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Background A plant-based diet protects against chronic oxidative stress-related diseases. Dietary plants contain variable chemical families and amounts of antioxidants. It has been hypothesized that plant antioxidants may contribute to the beneficial health effects of dietary plants. Our objective was to develop a comprehensive food database consisting of the total antioxidant content of typical foods as well as other dietary items such as traditional medicine plants, herbs and spices and dietary supplements. This database is intended for use in a wide range of nutritional research, from in vitro and cell and animal studies, to clinical trials and nutritional epidemiological studies. Methods We procured samples from countries worldwide and assayed the samples for their total antioxidant content using a modified version of the FRAP assay. Results and sample information (such as country of origin, product and/or brand name) were registered for each individual food sample and constitute the Antioxidant Food Table. Results The results demonstrate that there are several thousand-fold differences in antioxidant content of foods. Spices, herbs and supplements include the most antioxidant rich products in our study, some exceptionally high. Berries, fruits, nuts, chocolate, vegetables and products thereof constitute common foods and beverages with high antioxidant values. Conclusions This database is to our best knowledge the most comprehensive Antioxidant Food Database published and it shows that plant-based foods introduce significantly more antioxidants into human diet than non-plant foods. Because of the large variations observed between otherwise comparable food samples the study emphasizes the importance of using a comprehensive database combined with a detailed system for food registration in clinical and epidemiological studies. The present antioxidant database is therefore an essential research tool to further elucidate the potential health effects of phytochemical antioxidants in diet.
Flavonoids have been hypothesized to reduce cancer risk. Previous epidemiological studies conducted to evaluate this hypothesis have not assessed all flavonoids, including classes that could contribute to intake among Americans, which would result in an underestimation of intake. This misclassification could mask variability among individuals, resulting in attenuated effect estimates for the association between flavonoids and cancer. To augment flavonoid and lignan intake estimates, we developed a database that can be used in conjunction with a food-frequency questionnaire (FFQ). Coupling information derived from the available literature with the U.S. Department of Agriculture databases, we estimated content of 6 flavonoid classes and lignans for 50 food group items. We combined these estimates with responses from a modified Block FFQ that was self-completed in 1996-1997 by a population-based sample of women without breast cancer on Long Island, New York (n = 1,500). Total flavonoid and lignan content of food items ranged from 0 to 129 mg/100 g, and the richest sources were tea, cherries, and grapefruit. Individual intake estimates, from highest to lowest, were flavan-3-ols, flavanones, flavonols, lignans, isoflavones, anthocyanidins, and flavones. Each class of flavonoids and lignans exhibited a wide range of intake levels. This database is useful to quantify flavonoid and lignan intake for other observational studies conducted in the United States that utilize the Block FFQ.
Substantial data suggest that flavonoid-rich food could help prevent cardiovascular disease and cancer. Cocoa is the richest source of flavonoids, but current processing reduces the content substantially. The Kuna living in the San Blas drink a flavanol-rich cocoa as their main beverage, contributing more than 900 mg/day and thus probably have the most flavonoid-rich diet of any population. We used diagnosis on death certificates to compare cause-specific death rates from year 2000 to 2004 in mainland and the San Blas islands where only Kuna live. Our hypothesis was that if the high flavanoid intake and consequent nitric oxide system activation were important the result would be a reduction in the frequency of ischemic heart disease, stroke, diabetes mellitus, and cancer – all nitric oxide sensitive processes. There were 77,375 deaths in mainland Panama and 558 deaths in the San Blas. In mainland Panama, as anticipated, cardiovascular disease was the leading cause of death (83.4 ± 0.70 age adjusted deaths/100,000) and cancer was second (68.4 ± 1.6). In contrast, the rate of CVD and cancer among island-dwelling Kuna was much lower (9.2 ± 3.1) and (4.4 ± 4.4) respectively. Similarly deaths due to diabetes mellitus were much more common in the mainland (24.1 ± 0.74) than in the San Blas (6.6 ± 1.94). This comparatively lower risk among Kuna in the San Blas from the most common causes of morbidity and mortality in much of the world, possibly reflects a very high flavanol intake and sustained nitric oxide synthesis activation. However, there are many risk factors and an observational study cannot provide definitive evidence.
