[Suppression of lipid peroxidation by sho-saiko-to and its components in rat liver subcellular membranes].

In order to elucidate anti-inflammatory action of Sho-saiko-to, its components were analyzed and purified by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC), and their effects on lipid peroxidation were compared with those of Sho-saiko-to in guinea pig neutrophils, rat liver mitochondria and microsomes. The results obtained were as follows: 1) Sho-saiko-to gave no effect on arachidonate- and PMA (phorbol 13-myristate 12-acetate)-induced NADPH-O2- generation in neutrophils though it gave a weak LPS-like effect on the cells. No inhibition of reduced nicotinamido adenine dinucleotide phosphate (NADPH) oxidation was shown in liver microsomes. However, it markedly inhibited iron-induced lipid peroxidation in microsomes and mitochondria. 2) The active components to suppress lipid peroxidation could be concentrated in a lipid-soluble fraction from the Sho-saiko-to solution. The ED50 values to give 50% inhibition of the mitochondrial lipid peroxidation were 160 ng/mg prot, and 50 micrograms/mg prot, for the lipid-soluble fraction and Sho-saiko-to, respectively. 3) The components in the lipid-soluble fraction were further separated by TLC and HPLC, and their inhibitory effects on the lipid peroxidation were examined. The active components were baicalein, ginsenoside Rf and baicalin, of which ED50 values were 0.2, 0.2 and 1 nmol/mg prot, respectively. Glycyrrhizin and its derivatives, ginsenoside (except ginsenoside Rf), and saikosaponins gave no effect in the concentration examined. 4) From these results anti-inflammatory action of Sho-saiko-to was discussed.