Effects of catechin-rich oil palm leaf extract on normal and hypertensive rats’ kidney and liver

Catechin-rich oil palm (Elaeis guineensis) leaf extract (OPLE) possesses good ex vivo vasodilation, antioxidant and cardiovascular properties. This study evaluated the beneficial or toxic effects of OPLE on the liver and kidneys of normal and hypertensive rats. The OPLE (500 mg/kg body weight) were administered orally to normal Wistar Kyoto rats, spontaneously hypertensive rats (SHR) and N-ω-nitro-l-arginine methyl ester (l-NAME)-induced NO-deficient hypertensive rats. The OPLE reduced hypertension in NO-deficient rats, but not in SHR. Hepatocytes or glomeruli injury and oxidative markers were high in hypertensive rats compared to normal rats, and they were reduced (p < 0.05) by OPLE supplementation, even when there was no blood pressure reduction. Unlike the hypertensive drug captopril, the OPLE showed no toxicity to normal rats. The dose reported is equivalent 0.5 g of catechins/day for humans or 2.5 cups of tea. The catechins are from an abundant alternative source for potential use as functional food.     

High salt diet impairs memory‐related synaptic plasticity via increased oxidative stress and suppressed synaptic protein expression

1 Scope

A high salt (HS) diet is detrimental to cognitive function, in addition to having a role in cardiovascular disorders. However, the method by which an HS diet impairs cognitive functions such as learning and memory remains open.

2 Methods and results

In this study, we found that mice on a 7 week HS diet demonstrated disturbed short‐term memory in an object‐place recognition task, and both 4 week and 7 week HS treatments impaired long‐term memory, as evidenced in a fear conditioning test. Mechanistically, the HS diet inhibited memory‐related long‐term potentiation (LTP) in the hippocampus, while also increasing the levels of reactive oxygen species (ROS) in hippocampal cells and downregulating the expression of synapsin I, synaptophysin, and brain‐derived neurotrophic factor in specific encephalic region.

3 Conclusion

This suggests that oxidative stress or synaptic protein/neurotrophin deregulation was involved in the HS diet‐induced memory impairment. Thus, the present study provides novel insights into the mechanisms of memory impairment caused by excessive dietary salt, and underlined the importance of controlling to salt absorb quantity.     

Short‐term feeding of fermentable dietary fibres influences the gut microbiota composition and metabolic activity in rats

This study investigated the effects of dietary fibres on gut bacterial abundance and metabolic activity in rats fed short‐term. Faecal samples from rats fed for 7 days showed differences in the effects of dietary fibres on gut bacterial populations. Broccoli fibre, inulin, potato fibre and potato resistant starch significantly increased the faecal Bacteroides‐Prevotella‐Porphyromonas group compared with cellulose. Growth of pathogenic bacteria such as Clostridium perfringens, Escherichia coli and Enterococcus spp. was decreased significantly in rats fed barley β‐glucan, citrus pectin, inulin and broccoli fibre diets. An increase in Bifidobacterium spp. and butyric acid levels, the so‐called bifidogenic and butyrogenic effects, was observed in rats fed inulin and potato fibre diets. Organic acid concentrations and polysaccharide contents in the rat faeces confirm the fermentability of dietary fibres in the gut. This study demonstrates the positive effects of plant‐sourced dietary fibres on gut microbiota composition and metabolic activity.     

Dietary flavonoids: effects on endothelial function and blood pressure

Several population studies have found an inverse association between flavonoid intake and risk of cardiovascular disease. These studies have resulted in the hypothesis that dietary flavonoids protect against cardiovascular disease. Many in vitro studies, studies using animal models and human intervention trials have been carried out to investigate how flavonoids might provide protection. Emerging and largely consistent evidence suggests that flavonoids can improve endothelial function and may reduce blood pressure. In vitro studies show that a variety of flavonoids cause vasorelaxation of isolated arteries from rats. In human intervention trials, flavonoids derived from tea and cocoa or dark chocolate—both rich sources of catechins—have been found to improve endothelial function acutely and with regular ingestion. The evidence for benefits of flavonoids from other dietary sources is less clear. Improvements in endothelial function could contribute to lower blood pressure. Population studies have associated higher intake of tea and chocolate with lower blood pressure. Short‐term intervention studies in humans have shown blood pressure lowering with cocoa or dark chocolate, but short‐term regular ingestion of tea has not been found to lower blood pressure. The long‐term effects of regular ingestion of a flavonoid‐enriched diet on endothelial function and blood pressure have yet to be assessed. In addition, there is evidence that flavonoid metabolism is an important factor influencing the biological activity and effects of dietary flavonoids, but further studies are needed to investigate this area. Copyright © 2006 Society of Chemical Industry     

