Antinociceptive and Anti-inflammatory Effects of Triterpenes from Pluchea quitoc DC. Aerial Parts.

BACKGROUND: Pluchea quitoc DC. (Asteraceae), a medicinal plant known as "quitoco," "caculucage," "tabacarana" and "madre-cravo," is indicated for inflammatory conditions such as bronchitis, arthritis, and inflammation in the uterus and digestive system. OBJECTIVE: This study evaluated the analgesic and anti-inflammatory activities of the triterpenes compounds obtained from P. quitoc aerial parts. MATERIALS AND METHODS: The triterpenes compounds ß-amyrin, taraxasterol and pseudo-taraxasterol in a mixture (T); ß-amyrin, taraxasterol and pseudo-taraxasterol acetates in a mixture (Ta); ß-amyrin, taraxasterol, pseudo-taraxasterol acetates in a mixture with ß-amyrin, taraxasterol and pseudo-taraxasterol myristates (Tafe) were analyzed in the models of nociception and inflammation. The evaluation of antinociceptive activity was carried out by the acetic acid-induced writhing and tail-flick tests while leukocyte migration to the peritoneal cavity was used for anti-inflammatory profile. RESULTS: The oral administration of T or Tafe (40 mg/kg and 70 mg/kg) and Ta (70 mg/kg) to mice reduced acetic acid-induced writhing. The tail-flick response of mice was not affected by T or Tafe (40 mg/kg). T or Tafe (40 mg/kg) and Ta (70 mg/kg) also inhibited peritoneal leukocyte infiltration following the injection of carrageenan. CONCLUSION: The results demonstrate the anti-inflammatory and peripheral antinociceptive activity of the triterpenes ß-amyrin, taraxasterol, and pseudo-taraxasterol that were decreased when these were acetylated; while the acetylated triterpenes in mixture with myristyloxy triterpenes improved this activity. These compounds seem, at least in part, to be related to the plant's reported activity. SUMMARY: The mixtures of hydroxylated, acetylated, and myristate triterpenes isolated from hexanic extracts of Pluchea quitoc DC. were analyzed in the models of nociception and inflammation in mice. The results demonstrate the anti-inflammatory and peripheral antinociceptive activity of the triterpenes ß-amyrin, taraxasterol, and pseudo-taraxasterol. This study showed too that the activity of triterpenes may be decreased by their being acetylated, while the acetylated triterpenes in mixture with myristate triterpenes improved this activity.Abbreviations Used: T: Triterpenes compounds ß-amyrin, taraxasterol, and pseudo-taraxasterol in a mixture, Ta: Triterpenes compounds ß-amyrin, taraxasterol and pseudo-taraxasterol acetates in a mixture, Tafe: Triterpenes compounds ß-amyrin, taraxasterol, pseudo-taraxasterol acetates in a mixture with ß-amyrin, taraxasterol and pseudo-taraxasterol myristates, Ctrl: Control, Indo: Indomethacin, Dexa: Dexamethasone, EtOAc: Ethyl acetate, MeOH: Methanol.

Antihypertensive Effect of Syzygium cumini in Spontaneously Hypertensive Rats.

This study evaluated the in vivo potential antihypertensive effect of hydroalcoholic extract of Syzygium cumini leaves (HESC) in normotensive Wistar rats and in spontaneously hypertensive rats (SHR), as well as its in vitro effect on the vascular reactivity of resistance arteries. The hypotensive effect caused by intravenous infusion of HESC (0.01-4.0 mg/kg) in anesthetized Wistar rats was dose-dependent and was partially inhibited by pretreatment with atropine sulfate. SHR received HESC (0.5 g/kg/day), orally, for 8 weeks and mean arterial pressure, heart rate, and vascular reactivity were evaluated. Daily oral administration of HESC resulted in a time-dependent blood pressure reduction in SHR, with a maximum reduction of 62%. In the endothelium-deprived superior mesenteric arteries rings the treatment with HESC reduced by 40% the maximum effect (E max⁡) of contraction induced by NE. The contractile response to calcium and NE of endothelium-deprived mesenteric rings isolated from untreated SHR was reduced in a concentration-dependent manner by HESC (0.1, 0.25, and 0.5 mg/mL). This study demonstrated that Syzygium cumini reduces the blood pressure and heart rate of SHR and that this antihypertensive effect is probably due to the inhibition of arterial tone and extracellular calcium influx.

