Acetylcholine-induced aortic relaxation studied in salbutamol treated rats.

It has been proposed that the acetylcholine (ACh)-induced relaxation of the rat aorta is entirely mediated by endothelium derived-nitric oxide (NO). However, some authors have reported that indomethacin pretreatment attenuates ACh-induced relaxation of rat aortic ring preparations. Moreover, it has also been suggested that cAMP accumulation may regulate either nitric oxide synthase (NOS) or cyclooxygenase (COX) expression in different tissues. Thus, in this in vitro study we have investigated the endothelial mechanisms involved in the ACh-induced relaxation of ring preparations of the rat thoracic aorta, as well as the influence chronic treatment with the selective beta(2)-agonist salbutamol had upon such mechanisms. Results of functional experiments show that N(G)-monomethyl-L-arginine (L-NMMA, 3 x 10(-4) M) considerably inhibited the ACh-induced relaxation of rat aortic ring preparations. However, indomethacin (10(-5) M) was also found to partially attenuate this ACh response, suggesting that although NO is the most important mediator of the ACh-induced relaxation of the rat aortic ring preparations, vasorelaxation may also involve prostanoids. Moreover, the results suggest that treatment with salbutamol failed to produce any change in the ACh-induced relaxation of rat aortic ring preparations.

Anti-inflammatory action of ethanolic extract and clerodane diterpenes from Casearia sylvestris

ABSTRACT The present study aimed to investigate the anti-inflammatory activity of ethanolic extract from Casearia sylvestris Sw., Salicaceae, leaves and to identify the compounds responsible for this activity. The ethanolic extract from C. sylvestris leaves was fractionated by solid phase extraction and the chemical composition of extract and fractions were assessed by chromatographic techniques. Casearin-like clerodane diterpenes were quantified in ethanolic extract (27.4%, w/w) and in fraction 2 of solid phase extraction (50.6%, w/w). Carrageenan-induced paw edema and carrageenan-induced pleurisy assays (rats) were used to evaluate anti-inflammatory activity of ethanolic extract, its fractions and clerodane diterpenes from C. sylvestris - caseargrewiin F and casearin B. The ethanolic extract was tested in the rat paw edema model and the doses tested (10 and 100 mg/kg) had no effect. In the pleurisy model, the extract doses of 300 and 500 mg/kg showed inhibitory effect. The fraction 2 of solid phase extraction (10 mg/kg), caseargrewiin F and casearin B (0.5 mg/kg) showed a significant reduction (p < 0.05) of the carrageenan-induced paw edema in rats compared to indomethacin. Gastric ulcers were not observed in animals treated with samples from C. sylvestris. In conclusion, the ethanolic extract from C. sylvestris, its enriched fraction of clerodane diterpenes, casearin B and caseargrewiin F exhibited anti-inflammatory activity on in vivo models in rats. Casearin-like clerodane diterpenes may be considered active chemical markers for C. sylvestris leaves. On the other hand, these diterpenes are promising compounds in the development of new drugs with anti-inflammatory action without gastric side effects.