A HPLC method was developed for the analysis of secoisolariciresinol diglucoside (SDG) and hydroxycinnamic acid glucosides in milled defatted flaxseed flour. Direct extraction by 1 M NaOH for 1 h at 20 degrees C resulted in a higher yield than that obtained by hydrolysis of alcoholic extracts. An internal standard, o-coumaric acid, was used and the method was found to be easy, fast, and with good repeatability. On dry matter basis, different samples of flaxseeds varied considerably in their content of (+)-SDG (11.9-25.9 mg/g), (-)-SDG (2.2-5.0 mg/g), p-coumaric acid glucoside (1.2-8.5 mg/g), and ferulic acid glucoside (1.6-5.0 mg/g).
Coriander (Coriandrum sativum L.), a herbal plant, belonging to the family Apiceae, is valued for its culinary and medicinal uses. All parts of this herb are in use as flavoring agent and/or as traditional remedies for the treatment of different disorders in the folk medicine systems of different civilizations. The plant is a potential source of lipids (rich in petroselinic acid) and an essential oil (high in linalool) isolated from the seeds and the aerial parts. Due to the presence of a multitude of bioactives, a wide array of pharmacological activities have been ascribed to different parts of this herb, which include anti-microbial, anti-oxidant, anti-diabetic, anxiolytic, anti-epileptic, anti-depressant, anti-mutagenic, anti-inflammatory, anti-dyslipidemic, anti-hypertensive, neuro-protective and diuretic. Interestingly, coriander also possessed lead-detoxifying potential. This review focuses on the medicinal uses, detailed phytochemistry, and the biological activities of this valuable herb to explore its potential uses as a functional food for the nutraceutical industry. Copyright © 2012 John Wiley & Sons, Ltd.
The fruits (dates) of the date palm (Phoenix dactylifera L.) contain a high percentage of carbohydrate (total sugars, 44-88%), fat (0.2-0.5%), 15 salts and minerals, protein (2.3-5.6%), vitamins and a high percentage of dietary fibre (6.4-11.5%). The flesh of dates contains 0.2-0.5% oil, whereas the seed contains 7.7-9.7% oil. The weight of the seed is 5.6-14.2% of the date. The fatty acids occur in both flesh and seed as a range of saturated and unsaturated acids, the seeds containing 14 types of fatty acids, but only eight of these fatty acids occur in very low concentration in the flesh. Unsaturated fatty acids include palmitoleic, oleic, linoleic and linolenic acids. The oleic acid content of the seeds varies from 41.1 to 58.8%, which suggests that the seeds of date could be used as a source of oleic acid. There are at least 15 minerals in dates. The percentage of each mineral in dried dates varies from 0.1 to 916 mg/100 g date depending on the type of mineral. In many varieties, potassium can be found at a concentration as high as 0.9% in the flesh while it is as high as 0.5% in some seeds. Other minerals and salts that are found in various proportions include boron, calcium, cobalt, copper, fluorine, iron, magnesium, manganese, potassium, phosphorous, sodium and zinc. Additionally, the seeds contain aluminum, cadmium, chloride, lead and sulphur in various proportions. Dates contain elemental fluorine that is useful in protecting teeth against decay. Selenium, another element believed to help prevent cancer and important in immune function, is also found in dates. The protein in dates contains 23 types of amino acids, some of which are not present in the most popular fruits such as oranges, apples and bananas. Dates contain at least six vitamins including a small amount of vitamin C, and vitamins B(1) thiamine, B(2) riboflavin, nicotinic acid (niacin) and vitamin A. The dietary fibre of 14 varieties of dates has been shown to be as high as 6.4-11.5% depending on variety and degree of ripeness. Dates contain 0.5-3.9% pectin, which may have important health benefits. The world production of dates has increased 2.9 times over 40 years, whereas the world population has doubled. The total world export of dates increased by 1.71% over 40 years. In many ways, dates may be considered as an almost ideal food, providing a wide range of essential nutrients and potential health benefits.