Long-term high animal protein diet reduces body weight gain and insulin secretion in diet-induced obese rats

BACKGROUND: The effects of a high protein diet on insulin secretion and glucose metabolism have been quite controversial. The aim of this study was to evaluate the effects of long‐term isocaloric high animal protein intake on insulin secretion in diet‐induced obese rats. RESULTS: After the experimental period (24 weeks), the high‐fat diet‐induced obese rats that were fed isocaloric high‐protein diets (HP) had lower body weight gain (P < 0.01) and lower visceral fat (P < 0.05) than normal protein (NP) rats. Fasting plasma glucagon‐like peptide‐1 (GLP‐1) was also reduced significantly (P < 0.05), as well as serum insulin levels at 5 min and 10 min by intravenous insulin releasing test. In addition, insulin mRNA and pancreatic duodenal homeodomain‐1 (PDX‐1), GLP‐1 protein expression were both markedly lower in HP rats (P < 0.05), while PDX‐1 mRNA in HP rats had no difference from NP rats. CONCLUSION: These results suggest that long‐term isocaloric high animal protein intake reduces the acute insulin response in obese rats and the decrease of insulin is associated with both reduced weight gain and inhibition of PDX‐1 expression. GLP‐1 might be a negative feedback for the balance of energy metabolism secondary to changes of body weight and visceral fat. Copyright © 2012 Society of Chemical Industry     

Effects of Boiling on Dietary Fiber Components in Fresh and Stored White Cabbage (Brassica oleracea var. capitata)

The effects of boiling (10 min) and how differences in cultivars (n= 6), maturity (n= 2), and storage (n= 3) may affect dietary fiber in white cabbage were studied. A great variation in total dietary fiber content between boiled cabbage samples was seen (17.7 to 31.7 g/100 g dry weight basis). Total and insoluble dietary fiber following boiling could be predicted from the initial amount. Average losses for early and late cultivars were similar (about 10%) and were mainly due to insoluble polymers consisting of glucose and partly of uronic acids. The early cultivar ‘Balbro’ was least affected by heat treatment: only 2% total dietary fiber was lost. Harvesting before physiological maturity and short‐term storage increased the loss of soluble polymers (pectic substances), whereas long‐term storage decreased the loss.     

Enzyme deactivation treatments did not decrease the beneficial role of oat food in intestinal microbiota and short‐chain fatty acids: an in vivo study

BACKGROUND: Steaming and roasting treatments are widely used enzyme deactivation methods in the oat food industry in China. Whether or not the enzyme deactivation treatments affect the nutritional function of oat foods is unknown. In the current study, we examined the effects of 4‐week ingestion of steamed or roasted oat foods on the intestinal bacteria and short‐chain fatty acids of rats. RESULTS: Compared with rats taking no oat foods, rats taking normal oat foods or enzyme‐deactivated oat foods showed significantly higher (P < 0.05) counts of Lactobacillus spp. and Bifidobacterium spp. in colon, significantly lower (P < 0.05) counts of Enterococcus spp. and coliforms in colon, and significantly higher (P < 0.05) levels of butyrate and acetate in colonic digesta. In addition, rats taking infrared roasting (IR)‐treated oat foods also demonstrated significantly higher (P < 0.05) fecal Lactobacillus spp. counts and significantly lower (P < 0.05) cecal and fecal counts of E. coli, Enterococcus spp. and coliforms than rats taking no oat foods. As for the comparison between the enzyme‐undeactivated oat group and the three enzyme‐deactivated oat groups, there were no significant differences in most of the parameters (P > 0.05), though a few exceptions did exist. CONCLUSION: Enzyme deactivation treatments did not decrease the beneficial role of oat food in the intestinal microbes and short‐chain fatty acids of rats. © 2012 Society of Chemical Industry     

Prebiotics enhance magnesium absorption and inulin-based fibers exert chronic effects on calcium utilization in a postmenopausal rodent model

