Phenolic acids bioavailability

PHENOLIC ACIDS BIOAVAILABILITY Release of Phenolic Acids from Esters... 

Ferulic acid has often been reported as a model compound for the investigation of bioavailability of phenolic acids, as free or esterified forms (Table 2.3), since it is abundantly present in food. Absorption via the gastrointestinal tract has also been found for dimers of ferulic acid, or diferulic acids, released from cereal brans [Andreasen et al., 2001b]. 

The impact of plant products on the metabolism of synthetic dmgs results from the inhibition or activation of cytochrome P-450 (CYP) enzymes. Evaluation of the potential activation of CYP by administration of natural plant products or dietary supplements is important for prediction of interactions between their components and dmgs. Therefore, attention is directed to research on the impact of products available on the food market known as natural non-nutritive substances on dmg absorption. Non-nutritive dietary components are mainly secondary plant metabolites, which include, among others, phenolic compounds such as phenolic acids and flavonoids. The health effects of non-nutritive substances are not yet known. So far, there is no answer on the extent to which they are absorbed and metabolized by the body, and there is no information on the permitted daily intake for these compounds. This information is particularly important because certain non-nutritive natural substances are simultaneously considered to be anti-nutritional factors, mainly because they inhibit digestion and reduce the bioavailability of nutrients or dmgs. It is also possible that they form undesirable interactions with dmgs. The positive health effects of non-nutritive natural substances are not only attributed to their antioxidant properties. These substances are involved in various metabolic... 

Almond is a nutrition-dense food providing a spectrum of macro- and micronutrients. Moreover, it is an excellent source of bioavailable phytochemicals that are believed to possess health promotion potentials. Among these phenolic compounds, including phenolic acids and flavonoids, which are the major antioxidant active substances in almond. Other components such as tocopherols and terpenoids also make contribution to the antioxidant activity of almond. The health benefits of almond have been explored. Almond appears to be effective in reducing the risk of heart disease and cancer prevention, and consumption of ahnond is reconunended by FDA for better health conditions. 

Fermentation often increases the bioavailability of phytochemicals by releasing the esterifled compounds to free form. Only the free and conjugated phenolic acid forms were found to be bio-accessible (Patel, 2012). Oboh, Ademiluyi, and Akindahunsi... 

Phenolic compounds are widely distributed in plant parts from the roots to the seeds and include phenolic acids, flavo-noids and tannins. The tannins may reduce protein digestibility (Ford and Hewitt, 1979) and perhaps the bioavailability of other nutrients. The flavonoids have been reported to have a number of nutritional and pharmacological activities (Kuhnau, 1976). Phenolic acids include benzoic and cinnamic acid derivatives. The benzoic acid derivatives include p-hydroxy-benzoic, protochate-chuic, vanillic, gallic and syringic acids. The cinnamic acids, p-coumaric, caffeic, ferulic and sinapic are found in most oilseeds used to prepare protein concentrates and frequently occur in the form of esters with quinic acid or sugars. Chlorogenic acid for example is an ester of caffeic acid and quinic acid and is found in several isomeric and derivatized forms. 

Cecchi et al. (2004), however, classihed EDTA, ethyl acetate, methanol, or Mehlich III solutions as harsh extractants that appear to be helpful in determining irreversible sorption of phenolic acids but not bioavailable phenohc acids. I would strongly disagree particularly in regard to neutral EDTA extractions. Our data clearly indicate that this is not the case (see justification above). As a matter of fact it is known that roots and microbes in soil produce a number of chelahng agents that function in a similar manner to EDTA (Nagarajah et al. 1970 Doetsch and Cook 1973 Kaminsky and Muller 1977 Marschner and ROmheld 1996 Fisher 2002 Fisher and Bipp 2002). 

There is also a need to assess the role of the colonic microflora in the overall bioavailability and potential bioactivity of dietary flavonoids. The amoxmt of absorption of colonic metabolites is unclear at this time, and there is growing interest in the potential effects of the phenolic acids and their derivatives as potentially beneficial agents. For example, thehumanintestinalbacteriametabolites of rutin and quercetin, 3,4-dihydroxyphenylacetic acid, and 4-hydroxyl-phenyl-acetic acid have been shown to possess more effective antiplatelet aggregation activity than ratin and quercetin [107]. Furthermore, 2,4,6-trihydroxybenzaldehyde and quercetin were more effective than rutin in their cytotoxicity against tumor cell lines. The effects the phenolics themselves have on the microflora are an emerging field, and it is possible that a flavonoid-induced change in the rich colonic bacterial population may have an influence on the overall health of the individual. 

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