Rosilene Moretti Marçal

Analgesic and antidiarrheal properties of Ocimum selloi essential oil in mice

Ocimum selloi essential oil (2, 20, and 200 mg/kg; p.o.) reduced, in a dose-dependent way, the abdominal contraction induced by acetic acid (0.6%; i.p.) and the diarrhea episodes induced by castor oil in mice. At the higher dose (200 mg/kg; p.o.), the essential oil significantly reduced intestinal transit (P<0.05) in the charcoal meal test. The main component detected in O. selloi essential oil was methyl chavicol (98%; GC and GC/MS).These effects seems to support the use of O. selloi against diarrhea, intestinal spasm and visceral pain.

Evidence of the mechanism of action of Erythrina velutina Willd (Fabaceae) leaves aqueous extract

ETHNOPHARMACOLOGICAL RELEVANCE Erythrina velutina is traditionally used for sleepiness, convulsions and nervous system excitation in Brazil. Although central effects have been reported for Erythrina velutina, little is known about its mechanism of action. AIM OF THE STUDY To investigate the pharmacological evidences of mechanism of action of Erythrina velutina leaves aqueous extract (AE). MATERIALS AND METHODS Terminal segments of the guinea-pig ileum (n=5-8) were mounted in an organ bath and isotonic contractions were recorded. Phytochemical screening was carried out on AE. RESULTS AE (0.025-2.50 mg/ml) produced contractile response in the guinea-pig ileum, yielding typical concentration-response curves (EC50=0.63 mg/ml). Electrically evoked contractions were significantly increased in the presence of AE. AE-elicited contractions were significantly reduced by bicuculline, tetrodotoxin, atropine, verapamil or incubation in low calcium-high potassium solution. Atropine along with verapamil abolished AE contractile response. Alkaloids, catechins, steroids, flavonols, flavononols, flavonoids, phenols, saponins, tannins, triterpenoids, and xanthones were detected in AE. CONCLUSIONS AE contains important constituents for pharmacological activities. AE-induced contractions seem to involve GABAA receptor activation, acetylcholine release, muscarinic receptor activation, augmentation of Ca2+ entry through L-type calcium channels, and calcium release from the intracellular stores. These findings provide further support for Erythrina velutina traditional uses.

(−)-Carvone: Antispasmodic effect and mode of action

(-)-Carvone is a monoterpene ketone found in spearmint (Mentha spicata var. crispa) essential oil that is widely used as an odor and flavor additive. An intestinal antispasmodic effect was recently reported for (-)-carvone, and it has been shown to be more potent than its (+)-antipode. The mechanism of (-)-carvone action in the intestines has not been investigated. To gain a better understanding of the (-)-carvone antispasmodic effect, we investigated its pharmacological effects in the guinea pig ileum. Terminal portions of the ileum were mounted for isotonic contraction recordings. The effect of (-)-carvone was compared with that of the classical calcium channel blocker (CCB) verapamil. In isolated ileal smooth muscle, (-)-carvone did not produce direct contractile or relaxation responses and did not modify electrically elicited contractions or low K(+)-evoked contractions. The submaximal contractions induced by histamine (p<0.001), BaCl2 (p<0.05), and carbachol (p<0.01) were significantly reduced by (-)-carvone. The contractile response elicited by high concentrations of carbachol was reduced but not abolished by (-)-carvone. No additive action was detected with co-incubation of (-)-carvone and verapamil on carbachol-induced contraction. (-)-Carvone reduced the contraction induced by high K(+) and was almost 100 times more potent than verapamil. Thus, (-)-carvone showed a typical and potent CCB-like action. Many effects described for both (-)-carvone and spearmint oil can be explained as a CCB-like mode of action.

Effect of acute stresses on zebra fish (Danio rerio) metabolome measured by NMR-based metabolomics

We applied an acute stress model to zebra fish in order to measure the changes in the metabolome due to biological stress. This was done by submitting the fish to fifteen minutes of acute confinement (netting) stress, and then five minutes for the open field and light/dark field tests. A polar extract of the zebra fish was then subjected to (1)H nuclear magnetic spectroscopy. Multivariate data analysis of the spectra showed a clear separation associated to a wide range of metabolites between zebra fish that were submitted to open field and light/dark field tests. Alanine, taurine, adenosine, creatine, lactate, and histidine were high in zebra fish to which the light/dark field test was applied, regardless of stress, while acetate and isoleucine/lipids appeared to be higher in zebra fish exposed to the open field test. These results show that any change in the environment, even for a small period of time, has a noticeable physiological impact. This research provides an insight of how different mechanisms are activated under different environments to maintain the homeostasis of the body. It should also contribute to establish zebra fish as a model for metabolomics studies.

