus showed significant antihypertensive activity in SHR, C. schiedeanus being the most active. C. schiedeanus elicited dose-dependent decreases in mean arterial pressure and heart rate (5-100 mg/kg, i.v.) in SHR but 200 mg/kg administered orally did not show any significant effects, even after 3 h of observation. In intact rat aortic rings, ethanolic extracts from C. schiedeanus and Calea glomerata relaxed the contractions induced by KCl (80 mM) and phenylephrine (10(-6) M) in a concentration-dependent manner (10(-6)-3x10(-4) g/ml), with IC(50) of 6.5x10(-5) (7.3-5.8) g/ml and 7.1x10(-5) (7.9-6.4) g/ml, respectively. Bioguided phytochemical fractionation of the ethanolic extract from C. schiedeanus was started. More than one active principle seems to be present, flavonoids and terpenoids compounds were detected.
Journal of Pharmacy and Pharmacology | 2002
Mario Francisco Guerrero; Pilar Puebla; Rosalía Carrón; M.L. Martín; L. San Román
The vasorelaxant profile of quercetin 3,7‐dimethyl ether, a flavonoid isolated from Croton schiedeanus Schlecht (Euphorbiaceae), was assessed in aortic rings isolated from Wistar rats. To gain insight into its structure‐activity relationship, we compared this substance with quercetin 3,4′,7‐ trimethyl ether (ayanin), another flavonoid isolated from this plant, quercetin 3,3′,4′,7‐tetramethyl ether, a flavonoid synthesized by us, and quercetin. In addition we examined the interaction of quercetin 3,7‐dimethyl ether with the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway. According to their pEC50 values (concentration producing a 50% inhibition of the maximal contractile response) to phenylephrine‐induced precontraction in rat isolated aorta, the potency order was quercetin 3,7‐dimethyl ether > quercetin > quercetin 3,4′,7‐trimethyl ether > quercetin 3,3′,4′,7‐tetramethyl ether (4.70 ± 0.18; 3.96 ± 0.07; 3.64 ± 0.02; 3.11 ± 0.16). The relaxant effect of quercetin 3,7‐dimethyl ether was significantly decreased by the removal of endothelium as well as by methylene blue, an inhibitor of guanylyl cyclase, and by NG‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME), an NO‐synthase inhibitor. Therefore, quercetin 3,7‐dimethyl ether has a NO/cGMP pathway‐related profile, with increased vasorelaxant activity due to hydroxylation at positions 3 and 4 of the B ring. In addition, methylation at positions 3 and 7 with respect to quercetin of the C and A rings, respectively, seems to further enhance the vasorelaxant activity of quercetin 3,7‐dimethyl ether.
British Journal of Pharmacology | 1998
Asunción Morán; M. M. Fernández; Cristina González Velasco; M.L. Martín; L. San Román
1 A study was made of the effects of 5‐carboxamidotryptamine (5‐CT) on pressor responses induced in vivo by electrical stimulation of the sympathetic outflow from the spinal cord of pithed rats. All animals had been pretreated with atropine. Sympathetic stimulation (0.1, 0.5, 1 and 5 Hz) resulted in frequency‐dependent increases in blood pressure. Intravenous infusion of 5‐CT at doses of 0.01, 0.1 and 1 μg kg−1 min−1 reduced the pressor effects obtained by electrical stimulation. The inhibitory effect of 5‐CT was significantly more pronounced at lower frequencies of stimulation. In the present study we characterized the pharmacological profile of the receptors mediating the above inhibitory effect of 5‐CT. 2 The inhibition induced by 0.01 μg kg−1 min−1 of 5‐CT on sympathetically‐induced pressor responses was partially blocked after i.v. treatment with methiothepin (10 μg kg−1), WAY‐100,635 (100 μg kg−1) or GR127935T (250 μg kg−1), but was not affected by cyanopindolol (100 μg kg−1). 3 The selective 5‐HT1A receptor agonist 8‐OH‐DPAT and the selective 5‐HT1B/1D receptor agonists sumatriptan and L‐694,247 inhibited the pressor response, whereas the 5‐HT1B receptor agonists CGS‐12066B and CP‐93,129 and the 5‐HT2C receptor agonist m‐CPP did not modify the pressor symapthetic responses. 4 The selective 5‐HT1A receptor antagonist WAY‐100,635 (100 μg kg−1) blocked the inhibition induced by 8‐OH‐DPAT and the selective 5‐HT1B/1D receptor antagonist GR127935T (250 μg kg−1) abolished the inhibition induced either by L‐694,247 or sumatriptan. 5 None of the 5‐HT receptor agonists used in our experiments modified the pressor responses induced by exogenous noradrenaline (NA). 6 These results suggest that the presynaptic inhibitory action of 5‐CT on the electrically‐induced pressor response is mediated by both r‐5‐HT1D and 5‐HT1A receptors.
