Purification and characterization of a similar to 34 kDa antioxidant protein (beta-turmerin) from turmeric (Curcuma longa) waste grits

beta-Turmerin from turmeric (Curcuma longa) waste grits obtained after extraction of curcumin was purified by successive gel permeation chromatography. Homogeneity of beta-turmerin was confirmed by its movement as single band both in SDS-PAGE and as well as in native (basic) PAGE. The apparent molecular mass is similar to 34 kDa by SDS-PAGE. It is more hydrophobic protein and showed sharp single peak in RP-HPLC with retention time of 62.17 min. It is a glycoprotein as it shows the presence of amino sugars up to 0.021 gm%. In three different model systems i.e., linolenic acid micelles, erythrocyte membrane systems and liposomes, beta-turmerin at 0.125 mu M offered 70%, 64%, and 60% inhibition of lipid peroxidation, which is 3200 times more efficient than the standard antioxidants BHA (400 mu M) and alpha-tocopherol (400 mu M). 5-turmerin inhibited diene-triene and tetraene conjugation up to 54%, 72% and 47%, respectively. beta-turmerin also effectively scavenges hydroxyl radicals when compared to BHA and alpha-tocopherol. beta-turmerin (2.5 mu M) further inhibited the activation of PMNL mediated by fMLP up to the extent of 75%, where as standards BHA (400 mu M) and mannitol (10 mu M) inhibited the same to 65% and 55%, respectively. At 0.125 mu M dose beta-turmerin prevented t-BOOH induced cell death at all time intervals. In addition to the above properties, it is non-toxic to lymphocytes as it did not affect the viability of cells. The mechanism of antioxidant action of beta-turmerin could probably be by counteracting/quenching of reactive oxygen species (ROS). We report the purification and characterization of beta-turmerin (similar to 34 kDa), a potent antioxidant protein from turmeric waste grits. (C) 2009 Elsevier Masson SAS. All rights reserved.