Piper callosum Ruiz & Pavon, popularly known as (paregoric elixir), is a plant widely used in folk medicine for the treatment of many diseases, such as inflammatory and painful conditions and gastrointestinal problems. Despite the therapeutic potential of this species, few studies focused on the evaluation of their actual pharmacological and toxicological properties, and such studies are essential to ensure the efficacy and safety of plants traditionally used as medicinal. The objective of this study was to evaluate the antiedematogenic and antinociceptive activities of the P. callosum leaves aqueous extract (AEPC), investigate their possible neurotoxic and hepatotoxic effects and determine its phytochemical profile. The antiedematogenic activity was assessed using the paw edema test induced by carrageenan and the antinociceptive activity by the hot plate test. The possible neurotoxic effects were assessed using behavioral tests: the Morris water maze, rota-rod, open field, Y maze and light/dark box. Hepatotoxicity of the AEPC was evaluated by means of the enzymes aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AP). Phytochemical prospecting was determined by thin layer chromatography (TLC). The results showed that the AEPC significantly inhibited (p ≤ 0.05) the paw edema induced by carrageenan at all doses tested (240, 360 and 480 mg/kg), suggesting that it is potential as an agent acting anti- inflammatory, but showed no central analgesic effect. The both acute and subchronic treatment with the AEPC in the tested dose (480 mg/kg) caused no change on mobility, memory and learning of Wistar rats, indicating that it does not cause neurotoxic effects. The results for the levels of ALT, AST and serum AP in rats demonstrate that treatment for 21 days with AEPC at a dose of 480 mg / kg did not cause hepatotoxic effects. For classes of metabolites studied by TLC, it was identified only the presence of flavonoids. The results suggests a pharmacological potential of the AEPC, which explains in part the use of this species in folk medicine. However, it is necessary to conduct further studies to knowledge of the active principles and possible mechanisms of action of these substances.
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