Pharmacological screening of Ageratum conyzoides L. (mentrasto)

Memórias do Instituto Oswaldo Cruz

Lucia A. Yamamoto¹  Janete C. Soldera¹  José A. S. Emim¹  Rosely O. Godinho¹  Caden Souccar¹  Antonio J. Lapa¹ 

[1] ,Escola Paulista de Medicina Departamento de Farmacologia Setor de Produtos NaturaisSão Paulo,Brasil

关键词: Ageratum conyzoides L;    anti-inflammmatory;    analgesia;    medicianl plant;   

DOI  :  10.1590/S0074-02761991000600033

来源: SciELO

【 摘 要 】

The pharmacological activitiesof a water extract (WE) of Ageratum conyzoides L, a plant populary known for its analgesic and anti-inflamatory properties, were studied in vivo and in vitro preparations. Oral administration (p.o.) of the water extract (WE, 0.1 to 5 g/Kg) to rats and mice induced quietness and reduced the spontaneous motility. the sleeping time induced by sodium pentobarbital (50 mg/Kg, i.p.) in mice was not altered by previous treatment with We (2 g/Kg, p.o.). The same treatment did not influence the paw edema induced by carrageenan or dextran, nor did it reduce the chronic paw edema induced by complete Freund's adjuvant or formaldehyde in rats. The tail flick response in immersion test and writhings induced by 0.8%aceticacid in mice were not altered by WE either. In isolated guinea-pig ilea WE (0.4 to 4 mg/ml) did not alter the EC50 values of histamine or acetylcholine, but reduced the maximal response to the agonists by 20 to 50%. We (0.01 to 10 mg/ml) produced tonic contractions of the ileal smooth muscle proportional to the doses, reaching a maximum of 75% relatively to the maximum obtained with histamine. Those contractions were blocked by diphenhydramine (10 nM) and reduced by 32% in presence of atropine (10 nM). The results indicated that oral treatment of rodents with A. conyzoides L neither reduced the inflammatory edema nor did it decrease the reaction to pain stimuli. In vitro the extract presented an unexpected histamine-like activity characteristic of a partial agonist. The results did not confirm the popular medicinal indications of the plant.

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