Background: The speciesHimatanthus drasticusis popularly known in Northeast Brazil as "janaguba" and belongs to the family Apocynaceae. The latex collected from its stem bark is used for several purposes including anti-inflammatory properties and presents among its bioactive constituents the pentacyclic triterpene lupeol. The objective of the present work was to studyin vivoandin vitrothe lupeol acetate (LA) isolated from the plant latex, in several models of inflammation.Methods: Male Swiss mice (25-30 g, 6-24 animals per group) were administered with LA, 30 min before the test initiation. In the evaluation of analgesic activity the formalin test was used. The anti-inflammatory activity was evaluated by the following tests: paw edema induced by carrageenan and dextran, and the carrageenan-induced neutrophil migration into peritoneal cavities. Furthermore, the effect of LA on the myeloperoxidase release (MPO, an inflammation biomarker) from human neutrophils was also determined, as well as its antioxidant potential by the DPPH assay.Results: In the formalin test, LA (10, 25 and 50 mg/kg, i.p.) inhibited both the 1^st(neurogenic, 0-5 min) and mainly the 2^nd(inflammatory, 20-25 min) phase. Naloxone completely reversed the LA effect, indicating the participation of the opioid system. LA also significantly inhibited carrageenan- and dextran-induced paw edemas, as well as the neutrophil migration to the peritoneal cavity evaluated by the carrageenan-induced pleurisia. In this model, the effect of a very low dose of LA (0.1 mg/kg) was potentiated by the same dose of pentoxifylline (PTX), a known TNF-alpha inhibitor. LA (25 and 50 μg/ml) was also very effective in inhibiting MPO released from stimulated human neutrophils, and significantly decreased the number of cells expressing iNOS activity in the paw of mice submitted to carrageenan-induced edema, suggesting a drug involvement with the NO system.Conclusions: The anti-inflammatory effect of LA probably involves the opioid system, as indicated by the complete blockade of the opioid antagonist naloxone. Furthermore, the LA effect was potentiated by PTX (a TNF-alpha inhibitor). LA also decreased the number of iNOS cells, suggesting the participation of pro-inflammatory cytokines and the NO system in the drug action.

Os fitoterápicos são utilizados por automedicação ou por prescrição médica e a maior parte não tem o seu perfil tóxico bem conhecido. Atualmente estão incorporados aos vários Programas de Fitoterapia como opção terapêutica eficaz e pouco custosa. A importância da inclusão dos fitoterápicos nos programas de farmacovigilância vem sendo reconhecida nos últimos anos por vários países da Europa, como Reino Unido e Alemanha, onde várias plantas foram submetidas à farmacovigilância e muitas delas foram retiradas do mercado devido a importantes efeitos tóxicos e risco para uso humano. O aumento no número de reações adversas reportado é possivelmente justificado pelo aumento do interesse populacional pelas terapias naturais observado nas últimas décadas. A farmacovigilância de plantas medicinais e fitoterápicos é uma preocupação emergente e através do sistema internacional será possível identificar os efeitos indesejáveis desconhecidos, quantificar os riscos e identificar os fatores de riscos e mecanismos, padronizar termos, divulgar experiências, entre outros, permitindo seu uso seguro e eficaz. The herbal drugs are used by self-medication or by medical prescription and most of them do not have their toxic profile well know. Currently they are incorporate to the Phytotherapy Programs as an effective and little expensive therapeutic option. The importance of the inclusion of the herbal drugs in the pharmacovigilance programs has been recognized in the last years by several countries from Europe, like United Kingdom and Germany, where several plants were submitted to pharmacovigilance and many of them were removed from the market due to important toxic effects and risk for human use. The pharmacovigilance of medicinal plants and herbal drugs is an emergent concern and through the international system it will be possible to identify the ignored undesirable effects, to quantify the risks and to identify the risks factors and mechanisms, to standardize terms, to publish experiences, etc., allowing their safe and effective use