Xenohormesis is a biological principle that explains how environmentally stressed plants produce bioactive compounds that can confer stress resistance and survival benefits to animals that consume them. Animals can piggyback off products of plants' sophisticated stress response which has evolved as a result of their stationary lifestyle. Factors eliciting the plant stress response can judiciously be employed to maximize yield of health-promoting plant compounds. The xenohormetic plant compounds can, when ingested, improve longevity and fitness by activating the animal's cellular stress response and can be applied in drug discovery, drug production, and nutritional enhancement of diet.
The objective of this work is to review data from epidemiological and preclinical studies addressing the potential benefits of diets based on flavonoids for cancer prevention. Flavonoids are subdivided into subclasses including flavonols, flavones, flavanones, flavan-3-ols, anthocyanidins, and isoflavones. Epidemiological studies suggest dietary intake of flavonoids may reduce the risk of tumors of the breast, colon, lung, prostate, and pancreas. However, some studies have reported inconclusive or even harmful associations. A major challenge in the interpretation of epidemiological studies is that most of the data originate from case-control studies and retrospective acquisition of flavonoid intake. Differences in agricultural, sociodemographics, and lifestyle factors contribute to the heterogeneity in the intake of flavonoids among populations residing in the United States, Europe, and Asia. Dose and timing of exposure may influence the anticancer response to flavonoid-rich diets. A limited number of intervention trials of flavonoids have documented cancer preventative effects. Proposed anticancer mechanisms for flavonoids are inhibition of proliferation, inflammation, invasion, metastasis, and activation of apoptosis. Prospective studies with larger sample sizes are needed to develop biomarkers of flavonoid intake and effect. Mechanistic studies are needed to ascertain how flavonoid-rich diets influence gene regulation for cancer prevention.
Over the past few decades, inflammation has been recognized as a major risk factor for various human diseases. Acute inflammation is short-term, self-limiting and it's easy for host defenses to return the body to homeostasis. Chronic inflammatory responses are predispose to a pathological progression of chronic illnesses characterized by infiltration of inflammatory cells, excessive production of cytokines, dysregulation of cellular signaling and loss of barrier function. Targeting reduction of chronic inflammation is a beneficial strategy to combat several human diseases. Flavonoids are widely present in the average diet in such foods as fruits and vegetables, and have been demonstrated to exhibit a broad spectrum of biological activities for human health including an anti-inflammatory property. Numerous studies have proposed that flavonoids act through a variety mechanisms to prevent and attenuate inflammatory responses and serve as possible cardioprotective, neuroprotective and chemopreventive agents. In this review, we summarize current knowledge and underlying mechanisms on anti-inflammatory activities of flavonoids and their implicated effects in the development of various chronic inflammatory diseases. This journal is © The Royal Society of Chemistry 2010
We assess the evidence for health benefits of three commonly consumed plant food supplements (PFS), green tea, isoflavone and aloe vera, based on published systematic reviews of randomised controlled trials (RCTs). Whilst the potential benefits of green tea have been reported in a wide range of health areas, it is only in the area of the metabolic syndrome that the number of RCTs is approaching sufficient to judge such efficacy. Isoflavone supplements are widely used, and RCTs indicate that they affect bone resorption at lower doses in postmenopausal women undergoing estrogen-related bone loss, but this is only translated to attenuation of bone loss at higher doses of isoflavones. A systematic review on RCTs concluded that the effects of isoflavones on hot flashes in postmenopausal women were highly variable and no conclusions could be drawn. Despite the popularity of aloe vera as a PFS, the evaluation of its efficacy as a coadjuvant therapy for certain metabolic or digestive pathologies remains scarce; it constitutes a typical example of a naturally occurring ingredient whose efficacy in topical applications presupposes its efficacy in systemic applications. Nevertheless, its possible toxic effects on oral consumption call for caution in its utility as a PFS. Since 2007, efficacy evaluation of PFS in Europe has been covered by European Union Nutrition and Health Claims legislation. The European Food Safety Authority has adopted an approach relying on RCTs, while medicinal effects are accepted based on traditional use. In general, there are insufficient RCTs for claims to be made, and conclusive results on PFS should be obtained in the future by conducting studies with more homogeneous populations, by using supplements with optimised and measured bioavailability, and by conducting larger RCTs.
