Phenolics are broadly distributed in the plant kingdom and are the most abundant secondary metabolites of plants. Plant polyphenols have drawn increasing attention due to their potent antioxidant properties and their marked effects in the prevention of various oxidative stress associated diseases such as cancer. In the last few years, the identification and development of phenolic compounds or extracts from different plants has become a major area of health- and medical-related research. This review provides an updated and comprehensive overview on phenolic extraction, purification, analysis and quantification as well as their antioxidant properties. Furthermore, the anticancer effects of phenolics in-vitro and in-vivo animal models are viewed, including recent human intervention studies. Finally, possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.

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Plant phenolics: extraction, analysis and their antioxidant and anticancer properties.

Bioactive compounds in foods: their role in the prevention of cardiovascular disease and cancer

Phenolics and polyphenolics in foods, beverages and spices: Antioxidant activity and health effects – A review

Natural antioxidants from residual sources.

Bioavailability and bioefficacy of polyphenols in humans. II. Review of 93 intervention studies

Cranberry products and especially cranberry juice (CJ) have been consumed for health reasons primarily due to their effect on urinary tract infections. We investigated the quantity of both free and total (after hydrolysis) phenolic antioxidants in cranberry products using the Folin assay. The order of amount of total polyphenols in cranberry foods on a fresh weight basis was as follows: dried > frozen > sauce > jellied sauce. On a serving size basis for all cranberry products, the order was as follows: frozen > 100% juice > dried > 27% juice > sauce > jellied sauce. High fructose corn syrup (HFCS) is a major source of sugar consumption in the U.S. and contains both glucose and fructose, potential mediators of oxidative stress. We investigated the effect of the consumption of HFCS and ascorbate with CJ antioxidants or without CJ (control) given to 10 normal individuals after an overnight fast. Plasma antioxidant capacity, glucose, triglycerides, and ascorbate were measured 6 times over 7 h after the consumption of a single 240 mL serving of the two different beverages. The control HFCS caused a slight decrease in plasma antioxidant capacity at all time points and thus an oxidative stress in spite of the presence of ascorbate. CJ produced an increase in plasma antioxidant capacity that was significantly greater than control HFCS at all time points. Postprandial triglycerides, due to fructose in the beverages, were mainly responsible for the oxidative stress and were significantly correlated with the oxidative stress as measured by the antioxidant capacity. Cranberries are an excellent source of high quality antioxidants and should be examined in human supplementation studies.

Cranberries and cranberry products: powerful in vitro, ex vivo, and in vivo sources of antioxidants.

Vitamins and especially flavonoids in common beverages are powerful in vitro antioxidants which enrich lower density lipoproteins and increase their oxidative resistance after ex vivo spiking in human plasma.

Epidemiological studies have produced solid evidence that consumption of fruits results in a reduction of cancer and cardiovascular disease. Red wine has been hypothesized to reduce the risk of heart disease as a result of its antioxidant, endothelial relaxation, and antiplatelet aggregation mechanisms. We investigated a commercial California wine grapeseed extract, MegaNatural® Gold, and compared it to grapes, grape juice, red wine, other grapeseed extracts, and commercial extracts with respect to antioxidant activity, using an oxidation-reduction colorimetric assay. The quality of the antioxidants was determined with the use of an in vitro model of heart disease, a dose-response inhibition of low-density lipoprotein oxidation. MegaNatural® Gold had a superior quantity/quality antioxidant index compared with all other samples tested. In nine subjects given 600 mg of MegaNatural® Gold, the plasma antioxidant activity as measured by the RANDOX assay was significantly increased by 12% after both 1 and 2 hou...

MegaNatural((R)) Gold Grapeseed Extract: In Vitro Antioxidant and In Vivo Human Supplementation Studies.

Polyphenols and particularly flavonoids are well known in vitro antioxidants. Their consumption in foods has been shown to decrease the risk of heart disease in epidemiological studies. We examined two commonly consumed nonalcoholic juices (grape juice and orange juice) for their ability to act as in vitro plasma antioxidants, enrich lower-density lipoproteins after plasma spiking, and protect these lipoproteins from oxidation after supplementation to healthy subjects. We found that grape juice, but not orange juice, possesses all of these antioxidant properties and is an excellent nonalcoholic alternative to red wine. Grape juice is a powerful in vivo antioxidant, and this property, in combination with its platelet aggregation inhibition ability, can potentially reduce the risk of heart disease.

Grape juice, but not orange juice, has in vitro, ex vivo, and in vivo antioxidant properties.

Objective: To measure the ability of a multiple-barrier product to inhibit the passage of a highly water-soluble tracer into the skin when compared with products currently available on the market (Peri-Care; Sween Corp., and Double-Guard; C. R. Bard, Inc.)

Design: Dye extraction from the skin was measured at specified intervals and a spectrophotometric measurement of the amount of dye was obtained.

Setting and Subjects: Two groups of light-skinned volunteers, 6 young adults subjects, aged 22 to 31 years, and 6 older subjects, aged 61 to 73 years, were studied in a controlled laboratory setting.

Instruments: Spectronic 601 spectrophotometer.

Methods: Rectangles (1 inch × 4 inch), inscribed on the ventral forearm skin, were divided into 4 1 inch × 1-inch squares, onto which 50 μL of different barrier products were spread. Band-Aids (Johnson & Johnson), saturated with 70 μL of an FD&C red dye No. 40 solution, were placed over the treated squares and left in place for specified intervals up to 8 hours. Similarly treated Band-Aids placed onto untreated skin comprised the controls.

Main Outcome Measure: Amount of dye extracted from the skin as reflected by absorbance spectrophotometry.

Results: This multiple-barrier product inhibited the passage of the tracer into the skin significantly better than the other 2 products at all time points, except for 1 point in the elderly group.

Conclusion: Noninvasive preclinical methods show that this prototype barrier cream inhibits the absorption onto the skin of a solution simulating the density and ionic strength of urine. The advantages and limitations of the methods are clarified and directions for clinical research are suggested.

John Proch

Papers

Cranberries and cranberry products: powerful in vitro, ex vivo, and in vivo sources of antioxidants.

Vitamins and especially flavonoids in common beverages are powerful in vitro antioxidants which enrich lower density lipoproteins and increase their oxidative resistance after ex vivo spiking in human plasma.

MegaNatural((R)) Gold Grapeseed Extract: In Vitro Antioxidant and In Vivo Human Supplementation Studies.

Grape juice, but not orange juice, has in vitro, ex vivo, and in vivo antioxidant properties.

Inhibition of moisture penetration to the skin by a novel incontinence barrier product