<i>In vitro</i> studies on inhibitory effect of proanthocyanidins in modulation of neutrophils and macrophages

Abstract

The role of proanthocyanidins (PC), a novel flavonoid extracted from grape seeds was studied <i>in vitro</i> in the modulation of neutrophil and macrophage function. We attempted to assess the levels of non-enzymatic and enzymatic mediators in the presence or absence of PC in 4-phorbol-12-<img src='/image/spc_char/beta.gif'>-myristate-13-acetate (PMA)-stimulated neutrophils isolated from humans and rats, <i>E. coli</i> endotoxin-stimulated macrophages and macrophages<i> </i>isolated from<i> E. coli</i> endotoxin-induced experimental periodontitis in rats. Addition of PC at a concentration of 50 µg/ml effectively blocked the release of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and exhibited a marked inhibition of myeloperoxidase (MPO) and lysosomal enzymes (<i style="">p</i><0.001), as compared to PMA-stimulated neutrophils (human and rats) and neutrophils isolated from experimental periodontitis in rats. The levels of ROS, RNS and lysosomal enzymes were found to be elevated (<i style="">p</i><0.001) and addition of PC significantly (<i style="">p</i><0.001) reduced these levels<i> </i>as compared<i> </i>to those from <i>E. coli</i> endotoxin-stimulatedmacrophages from rats and macrophages<i> </i>isolated from<i> </i>experimental periodontitis in rats (<i style="">p</i><0.001). Thus, the study demonstrated that PC decreased the levels of ROS and RNS and also inhibited the MPO and lysosomal enzymes activities in experimental periodontitis in rats. In addition, this study clearly indicated that PC could be developed as an effective antiinflammatory agent.