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Subjective alertness and optimal cognitive function, including in terms of attention, spatial/working memory and executive function, are intrinsic to peak performance in many sports. Consumption of a number of plant-derived 'secondary metabolite' phytochemicals can modulate these psychological parameters, although there is a paucity of evidence collected in a sporting context. The structural groups into which these phytochemicals fall—phenolics, terpenes and alkaloids—vary in terms of the ecological roles they play for the plant, their toxicity and the extent to which they exert direct effects on brain function. The phenolics, including polyphenols, play protective roles in the plant, and represent a natural, benign component of the human diet. Increased consumption has been shown to improve cardiovascular function and is associated with long-term brain health. However, whilst short-term supplementation with polyphenols has been shown to consistently modulate cerebral blood-flow parameters, evidence of direct effects on cognitive function and alertness/arousal is currently comparatively weak. Terpenes play both attractant and deterrent roles in the plant, and typically occur less frequently in the diet. Single doses of volatile monoterpenes derived from edible herbs such as sage (Salvia officinalis/lavandulaefolia) and peppermint (Mentha piperita), diterpene-rich Ginkgo biloba extracts and triterpene-containing extracts from plants such as ginseng (Panax ginseng/quinquefolius) and Bacopa monnieri have all been shown to enhance relevant aspects of cognitive function and alertness. The alkaloids play toxic defensive roles in the plant, including via interference with herbivore brain function. Whilst most alkaloids are inappropriate in a sporting context due to toxicity and legal status, evidence suggests that single doses of nicotine and caffeine may be able to enhance relevant aspects of cognitive function and/or alertness. However, their benefits may be confounded by habituation and withdrawal effects in the longer term. The efficacy of volatile terpenes, triterpene-rich extracts and products combining low doses of caffeine with other phytochemicals deserves more research attention. [ABSTRACT FROM AUTHOR]

Dietary sources of polyphenols, which are derivatives and/or isomers of flavones, isoflavones, flavonols, catechins and phenolic acids, possess antioxidant properties and therefore might be important in preventing oxidative-stress-induced platelet activation and attenuating adverse haemostatic function. Free radicals, including reactive oxygen and nitrogen species, promote oxidative stress, leading to platelet hyperactivation and the risk of thrombosis. The consumption of antioxidant/polyphenol rich foods might therefore impart anti-thrombotic and cardiovascular protective effects via their inhibition of platelet hyperactivation or aggregation. Most commonly-used anti-platelet drugs such as aspirin block the cyclooxygenase (COX)-1 pathway of platelet activation, similar to the action of antioxidants with respect to neutralising hydrogen peroxide (H2O2), with a similar effect on thromboxane production via the COX-1 pathway. Polyphenols also target various additional platelet activation pathways (e.g. by blocking platelet- ADP, collagen receptors); thus alleviating fibrinogen binding to platelet surface ( GPIIb- IIIa) receptors, reducing further platelet recruitment for aggregation and inhibiting platelet degranulation. As a result of the ability of polyphenols to target additional pathways of platelet activation, they may have the potential to substitute or complement currently used anti-platelet drugs in sedentary, obese, pre-diabetic or diabetic populations who can be resistant or sensitive to pharmacological anti-platelet therapy. [ABSTRACT FROM AUTHOR]

Polyphenols are suggested to have human health benefits, yet debate still exists over their value in the diet. This review examines their efficacy and the effect of structural diversity on their reactivity and any implications this may have with respect to possible unfavourable adverse effects. We propose that polyphenols are of benefit to humans through dietary consumption, yet care should be taken over excessive consumption, particularly in some subgroups of the population, e.g. those on certain medications because of complex nutrient-drug interactions. Pharmaceutical application should be avoided until there is greater understanding of absorption and behaviour of polyphenols within the body. [ABSTRACT FROM AUTHOR]

It has been reported that ingestion of cocoa or chocolate reduces blood pressure in the subjects with hypertension. To clarify the hypotensive activity of cocoa, we carried out the research on microcirculation using intravital microscopic technique. First, we estimated the influence of repeated treatment of cocoa on microcirculation. Male rats fed normal diet (ND) or 15% fat containing high fat diet (HFD) or 0.2% flavan-3-ols containing HFD for 6weeks. Under anesthesia, the arteriole function of mesentery in rat was observed under physiological condition. Vasocontraction induced by the phenylephlin was significantly reduced in the HFD group compared with that in ND group, there was not such change in the HFD with cocoa group. Endothelium dependent vasodilatation stimulated by acetylcholine was significantly decreased in the HFD group compared with that in ND group. On the other hand, endothelial dysfunction of arteriole induced by HFD was not shown in cocoa group. In addition, single oral administration of cocoa or its flavan 3-ols on microcirculation in skeletal muscle was estimated. Cocoa (100 mg/kg) or flavan-3-ols derived from cocoa (10 mg/kg) was administrated through a feeding tube to the animals, velocity of red blood cells in precapillary arteriole and the number of newly recruited capillary in cremaster muscle were significantly increased by the treatment of cocoa or flavon-3-ols compared with vehicle, accompany with elevation of heart rate and blood pressure. These research has revealed that the ingestion of cocoa improves endothelial dysfunction of arterioles which is major determining of blood pressure induced by the high fat diet and single oral administration of flavan 3-ols in cocoa altered microcirculation in skeletal muscle and general circulation. These acute effects might be related with the preventive action of flavan-3-ols on cardiovascular disease. [ABSTRACT FROM AUTHOR]