Abstract: Age‐related changes in calcium metabolism play a role in the development of osteoporosis. A 4‐wk feeding study was conducted in 5‐mo‐old ovariectomized (OVX) Sprague‐Dawley rats to assess the effect of various dietary fibers on mineral metabolism and bone health parameters. There were 6 treatment groups: sham‐Control, OVX‐Control, OVX rats receiving daily estradiol (E₂) injections, and OVX rats receiving an AIN‐93M diet supplement with either an inulin‐based fiber (Synergy1® or Fruitafit HD®) or a novel fiber (polydextrose) at 5% wt. of diet. Calcium and magnesium metabolic balances were performed after early (3 d) and late exposure (4 wk) to dietary treatments. Rats receiving polydextrose had significantly higher net calcium absorption efficiency and retention than all control groups and a trend (P≤ 0.10) for higher calcium absorption when compared to inulin‐based fibers after early exposure but the advantage did not persist over long‐term exposure. The inulin‐based fibers had positive chronic effects on calcium metabolism that were related to changes in the gut, that is, production of short chain fatty acids and higher cecal wall weights. All fibers improved magnesium absorption and retention in early and late metabolic balances; effects on magnesium metabolism were more pronounced than for calcium. Practical Application: Steady growth in US middle‐aged and elderly populations has led to higher incidences of several chronic diseases including osteoporosis, a bone disease that primarily affects postmenopausal women. Recent research suggests that certain dietary fibers (prebiotics) enhance mineral absorption and may impart bone health benefits. This work examines the impact of prebiotic supplementation on mineral metabolism and bone health using a postmenopausal rat model. Study findings will aid future investigations in ascertaining the factors related to potential bone health benefits of prebiotic which will aid in developing an effective prebiotics food product/supplement that will address the bone health needs of consumers.     

Effects of Potato Fiber and Potato‐Resistant Starch on Biomarkers of Colonic Health in Rats Fed Diets Containing Red Meat

Abstract: The effects of red meat consumption with and without fermentable carbohydrates on indices of large bowel health in rats were examined. Sprague‐Dawley rats were fed cellulose, potato fiber, or potato‐resistant starch diets containing 12% casein for 2 wk, then similar diets containing 25% cooked beef for 6 wk. After week 8, cecal and colonic microbiota composition, fermentation end‐products, colon structure, and colonocyte DNA damage were analyzed. Rats fed potato fiber had lower Bacteroides‐Prevotella‐Porphyromonas group compared to other diet groups. Colonic Bifidobacterium spp. and/or Lactobacillus spp. were higher in potato fiber and potato‐resistant starch diets than in the cellulose diet. Beneficial changes were observed in short‐chain fatty acid concentrations (acetic, butyric, and propionic acids) in rats fed potato fiber compared with rats fed cellulose. Phenol and p‐cresol concentrations were lower in the cecum and colon of rats fed potato fiber. An increase in goblet cells per crypt and longer crypts were found in the colon of rats fed potato fiber and potato‐resistant starch diets. Fermentable carbohydrates had no effect on colonic DNA damage. Dietary combinations of red meat with potato fiber or potato‐resistant starch have distinctive effects in the large bowel. Future studies are essential to examine the efficacy of different types of nondigestible carbohydrates in maintaining colonic health during long‐term consumption of high‐protein diets. Practical Application: Improved understanding of interactions between the food consumed and gut microbiota provides knowledge needed to make healthier food choices for large bowel health. The impact of red meat on large bowel health may be ameliorated by consuming with fermentable dietary fiber, a colonic energy source that produces less harmful by‐products than the microbial breakdown of colonic protein for energy. Developing functional red meat products with fermentable dietary fiber could be one way to promote a healthy and balanced macronutrient diet.     

Antihypertensive Properties of a Pea Protein Hydrolysate during Short‐ and Long‐Term Oral Administration to Spontaneously Hypertensive Rats

