Modulatory Effect of an Urera Aurantiaca Extract on Immune and Tumoral Cells During Inflammation.

There is a well known link between inflammation and cancer during initiation, propagation and metastasis. Urera aurantiaca (UA) Wedd. (Urticaceae) is a medicinal plant used in traditional medicine to treat inflammatory processes with proven in vivo antiinflammatory and antinociceptive effects. The effects of a methanolic extract (UA) and a purified fraction (PF) on the proliferation of normal and tumoral lymphocytes under the effect of prostaglandin E2 (PGE2 ) and on nitric oxide production by lipopolysaccharide-stimulated macrophages was evaluated. Both UA and PF stimulated normal lymphocytes but, in presence of PGE2, a modulatory effect was observed. The normal lymphocyte proliferation induced by PGE2 was driven by pathways involving both PKC and H2 O2 . In macrophages, UA and PF did not modify cell viability and abrogated the synthesis of nitric oxide induced by lipopolysaccharide. In tumoral lymphocytes, the UA exerted a biphasic effect: at low concentrations it increased cell proliferation, while at high concentrations, it displayed an antiproliferative effect. UA and PF were capable of reverting the proliferative action of PGE2 . The tumoral cell proliferation induced by PGE2 is related to PKC, ERK 1/2 and MAP Kinase P38 pathways. The observed effects could be attributed to polyphenols, flavonoids and tannins. This work demonstrates the modulatory effects of the UA on different cell types during inflammatory conditions, which reinforces its antiinflammatory action.