Modulatory effect of an Urera aurantiaca extract on immune and tumoral cells during inflammation

Abstract

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 treatinflammatory processes with proven in vivo antiinflammatory and antinociceptive effects. The effects of amethanolic extract (UA) and a purified fraction (PF) on the proliferation of normal and tumoral lymphocytesunder the effect of prostaglandin E2 (PGE2) and on nitric oxide production by lipopolysaccharide-stimulatedmacrophages was evaluated. Both UA and PF stimulated normal lymphocytes but, in presence of PGE2, amodulatory effect was observed. The normal lymphocyte proliferation induced by PGE2 was driven by pathwaysinvolving both PKC and H2O2. In macrophages, UA and PF did not modify cell viability and abrogated thesynthesis of nitric oxide induced by lipopolysaccharide. In tumoral lymphocytes, the UA exerted a biphasiceffect: at low concentrations it increased cell proliferation, while at high concentrations, it displayed anantiproliferative effect. UA and PF were capable of reverting the proliferative action of PGE2. The tumoral cellproliferation induced by PGE2 is related to PKC, ERK 1/2 and MAP Kinase P38 pathways. The observed effectscould be attributed to polyphenols, flavonoids and tannins. This work demonstrates the modulatory effects ofthe UA on different cell types during inflammatory conditions, which reinforces its antiinflammatory action.