No abstract

Spices, like vegetables, fruit, and medicinal herbs, are known to possess a variety of antioxidant effects and other biological activities. Phenolic compounds in these plant materials are closely associated with their antioxidant activity, which is mainly due to their redox properties and their capacity to block the production of reactive oxygen species. More recently, their ability to interfere with signal transduction pathways involving various transcription factors, protein kinases, phosphatases, and other metabolic enzymes has also been demonstrated. Many of the spice-derived compounds which are potent antioxidants are of great interest to biologists and clinicians because they may help protect the human body against oxidative stress and inflammatory processes. It is important to study the bioactive compounds that can modulate target functions related to defence against oxidative stress, and that might be used to achieve health benefits individually. In the present review, an attempt has been made to summarize the most current scientific evidence about the in vitro and in vivo effects of the bioactive compounds derived from herbs and spices, focused on anti-inflammatory and antioxidant effects, in order to provide science-based evidence for the traditional uses and develop either functional foods or nutraceuticals.

No abstract

Among procyanidins (PC), monomers, such as catechin and epicatechin, have been widely studied, whereas dimer and trimer oligomers have received much less attention, despite their abundance in our diet. Recent studies have showed that as dimers and trimers could be important in determining the biological effects of procyanidin-rich food, understanding their bioavailability and metabolism is fundamental. The purpose of the present work is to study the stability of PC under digestion conditions, the metabolism and the bioavailability by using a combination of in vitro and in vivo models. Simultaneously, the matrix effect of a carbohydrate-rich food on the digestibility and bioavailability of PC is investigated. The results show a high level of stability of PC under gastric and duodenal digestion conditions. However, the pharmacokinetic study revealed limited absorption. Free forms of dimers and trimers have been detected in rat plasma, reaching the maximum concentration 1 h after oral intake of a grape seed extract.Procyanidins: Dimers: Trimers: Digestion: Bioavailability Procyanidins (PC) are found in most plants and in a wide range of foods, such as red wine, cocoa, tea and fruits, and thus they are a part of the human diet. PC belong to the group of flavonoids, and are phenolic compounds mainly formed of (þ)-catechin and (2 )-epicatechin units with C 4 -C 8 and/or C 4 -C 6 bonds. PC are formed from the condensation of monomeric units, between two and five units for oligomers and over five units for polymers (1) .Grape seed procyanidin extracts (GSPE) have shown several bioactivities. They improve antioxidant cell defences (2) and the plasma lipid profile (3,4) , limit adipogenesis (5) and function as insulinomimetic (6) and anti-inflammatory (7) agents. A preliminary study of an in vitro model by the authors has also determined that dimeric and trimeric oligomers are the most powerful PC molecules that mimic the complete GSPE (8) . Thus, to explain these health effects of PC and understand the mechanism by which PC act at the cellular level in vivo, it is essential to determine PC stability during the digestive process as well as their bioavailability.Despite it being clear that monomers are absorbed in human subjects and animals, there are controversies about the bioavailability of oligomeric forms. Different studies, following the ingestion of chocolate (9 -12) , black and green tea (13 -16) , red wine (17,18) and grape seed extract (1) , have shown that during digestion, the oligomers are fragmented into monomeric units of catechin and epicatechin. These are then absorbed, appearing in plasma and urine primarily as glucuronidated, methylated and sulphated metabolites. A study by Rios et al. (19) with six healthy subjects who consumed a rich PC cocoa beverage studied the depolymerisation of PC in the stomach and proved that they were remarkably stable in the stomach environment. Another study by Sano et al. (20) was the first work to detect procyanidin B1 in human serum after oral intake of a GSPE, the ma...

After a single ingestion of olive oil phenolic compounds, these were absorbed, metabolized and distributed through the blood stream to practically all parts of the body, even across the blood-brain barrier.