Effect of artichoke extract (Cynara scolymus L.) on palmitic-1-14C acid oxidation in rats

Studies on the effect of the artichoke extract (AE) on oxidation of palmitic-1-14C acid administered intravenously to rats at a dose 25 and 50 mg/kg bw demonstrated marked enhancement of both 14CO2 expiration rate and 14CO2 recovery in the expired air. The extract suppressed accumulation of palmitic-1-14C acid in serum lipids and epididymal fat pad tissue as well. The effects of the extract on 14CO2 expiration rate, 14CO2 recovery, as well as accumulation of palmitic-1-14C acid were dose dependent. Total14CO2 recovery in expired air during 60 min was elevated by 17.3% (p < 0.05) and 52.1% (p < 0.001) in rats administered the extract at a dose of 25 and 50 mg/kg, respectively. The rats supplemented with the AE at a dose of 25 and 50 mg/kg bw were characterized by 10.0% (not significant) and 19% (p < 0.05) decrease in( 14)C radioactivity of serum lipids as well as reduction of epididymal fat tissue 14C radioactivity by 8.7 and 17.5% (p < 0.05), respectively, in comparison with the control rats. Thus, the results demonstrate that the AE possess stimulatory properties with respect to oxidation of palmitic acid administered to rats, and provide new information on the mechanism of antilipemic activity of the extract associated with activation of lipid oxidation in the organism.     

Hypoglycaemic role of Cucurbita ficifolia (Cucurbitaceae) fruit extract in streptozotocin‐induced diabetic rats

Cucurbita ficifolia is commonly used as an antidiabetic and antihyperglycaemic agent in Asia. However, the mechanisms of antidiabetic action of the plant remain to be clarified. This study was undertaken to investigate the effects of C. ficifolia fruit extract on blood plasma, plasma insulin level, lipid peroxidation and number of β cells in normal and streptozotocin (STZ)‐induced diabetic rats. The results indicated that feeding with C. ficifolia fruit extract caused reduction in STZ‐induced hyperglycaemia while increase plasma insulin level in STZ diabetic rats, and markedly reduced the STZ‐induced lipid peroxidation in pancreas of the rats. Further there was a significant increase in the number of β cells in C. ficifolia‐treated animals when compared with untreated diabetics, however, their number was still less than that obtained for normal rats, indicating the mode of protection of C. ficifolia fruit extract on pancreatic β cells. The present study thus confirms a hypoglycaemic effect of C. ficifolia fruit extract and suggests that oral feeding of C. ficifolia fruit extract may have a role in the renewal of β cells in STZ diabetic rats or, alternatively, may permit the recovery of partially destroyed β cells. Our results provide some documentation to define the role and mode of action of C. ficifolia fruit extract in its potential and promising use in treating diabetes. Copyright © 2007 Society of Chemical Industry     

Protective effect of polyphenol‐rich extract prepared from Malaysian cocoa (Theobroma cacao) on glucose levels and lipid profiles in streptozotocin‐induced diabetic rats

BACKGROUND: Cocoa beans are used for preparing cocoa liquor and cocoa powder, which are the main ingredients of cocoa‐based products. Previous studies have reported the health benefits of cocoa polyphenols in reducing the risk of cardiovascular diseases. However, there is no report on the efficacy of cocoa polyphenols on diabetes mellitus. Therefore this study was designed to evaluate the protective effect of cocoa polyphenol‐rich extract (CE) on glucose levels and lipid profiles in streptozotocin (STZ)‐induced diabetic rats. Male Sprague‐Dawley rats were divided into diabetic control, diabetic CE and diabetic glibenclamide groups. RESULTS: Three different dosages of CE (10, 20 and 30 mg per 100 g body weight) were administered orally once a day for 1 week before STZ injection and for 3 weeks thereafter. The results showed that CE could normalise the body weight loss caused by STZ. In the 20 mg CE‐pretreated group there was a 143% increase in plasma glucose levels, compared with a 226% increase in diabetic control rats. CE could also normalise total cholesterol, triglycerides and high‐density lipoprotein cholesterol at the end of the experiment compared with the baseline. CONCLUSION: The present study suggests that pretreatment with CE from roasted cocoa beans could prevent the development of diabetes induced by STZ injection in rats. Copyright © 2008 Society of Chemical Industry     