This study investigated short‐term (24 h) and long‐term (5 wk) systolic blood pressure (SBP)‐lowering effects in spontaneously hypertensive rats (SHR) of a 5 kDa membrane pea protein hydrolysate permeate (PPH‐5) produced through thermoase hydrolysis of pea protein isolate (PPI). Amino acid analysis showed that the PPH‐5 had lower contents of sulfur‐containing amino acids than the PPI. Size‐exclusion chromatography indicated mainly low molecular weight (<10 kDa) peptides in PPH‐5 but not in the PPI. The PPH‐5 had renin and angiotensin converting enzyme inhibition IC₅₀ values of 0.57 and 0.10 mg/mL (P < 0.05), respectively, and consisted mainly of peptides with 2 to 6 amino acids. Mass spectrometry analysis revealed mainly hydrophilic tetrapeptide sequences. After a single oral administration (100 mg/kg body weight) to SHR, the unheated PPI showed weakest (P < 0.05) SBP‐lowering effect with a –4 mm Hg maximum when compared to –25 mm Hg for heat‐treated PPI and –36 mm Hg for PPH‐5. Incorporation of the PPH‐5 as 0.5% or 1% (w/w) casein substitute in the SHR diet produced maximum SBP reductions of –22 or –26 mm Hg (P < 0.05), respectively after 3 wk. In comparison, the unhydrolyzed PPI produced a maximum SBP reduction of –17 mm Hg also after 3 wk. Potency of the pea products decreased in the 4th and 5th wk, though SBP values of the treated rats were still lower than the untreated control. We conclude that the antihypertensive potency of PPH‐5 may have been due to the presence of easily absorbed hydrophilic peptides.     

Comparative evaluation of weaning foods from Glyricidia and Leucaena leaf protein concentrates and some commercial brands in Nigeria

Three studies were conducted to evaluate the nutritive potential of Glyricidia leaf protein concentrate (GLPC) and Leucaena leaf protein concentrate (LLPC) in infant weaning foods. The first two trials evaluated 10 laboratory‐formulated weaning foods, in which soybean meal (SBM) was replaced at levels of 0, 25, 50, 75 and 100% with either GLPC or LLPC, and subsequently compared them nutritionally with three commercial weaning foods (coded CFB, CFC and CFN) currently on sale in Nigeria in a 28 day feeding trial using weanling albino rats. Thereafter the best GLPC‐ and LLPC‐based weaning foods, in terms of animal performance consistent with low cost of the foods (designated GL50 and LL25 respectively), were compared with the best commercial weaning food (CFB) in a 14 day rehabilitative potential trial using rats that had previously been protein depleted. In the first trial the final weight was highest in rats fed the 50% GLPC‐based food (159.8 ± 9.5 g) and lowest in rats fed CFN (114.7 ± 9.7 g), while the feed efficiency was best in rats fed the 50% GLPC‐based food and CFC and worst in rats fed the 100% GLPC‐based food and CFN. The nitrogen retention (NR) did not differ significantly (P ≥ 0.05), while the apparent nitrogen digestibility (AND) and ‘operative’ protein efficiency ratio (PER) decreased with increasing level of replacement of SBM with GLPC (R² = 0.61, P ≤ 0.05 and R² = 0.67, P ≤ 0.05 respectively). In the second trial the highest weight gain was observed in rats fed the 25% LLPC‐based food (3.4 ± 0.5 g day^?1). Feed consumption was not significantly (P ≥ 0.05) influenced by dietary treatment, but rats fed the laboratory‐formulated diets containing 0 and 25% LLPC utilised their food more efficiently (3.0 ± 0.4/0.2 respectively) than rats fed the other diets, including the commercial foods. While NR did not differ significantly (P ≥ 0.05), there was a decrease in AND and PER with increasing level of SBM replacement with LLPC (R² = 0.96, P ≤ 0.01 and R² = 0.89, P ≤ 0.05 respectively). Among all the organs weighed in the first two trials, only the relative weight of the lungs was significantly (P ≤ 0.05) affected. Neither the haematological variables nor the serum metabolites were significantly influenced by dietary treatment, except for the packed cell volume of rats fed the LLPC‐based foods. The economics of food production showed that all the laboratory‐formulated foods were cheaper than the commercial foods, with the 50% SBM + 50% GLPC (GL50) and 75% SBM + 25% LLPC (LL25) formulae proving to be the most nutritious. On rehabilitation, rats fed LL25 recovered lost weight faster than those fed GL50, followed by rats fed the best commercial diet (CFB), while the whole‐body and liver protein contents were identical. The incorporation of LPC/SBM mixtures into local food formulae is suggested as a valid intervention strategy for tackling the endemic protein under‐nutrition, especially among vulnerable groups, in sub‐Saharan Africa. Copyright © 2003 Society of Chemical Industry     

Nanoparticles of chromium picolinate enhance chromium digestibility and absorption