British Journal of Pharmacology | 1994
Asunción Morán; Cristina González Velasco; T. Salvador; M.L. Martín; L. San Román
1 A study was made of the effects of 5‐hydroxytryptamine (5‐HT) on pressor response induced in vivo by electrical stimulation of the sympathetic outflow from the spinal cord of pithed rats. All animals had been pretreated with atropine. Intravenous infusion of 5‐hydroxytryptamine at doses of 10 and 20 μg kg−1 min−1 reduced the pressor effects obtained by electrical stimulation at intervals of 10 min over the 1 h of infusion. 2 This inhibitory action of 5‐HT was depressed by cyproheptadine and methiothepin but was not modified by ketanserin or MDL‐72222. By contrast, the inhibitory action of 5‐HT was lost in pithed rats that had been pretreated with exogenous noradrenaline. 3 The 5‐HT1 receptor agonist 5‐carboxamidotryptamine (5‐CT) caused an inhibition of the pressor response, whereas the 5‐HT3 receptor agonist, 1‐phenylbiguanide, produced a variable but significant increase in the pressor response. The 5‐HT2 receptor agonist, m‐CPP, did not modify the pressor sympathetic response. 4 Our results suggest that 5‐hydroxytryptamine interferes with sympathetic neurotransmission by inhibiting pressor effects as a result of stimulation of the complete sympathetic outflow, and that this inhibition is mainly through a presynaptic 5‐HT1 mechanism.
Journal of Ethnopharmacology | 1989
Asunción Morán; M.L. Martín; M.J. Montero; A.V.Ortiz de Urbina; María A. Sevilla; L. San Román
The essential oil of Artemisia caerulescens subsp. gallica was observed to have analgesic, antipyretic and anti-inflammatory actions when administered intraperitoneally to rats and mice at doses one-fourth to one-third that of its LD50 of 1.35 ml/kg. Lysine acetylsalicylate was used as a reference compound.
Journal of Ethnopharmacology | 2001
Mario Francisco Guerrero; Rosalía Carrón; M.L. Martín; L. San Román; M.T. Reguero
Antihypertensive and vasorelaxant effects of treatment with the aqueous extract of Croton schiedeanus Schlecht (AECS) were investigated in anaesthetized spontaneously hypertensive rats (SHR). Intravenous bolus injections of AECS (5-100 mg/kg) elicited dose-dependent decreases in mean arterial pressure (MAP) and heart rate (HR). Additionally, AECS (10(-6)-3x10(-3)g/ml) completely relaxed the contractions induced by high K(+) concentrations in intact rat aortic rings in a concentration-dependent manner.
Journal of Ethnopharmacology | 1989
A.V.Ortiz de Urbina; M.L. Martín; M.J. Montero; Asunción Morán; L. San Román
The essential oil of Calamintha sylvatica subsp. ascendens exerts significant sedating and antipyretic activities in the rat. The components responsible for these activities appear to be the major monoterpenes present: pulegone, menthone and eucalyptol (1,8-cineol).
Journal of Ethnopharmacology | 1988
M.L. Martín; A.V.Ortiz de Urbina; M.J. Montero; Rosalía Carrón; L. San Román
Two lactone compounds, protoanemonin and anemonin, were determined in the flowering aerial parts of P. alpina subsp. apiifolia. Anemonin is the primary compound responsible for the antipyretic activity and both anemonin and protoanemonin participate in the sedating effect.
Pharmacology | 2004
Elena Calama; Asunción Morán; A.V.Ortiz de Urbina; M.L. Martín; L. San Román
In this work we studied the responses and receptors involved in the effects of intra-arterial 5-hydroxytryptamine (5-HT) in the in situ autoperfused hindquarters of spontaneously hypertensive rats (SHR). Intra-arterial administration of the highest doses (50–1,000 ng/kg) produced a vasoconstrictor effect that was inhibited by ritanserin (a selective 5-HT2 receptor antagonist), SB 206553 (a selective 5-HT2B/2C receptor antagonist) and spiperone (a nonspecific 5-HT1/2A receptor antagonist), and was mimicked by α-methyl-5-HT (a selective 5-HT2 receptor agonist) and m-CPP (a selective 5-HT2C receptor agonist), but not by the intra-arterial administration of BW 723C86, a selective 5HT2B receptor agonist. SB 206553 and spiperone inhibited α-methyl-5HT-induced vasoconstriction in the hindquarters of SHR. Our data suggest that the vasoconstrictor response induced by 5-HT in the autoperfused hindquarters of SHR is mainly mediated by the activation of 5-HT2A and 5-HT2C receptors.
Journal of Ethnopharmacology | 1988
M.L. Mabtín; Asunción Morán; Rosalía Carrón; M.J. Montero; L. San Román
Abstract The antipyretic activity of two sesquiterpene lactones, β-santonin and arsubin, isolated from the lipid fraction of Artemisia coerulescens subsp. gallica was determined in rats along with the activity of α-santonin. In its α-and β-forms, santonin caused a decrease in the body temperature of rats made febrile by the subcutaneous injection of beer yeast. This decrease, more pronounced in the case of β-santonin, was dose-dependent and antagonized by pretreatment with haloperidol, an agent that also opposes the antipyretic activity of dopamine. These findings seem to show that the α- and β-forms of santonin act on rectal temperature in a way similar to dopamine.