Igor A.C. Menezes

Hypotensive Activity of Terpenes Found in Essential Oils

The cardiovascular activity of essential oils has been reported. Some studies showed that the main chemical components of these oils contribute to their pharmacological activity. Therefore, the cardiovascular activity of four monoterpenes and one sesquiterpene was evaluated in the present work. In non-anaesthetized normotensive rats, (+)-α-pinene, (-)-β-pinene, (±)-citronellol and (±)-linalool (1, 5, 10, and 20 mg/kg, i.v.) induced hypotension [maximal effect: (-35 ± 3)%, (-46 ± 4)%, (- 48 ± 2)% and (- 40 ± 2)%, respectively; n = 6] and tachycardia [maximal effect: (13 ± 4)%, (16 ± 7)%, (21 ± 1)% and (19 ± 3)%, respectively; n = 6] while (-)-α-bisabolol (1, 5, 10, and 20 mg/kg, i.v.) induced hypotension [maximal effect: (- 47 ± 8)%, n = 6] and bradycardia [maximal effect: (-57 ± 3)%]. In conclusion, these results demonstrated that all terpenes tested had hypotensive activity in rats and that the pharmacological effect of the terpene alcohols was more effective than that of the terpene hydrocarbons.

Cardiovascular effects induced by Cymbopogon winterianus essential oil in rats: involvement of calcium channels and vagal pathway.

Objectives This study has investigated the cardiovascular effects of the Cymbopogon winterianus essential oil (EOCW) in rats. C. winterianus is a plant used in folk medicine for the treatment of hypertension.

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.

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.