Effect of the metanolic extract from the leaves of Garcinia humilis Vahl (Clusiaceae) on acute inflammation.

Garcinia humilis is popularly used to treat digestive, intestinal and inflammatory illness. We investigated the in vivo and in vitro effects of the methanol extract of G. humilis leaves (MEGh) on inflammatory cells behavior (migration and chemical mediators release) and hypersensitivity. Anti-inflammatory activity was investigated using carrageenan-induced inflammation in the subcutaneous tissue of male Swiss mice treated orally with MEGh (0.1-30 mg/kg). Leucocyte migration, chemical mediators secretion (TNF, IL-1β, IL-6 and CXCL1) and protein exudation were quantified in the exudate. The adhesion molecules expression (CD62L and CD18), chemical mediators and chemotaxis was evaluated using neutrophils or macrophages RAW.264.7 previously treated with the extract (1-100 µg/mL) and activated with LPS. The anti-inflammatory activity of the isolated compounds friedelin, canophyllol, amentoflavone and 3-desmethyl-2-geranyl-4-prenylbellidypholine xanthone (10 μM) was evaluated in macrophages nitric oxide (NO) and TNF release. MEGh, given orally (30 mg/kg), significantly reduced neutrophil migration and decreased TNF, IL-1β and CXCL1 levels, without interfering with protein exudation and IL-6. In vitro, the extract significantly reduced IL-1β and IL-6 levels but did not alter TNF and CXCL1. The MEGh also reduced the expression of CD62L and CD18 and consequently neutrophil chemotaxis. The compounds friedelin, amentoflavone and 3-demethyl-2-geranyl-4-prenylbellidypholine xanthone decreased the secretion of NO and TNF by RAW264.7. The MEGh effects were extended to the pain-like behaviour induced by carrageenan in the mice hindpaw. MEGh presented important anti-inflammatory effects probably due to its activity on neutrophil migration and on important chemical mediator release, scientifically reinforcing its use as medicinal plant.