Effects of the methanol extract of Cirsium japonicum var. ussuriense and hispidulin 7-O-neohesperidoside isolated from the plant on hepatic alcohol-metabolizing enzymes and lipid peroxidation were studied in rats treated with ethanol. Rats treated with 10% alcohol solution for 6 weeks were orally administered with 250 or 500 mg of methanol extract or 10 or 20 mg of hispidulin 7-O-neohesperidoside per kg body weight daily during the last week of ethanol treatment. The administration of the methanol extract of herbal plant and hispidulin 7-O-neohesperidoside in ethanol-treated rats significantly enhanced the activities of hepatic alcohol dehydrogenase, microsomal ethanol-oxidizing system and aldehyde dehydrogenase in a dose-dependent manner. The extract and the compound decreased hepatic lipid peroxidation along with an increase in hepatic content of reduced glutathione. The methanol extract and hispidulin 7-O-neohesperidoside of C. japonicum var. ussuriense also increased the activity of glutathione reductase, but had no effect on gamma-glutamylcysteine synthase. The results suggest that C. japonicum var. ussuriense may alleviate alcoholic toxicity by enhancing ethanol oxidation as well as inhibiting lipid peroxidation, and hispidulin 7-O-neohesperidoside is one of the active substances responsible for the protective effects of this plant.

The effect of methanol extract and protocatechuic acid from the leaves of Zanthoxylum piperitum on lipid peroxidation and drug metabolizing enzymes were investigated in the liver of bromobenzene-treated rats. The methanol extract and protocatechuic acid reduced the level of lipid peroxide induced by bromobenzene. The methanol extract and protocatechuic acid reduced the activity of aniline hydroxylase that had been increased by bromobenzene, while did not affect the activities of aminopyrine N-demethylase and glutathione S-transferase. The methanol extract and compound effectively restored the activity of epoxide hydrolase which had been decreased by bromobenzene. These results may suggest that the methanol extract of Z. piperitum and protocatechuic acid prevented lipid peroxidation by reducing the activity of aniline hydroxylase, an epoxide-producing enzyme, and by enhancing the activity of epoxide hydrolase, an epoxide-removing enzyme, in rats that had been intoxicated with bromobenzene.

We have reported recently that enrichment of high-density lipoprotein (HDL) with phosphatidylcholine (PC) liposomes is effective in solubilizing cholesterol from isolated human atherosclerotic plaques. In the present study, we investigated the in vivo effect of enrichment of HDL with PC on regression of diet-induced atherosclerosis in rabbits. As part of the study, a preliminary in vitro study on blood collected from the cholesterol-fed rabbits was performed to assess the capacity of the HDL density (d > 1.063 g/mL) plasma fraction from cholesterol-fed rabbits to assimilate multilamellar liposomes of synthetic dimyristoylphosphatidylcholine (DMPC). This was compared with the capacities of egg- and soy-PC liposomes to be assimilated into the HDL density plasma fraction. The capacity of the HDL density fraction to absorb PC from DMPC liposomes (11.5 mg/mL) was more than 10 times greater than egg or soy liposomes. Therefore, DMPC liposomes were chosen to infuse into cholesterol-fed rabbits. Cholesterol-fed rabbits infused weekly with DMPC liposomes (300 mg/kg body weight) for five weeks had significantly decreased aortic cholesterol contents (P < 0.05) compared with saline-infused cholesterol-fed controls. Atherosclerotic plaque volume, as measured by a type of new magnetic resonance imaging analysis, also decreased significantly (P < 0.05) after DMPC treatment. The present findings suggest that the enrichment of HDL with PC via intravenous infusion of synthetic DMPC liposomes could be a potential therapeutic approach for atherosclerotic plaque regression.

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