Farmacologia da Cecropia sciadophylla mart. nativa da Amazônia: efeitos antiúlcera gástrica e na musculatura esquelética correlacionados com a atividade da h+, k+-atpase e da ca+2-atpase.

Abstract

Species of the genus Cecropia known as embaúba, are used in the folk medicine to treat hypertension, bronchitis, gastric ulcer, diabetes, arthritis and other regional endemic affections. Several authors have mentioned the anti-malarial activity of some species. With the aim to compare the activity of an Amazonian species without previous pharmacological study, the present work describes the Cecropia sciadophylla Mart, its collect and extraction, the chemical standardization criteria and the purification of the leaves aqueous extract (AE). The obtention of the semi-purified buthanolic fraction (BuF) and the pharmacological effects of these extracts, emphasizing the actions in the central nervous system, the antinociceptive effect, the action in the arterial blood pressure, the muscular action and the gastrointestinal activity are also described in this work. Partition of the aqueous extract of the leaves 2,5% (AE) with n-buthanol originated the BuF, more stable, more concentrated and more active, with the same chromatographic fingerprint of AE in the HPLC. For future molecular studies, 26 fractions with well defined retention times were isolated from BuF; some of them were already identified: catechin, quercetin-3-O-β-glucopyranoside and 2" -O-ramnosilvitexin. The general pharmacological screening of the extracts in mice showed hyperactivity and increased motricity, not described in other Cecropia species, but the anti-depressive effect was common to the others. The antinociceptive and the anti-inflammatory effects were poorly consistent, perhaps by the central stimulating activity. The intravenous injection of BuF produced hypotension without interfering with the noradrenalin action or with the cardiac activity. In vitro, the BuF relaxed the adrenergic tonus only in the intact endothelium aortic rings, indicating vasodilatory action dependent on the NO synthesis. Previous treatment of rats with the BuF protected the gastric mucosal against cold stress- and ethanol-induced ulcers; this effect was correlated with the reduction of the gastric secretion acidity and the in vitro inhibition of the H+, K+-ATPase activity. In rodents isolated diaphragm, the BuF potentiated the direct elicited twitches of the muscle fiber; this effect was correlated to the inhibition of the Ca+2-ATPase activity, but not by the acetylcholinesterase inhibition.