BACKGROUND: Trivalent chromium (Cr) is a trace element that is difficult to digest and absorb. The objective of this study was to determine whether reducing organic Cr to nanometre size would increase its digestibility. RESULTS: Forty‐eight 8‐week‐old female Sprague‐Dawley rats were randomly assigned to one of four dietary treatments: (1) basal diet (control); (2) basal diet plus 300 µg kg^?1 Cr as chromium chloride (CrCl₃); (3) basal diet plus 300 µg kg^?1 Cr as chromium picolinate (Crpic); (4) basal diet plus 300 µg kg^?1 Cr as nanoparticulate Crpic (nanoCrpic). NanoCrpic was prepared from Crpic with a particle size of 55–100 nm. The experiment lasted 48 days. Cr digestibility and serum Cr concentration were 1.66 and 1.96 times greater respectively in rats fed nanoCrpic than in rats fed Crpic (P < 0.05). The average daily gain was greater in rats fed nanoCrpic or Crpic than in control rats (P < 0.05). The high‐density lipoprotein content increased while the very‐low‐density plus low‐density lipoprotein content decreased in rats fed nanoCrpic as compared with rats fed Crpic or CrCl₃ (P < 0.05). CONCLUSION: This study indicates that reducing the particle size of Crpic enhances Cr digestibility and absorption in rats and alters some blood metabolite concentrations. Copyright © 2009 Society of Chemical Industry     

Short-term toxicity studies of Ficus thonningii Blume (Moraceae) leaf extract in rats

The short‐term toxicity of Ficus thonningii Blume (FT) was studied in Wistar rats following daily oral administration of the leaf extract (250–500 mg kg^?1) for 15 days. Acute toxicity, body weight changes, organ weight, food intake, clinical signs, haematology, gross and tissue histology were monitored. The body weights of treated rats increased progressively, but the changes were not significantly different from control. The relative weights of the essential organs of treated rats were unaffected in both male and female rats. Of the sixteen haematological parameters studied, only the total leukocyte counts and plateletcrit values in male rats fed 500 mg kg^?1 of FT were significantly greater than similar parameters in controls. Histological findings indicated possible testicular, lung and hepatic toxicities. The LD₅₀ of FT was estimated to be >3000 mg kg^?1. The results suggest that short‐term oral application of F. thonningii may not exert severe toxic effects in rats at doses lower than 500 mg kg^?1.     

Effect of processing of corn for production of masa,tortillas and tortilla chips on the scavenging capacity of reactive nitrogen species

The effect of processing conventional and pigmented corn into masa, tortilla and tortilla chips on the ability to scavenge nitric oxide (NO) and peroxynitrite (ONOO^?) was investigated. The level of retention of nitric oxide and peroxynitrite (mediated for inhibition of nitrite formation scavenging capacity for masa, tortilla and tortilla chips) ranged 56.2–78.2%, 67.4–45%, 40.3–62.0% (for nitric oxide) and 38.6–81.7%, 23.3–47.7%, 19.3–67.2% (for inhibition of nitrite formation), respectively. The antinitrosative activities were affected significantly (P > 0.05) by nixtamalisation, but not by processing masa into tortilla and tortilla chips (P > 0.05). The yellow variety and its corresponding products showed the greatest capacity to scavenge nitric oxide and inhibition of nitrite formation among conventional varieties and the purple variety ranked highest among the pigmented varieties.     

Effect of long‐term dietary administration of oregano and rosemary on the antioxidant status of rat serum,liver, kidney and heart after carbon tetrachloride‐induced oxidative stress

BACKGROUND: This study was performed on female Wistar rats allocated to eight groups of six animals each. Groups 1 and 2 were fed the basal diet, groups 3 and 4 were fed the basal diet supplemented with ground oregano at 20 g kg^?1 level, groups 5 and 6 were fed the basal diet supplemented with ground rosemary at 20 g kg^?1 level, while groups 7 and 8 were fed the basal diet supplemented with both oregano and rosemary, each at 20 g kg^?1 level. Following 6 weeks feeding, groups 2, 4, 6 and 8 were injected with CCl₄ at 1 mL kg^?1 body weight, and 6 h thereafter all animals were sacrificed. RESULTS: Administration of CCl₄ to the control rats enhanced (P < 0.05) aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) activities, decreased cholesterol and triglycerides content in serum, increased (P < 0.05) lipid peroxidation and decreased (P < 0.05) the ABTS radical cation, the hydroxyl anion radical, the superoxide anion radical, and the hydrogen peroxide scavenging activities in all tested tissues, as compared to the control. Feeding oregano, rosemary or both before CCl₄ treatment resulted in decline (P < 0.05) of the increase in AST, ALT and ALP activities, increase (P < 0.05) of cholesterol and triglycerides in serum, decrease (P < 0.05) of lipid peroxidation, and increase (P < 0.05) of the ABTS radical cation, hydroxyl anion radical, superoxide anion radical and hydrogen peroxide scavenging activity. CONCLUSION: The results of this study suggest that long‐term dietary administration of oregano and rosemary has the potential to quench free radicals and alleviate CCl₄‐induced oxidative stress in rats. Copyright © 2009 Society of Chemical Industry     

