Author
John Proch
Bio: John Proch is an academic researcher from University of Scranton. The author has contributed to research in topics: Antioxidant & Dark chocolate. The author has an hindex of 10, co-authored 10 publications receiving 1410 citations.
Papers
More filters
TL;DR: Dried fruits, especially figs, are a convenient and superior source of some nutrients, but in the American diet amount to less than 1% of total fruit consumed, the findings suggest that dried fruits should be a greater part of the diet as they are dense in phenol antioxidants and nutrients, most notably fiber.
Abstract: Objective: The goal of this work is to determine the amount and quality of phenol antioxidants in dried fruits and compare them with the corresponding fresh fruits; to compare the nutrients in fresh and dried fruits; to determine if figs are a source of in vivo antioxidants when eaten.Methods: Commercial samples of dried fruits and fresh fruits were compared in the in vitro studies using a colorimetric method to measure phenolic antioxidants. The quality of the antioxidants was measured by inhibition of lower density lipoprotein oxidation. Ten normal free-living subjects were tested in the human study. Fasting subjects were given 40 g of figs with or without a carbonated beverage and the plasma antioxidant capacity was measured for six hours using the trolox equivalent antioxidant capacity assay.Results: Dates have the highest concentration of polyphenols among the dried fruits. Figs and dried plums have the best nutrient score among the dried fruits, and dates among the fresh fruits. Processing to produc...
423 citations
TL;DR: Cocoa powder and dark chocolate may favorably affect cardiovascular disease risk status by modestly reducing LDL oxidation susceptibility, increasing serum total antioxidant capacity and HDL-cholesterol concentrations, and not adversely affecting prostaglandins.
342 citations
172 citations
TL;DR: The methods described in this article are quick, simple, and inexpensive to perform and can be employed to compare antioxidants as pure compounds, or in mixtures after quantitating the polyphenols.
Abstract: The methods described in this article are quick, simple, and inexpensive to perform. The Folin quantitation method can determine both free and total polyphenol antioxidants in foods and beverages as described, as well as botanical extracts. This assay may also be used to estimate the daily per capita consumption of polyphenols in foods. The dose-response in vitro lower density lipoprotein antioxidant activity measurement (IC50) can be employed to compare antioxidants as pure compounds, or in mixtures after quantitating the polyphenols. The ex vivo lipoprotein-binding antioxidant activity can be measured simply and rapidly to determine possible in vivo binding of pure compounds or extracts from foods. Supplementation and epidemiology studies can utilize the rapid and inexpensive affinity column isolation method of lower density lipoproteins for the determination of lipoprotein oxidative susceptibility.
145 citations
TL;DR: The pure polyphenol hesperidin, which is common in juices, ascorbic acid, and the citrus juices, were not able to bind with LDL+VLDL and protect it from oxidation, while the juices were able to significantly inhibit atherosclerosis and lowered cholesterol and triglycerides.
Abstract: It is well known that eating fruits and vegetables lowers the risk of chronic diseases such as heart disease and cancer. The question of what is/are the active ingredient(s) is still unresolved. The initial hypothesis was that the antioxidant vitamins were responsible. However, recently the polyphenols have been investigated since they have been found to have beneficial properties such as being strong antioxidants. We measured the polyphenol content of citrus juices by an oxidation-reduction colorimetric method (Folin) using catechin as the standard. The order was tangerine juice > grapefruit juice > orange juice. The antioxidant contribution of ascorbic acid was measured by the difference in Folin reactive content following removal by ascorbate oxidase. Ascorbate contributed 56 to 77% of the antioxidant content of orange juice, 46% of the single tangerine juice measured, and 66 to 77% of grapefruit juices. Polyphenol quality in the juices was analyzed by using the inhibition of lower density lipoprotein oxidation promoted by cupric ion, an in vitro model of heart disease. Quality decreased in the following order: orange juice > grapefruit juice > tangerine juice. In orange juice polyphenols accounted for 84–85% of antioxidant quality. The pure polyphenol hesperidin, which is common in juices, ascorbic acid, and the citrus juices, were not able to bind with LDL+VLDL and protect it from oxidation. In a hamster model of atherosclerosis, the juices were able to significantly inhibit atherosclerosis and lowered cholesterol and triglycerides. Ascorbic acid alone in the dose provided by the juices was found to have the same effect on atherosclerosis. However, the polyphenols in the citrus juices are responsible for the hypolipemic effects. In a crossover study neither 200 mg of vitamin C alone or in orange juice had an in vivo antioxidant effect on either plasma or LDL+VLDL, and no hypolipemic effects in 8 normal human subjects.
114 citations
Cited by
More filters
TL;DR: The anticancer effects of phenolics in-vitro and in- vivo animal models are viewed, including recent human intervention studies, and possible mechanisms of action involving antioxidant and pro-oxidant activity as well as interference with cellular functions are discussed.
Abstract: 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.
3,213 citations
TL;DR: Many bioactive compounds are extranutritional constituents that typically occur in small quantities in foods and are grouped accordingly as phenolic compounds, including their subcategory, flavonoids as discussed by the authors.
2,091 citations
TL;DR: A review of phenolic and polyphenolic compounds can be found in this article, which summarizes both the synthetic and natural phenolic antioxidants, emphasizing their mode of action, health effects, degradation products and toxicology.
1,800 citations
TL;DR: In this paper, the authors focus on the extraction of polyphenols from agricultural and industrial wastes, and summarize available data on the factors affecting their antioxidant activity and stability, and, in some cases, the reported major active compounds identified.
1,614 citations
TL;DR: It is time to rethink the design of in vitro and in vivo studies, so that these issues are carefully considered, and the length of human intervention studies should be increased, to more closely reflect the long-term dietary consumption of polyphenols.
1,409 citations