The toxicity evaluation of Syzygium cumini leaves in rodents

This study aimed to evaluate the safety of the hydroalcoholic extract (HE) of Syzygium cumini (L.) Skeels, Myrtaceae, leaves in rodents. Acute toxicity was evaluated through the determination of a LD50 in mice and rats (up to 14 days). In mice, the oral administration (p.o.) of the HE (0.1 at 6 g/kg) did not cause any death. When administered by intraperitoneal route (i.p.) the HE (0.1 at 1 g/kg) caused death of the animals (LD50 of 0.489 g/kg). In rats, the HE (0.5, 1 and 2 g/kg, p.o.) did not cause any death, while by i.p., only the 2 g/kg dose was lethal to 67 percent of the animals. To evaluate chronic toxicity, groups of rats daily received the HE (0.05, 0.1 and 0.25 g/kg) through p.o., during 30, 90 or 180 days and the effects on behavior, body weight, feed consumed were measured. Histology, hematology and biochemical parameters were measured at the end of the treatment. After a 30-day treatment, the HE caused changes in some biochemical parameters. Histological examination of the liver, kidneys, lungs, heart, stomach, intestine and pancreas showed normal architecture suggesting no morphological disturbances. These data may mean that the HE of S. cumini does not exert acute or chronic toxic effects by oral administration.

Antispasmodic effect of Jatropha gossypiifolia is mediated through dual blockade of muscarinic receptors and Ca2+ channels

The antispasmodic activity of Jatropha gossypiifolia L., Euphorbiaceae, aerial parts was investigated in rodents using the mouse intestinal transit model and acetylcholine (ACh, 10-9 to 10-4 M) and calcium (CaCl2, 10-4 to 10-1 M)-induced contractions of isolated rat jejunum. Similar to atropine (1 mg/kg), oral doses of ethanolic extract (EE) of J. gossypiifolia (500, 1000 and 2000 mg/kg) produced a decrease in intestinal transit (37.6 to 57.1 percent) when compared with control. The ACh-induced contraction in the jejunum was inhibited by EE (0.5, 1.0 and 2.0 mg/mL), chloroformic (CF) and aqueous fractions (0.1 and 0.5 mg/mL) and methanolic subfraction (0.05 and 0.25 mg/mL), suggesting an antimuscarinic mechanism. CaCl2 - induced responses in jejunum were also attenuated in the presence of CF (0.05 and 0.1 mg/mL) implying a direct interference of CF with the influx of calcium ions in the cells. Only the organic fraction of the extract had a calcium-antagonist effect, whereas both chloroformic and aqueous fractions had anticholinergic effect. These results suggest that the antispasmodic effect of J. gossypiifolia may be due a combination of anticholinergic and calcium antagonist mechanisms.

In vivo inhibition of gastric acid secretion by the aqueous extract of Scoparia dulcis L. in rodents.