Chemical Acylation of Water‐Soluble Antioxidant of Bamboo Leaves (AOB‐w) and Functional Evaluation of Oil‐Soluble AOB (cAOB‐o)

Antioxidant of bamboo leaves (AOB) is a novel natural food antioxidant approved in China since 2004. Natural phenolics contained in the current AOB are usually polyhydroxy derivatives exhibiting hydrophilic character, which has been marked as water‐soluble AOB (AOB‐w). In order to broaden the application fields, oil‐soluble AOB (cAOB‐o) was obtained by chemical acylation of AOB‐w with different chain‐length fatty acids varying from C8 to C18. Results indicated that the yield and solubility of cAOB‐o in 1‐octanol solvent depended on the carbon chain length of acyl donor, and cAOB‐o derived from C12 fatty acid exhibited the more powerful antioxidant activity evaluated by β‐carotene/linoleic acid bleaching assay. Total phenolic content decreased by Folin–Ciocalteu assay. Fourier transform infrared spectra showed the increase of a carbonyl (C = O) peak at 1701 cm^?1 and a decrease in the intensity of the absorption at 3400 cm^?1 (O‐H stretching) in cAOB‐o. Acylation was inferred to mainly occur on the hydroxyl groups of flavones C‐glycosides according to the change of high‐performance liquid chromatography spectra and the contents of total flavonoids and phenolic acids. cAOB‐o with the addition of 0.02% significantly increased oxidative stability of palm oil 1.59 times, lard 3.74 times, and fried potato chips 2.08 times, which was better than the effect of oil‐soluble tea polyphenol (P < 0.01). Moreover, cAOB‐o was identified to be actually nontoxicity by an acute oral toxicity test. All the above results indicated that cAOB‐o could be used as a novel and effective oil‐soluble antioxidant in the food industry.     

Phenolic-rich extract from the Costa Rican guava (Psidium friedrichsthalianum) pulp with antioxidant and anti-inflammatory activity. Potential for COPD therapy

The potential therapeutic effects of Costa Rican guava (Psidium friedrichsthalianum) extracts for chronic obstructive pulmonary disease were examined. The ethyl acetate fraction displayed the highest antioxidant activity, as compared to the hexane, chloroform, and n-butanol fractions, as well as the crude extract. This fraction was evaluated for its anti-inflammatory activity response relationship against interleukin-8 (IL-8) and inhibition of matrix metalloproteinase-1 (MMP-1) expression before and after treatment with cigarette smoke. The ethyl acetate fraction exhibited inhibitory activity against IL-8 production and MMP-1 expression, showing the most potent inhibitory activities in both assays at 100 μg/mL, and nine compounds (1–9) were found. Phenolic compounds 1-O-trans-cinnamoyl-β-d-glucopyranose (2), ellagic acid (3), myricetin (4), quercitrin (7), and quercetin (9) were identified using standard compounds or literature reports from related species. Compounds 1, 5, 6, and 8 were tentatively identified as 1,5-dimethyl citrate (1), sinapic aldehyde 4-O-β-d-glucopyranose (5), 3,3′,4-tri-O-methylellagic acid-4′-O-d-glucopyranoside (6), and 1,3-O-diferuloylglycerol (8), All nine compounds are reported for the first time in Costa Rican guava.     

