Antimicrobial, antiproliferative and proapoptotic activities of extract, fractions and isolated compounds from the stem of Erythroxylum caatingae plowman.

In the study, we have examined the antitumor and antimicrobial activities of the methanol extract, the fractions, a fraction of total alkaloids and two alkaloids isolated from the stem of Erythroxylum caatingae Plowman. All test fractions, except the hexane fractions, showed antimicrobial activity on gram-positive bacteria and fungi. The acetate: methanol (95:5), acetate, chloroform and hexane fractions show the highest cytotoxicity activity against the NCI-H292, HEp-2 and K562 cell lines using MTT. The absence of hemolysis in the erythrocytes of mice was observed in these fractions and 6ß-Benzoyloxy-3α-(3,4,5- trimethoxybenzoyloxy) tropane (catuabine B). Staining with Annexin V-FITC and JC-1 was used to verify the mechanism of action of the compounds of E. caatingae that showed cytotoxicity less than 30 µg/mL in leukemic cells. After 48 h of incubation, we observed that the acetate: methanol (95:5), acetate, and chloroform fractions, as well as the catuabine B, increased in the number of cells in early apoptosis, from 53.0 to 74.8%. An analysis of the potential of the mitochondrial membrane by incorporation of JC-1 showed that most cells during incubation of the acetate: methanol (95:5) and acetate fractions (63.85 and 59.2%) were stained, suggesting the involvement of an intrinsic pathway of apoptosis.

Role of NO-cGMP pathway in ovine cervical relaxation induced by Erythroxylum caatingae Plowman.

Erythroxylum caatingae Plowman has a myorelaxing effect on smooth muscle tissue. We investigated the effect of the crude ethanolic extract of E. caatingae Plowman (Ec-EtOH) on the contractility of the ovine cervix. In an isometric system, circular strips were subjected to 90mM potassium (K(+)) or 30µM carbamylcholine (CCh)-induced contraction. We then exposed the tissue to cumulative concentrations of Ec-EtOH (1-729 µg/ml). In other bath solutions, the tissues were exposed to l-NG-nitroarginine methyl ester (l-NAME; 100µM), l-NAME (100µM)+l-arginine (300µM), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ; 5µM), 4-aminopyridine (4-AP; 3mM), tetraethylammonium (TEA; 0.3mM), glybenclamide (1µM), atosiban (10µM) or verapamil (3µM), followed by the addition of Ec-EtOH (1-729 µg/ml). We also evaluated the effect of cervical Ec-EtOH infusion (2mg) on cervical contractility in vivo. Ec-EtOH decreased cervical contractility induced by K(+) or CCh, and 729 µg/ml Ec-EtOH decreased 85.4±5.1% the amplitude of basal contractility in vitro, with an EC50 of 17.9±3.7 µg/ml. This effect of Ec-EtOH was prevented by l-NAME or ODQ. l-arginine impaired the blunting effect of l-NAME on cervical relaxation caused by Ec-EtOH. However, the potassium channel blockers 4-AP, TEA, and glybenclamide did not modify this myorelaxation triggered by Ec-EtOH. Ec-EtOH also decreased acetylcholine-induced contractions in tissue preincubated with verapamil. In addition, Ec-EtOH decreased ovine cervical contractions in vivo. Thus, Ec-EtOH had a relaxant effect on ovine cervical contractions. This may involve the nitric oxide signal, mediated by cGMP cellular transduction, and be related to intracellular calcium sequestration.

Antinociceptive activity of the extract of Erythroxylum caatingae / Actividad antinociceptiva del extracto de Erythroxylum caatingae

The genus Erythoxylum plants are popularly used as anti-inflammatory, anti-bacterial, and diuretic agentes, and for treating of respiratory problems. This study investigated the antinociceptive activity of methanolic extract of Erythroxylum caatingae (EcME) in chemical (formalin test and acetic acid test) and thermal models (hot plate test) of nociception. Intraperitoneal pre-treatment with EcME reduced the number of abdominal contortions and the licking time in the second phase of the formalin test. EcME did not show a significant effect in the hot plate test, rota-rod test, and the elevated plus maze test. These findings indicate that the antinociceptive activity of EcME is not because of a depressor effect on the central nervous system, and EcME is not a muscle relaxant. Nevertheless, Erythroxylum caatingae demonstrated peripheral antinociceptive activity, which confirms its popular use and contributes to the scientific knowledge of the species.

El género Erythoxylum es popularmente utilizado como agente anti-inflamatorio, antibacteriano y para el tratamiento de problemas respiratorios. Este estudio tiene como objetivo investigar la actividad antinociceptiva del extracto metanólico Erythroxylum caatingae (EcME), utilizando modelos químicos (prueba de la formalina y prueba de ácido acético) y térmico (prueba de la placa caliente) de nocicepción. El pretratamiento EcME por la vía intraperitoneal (i.p.), fue capaz de reducir el número de contorsiones abdominales y el tiempo de lamida en la segunda fase del test de formalina. EcME no tuvo efecto significativo en el test de la placa caliente, Rota-Rod y Laberinto en Cruz Elevado, mostrando que el efecto antinociceptivo no está relacionado con un efecto depresor del sistema nervioso central o miorelajante. Los datos experimentales muestran que Erythroxylum caatingae posee una actividad antinociceptiva periférica que confirma su uso popular, contribuyendo para el conocimiento científico de la especie.