This study was pcrformed to evaluate the antioxidant activity of silymarin against human low density lipoproteins(LDL) oxidation. Silymarin extracted from Silybum marianum was successively purified with solvent fractionation and followed by silica gel column chromatography. The active substances were separated by HPLC and the isolated active substances, silymarin were identified by IR, NMR, GC-MS as silymarin. Silymarin inhibited at the 5 uM Cu^(2+)-mediated oxidation of human low density lipoprotein (LDL) in a dose dependent manner. Silymarin completely inhibited LDL oxidation at 50 ug/ml concentration. These findings suggest that silymarin may protect LDL against oxidation in atherosclerotic lessions.

Bacillus subtilis SH-1 have been isolated and identified from coastal sea, in Pusan. The optimal cultural characterization of Bacillus subtilis SH-1 for the production of bacteriolytic enzyme was determined. Bacillus subtilis SH-1 produced the bacteriolytic enzyme well in the medium consist of 1.0% glucose, 1.0% yeast extract, 1.0% NaCl, 0.02% K₂HPO₄, 0.002% MgSO₄, 7H₂O, 0.001% MnSO₄, 5H₂O, and 0.0001% FeSO₄, 7H₂O. The optimal medium pH, incubation temperature, and shaking time for the highest production of the enzyme were 8.0, 30℃ and 28 hours respectively.

Thiobacillus neopolitanus R-10, which produces a active thiosulfate oxidase, was isolated from nightsoil. The optimal culture conditions of Thiobacillus neopolitanus R-10 for the production of enzyme was determined as followed: 0.8% Na2S203, 0.2% KH2P04, 0.2% K2HP04, 0.04% Na2C03, 0.02% MgSO4·7H2O, 2ml trace elements solution, and pH 6.5 at 30℃ and 72hr cultivation. The oxidase was successively purified 83 folds yield by (NH2)2S04 fractionation, DEAE-Cellulose, Sephadex A-50 column chromatogrophy and gel Sephadex G-150 gel filteration with yield of 5.9%. The molecular weight of purified enzyme was estimated to be 43.000 dalton by SDS-polyacrylamide gel electrophoresis and gel filteration column chromatography. The enzyme activity was highest at 40℃ and pH 7.0 The enzyme activity was relatively high by β-mercaptoethanol but strongly inhibited by cysteine.