Effect of curcumin and capsaicin on arachidonic acid metabolism and lysosomal enzyme secretion by rat peritoneal macrophages

The inflammatory mediators secreted by macrophages play an-important role in autoimmune diseases. Spice components, such as curcumin from turmeric and capsaicin from red pepper, are shown to exhibit antiinflammatory properties. The influence of these spice components on arachidonic acid metabolism and secretion of lysosomal enzymes by macro phages was investigated. Rat peritoneal macrophages preincubated with 10 mu M curcumin or capsaicin for 1 h inhibited the incorporation of arachidonic acid into membrane lipids by 82. and 76%: prostaglandin E-2 by 45 and 48%; leukotriene B-4 by 61 and 46%, and leukotriene C-4 by 34 and 48%, respectively, but did not affect the release of arachidonic add from macrophages stimulated by phorbol myristate acetate. However, the secretion of 6-keto PG F-1 alpha was enhanced by 40 and 29% from macrophages preincubated with 10 mu M curcumin or capsaicin, respectively, as compared to those produced by control cells. Curcumin and capsaicin also inhibited the secretion of collagenase, elastase, and hyaluronidase to the maximum extent of 57, 61, 66%, and 46, 69, 67%, respectively. These results demonstrated that curcumin and capsaicin can control the release of inflammatory mediators such as eicosanoids and hydrolytic enzymes secreted by macrophages and thereby may exhibit antiinflammatory properties.