Low-density lipoprotein LDL oxidation

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

This method is also used to measure ex vivo low-density lipoprotein (LDL) oxidation. LDL is isolated fresh from blood samples, oxidation is initiated by Cu(II) or AAPH, and peroxidation of the lipid components is followed at 234 nm for conjugated dienes (Prior and others 2005). In this specific case the procedure can be used to assess the interaction of certain antioxidant compounds, such as vitamin E, carotenoids, and retinyl stearate, exerting a protective effect on LDL (Esterbauer and others 1989). Hence, Viana and others (1996) studied the in vitro antioxidative effects of an extract rich in flavonoids. Similarly, Pearson and others (1999) assessed the ability of compounds in apple juices and extracts from fresh apple to protect LDL. Wang and Goodman (1999) examined the antioxidant properties of 26 common dietary phenolic agents in an ex vivo LDL oxidation model. Salleh and others (2002) screened 12 edible plant extracts rich in polyphenols for their potential to inhibit oxidation of LDL in vitro. Gongalves and others (2004) observed that phenolic extracts from cherry inhibited LDL oxidation in vitro in a dose-dependent manner. Yildirin and others (2007) demonstrated that grapes inhibited oxidation of human LDL at a level comparable to wine. Coinu and others (2007) studied the antioxidant properties of extracts obtained from artichoke leaves and outer bracts measured on human oxidized LDL. Milde and others (2007) showed that many phenolics, as well as carotenoids, enhance resistance to LDL oxidation. 

Garlic clearly has antithrombotic properties. Ajoene (an allicin metabolite) and methyl allyl trisulfide inhibit platelet aggregation. Garlic may promote vasodilation by relaxing smooth muscle, and it may reduce low-density lipoprotein (LDL) oxidation. 

Handelman et al. (1999) treated milled oat groat pearlings, trichomes, flour, and bran with methanol and tested the fractions for antioxidant capacity against low-density lipoprotein (LDL) oxidation and R-phycoerythrin protein oxidation in the oxygen radical absorbance capacity... 

Phenolic compounds also have important antioxidant properties, protecting food from oxidation [9]. The antioxidant properties of phenolic compounds can have an impact on human health and they are regarded as having a protective effect against low-density lipoprotein (LDL) oxidation and cardiovascular diseases [3], Recently phenolic compounds have been widely used in cosmetic preparations to delay aging [10]. 

Zarev, S., Therond, P., Bonnefont-Rousselot, D. Beaudeux, J.-L., Gardes-Albert, M., Legrand, A. 1999. Major differences in oxysterol formation in human low density lipoproteins (LDLs) oxidized by OH/O free radicals or by copper. FEBS Letts. 451, 103-108. 

Furthermore, lacidipine was found to possess antioxidant activity at the same level of that of vitamin E in many tests, including hydrogen peroxide oxidation of rat neuronal cells [14]. The antioxidant property of lacidipine was further confirmed by experiments in vivo, in which low-density lipoprotein (LDL) oxidation was completely abolished [15]. Lacidipine also shows a direct protective effect on the vasculature at non-antihypertensive doses, indicating that its high lipophilicity combined with antioxidant potential can exert an additional therapeutic benefit [16-18]. 

Antioxidation effects in both Fe -mediated and non-metal indueed human low-density lipoprotein (LDL) oxidations. Morelloflavone has shown antioxidative, antiviral, and antiinflammatory properties. 

Various lipidic markers have been studied (Narula and Strauss, 2005) native low-density lipoprotein (LDL), oxidized LDL, and anti-LDL antibodies. Other components such as cholesterol esters or apoprotein B (Kritz et al, 1998) were marked. 

Documented effects Resins from the leaves decrease blood pressure. An infusion of the leaves was shown to slightly reduce blood sugar levels (Gammerman et al. 1990). The flavonoid leachianone G was isolated from the root bark and showed potent antiviral activity against herpes simplex type 1 virus (Du et al. 2003). Two flavonoids isolated from the leaves significantly inhibited the growth of a human leukemia cell line (Kim et al. 2000). Flavonol glycosides, isolated from an extract of the leaves, showed some inhibition of low-density lipoprotein (LDL) oxidation (Katsube et al. 2004, 2006). 

Lariciresinol and pinoresinol isolated from methanolic extract of Cornus kousa fruits exhibited an efficient inhibitory activity against low density lipoprotein (LDL) oxidation [Lee et al., 2007c Lee et al., 2010]. 

---