Dioxins invade the body mainly through the diet, and produce toxicity through the transformation of aryl hydrocarbon receptor (AhR). An inhibitor of the transformation should therefore protect against the toxicity and ideally be part of the diet. We examined flavonoids ubiquitously expressed in plant foods as one of the best candidates, and found that the subclasses flavones and flavonols suppressed antagonistically the transformation of AhR induced by 1 nM of 2,3,7,8-tetrachlorodibenzo-p-dioxin, without exhibiting agonistic effects that transform AhR. The antagonistic IC(50) values ranged from 0.14 to 10 microM, close to the physiological levels in human.
Growing evidence from tissue culture, animal, and clinical models suggests that the flavonoid-rich fruits of the North American cranberry and blueberry (Vaccinium spp.) have the potential ability to limit the development and severity of certain cancers and vascular diseases including atherosclerosis, ischemic stroke, and neurodegenerative diseases of aging. The fruits contain a variety of phytochemicals that could contribute to these protective effects, including flavonoids such as anthocyanins, flavonols, and proanthocyanidins; substituted cinnamic acids and stilbenes; and triterpenoids such as ursolic acid and its esters. Cranberry and blueberry constituents are likely to act by mechanisms that counteract oxidative stress, decrease inflammation, and modulate macromolecular interactions and expression of genes associated with disease processes. The evidence suggests a potential role for dietary cranberry and blueberry in the prevention of cancer and vascular diseases, justifying further research to determine how the bioavailability and metabolism of berry phytonutrients influence their activity in vivo.
The objective of this study was to evaluate, in a phase 2 pilot study, tolerability and the effect of 6 weeks of flaxseed therapy on hot flash scores in women not wishing to receive estrogen therapy. Eligibility included 14 hot flashes per week for at least 1 month. In the baseline week, participants took no study medication and documented the characteristics of their hot flashes. Thereafter, crushed flaxseed was administered at 40 g daily. Participants provided weekly toxicity reports and health-related quality of life information. The primary end point was a change in hot flash score prospectively reported in a daily hot flash diary. Thirty women were enrolled between June 17 and November 8, 2005. The mean decrease in hot flash scores after flaxseed therapy was 57% (median decrease 62%). The mean reduction in daily hot flash frequency was 50% (median reduction 50%), from 7.3 hot flashes to 3.6. Fourteen of the 28 participants (50%) experienced mild or moderate abdominal distention. Eight participants (29%) experienced mild diarrhea, one experienced flatulence, and six (21%) withdrew because of toxicities. This study suggests that dietary therapy decreases hot flash activity in women not taking estrogen therapy. This reduction is greater than what would be expected with placebo.
Various dietary flavonoids were evaluated in vitro for their inhibitory effect on xanthine oxidase, which has been implicated in oxidative injury to tissue by ischemia-reperfusion. Xanthine oxidase activity was determined by directly measuring uric acid formation by HPLC. The structure-activity relationship revealed that the planar flavones and flavonols with a 7-hydroxyl group such as chrysin, luteolin, kaempferol, quercetin, myricetin, and isorhamnetin inhibited xanthine oxidase activity at low concentrations (IC50 values from 0.40 to 5.02 microM) in a mixed-type mode, while the nonplanar flavonoids, isoflavones and anthocyanidins were less inhibitory. These results suggest that certain flavonoids might suppress in vivo the formation of active oxygen species and urate by xanthine oxidase.