Immunomodulatory activities and antioxidant properties of polysaccharides from Monascus-fermented products in vitro

BACKGROUND: Monascus ‐fermented products have featured in Chinese cuisine for thousands of years and are widely used as food colourants and dietary materials in many Asian countries. Rice and dioscorea fermented with Monascus purpureus NTU 568 have health‐promoting attributes in vitro and in vivo . The aim of this study was to investigate the immunomodulatory and antioxidant effects of polysaccharides from red mould rice (RMRP) and red mould dioscorea (RMDP) in Raw 264.7 cells. RESULTS: The results showed the antioxidant capabilities (including scavenging, chelating, inhibition of lipid peroxidation, and reducing power) of RMRP and RMDP at a concentration of 10 mg mL^?1. RMRP and RMDP also stimulated cell proliferation, nitric oxide production, phagocytosis and cytokine production (including IL1‐β, IL‐6 and TNF‐α) in Raw 264.7 cells. CONCLUSION: These findings demonstrate that RMRP and RMDP have antioxidant and immunomodulation potential to be developed as novel dietary supplements. Copyright © 2011 Society of Chemical Industry     

Endogenous lysine flow at the distal ileum of the protein-fed rat: Investigation of the effect of protein source using radioactively labelled acetylated lysine or lysine transformed to homoarginine

The study aimed to determine if the source of purified dietary protein influenced endogenous lysine flow at the terminal ileum of the growing rat. Partially guanidinated gelatin and isolated soya bean protein based diets, containing chromic oxide as an indigestible marker, were given to 225-g liveweight rats. The endogenous flow of lysine at the terminal ileum was then determined indirectly, based on the absorption of homoarginine, after sampling of ileal contents at slaughter. Endogenous lysine flow was also determined by reference to chromium levels in sampled ileal digesta, after feeding rats either gelatin or isolated soya bean protein or casein based diets in which some of the lysine had been acetylated with [¹⁴C]-acetic anhydride. The [¹⁴C] acetylated lysine was used to distinguish between lysine of dietary and endogenous origin. Mean endogenous ileal lysine flows were 426 and 442 μ g^?1 dietary freeze dry matter intake for the guanidinated gelatin (n=6) and soya bean (n = 6) treatments, respectively, and there was no significant (P>0.05) effect of protein source on endogenous flow. Nor did there appear to be any effect of dietary protein source on endogenous ileal lysine flow when measurement was based on the radio-actively labelled acetylated lysine. The data, considered together, indicate no effect of the source of dietary protein per se on endogenous ileal lysine flow in the rat when purified proteins were given over a short (8-h) time period. The mean true ileal digestibility coefficients for dietary lysine (0.897, 0.904, 0.926, 0.971, 0.916; acetylated gelatin, guanidinated gelatin, guanidinated soya bean, acetylated soya bean, acetylated casein, respectively) indicated a high degree of absorption of lysine before the end of the ileum in the growing rat.     

Correlation of In Vivo and In Vitro Assay Results for Assessment of Free Radical Scavenging Activity of Green Tea Nutraceuticals

