The positive inotropic effect of the ethyl acetate fraction from Erythrina velutina leaves on the mammalian myocardium: the role of adrenergic receptors.

OBJECTIVES: We studied the effects of ethyl acetate fraction (EAcF) obtained from Erythrina velutina leaves on mammalian myocardium. METHODS: The effect of EAcF on the contractility was studied using guinea-pig left atria mounted in a tissue bath (Tyrode's solution, 29°C, 95% CO2 , 5% O2 ) and electrically stimulated (1 Hz). Concentration-response curves of EAcF were obtained in the presence of propranolol (1 µm), nifedipine (1 µm) and in reserpinized animals (5 mg/kg). The involvement of l-type calcium current (ICa,L ) on the EAcF effect was observed in cardiomyocytes of mice assessed using patch-clamp technique. KEY FINDINGS: EAcF (550 µg/ml) had a positive inotropic effect, increasing the atrial force by 164% (EC50 = 157 ± 44 µg/ml, n = 6), but it was less potent than isoproterenol (EC50 = 0.0036 ± 0.0019 µg/ml, n = 8). The response evoked by EAcF was abolished by propranolol or nifedipine. Reserpine did not alter the inotropic response of EAcF. Furthermore, an enhancement of the ICa,L peak (31.2%) with EAcF was observed. Chemical analysis of EAcF revealed the presence of at least 10 different flavonoid glycoside derivatives. Two were identified as vicenin II and isorhoifolin. CONCLUSIONS: We conclude that EAcF increases the cardiac contractile force by increasing the l-type calcium current and activating the adrenergic receptor pathway.

Therapeutic benefits of Sideroxylon obtusifolium (Humb. ex Roem. & Schult.) T.D. Penn., Sapotaceae, in experimental models of pain and inflammation / Benefícios terapêuticos da Sideroxylon obtusifolium (Humb. ex Roem. & Schult.) T.D. Penn., Sapotaceae, em modelos experimentais de dor e inflamação

Sideroxylon obtusifolium (Humb. ex Roem. & Schult.) T.D. Penn., Sapotaceae, is a plant with analgesic and anti-inflammatory activities used in folk medicine. In order to evaluate the actions of this plant, studies were performed on antinociceptive and anti-inflammatory activities with the ethanol extract (EE) of inner bark (100-400 mg/kg). Oral treatment with the EE elicited inhibitory activity (200 and 400 mg/kg, p<0.01) on acetic acid effect and reduced (100, 200, and 400 mg/kg, p<0.001) the formalin effect at the second-phase, however it did not elicit any inhibitory effect on hot-plate test. Carrageenan-induced oedema formation and leukocyte migration into the peritoneal cavity were reduced with the EE at 100, 200, and 400 mg/kg (p<0.001). In conclusion, the EE of Sideroxylon obtusifolium shows antinociceptive and anti-inflammatory activities, supporting the folkloric usage of the plant to treat pain and various inflammatory diseases.

A Sideroxylon obtusifolium (Humb. ex Roem. & Schult.) T.D. Penn., Sapotaceae, é utilizada na medicina popular em processos dolorosos e inflamatórios. Para avaliar as atividades analgésica e anti-inflamatória desta planta, estudos foram realizados com o extrato etanólico (EE) da entrecasca (100-400 mg/kg). O tratamento oral único dos animais com o EE inibiu (200 e 400 mg/kg, p<0,01) o efeito do ácido acético e reduziu (100, 200 e 400 mg/kg, p<0,001) o efeito da formalina na segunda fase; entretanto, não apresentou efeito no teste da placa quente. A formação de edema e a migração de leucócitos para a cavidade peritoneal induzidas pela carragenina foram reduzidas pelo tratamento com o EE (100, 200 e 400 mg/kg, p<0,001). Desta forma conclui-se que o EE da Sideroxylon obtusifolium apresenta atividades antinociceptiva e anti-inflamatória, suportando seu uso popular no tratamento da dor e de doenças inflamatórias.