Flavonoids, a group of phenolic compounds found naturally in fruit, vegetables, nuts, flowers, seeds and bark are an integral part of the human diet. They have been reported to exhibit a wide range of biological effects, including anti-ischemic, antiplatelet, antineoplastic, antiinflammatory, antiallergic, antilipoperoxidant or gastroprotective actions. Furthermore, flavonoids are potent antioxidants, free radical scavengers and metal chelators, and inhibit lipid peroxidation. Oxidative modification of low-density lipoproteins (LDLs) is believed to play a crucial role in atherogenesis. Epidemiological studies have shown that the consumption of fruits and vegetables, and regular red wine consumption is related with a reduced risk of cardiovascular diseases., G. Mojžišová, M. Kuchta., and Obsahuje bibliografii
The oxidative modification of low density lipoprotein (LDL) plays an important role in the pathogenesis of atherosclerosis. LDL of subjects with atherogenic lipoprotein phenotype (ALP) is known to be more susceptible to oxidation. We studied the effect of the hypolipidaemic drug ciprofibrate on the susceptibility of LDL to in vitro oxidation. Nine patients with primary hypertriglyceridaemia and hypoalphalipoproteinaemia (mean plasma triglycerides 3.76 mmol.L1 and HDL-cholesterol 0.74 mmol.l-1) were treated with ciprofibrate for 12 weeks. The susceptibility of LDL to in vitro Cu2 +-mediated oxidation was assessed by measuring conjugated diene formation at 234 nm. Ciprofibrate therapy significantly prolonged the lag time (93±7 min vs. 102±11 min, P = 0.02). The maximal rate of diene production was 11 % lower, but the decrease was not significant. A significant positive correlation was observed between maximal rate and maximal amount of dienes formed. Thiobarbituric acid reacting substances (TBARS) and lipid hydroperoxides (LPO) in oxidatively-modified LDL, isolated from the plasma of patients before and after drug treatment, were unchanged. The results suggest that ciprofibrate therapy has a favourable effect by increasing the in vitro resistance of LDL against oxidation.
Particle size of low density (LDL) and high density (HDL) lipoproteins and cholesterol esterification rate in HDL plasma (FERHDL) are important independent predictors of coronary artery diseases (CAD). In this study we assessed the interrelations between these indicators and routinely examined plasma lipid parameters and plasma glucose concentrations. In 141 men, healthy volunteers, we examined plasma total cholesterol (TC), triglycerides (TG), HDL and LDL cholesterol (HDL-C, LDL-C) an
d HDL unesterified cholesterol (HDL-UC). Particle size distribution in HDL
and LDL was assessed by gradient gel electrophoresis and FERHDL was estimated by radioassay. An effect of particle size and FERHDL on atherogenic indexes as the Log(TG/HDL-C) and TC/HDL-C was evaluated. Subjects in the study had plasma concentrations (mean ± S.D.) of TC 5.2±0.9
mmol/l, HDL-C 1.2±0.3 mmol/l, TG 2.1±1.7 mmol/l, glucose 5±0.8 mmol/l. Relative concentration of HDL2b was 17.6±11.5 % and 14.6±11.8 % of HDL
3b,c. The mean diameter of LDL particles was 25.8±1.5 nm. The increase in FERHDL significantly correlated with the decrease in HDL2b and LDL
particle size (r = –0.537 and –0.583, respectively, P<0.01) and
the increase in HDL3b,c (0.473, P<0.01). Strong interrelations among TG and HDL-C or HDL-UC and FERHDL and particle size were found, but TC or LDL-C did not have such an effect. Atherogenic indexes Log(TG/HDL-C) and TC/HDL-C correlated with FERHDL (0.827 and 0.750, respectively, P<0.0001) and with HDL and LDL particle size.