Green tea (GT)‐derived catechins; epigallocatechin gallate (EGCG) in particular are commonly used nutraceuticals for their free‐radical scavenging activity (FRSA). The influence of photodegradation on the protective power of GT nutracenticals against oxidative stress was thoroughly explored. Photodegradation of GT extracts was carried out and monitored using orthogonal stability‐indicating testing protocol; in vitro and in vivo assays. Total polyphenol content (TPC) and FRSA were determined spectrophotometrically while EGCG was selectively monitored using SPE‐HPLC. In vivo assessment of photodegraded samples was investigated via measuring a number of biomarkers for hepatic oxidative stress and apoptosis (caspase‐3, inducible nitric oxide synthase, nitric oxide, mitogen‐activated protein kinase, glutathione, thiobarbituric acid reactive substances, nuclear factor kappa beta, and nuclear factor erythroid 2‐related factor) as well as liver damage (alanine transaminase and aspartate transaminase) in serum of rats previously subjected to oxidative stress. Results showed complete degradation of EGCG in photodegraded green tea samples with no correlation with either TPC or FRSA. On the other hand, in vivo assay results revealed not only loss of activity but formation of harmful pro‐oxidants. Photostability was found crucial for the protective effect of GT extract against lead acetate insult. Results confirmed that careful design of quality control protocols requires correlation of chemical assays to bioassays to verify efficacy, stability, and most importantly safety of nutraceuticals.     

Integrated community‐based growth monitoring and vegetable gardens focusing on crops rich in β‐carotene: Project evaluation in a rural community in the Eastern Cape,South Africa

BACKGROUND: Cultivation in β‐carotene vegetables was promoted in a crop‐based intervention in Lusikisiki, Eastern Cape, South Africa. The project also included nutrition education and community‐based growth monitoring, and focused on technology transfer and mobilisation of local organisations. Three years after initiation of the project, participating (n = 219) and non‐participating (n = 223) households were compared in terms of child morbidity, nutritional knowledge, dietary intake and gardening practices. RESULTS: Compared to control households, more caregivers from project households thought that yellow fruit and vegetables were good for their children (73% vs. 45%; P < 0.001), were familiar with the term ‘vitamin A’ (89% vs. 63%; P < 0.001), knew that vitamin A is a nutrient in food (83% vs. 53%; P < 0.001), and could name three food sources rich in vitamin A (56% vs. 27%; P < 0.001). Fewer 1–5‐year‐old children in the project households reportedly experienced vomiting (6% vs. 13%; P = 0.012), fever (30% vs. 42%; P = 0.008), sores on the skin (6% vs. 19%; P < 0.001), continuous runny nose (20% vs. 33%; P = 0.002), diarrhoea (2% vs. 7%; P = 0.026) and poor appetite (7% vs. 14%; P = 0.016). Children from project households consumed carrot (P = 0.008), butternut (P = 0.002), spinach (P = 0.004) and orange‐fleshed sweetpotato (P = 0.028) more frequently than children from control households. CONCLUSION: The agricultural intervention, combined with nutrition education and community‐based growth monitoring, showed a favourable effect on child morbidity, nutritional knowledge and dietary intake of β‐carotene‐rich vegetables. Agricultural interventions can therefore contribute significantly towards nutritional outcomes. Copyright © 2008 Society of Chemical Industry     

Effects of cocoa extract containing polyphenols and methylxanthines on biochemical parameters of obese‐diabetic rats

BACKGROUND: Previous studies have indicated that cocoa extract possesses hypoglycaemic and hypocholesterolaemic properties in streptozotocin‐induced diabetic rats. However, there has been limited research on the effects of cocoa extract on obese‐diabetic (Ob‐db) rats that mimic human diabetes syndrome. Hence this study was initiated to determine the effect of cocoa extract containing polyphenols and methylxanthines on several biochemical parameters, namely glucose level, insulin sensitivity and lipid profiles of Ob‐db rats. RESULTS: Intake of cocoa extract supplemented with polyphenols (2.17 mg epicatechin, 1.52 mg catechin, 0.25 mg dimer and 0.13 mg trimer g^?1 cocoa extract) and methylxanthines (3.55 mg caffeine and 2.22 mg theobromine g^?1 cocoa extract) for 4 weeks significantly (P < 0.05) reduced the plasma total cholesterol, triglycerides and low‐density lipoprotein cholesterol of obese‐diabetic rats (Ob‐db + cocoa) compared with non‐supplemented animals (Ob‐db). Short‐term (acute) supplementation of cocoa extract significantly (P < 0.05) reduced the plasma glucose level at 60 and 90 min compared with untreated rats as assessed by the oral glucose tolerance test. However, no significant differences were observed in plasma glucose level, insulin level and insulin sensitivity after chronic (4 weeks) cocoa extract supplementation. CONCLUSION: The results of this study suggest that cocoa extract possesses hypocholesterolaemic properties and can exert a transient glucose‐lowering effect but not long‐term glucose control. Copyright © 2008 Society of Chemical Industry