Effect of flavonol glycoside in mulberry (Morus alba L.) leaf on glucose metabolism and oxidative stress in liver in diet‐induced obese mice

BACKGROUND: Mulberry therapies on type 2 diabetic patients or streptozotocin‐induced diabetic rats have been reported to improve fasting blood glucose levels. We investigated the effects of dietary consumption of mulberry‐leaf powder and purified quercetin 3‐(6‐malonylglucoside), the quantitatively major flavonol glycoside in mulberry leaves, on glucose and lipid metabolism in high‐fat diet‐induced obese mice. Male C57BL/6J mice aged 8 weeks were assigned to three groups (control, mulberry leaf powder (MLP), and quercetin 3‐(6‐malonylglucoside) (Q3MG)) and treated with their respective diets for 8 weeks. RESULTS: We found that dietary supplementation of 10 g MLP kg^?1 or 1 g Q3MG kg^?1 in high‐fat diet effectively suppressed blood glucose levels. We also noted increased expression of glycolysis‐related genes and suppression of thiobarbituric acid reactive substances concentrations in the liver of Q3MG group compared to control mice. CONCLUSION: Dietary consumption of Q3MG, the quantitatively major flavonol glycoside in mulberry leaves, improved hyperglycemia in obese mice and reduced oxidative stress in the liver. Copyright © 2010 Society of Chemical Industry     

Effect of calcium propionate on the microstructure and pectin methy‐ lesterase activity in the parenchyma of fresh‐cut Fuji apples

There is an increasing demand for fresh‐cut fruits. One of the main problems with these products is their short shelf life. The use of additives such as calcium propionate may increase their shelf life, because calcium preserves the structural integrity of the cells and propionate acts as food preservative. This work analyses the microstructure of Fuji apple parenchyma treated with calcium propionate immediately after treatment and after storage for 1 and 2 weeks at 4 °C by using light microscopy (LM) and low‐temperature scanning electron microscopy (cryo‐SEM). This work also studies the effects of treatment and storage time on the enzymatic activity of pectin methylesterase (PME) by measuring the amount of acid released per unit of time at pH 7 and at 63 °C. The results show that calcium propionate treatment has consolidating and structuring effects on the parenchyma and partially minimises the degrading effects of fresh‐cut apples. In addition, treatment with calcium propionate decreases the activity of the PME both in non‐stored apples and in those stored for 1 and 2 weeks probably due to the inhibiting effect of propionate. Copyright © 2006 Society of Chemical Industry     

Formation of 4(5)‐Methylimidazole in Aqueous d‐Glucose‐Amino Acids Model System

The International Agency for Research on Cancer (IRAC) has classified 4(5)‐methylimidazole (4‐MeI) as a group 2B possible human carcinogen. Thus, how 4‐MeI forms in a d ‐glucose (Glu) amino acids (AA) model system is important, as it is how browning is affected. An aqueous solution of Glu was mixed individually in equimolar amounts at 3 concentrations (0.05, 0.1, and 0.15 M) with aqueous solutions of l ‐Alanine (Ala), l ‐Arginine (Arg), Glycine (Gly), l ‐Lysine (Lys), and l ‐Serine (Ser). The Glu‐AA mixtures were reacted at 60, 120, and 160 °C for 1 h. The 4‐MeI levels were measured by gas chromatography‐mass spectrometry after derivatization with isobutylchloroformate. No 4‐MeI was formed at 60 °C for any treatment combination; however, at 120 °C and 0.05 M, Glu‐Arg and Glu‐Lys produced 0.13 and 0.14 mg/kg of 4‐MeI. At 160 °C and 0.05 M all treatment combinations formed 4‐MeI. At 160 °C and 0.15 M, the observed levels of Glu‐Ala, Glu‐Arg, Glu‐Gly, Glu‐Lys, and Glu‐Ser were 0.21, 1.00, 0.15, 0.22, and 0.16 mg/kg. The AA type, reactant concentrations, and temperature significantly affected (P < 0.001) formation of 4‐MeI as well as browning. Glu‐Lys treatment in all combinations produced the most browning, but Glu‐Arg produced the most 4‐MeI. This method showed that foods processed using low temperatures may have reduced levels of 4‐MeI.