Marine animals produce astaxanthin which is a carotenoid and antioxidant. In this study we determined the in vitro and ex vivo effects of astaxanthin on LDL oxidation. The oxidation of LDL was measured in a 1 ml reaction system consisting of increasing concentrations of astaxanthin (12.5, 25.0, 50.0 microg/ml), 400 microM V-70 (2, 2'-azobis(4-methoxy-2, 4-dimethylvaleronitrile)), and LDL (70 microg/ml protein). Astaxanthin dose, dependently significantly prolonged the oxidation lag time (31.5, 45.4, 65.0 min) compared with the control (19.9 min). For the ex vivo study 24 volunteers (mean age 28.2 [SD 7.8] years) consumed astaxanthin at doses of 1.8, 3.6,14.4 and 21.6 mg per day for 14 days. No other changes were made in the diet. Fasting venous blood samples were taken at days 0, +14. LDL lag time was longer (5.0, 26.2, 42.3 and 30.7% respectively) compared with day 0 after consuming astaxanthin at doses of 1.8, 3.6,14.4 and 21.6 mg for 14 days compared with day 0, but there was no difference in oxidation of LDL between day 0 (lag time 59.9+/-7.2 min) and day 14 (57.2+/-6.0 min) in the control group. Our results provide evidence that consumption of marine animals producing astaxanthin inhibits LDL oxidation and possibly therefore contributes to the prevention of atherosclerosis.

SummaryFlavonoids, a group of polyphenolic compounds, exist naturally and serve as antioxidants in vegetables, fruits, and so on. The inhibition of low density lipoprotein (LDL) oxidation may be an effective way to prevent or delay the progression of atherosclerosis. In the present study, we analyzed the radical scavenging capacity of 10 flavonoids (catechin,, myricetin, quercetiji, apigenin, kaempferol, and luteolin) toward 1,1-Biphenyl-2 picryl-hydrazyl [DPPH]. After 20min of incubation, EGCg was the most effective DPPH radi cal scavenger, luteolin being the least active of this flavonoid group. The mutual antioxidant effect of flavonoids with a-tocopherol (a-toc) on LDL oxidizability was investigated by using the lipophilic azo radical initiator 2 ,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) . An inhibitory effect of flavonoids on LDL oxidation was observed in the order of luteolin>ECg>EC>quercetin>catechin>EGCg>EGC>myricetin>kaempferol> apigenin. The shortened lag time induced by higher doses of a-toc (6mg/100mL) was re stored by flavonoids. These results suggest that 1) radical trapping effects of flavonoids differ according to their structure, and 2) flavonoids act as hydrogen donors to a-toc radical; fur thermore, by interaction with a-toc, they have a greater potential to delay the oxidation of LDL.

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The IL-1 gene polymorphisms were found to play a role in the development of CAD, especially MI, in patients with CP infection.

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The effects of cacao liquor polyphenols (CLP) on the susceptibility of low-density lipoprotein (LDL) to oxidation in hypercholesterolemic rabbits were examined. Six Japanese white rabbits which had been fed a high cholesterol diet (HCD) for 3 weeks were fed HCD containing 1% CLP for the following 10 days. The susceptibility of LDL to oxidation induced by 2-2'-azobis(4-methoxy-2, 4-dimethylvaleronitrile) (V-70) was evaluated by measuring the production of conjugated dienes and thiobarbituric acid reactive substances (TBARS). The lag time was significantly prolonged from 37.7 min before intake of CLP to 42.9, 44.2 and 45.8 min after 4, 7 and 10 days of CLP intake. TBARS production after intake of CLP was also markedly reduced compared with the level before intake. There was no difference in plasma lipid concentrations comparing the levels before and after CLP intake. In conclusion, in hypercholesterolemic rabbits, orally administered CLP was absorbed and distributed to the blood, and the resistance of LDL to oxidation was thereby increased.