Anthocyanins from tart cherries, Prunus cerasus L. (Rosaceae) cv. Balaton and Montmorency; sweet cherries, Prunus avium L. (Rosaceae); bilberries, Vaccinum myrtillus L. (Ericaceae); blackberries, Rubus sp. (Rosaceae); blueberries var. Jersey, Vaccinium corymbosum L. (Ericaceae); cranberries var. Early Black, Vaccinium macrocarpon Ait. (Ericaceae); elderberries, Sambucus canadensis (Caprifoliaceae); raspberries, Rubus idaeus (Rosaceae); and strawberries var. Honeoye, Fragaria x ananassa Duch. (Rosaceae), were investigated for cyclooxygenase inhibitory and antioxidant activities. The presence and levels of cyanidin-3-glucosylrutinoside 1 and cyanidin-3-rutinoside 2 were determined in the fruits using HPLC. The antioxidant activity of anthocyanins from cherries was comparable to the commercial antioxidants, tert-butylhydroquinone, butylated hydroxytoluene and butylated hydroxyanisole, and superior to vitamin E, at a test concentration of 125 microg/ml. Anthocyanins from raspberries and sweet cherries demonstrated 45% and 47% cyclooxygenase-I and cyclooxygenase-II inhibitory activities, respectively, when assayed at 125 microg/ml. The cyclooxygenase inhibitory activities of anthocyanins from these fruits were comparable to those of ibuprofen and naproxen at 10 microM concentrations. Anthocyanins 1 and 2 are present in both cherries and raspberry. The yields of pure anthocyanins 1 and 2 in 100 g Balaton and Montmorency tart cherries, sweet cherries and raspberries were 21, 16.5; 11, 5; 4.95, 21; and 4.65, 13.5 mg, respectively. Fresh blackberries and strawberries contained only anthocyanin 2 in yields of 24 and 22.5 mg/100 g, respectively. Anthocyanins 1 and 2 were not found in bilberries, blueberries, cranberries or elderberries.
Flaxseed is one of the most important oilseed crops for industrial as well as food, feed, and fiber purposes. Almost every part of the flaxseed plant is utilized commercially, either directly or after processing. The stem yields good quality fiber having high strength and durability. The seed provides oil rich in omega-3, digestible proteins, and lignans. In addition to being one of the richest sources of α-linolenic acid oil and lignans, flaxseed is an essential source of high quality protein and soluble fiber and has considerable potential as a source of phenolic compounds. Flaxseed is emerging as an important functional food ingredient because of its rich contents of α-linolenic acid (ALA), lignans, and fiber. Lignans appear to be anti-carcinogenic compounds. The omega-3s and lignan phytoestrogens of flaxseed are in focus for their benefits for a wide range of health conditions and may possess chemo-protective properties in animals and humans. This paper presents a review of literature on the nutritional composition of flaxseed, its health benefits, and disease-prevention qualities, utilization of flaxseed for food, feed, and fiber, and processing of flaxseed.
Cocoa and chocolate have recently been found to be rich plant-derived sources of antioxidant flavonoids with beneficial cardiovascular properties. These favorable physiological effects include: antioxidant activity, vasodilation and blood pressure reduction, inhibition of platelet activity, and decreased inflammation. Increasing evidence from experimental and clinical studies using cocoa-derived products and chocolate suggest an important role for these high-flavanol-containing foods in heart and vascular protection.
Presence of omega-3, omega-6 rich oil, alpha-linoleic acid, dietary fibers, secoisolariciresinol diglucoside, protein and minerals in flaxseed constitute a very strong basis for the utilization of flaxseed in various food preparations as a curative agent. An extensive body of literature illustrates that flaxseed has gained a significant position in the domain of nutritional sciences owing to its pivotal role as an antioxidant agent. The review discusses at length, numerous health benefits of flaxseed typically focusing its preventive role against cardiovascular diseases, cancer, diabetes and enhancement of spatial memory. Massive increase in the size of population with a special emphasize to the developing countries, there is an urge for exploration of the alternative dietary resources that can meet the dietary and nutritional needs of forthcoming generations. With respect to its remarkable nutritional importance, the review in question enables researchers engaged in nutritional sciences to further investigate the therapeutic value of flaxseed functional components and their dietary application in various food products and availability in processed foods as well as in the human cell line.
