Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

The Effects of Plant Flavonoids on Mammalian Cells:Implications for Inflammation, Heart Disease, and Cancer

Polyphenols are the most abundant antioxidants in the diet and are widespread constituents of fruits, vegetables, cereals, dry legumes, chocolate, and beverages, such as tea, coffee, or wine. Experimental studies on animals or cultured human cell lines support a role of polyphenols in the prevention of cardiovascular diseases, cancers, neurodegenerative diseases, diabetes, or osteoporosis. However, it is very difficult to predict from these results the effects of polyphenol intake on disease prevention in humans. One of the reasons is that these studies have often been conducted at doses or concentrations far beyond those documented in humans. The few clinical studies on biomarkers of oxidative stress, cardiovascular disease risk factors, and tumor or bone resorption biomarkers have often led to contradictory results. Epidemiological studies have repeatedly shown an inverse association between the risk of myocardial infarction and the consumption of tea and wine or the intake level of some particular flavonoids, but no clear associations have been found between cancer risk and polyphenol consumption. More human studies are needed to provide clear evidence of their health protective effects and to better evaluate the risks possibly resulting from too high a polyphenol consumption.

Dietary polyphenols and the prevention of diseases

Phenolics in Food and Nutraceuticals is the first single-source compendium of essential information concerning food phenolics. This unique book reports the classification and nomenclature of phenolics, their occurrence in food and nutraceuticals, chemistry and applications, and nutritional and health effects. In addition, it describes antioxidant activity of phenolics in food and nutraceuticals as well as methods for analysis and quantification. Each chapter concludes with an extensive bibliography for further reading. Food scientists, nutritionists, chemists, biochemists, and health professionals will find this book valuable.

Phenolics in food and nutraceuticals

Antidiabetic plants and their active constituents.

Significantly, much of the activity of Citrus flavonoids appears to impact blood and microvascular endothelial cells, and it is not surprising that the two main areas of research on the biological actions of Citrus flavonoids have been inflammation and cancer. Epidemiological and animal studies point to a possible protective effect of flavonoids against cardiovascular diseases and some types of cancer. Although flavonoids have been studied for about 50 years, the cellular mechanisms involved in their biological action are still not completely known. Many of the pharmacological properties of Citrus flavonoids can be linked to the abilities of these compounds to inhibit enzymes involved in cell activation. Attempts to control cancer involve a variety of means, including the use of suppressing, blocking, and transforming agents. Suppressing agents prevent the formation of new cancers from procarcinogens, and blocking agents prevent carcinogenic compounds from reaching critical initiation sites, while transfo...

Update on uses and properties of citrus flavonoids: new findings in anticancer, cardiovascular, and anti-inflammatory activity.

The juice of whole fruits of Sicilian cultivars of prickly pear (Opuntia ficus indica (L.) Mill.) was investigated, and the contents of ascorbic acid, total polyphenols, and flavonoids were determined. In the juice, ferulic acid was the chief derivative of hydroxycinnamic acid and the mean concentration of total phenolic compounds was 746 μg/mL. The flavonoid fraction, analyzed by high-performance liquid chromatography−diode array detection, consisted of rutin and isorhamnetin derivatives. The juice showed antioxidant activity in the DPPH• test, probably due to the phenolic compounds that are effective radical scavengers. The preventive administration of the juice inhibited the ulcerogenic activity of ethanol in rat. Light microscopy observations showed an increase in mucus production and the restoration of the normal mucosal architecture. The juice is nutritionally interesting, and its dietary intake could provide protection against oxidative damage. Keywords: Opuntia ficus indica; fruit juice; antioxida...

Chemical characterization and biological effects of Sicilian Opuntia ficus indica (L.) mill. Fruit juice: antioxidant and antiulcerogenic activity.

The present study was undertaken to define in vivo the antiinflammatory and analgesic activities of hesperidin, an important flavanone of Citrus sp We used hesperidin obtained from the solid residue of orange peel after an acidic pretreatment Our results showed that hesperidin possesses significative antiinflammatory and analgesic effects

Biological effects of hesperidin, a citrus flavonoid. (Note I): antiinflammatory and analgesic activity.

Hesperidin, the most important flavanone of Citrus sp., significantly increases HDL and lowers cholesterol, LDL, total lipid and triglyceride plasma levels in normolipidemic rats and in rats with diet- and triton-induced hyperlipidemia.

Enza Maria Galati

Papers

Chemical characterization and biological effects of Sicilian Opuntia ficus indica (L.) mill. Fruit juice: antioxidant and antiulcerogenic activity.

Biological effects of hesperidin, a citrus flavonoid. (Note I): antiinflammatory and analgesic activity.

Biological effects of hesperidin, a Citrus flavonoid. (note II) hypolipidemic activity on experimental hypercholesterolemia in rat

Antiulcer activity of Opuntia ficus indica (L.) Mill. (Cactaceae): ultrastructural study.

Biological effect of Opuntia ficus indica (L.) Mill. (Cactaceae) waste matter. Note I: diuretic activity.