The freeze-dried aqueous extract (AE) from the aerial parts of Scoparia dulcis was tested for its effects on experimental gastric hypersecretion and ulcer in rodents. Administration of AE to animals with 4h pylorus ligature potently reduced the gastric secretion with ED(50)s of 195 mg/kg (rats) and 306 mg/kg (mice). The AE also inhibited the histamine- or bethanechol-stimulated gastric secretion in pylorus-ligated mice with similar potency suggesting inhibition of the proton pump. Bio-guided purification of the AE yielded a flavonoid-rich fraction (BuF), with a specific activity 4-8 times higher than the AE in the pylorus ligature model. BuF also inhibited the hydrolysis of ATP by H(+),K(+)-ATPase with an IC(50) of 500 microg/ml, indicating that the inhibition of gastric acid secretion of Scoparia dulcis is related to the inhibition of the proton pump. Furthermore, the AE inhibited the establishment of acute gastric lesions induced in rats by indomethacin (ED(50)=313 mg/kg, p.o.) and ethanol (ED(50)=490 mg/kg, p.o.). No influence of the AE on gastrointestinal transit allowed discarding a possible CNS or a cholinergic interaction in the inhibition of gastric secretion by the AE. Collectively, the present data pharmacologically validates the popular use of Scoparia dulcis in gastric disturbances.

Efeito da ropivacaína na recaptação neuronal de noradrenalina em músculo liso / Effect of ropivacaine on neuronal norepinephrine reuptake in smooth muscle

JUSTIFICATIVA E OBJETIVOS: Além da ação anestésica local, a ropivacaína apresenta efeito vasoconstritor, clinicamente significativo, que pode ser observado quando da anestesia infiltrativa, o que a torna um anestésico importante no bloqueio de campo. Este trabalho teve por objetivo caracterizar o mecanismo de ação constritora da ropivacaína em músculo liso. MÉTODO: Em preparações isoladas de ducto deferente de ratos foram construídas curvas concentração-efeito de noradrenalina na ausência ou na presença da ropivacaína. Em outra série de experimentos os ratos foram tratados com reserpina (10 mg.kg-1, por via intraperitoneal) para avaliar a reatividade dos ductos deferentes à tiramina ou noradrenalina, na ausência ou presença da ropivacaína. RESULTADOS: A ropivacaína nas concentrações de 5 ou 10 æg.mL-1 potencializou o efeito máximo (Emax) da noradrenalina em 47 por cento e 35 por cento, respectivamente, enquanto que nas concentrações de 50 ou 100 æg.mL-1 inibiu o efeito máximo produzido por este agonista. Em ductos deferentes isolados de ratos reserpinizados, a ropivacaína (10 ou 20 æg.mL-1) potencializou (150 por cento e 25 por cento, respectivamente) as contrações induzidas pela noradrenalina, enquanto que as concentrações de 50 ou 100 æg.mL-1 não alteraram as respostas à noradrenalina. CONCLUSÕES: Os resultados obtidos permitem concluir que a ropivacaína bloqueia a recaptação neuronal de noradrenalina pelos terminais nervosos simpáticos.

[Effect of ropivacaine on neuronal norepinephrine reuptake in smooth muscle.]. / Efeito da ropivacaína na recaptação neuronal de noradrenalina em músculo liso.

BACKGROUND AND OBJECTIVES: In addition to local anesthetic action, ropivacaine has clinically significant vasoconstrictor effects, which may be observed at infiltrative anesthesia, making it an important anesthetic for field blockade. This study aimed at characterizing the constrictor mechanism of ropivacaine on smooth muscles. METHODS: Norepinephrine concentration-effect curves in the absence or presence of ropivacaine were plotted on isolated preparations of vas deferens of rats. In another series of experiments rats were treated with reserpine (10 mg.kg-1, i.p.) to evaluate vas deferens reactivity to tyramine or norepinephrine, in the absence or presence of ropivacaine. RESULTS: Ropivacaine 5 or 10 microg.mL-1 potentiated maximum norepinephrine effect (Emax) in 47% and 35%, respectively, while higher concentrations (50 or 100 microg.mL-1) inhibited its maximum effect. In isolated vas deferens of rats treated with reserpine, ropivacaine (10 or 20 microg.mL-1) potentiated (150% and 25%, respectively) norepinephrine-induced contractions, while higher concentrations (50 or 100 microg.mL-1) have not changed responses to norepinephrine. CONCLUSIONS: Ropivacaine blocks neuronal norepinephrine reuptake by sympathetic nerve terminals.