The food mutagens IQ (2-amino-3-methylimidazo[4,5-f]quinoline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) are heterocyclic amines (HCA), generated when heating proteinaceous food. This study investigates the protective potential of the flavonoids quercetin (Q) and rutin (R) against oxidative stress induced in vitro by IQ and PhIP in lymphocytes from healthy individuals and untreated, newly diagnosed colon cancer patients using the Comet assay. In the presence of up to 500μM Q and R, the DNA damage resulting from a high dose of PhIP (75μM) or IQ (150μM) was significantly reduced (P<0.001) to levels comparable to six times lower IQ or 7.5 times lower PhIP doses. Lymphocytes from colon cancer patients had greater baseline DNA damage than those from healthy individuals (P<0.01) and this higher level of damage was also observed throughout in vitro treatment. Except for the >50years of age group and male gender, confounding factors such as smoking, drinking and/or dietary habits were not found to be significant. In conclusion, flavonoids reduced oxidative stress caused by food mutagens in vitro in lymphocytes of healthy individuals and colon cancer patients. Thus, dietary supplementation with flavonoid-rich vegetables and fruits may prove very effective in protecting against oxidative stress. Copyright © 2011 Elsevier Ltd. All rights reserved.
Essential oils have been used as remedies for a long time in different cultures across the world. However, scientific proof of such application is scarce. We included 72 patients between the ages of 22 and 57 while waiting for dental treatment in our study. The participants were assigned to either a control group (14 men, 23 women) or to an odor group (18 men and 17 women). Ambient odor of orange was diffused in the waiting room through an electrical dispenser in the odor group whereas in the control group no odor was in the air. We assessed by means of self-report demographic and cognitive variables, trait and state anxiety, and current pain, mood, alertness, and calmness. In this study, we report that exposure to ambient odor of orange has a relaxant effect. Specifically, compared to the controls, women who were exposed to orange odor had a lower level of state anxiety, a more positive mood, and a higher level of calmness. Our data support the previous notion of sedative properties of the natural essential oil of orange (Citrus sinensis).
This paper presents a new interpretation of a unique Bronze Age (c. 3000-1100 BCE) Aegean wall painting in the building of Xeste 3 at Akrotiri,Thera. Crocus carturightianus and its active principle, saffron, are the primary subjects at Xeste 3. Several lines of evidence suggest that the meaning of these frescoes concerns saffron and healing: (1) the unusual degree of visual attention given to the crocus, including the variety of methods for display of the stigmas; (2) the painted depiction of the line of saffron production from plucking blooms to the collection of stigmas; and (3) the sheer number (ninety) of medical indications for which saffron has been used from the Bronze Age to the present. The Xeste 3 frescoes appear to portray a divinity of healing associated with her phytotherapy, saffron. Cultural and commercial interconnections between the Therans, the Aegean world, and their neighboring civilizations in the early 2nd millennium BCE indicate a close network of thematic exchange, but there is no evidence that Akrotiri borrowed any of these medicinal (or iconographic) representations. The complex production line, the monumental illustration of a goddess of medicine with her saffron attribute, and this earliest botanically accurate image of an herbal medication are all Theran innovations.
Artemisia dracunculus L. (tarragon) has a long history of use as a spice and remedy. Two well-described "cultivars" (Russian and French) are used widely and differ in ploidy level, morphology, and chemistry. Key biologically active secondary metabolites are essential oils (0.15-3.1%), coumarins (>1%), flavonoids, and phenolcarbonic acids. In vivo studies mainly in rodents, particularly from Russian sources, highlight potential anti-inflammatory, hepatoprotective, and antihyperglycemic effects. Despite concerns about the toxic effects of two of its main constituents, estragole (up to 82%) and methyleugenol (up to 39%), no acute toxicity or mutagenic activity has been reported at doses relevant for human consumption. Water extracts of A. dracunculus contain very low amounts of estragole and methyleugenol and, therefore, are considered to pose a very limited risk. Overall, a stronger focus on clinical studies and precise taxonomic and phytochemical definition of the source material will be essential for future research efforts.
