Pharmacological study of anti-inflammatory activity of aqueous extracts of Mikania glomerata (Spreng.) and Mikania laevigata (Sch. Bip. ex Baker).

ETHNOPHARMACOLOGICAL RELEVANCE: Mikania glomerata Spreng. (MG) and Mikania laevigata Sch. Bip. ex Baker (ML), popularly known as guaco, are medicinal plants similar in morphology, chemical composition and medicinal uses. Both species are often used and sold without distinction; however, it is believed that their chemical composition is different.

AIM: Thus, the aim of this study is to investigate if the aqueous extract of MG and ML present similar anti-inflammatory activity to the point of being used interchangeably.

MATERIAL AND METHODS: Different doses of both extracts and coumarin were given to rats in different experimental models to assess the anti-inflammatory activity between these two species. For this, the animals were submitted to paw edema, pleurisy and degranulation of peritoneal mast cell and the extracts were also characterized by Ultra High Efficiency Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS).

RESULTS: The chromatographic method showed that ML presents ten times more coumarin than MG. Oral administration of MG, ML and coumarin inhibited paw edema induced by carrageenan (400 mg/kg, 55% inhibition; 400 mg/kg, 57% inhibition; 75 mg/kg, 38% inhibition; p < 0.05, respectively). MG, ML and coumarin treatment also inhibited the edema induced by compound 48/80 (400 mg/kg, 56% inhibition; 400 mg/kg, 69% inhibition; 75 mg/kg, 40% inhibition; p < 0.05, respectively). MG, ML and coumarin did not prevent mast cell degranulation and the consequent histamine release in Wistar rat peritoneal mast cells induced by compound 48/80. MG did not inhibit cell infiltration in pleurisy nor the highest dose tested, while ML decreased the leukocyte migration (200 and 400 mg/kg, 23% and 30% inhibition; p < 0.001, respectively) and, to a lesser extent, coumarin also reduced cell infiltration (10, 50 and 75 mg/kg; 15%, 16% and 17% inhibition; p < 0.001, respectively).

CONCLUSION: The variation of the results of the anti-inflammatory activity found in M. glomerata and M. laevigata demonstrates that these two species should not be used interchangeably. Coumarin, as already proven, has anti-inflammatory action however, we have suggested that it probably is not the only component responsible for this therapeutic effect in the extracts.