Avaliação do efeito antinociceptivo e da toxicidade aguda do extrato aquoso da Hyptis fruticosa Salmz. ex Benth

The antinociceptive effect and the acute toxicity of Hyptis fruticosa leaves were evaluated through the administration of its aqueous extract in mice. The extract, administered orally (200, 400, and 500 mg/kg), reduced the nociceptive response in the writhing test as well as in the early phase of the formalin test (100 and 400 mg/kg) and it increased the latency time in the hot plate test (100 and 200 mg/kg). The antinociceptive effect was reversed by naloxone (5 mg/kg, i.p.). Moreover, no animal deaths were observed in doses up to 5 g/kg. In conclusion, the aqueous extract of Hyptis fruticosa showed no acute toxicity at the evaluated doses and revealed antinociceptive effect in mice. Such effects are possibly associated with the opioid system activation.

In vitro and ex vivo anticholinesterase activities of Erythrina velutina leaf extracts

Context: Erythrina velutina (EV) Willd (Fabaceae–Faboideae) is a medicinal tree that is commonly used in Brazil for the treatment of several central nervous system disorders. Objective: The anticholinesterase activity of EV is described in this work. Methods: Concentration-response curves (0–1.6 mg/mL) for EV leaf aqueous extract (AE) and alkaloid-rich extracts (AKEs) were performed in vitro. Cholinesterase inhibition was examined in mouse brains, as the cholinesterase source, and in pure acetylcholinesterase (AChE) or butyrylcholinesterase (BuChE). Mice were treated with AE or AKE (100, 200, and 400 mg/kg, p.o.) and their brains were used for the measurement of cholinesterase activity (CA) ex vivo. Results: CA was inhibited by AE (IC50 = 0.57 [0.43–0.75] mg/mL) and AKE (IC50 = 0.52 [0.39–0.70] mg/mL) in brain homogenates in a concentration-dependent manner. The ex vivo experiments indicated that AE (400 mg/kg, p < 0.05, 32.2 ± 3.9% of inhibition) and AKE (all doses: p < 0.05–p < 0.001, 29.6 ± 3.2% as the maximum inhibition) significantly inhibited CA in the central nervous system after oral administration. AE and AKE inhibited AChE and BuChE activities in a concentration-dependent manner (AE: IC50AChE = 0.56 [0.38–0.81] mg/mL, IC50BuChE = 2.95 [1.51–5.76] mg/mL, AKE: IC50AChE = 0.87 [0.60–12.5] mg/mL, IC50BuChE = 2.67 [0.87–8.11] mg/mL). Discussion and conclusions: These data indicated that AE and AKE crossed the blood-brain barrier to inhibit CA in the brain. AE and AKE also exhibited a dual inhibitory action on acetyl- and BuChE.

Avaliação dos efeitos miorelaxante, antiespasmódico e antinociceptivo do extrato aquoso da Phoradendron piperoides (Kunt.) Trel. (Viscaceae)

The present work evaluated the antinociceptive, miorelaxant and antispasmodic effects as well as the acute toxicity of the aqueous extract from leaves of Phoradendron piperoides. In guinea pig ileum, the plant extract (0.05 - 2.0 mg/kg) decreased the preparations basal tone in a dose-dependent manner (IC50 = 0.114 mg/mL) and it (1.5 mg/mL) reduced (p < 0.001) the contractions induced by carbachol (2 µM), histamine (2 µM) and BaCl2 (0.03M). The extract, at oral doses of 100, 200, and 400 mg/kg, did not manifest a significant antinociceptive effect in the writhing, formalin and hot-plate tests. Moreover, no animal deaths were observed in doses up to 5 g/kg. In conclusion, the aqueous extract of Phoradendron piperoides showed no antinociceptive effect and no acute toxicity in mice. Indeed, it revealed miorelaxant and antispasmodic activities that are probably miogenic and not specific for neurotransmitters.

Antispasmodic effect of Ocimum selloi essential oil on the guinea-pig ileum

Ocimum selloi is an herbal species popularly used in Brazil as antispasmodic. Herein, we report the antispasmodic effect of O. selloi essential oil (OS) in segments of guinea-pig ileum. OS did not reduce the tonus of the ileum. In contrast, OS reduced the contraction induced by carbachol (100 μM), BaCl2 (0.03 M) and low- and high-K+ concentrations (25 and 60 mM, respectively). OS shifted the concentration–response curve for calcium to the right in a parallel manner. GC/MS analysis showed that OS consists mostly of methyl chavicol (97.57%). These results suggest that OS antispasmodic effect is mediated through calcium channel blockade. In addition, OS effect and mode of action could be accounted for methyl chavicol.