Triacontanol inhibits both enzymatic and nonenzymatic lipid peroxidation

The effect of the plant growth regulator, triacontanol (TRIA) on lipid pero xidation was studied in three different systems: (i) isolated chloroplasts of spinach (Spinacea oleracea L.) leaves; (ii) egg lecithin liposomes; and (iii) soybean lipoxygenase (LOX) system. The nonenzymatic lipid peroxidatio n in isolated chloroplasts and egg lecithin liposomes was measured as the a mount of thiobarbituric acid reactive substances (TBARS) formed. Inhibition of Fe2+ and/or light-induced lipid peroxidation by TRIA was observed in bo th isolated chloroplasts and egg lecithin liposomes. The kinetics of soybea n lipoxygenase-I (LOX-1) was studied using linoleic acid as the substrate. The enzyme was competitively inhibited by TRIA. The K-i for TRIA inhibition of the enzyme was estimated to be 3.2-5.0 mu M according to different meth ods of estimation. TRIA has been known to exhibit antiinflammatory action i n animals and this anti-inflammatory effect of TRIA might be mediated throu gh inhibition of lipid peroxidation. Since LOX inhibitors have been extensi vely used as therapeutic agents, TRIA, being a natural compound has been su ggested to be an effective anti-inflammatory drug. (C) 2000 Elsevier Scienc e Ltd. All rights reserved.