Flavonoids health benefits

Tea flavonoids, or tea extracts, have been linked to benefits in reducing the risk of certain cancers and cardiovascular diseases in experimental animals. However, epidemiological studies have produced inconsistent evidence in the relationship between tea drinking and cancer (Blot et a/., 1997 Goldbohm etal, 1996 Hertog eta/., 1997 Yang eta/., 1996). Therefore, further research is needed before definitive conclusions on the impact of tea consumption upon the cancer risk in humans can be reached. The metabolites of catechins and flavonols after consumption of tea infusions have scarcely been investigated, and thus more research is needed as to the role of those compounds in the reported health benefits of tea consumption. 

Among the plant phenols, the flavonoids and the anthocyanidins, belonging to the 1,3-diphenylpropans, have been studied in most detail, mainly because of their potential health benefits. With more than 4,000 different flavonoids known, systematic studies of the effects of variation in molecular structure on physico-chemical properties of importance for antioxidative effects have also been possible (Jovanovic et al, 1994 Seeram and Nair, 2002). Flavonoids were originally found not to behave as efficiently as the classic phenolic antioxidants like a-tocopherol and synthetic phenolic antioxidants in donating... 

Phytochemicals such as flavonoids are a major contributor to the health benefit of fruits and vegetables however, in a recent study of 43 fruits and vegetables, it was found that the nutritional value of these food plants has declined in the past 50 years (Davis... 

A large variety of phytochemicals are found within agricultural commodities. This chapter focuses on four main groups phenolics, carotenoids, sterols, and alkaloids. In addition, recent research related to the health benefits of these phytochemicals will be briefly reviewed. Table 9.1 summarizes the main chemical structure and solubility in organic solvents of phytochemicals such as phenolics (flavonoids), carotenoids, sterols, and alkaloids. 

Plant flavonoids have been shown in recent years to be of vital significance to mankind as well as to plants. They have been strongly implicated as active contributors to the health benefits of beverages such as tea and wine, foods such as fruit and vegetables, and even,... 

Other potential health benefits of dietary flavonoids are too numerous to mention here. Suffice it to say that our understanding of the importance of flavonoids in the human diet is continuing to advance rapidly. One suspects that much of the physiological activity associated with flavonoids can be attributed to (i) their proven effectiveness as antioxidants and free radical scavengers, (ii) to their metal complexing capabilities (a capability that drove early advances in absorption spectroscopy and NMR studies), and (iii) to their ability to bind with a high degree of specificity to proteins. 

Because of the incredible advances that have taken place, my involvement in flavonoid studies over the past 40 years has been exciting and stimulating. I feel privileged to have been part of the discovery process. During this period flavonoids as a natural product group have risen from relative obscurity (at least in the popular media) to such prominence that educated people in the West are now not only aware of the name, but also aware of the publicized health benefits associated with their consumption. 

Plant polyphenols have been of interest for long time owing to their role in plant pigmentation, reproduction and protection against predators and pathogens. Recently, interest in the biological effects of plant polyphenols (particularly flavonoids) has increased, because of the the potential health benefits associated with some dietary polyphenols. This... 

Spices (rosemary, sage, thyme) contain considerable amounts of flavonols and flavones, mainly in the glycoside form (154). Thus, phenolic analyses in spices were often considered in order to determine the optimum time for plant collection to give maximum flavonoid contents and for health benefits (154,155). Flavonoids (naringin, luteolin, apigenin, and chrysoeriol) were extracted from spices using a percolation process at room temperature with solvents (MeOH and EtOAc), and HPLC analysis was carried out (155). 

Health Benefits and Mode of Action of Flavonoids and Phenolic Compounds 2... 

HEALTH BENEFITS AND MODE OF ACTION OF FLAVONOIDS AND PHENOLIC COMPOUNDS... 

Phenolic compounds and flavonoids are a unique category of plant phytochemicals especially in terms of their vast po ential health-benefiting properties. They represent the most abundant and the most widely represented class of plant natural products. A substantial amount of research has been carried out over the past two decades yet large information gaps still exist. For example, the inventory of these compounds is still incomplete, although there is continuous effort to provide new structures. In addition the dissection of the metabolic pathways for certain phenolic compounds remains to be resolved. Recent reports underline that important questions that still need to be answered in the field of proanthocyanidin and tannin biosynthesis [Xie and Dixon, 2005], and even the exact nature of the biosynthetic pathway(s) leading to lignin monomers is not fully elucidated. 

Polyphenol consumption as flavonoids has been shown to decrease the risk of heart disease in a cross-cultural epidemiological study. Most recently, an epidemiological study found that Harvard male graduates who ate a moderate amount of chocolate and other candy had a 36% lower risk of death compared with non-candy eaters. The authors speculate that it is the antioxidants present in the chocolate that provide a health benefit. 

Tribulus terrestris — A plant found throughout Australia, Asia, Africa, and North and South America. It contains saponins, polysaccharides, sterols, flavonoids, and fatty acids, many of which are indicated to have general health benefits. Tribulus terrestris is a natural testosterone enhancer, shown in clinical studies to increase testosterone levels by aiding in the production of the luteinizing hormone (LH), a hormone that influences sex drive. Tribulus terrestris has been used to increase fertility and aid impotence. 

As previously mentioned, flaxseed is a rich source of dietary fiber (28%). Dietary fiber has been widely viewed as a component essential to lowering the risk of colon cancer. The flaxseed protein is similar to soy thus may be beneficial to health. Bhathena et al. (2002) first reported that flaxseed protein was effective in lowering plasma cholesterol and triacylglycerides (TAG) compared to soy and casein protein in male F344 and obese SHR/N-cp rats. The role of protein in disease prevention warrants further investigation. Components, such as PAs and flavonoids, may also contribute to the health benefits of flaxseed. 

The accurate measurement of carotenoids and flavonoids in crops and finished foods is becoming increasingly important as the role for these compounds in promoting human health becomes more evident. Reliable and sensitive methods are critical for database development, estimating intake, and assessing the potential health benefits associated with the consumption of specific foods or diets. 

Keywords Citrus flavonoids health benefits phenolics determination sample preparation identification HPLC LC-MS NMR... 

The health benefits of food and food constituents is currently gaining much attention. New biotechnological techniques allow the enrichment of food with micro- and macro-nutrients such as rice with high levels of vitamin A, tomatoes with extra flavonoids and also milk with additional calcium. These frmctional foods are often coimected with health benefits. Specific food constituents in a pharmaceutical formulation are called nutraceuticals. These are frequently associated with medical claims. 

While the positive health benefits associated with the consumption of a flavonoid-rich diet cannot be attributed to any one factor, the antioxidant properties of certain flavonoids have been the focus of considerable attention [8]. The antioxidant actions of chocolate flavonoids were first studied inhibiting LDL-oxidation [9,10]. As a consequence of the availability of purified procyanidins from cocoa (dimer-decamer), this particular family of... 

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