Procyanidins protective effects

The effects of catechin, epicatechin, procyanidin B2, caffeic acid, / -coumaric acid, myricetrin, and quercetrin on the color intensity and stability of malvidin 3-glucoside at a molar ratio of 1 1 under conditions similar to red wine were evaluated. " Flavan 3-ols appeared to have the lowest protective effects and flavonols the highest strong color changes were visually perceptible. " In the complexation of malvin chloride and natural polyphenols, flavonol glycosides by far exerted the best protector effect. ... 

Hypertension is an important risk factor for coronary heart disease and stroke. Since ancient times, hypertensive patients have been treated orally with plant extracts based on folk medicine. However, and despite their in vitro vasodilator effects, little information about the protective effects of flavonoids on hypertension is available in the literature. Flavonoids have been considered as active principles of several antihypertensive plant extracts (e.g. rhamnoglycoside of limocitrin isolated from Citrus limonum, kaempferol 4 -0-glucose and hyperin from Euphorbia maddeni, moracenins from Morus alba, procyanidin glycoside from Rhamnus lycioides) [150,151]. In all cases, only the acute antihypertensive effects after i.v. administration in anaesthetised normotensive and/or hypertensive animals have been described. In addition to the direct vasodilator effects discussed above, the inhibition of angiotensin-converting enzyme reported... 

The finding that water-soluble flavonoids could exert their beneficial properties at the hydrophobic portion of the membrane was also observed in in vivo studies and in cells in culture. For example, erythrocytes obtained from animals fed a flavanol- and procyanidin-rich meal showed reduced susceptibility to free-radical-mediated hemolysis [Zhu et al., 2002]. Consistently, we demonstrated that procyanidin hexamers, which interact with membranes but would not be internalized, protected Caco-2 cells from AMVN- and bile-induced oxidation [Erlejman et al., 2006]. When liposomes were preincubated with a series of flavonoids with diverse hydrophobicity, not only hydrophobic flavonoids prevented AMVN-mediated lipid oxidation but also the more hydrophilic ones [Erlejman et al., 2004]. Similarly to what was previously found in liposomes, the protective effects of flavonoids against AMVN-supported oxidation was strongly associated with their capacity to prevent membrane disruption by detergents, supporting the hypothesis of a physical protection of membranes by preventing oxidants to reach fatty acids. 

HTST treatment had a protective effect, the procyanidins being reasonably stable through subsequent processing steps. They completely disappeared, however, after nine months storage as a concentrate. 

Arteel and Sies (1999) examined procyanidin oligomers of different size, isolated from the seeds of Theobroma cacao, for their ability to protect against nitration of tyrosine. Serraino and others (2003) investigated antioxidant activity of the blackberry juice and cyanidin-3-O-glucoside on endothelial dysfunction in cells and in vascular rings exposed to peroxynitrite. However, more work is needed in this area, and the confounding effects of oxidized protein/amino acids in the diet need to be elucidated. 

Over the last two decades, the scientific community has become aware of the potential health-related benefits of antioxidants and the properties of polyphenols-rich dark chocolate and cocoa. More than 200 studies were reported on bioactive compounds, chemical compositions, and health benefits of cocoa and cocoa products. Many of the proposed health-protective activities associated with the crmsumption of cocoa and chocolate have been attributed to flavan-3-ols, including monomers. Reported pharmacological activities of procyanidins include antioxidative and anticancer effects, protection against cardiovascular disease, risk reduction of blood clotting, protection against urinary tract infectirms, decrease of LDL-c, decrease of blood pressure, and improvement of endothelium vasodilatation. Moreover, there is some scientific evidence about an increase in blood flow and perfusion of the brain by... 

A study carried out on rat blood cells showed that ingestion of an aqueous extract of U. sinensis caused a dose dependent decrease in susceptibility of RBC to lysis. Phenolic antioxidants including procyanidin B-1, catechin, epi-catechin, and caffeic acid were evaluated for their antioxidant activity. These results showed that they exhibit a strong and dose-dependent protection of the cell membrane [86]. Another study was conducted to evaluate the neuropro-tective effects of methanol extracts of U. rhynchophylla in rats upon transient global ischemia [78]. The study revealed that the extract significantly reduced the death of CAl hippocampal neurons by 72% at a dose of 100 mg/kg body weight [87]. 

---