Skin bioavailability of dietary vitamin E, carotenoids, polyphenols, vitamin C, zinc and selenium

Dietary bioactive compounds (vitamin E, carotenoids, polyphenols, vitamin C, Se and Zn) have beneficial effects on skin health. The classical route of administration of active compounds is by topical application direct to the skin, and manufacturers have substantial experience of formulating ingredients in this field. However, the use of functional foods and oral supplements for improving skin condition is increasing. For oral consumption, some dietary components could have an indirect effect on the skin via, for example, secondary messengers. However, in the case of the dietary bioactive compounds considered here, we assume that they must pass down the gastrointestinal tract, cross the intestinal barrier, reach the blood circulation, and then be distributed to the different tissues of the body including the skin. The advantages of this route of administration are that the dietary bioactive compounds are metabolized and then presented to the entire tissue, potentially in an active form. Also, the blood continuously replenishes the skin with these bioactive compounds, which can then be distributed to all skin compartments (i.e. epidermis, dermis, subcutaneous fat and also to sebum). Where known, the distribution and mechanisms of transport of dietary bioactive compounds in skin are presented. Even for compounds that have been studied well in other organs, information on skin is relatively sparse. Gaps in knowledge are identified and suggestions made for future researc

Plasma appearance and correlation between coffee and green tea metabolites in human subjects

Coffee and green tea are two of the most widely consumed hot beverages in the world. Their respective bioavailability has been studied separately, but absorption of their respective bioactive phenolics has not been compared. In a randomised cross-over design, nine healthy subjects drank instant coffee and green tea. Blood samples were collected over 12h and at 24h to assess return to baseline. After green tea consumption, (−)-epigallocatechin (EGC) was the major catechin, appearing rapidly in the plasma; (−)-EGC gallate (EGCg) and (−)-epicatechin (EC) were also present, but (−)-EC gallate and C were not detected. Dihydroferulic acid and dihydrocaffeic acid were the major metabolites that appeared after coffee consumption with a long time needed to reach maximum plasma concentration, suggesting metabolism and absorption in the colon. Other phenolic acid equivalents (caffeic acid (CA), ferulic acid (FA) and isoferulic acid (iFA)) were detected earlier, and they peaked at lower concentrations. Summations of the plasma area under the curves (AUC) for the measured metabolites showed 1·7-fold more coffee-derived phenolic acids than green tea-derived catechins (P=0·0014). Furthermore, we found a significant correlation between coffee metabolites based on AUC. Inter-individual differences were observed, but individuals with a high level of CA also showed a correspondingly high level of FA. However, no such correlation was observed between the tea catechins and coffee phenolic acids. Correlation between AUC and maximum plasma concentration was also significant for CA, FA and iFA and for EGCg. This implies that the mechanisms of absorption for these two classes of compounds are different, and that a high absorber of phenolic acids is not necessarily a high absorber of catechin

Metabolite profiling of hydroxycinnamate derivatives in plasma and urine after the ingestion of coffee by humans: identification of biomarkers of coffee consumption. Drug Metab Dispos 37:1749–58

ABSTRACT: Human subjects drank coffee containing 412 µmol of chlorogenic acids and plasma and urine were collected 0-24 h after ingestion and were analyzed by HPLC-PDA-M

Fibroblast growth factors in epithelial repair and cytoprotection.

Growth factors are polypeptides that stimulate the division of certain cell types at low concentrations. Fibroblast growth factor (FGF) 7 (FGF-7) and its homologue FGF-10 act specifically on various types of epithelial cells including keratinocytes of the skin, intestinal epithelial cells and hepatocytes. In addition, FGF-7 and FGF-10 have been shown to be more than growth factors: they can protect epithelial cells from damaging effects induced, for example, by radiation and oxidative stress. Therefore, they are currently in clinical trials for the treatment of oral mucositis, a severe side-effect of cancer therapy characterized by painful inflammation and ulceration of the oral epithelium. To gain insight into the mechanisms of FGF-7/FGF-10 action in epithelial cells, we searched for genes that are regulated by these growth factors. Indeed, we identified genes that help us to explain the mechanisms that underlie the effects of FGF-7. Most interestingly, several genes were identified that are likely to mediate the cytoprotective effect of FGF-7 for epithelial cells in vitro and possibly also in injured and diseased tissues in vivo

First synthesis, characterization, and evidence for the presence of hydroxycinnamic acid sulfate and glucuronide conjugates in human biological fluids as a result of coffee consumption

A systematic investigation of the human metabolism of hydroxycinnamic acid conjugates was carried out. A set of 24 potential human metabolites of coffee polyphenols has been chemically prepared, and used as analytical standards for unequivocal identifications. These included glucuronide conjugates and sulfate esters of caffeic, ferulic, isoferulic, m-coumaric and p-coumaric acids as well as their dihydro derivatives. A particular focus has been made on caffeic and 3,4-dihydroxyphenylpropionic acid derivatives, especially the sulfate conjugates, for which regioselective preparation was particularly challenging, and have so far never been identified as human metabolites. Ten out of the 24 synthesized conjugates have been identified in human plasma and/or urine after coffee consumption. A number of these conjugates were synthesized, characterized and detected as hydroxycinnamic acid metabolites for the first time. This was the case of dihydroisoferulic acid 3'-O-glucuronide, caffeic acid 3'-sulfate, as well as the sulfate and glucuronide derivatives of 3,4-dihydroxyphenylpropionic acid

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

ETHNOPHARMACOLOGICAL IMPORTANCE : Infections and gastrointestinal (GIT) disorders such as diarrhoea causes many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat various diseases by rural people in Africa and Asia. Much of the work done to date on some species to validate their ethnopharmacological use was on the non-polar or intermediate polarity components. Many species are yet to be studied against relevant disease parameters using more polar extracts. AIMS : The polar components were extracted and fractionated by solvent-solvent fractionation to yield fractions of different polarities. The activity of these fractions on different parameters that could be involved in infectious and gastrointestinal track (GIT) disorders was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals. MATERIALS AND METHODS : Phenolic-enriched leaf extracts of Combretum bracteosum (Cob), Combretum padoides (Cop), Combretum vendae (Cov) and Combretum woodii (Cow) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. The extract was sequentially treated by solvent-solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures. The antioxidant activities were determined using various standard methods. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out. RESULT : Some of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21-12 μg/ml (Cop), 0.25-16 μg/ml (Cov), 0.33-9.41 μg/ml (Cow) and 4.97-85 μg/ml (Cob) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28-1.51 and 1.02-1.19 μg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 μg/ml. Even though some crude extracts had relatively low antimicrobial activity, fractions from these had high activity. Cop had the highest antibacterial activity with MICs ranging between 19-2500 μg/ml,followed by Cov with MICs ranging between 39-625 μg/ml. Cop also had the highest antifungal activity with MICs between 19-625 μg/ml. The MIC for Cow and Cov ranged from 19 to 1250 μg/ml. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentrations of hydrolysable tannin (gallotannin). A good correlation (R2= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity. CONCLUSION : The results obtained in this study provided a scientific basis for the use of leaf extracts from these plant species to treatinfectious and GIT disorders. In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity.South African Medical Research Council and the National Research Foundation (NRF), South Africa.http://www.elsevier.com/locate/jephb201