Persea americana is much sought after both for the nutritional value of its fruit and the medicinal values of its various plant parts. A chromosomal aberration assay was undertaken to evaluate the potential genotoxicity of crude extracts from avocado fruits and leaves. Chromosomal aberrations were observed in cultured human peripheral lymphocytes exposed to separately increasing concentrations of 50% methanolic extracts of Persea americana fruit and leaves. The groups exposed to leaf and fruit extracts, respectively, showed a concentration-dependent increase in chromosomal aberrations as compared to that in a control group. The mean percentage total aberrant metaphases at 100 mg/kg, 200 mg/kg, and 300 mg/kg concentrations of leaf extract were found respectively to be 58 ± 7.05, 72 ± 6.41, and 78 ± 5.98, which were significantly higher (p < 0.0001 each) than that in the control group (6 ± 3.39). The mean percentage total aberrant metaphases at 100 mg/kg, 200 mg/kg, and 300 mg/kg concentrations of fruit extract were found to be 18 ± 5.49, 40 ± 10.00, and 52 ± 10.20, respectively, which were significantly higher (p = 0.033, p < 0.0001, and p < 0.0001, respectively) than that for control (6 ± 3.39). Acrocentric associations and premature centromeric separation were the two most common abnormalities observed in both the exposed groups. The group exposed to leaf extracts also showed a significant number of a variety of other structural aberrations, including breaks, fragments, dicentrics, terminal deletion, minutes, and Robertsonian translocations. The group exposed to leaf extract showed higher frequency of all types of aberrations at equal concentrations as compared to the group exposed to fruit extract.
The Kuna Indians who reside in an archipelago on the Caribbean Coast of Panama have very low blood pressure levels, live longer than other Panamanians, and have a reduced frequency of myocardial infarction, stroke, diabetes mellitus, and cancer -- at least on their death certificates. One outstanding feature of their diet includes a very high intake of flavanol-rich cocoa. Flavonoids in cocoa activate nitric oxide synthesis in healthy humans. The possibility that the high flavanol intake protects the Kuna against high blood pressure, ischemic heart disease, stroke, diabetes mellitus, and cancer is sufficiently intriguing and sufficiently important that large, randomized controlled clinical trials should be pursued.
Understanding mechanisms associated with flavonoid neuroprotection is complicated by the lack of information on their ability to enter the CNS. This study examined naringenin and quercetin permeability across the blood-brain barrier (BBB), using in vitro (ECV304/C6 coculture) and in situ (rat) models. We report measurable permeabilities (P(app)) for both flavonoids across the in vitro BBB model, consistent with their lipophilicity. Both flavonoids showed measurable in situ BBB permeability. The rates of uptake (K(in)) into the right cerebral hemisphere were 0.145 and 0.019 ml min(-1) g(-1) for naringenin and quercetin, respectively. Quercetin K(in) was comparable to that of colchicine (0.006 ml min(-1) g(-1)), a substrate for P-glycoprotein (P-gp). Preadministration of the P-gp inhibitor PSC833 or GF120918 (10 mg/kg body wt) significantly increased colchicine K(in), but only GF120918 (able to inhibit breast cancer resistance protein, BCRP) affected K(in) for quercetin. Naringenin K(in) was not affected. The influence of efflux transporters on flavonoid permeability at the BBB was further studied using MDCK-MDR1 and immortalized rat brain endothelial cells (RBE4). Colchicine, quercetin, and naringenin all showed measurable accumulation (distribution volume, V(d) (microl/mg protein)) in both cell types. The V(d) for colchicine increased significantly in both cell lines following coincubation with either PSC833 (25 microM) or GF120918 (25 microM). Both inhibitors also caused an increase in naringenin V(d); by contrast only GF120918 coincubation significantly increased quercetin V(d). In conclusion, the results demonstrate that flavonoids are able to traverse the BBB in vivo. However, the permeability of certain flavonoids in vivo is influenced by their lipophilicity and interactions with efflux transporters.