Effect of grape antioxidant dietary fiber on the total antioxidant capacity and the activity of liver antioxidant enzymes in rats

Dietary inclusion of sorghum (Sorghum bicolour) straw dye protects against cisplatin-induced nephrotoxicity and oxidative stress in rats

CONTEXT

Sorghum straw (dried leaves and stem fiber) extracts and infusion are employed in the management of several ailments in folklore, and it is also a natural dye source used in food preparation.

OBJECTIVE

This study sought to investigate the modulatory effect of dietary inclusion of Sorghum straw dye on cisplatin-induced nephrotoxicity and antioxidant status in rats.

MATERIALS AND METHODS

Adult male rats were randomly divided into four groups of six animals each. Groups I (normal rats) and II (control rats) were fed with basal diet while Groups III and IV were fed with diets containing 0.5% and 1% sorghum straw dye, respectively. Nephrotoxicity was induced in Groups I-IV on the 20th day by the administration of a single dose of cisplatin solution (7 mg/kg body weight, i.p.) and the experiment was terminated 3 d after. Thereafter, the kidney and plasma of the rats were analyzed for kidney function (creatinine, urea, uric acid, and blood urea nitrogen) and antioxidant indices [superoxide dismutase (SOD), catalase, glutathione-S-transferase (GST), malondialdehyde (MDA), vitamin C, and reduced glutathione (GSH)].

RESULTS

The average feed intake of the rats in all the groups ranged from 9.0 to 9.5 (g/rat/day). Furthermore, the result indicated that administration of cisplatin caused significant (p < 0.05) elevation in plasma creatinine (2.2 mg/dL), uric acid (39.3 mg/dL), urea (81.4 mg/dL), and blood urea nitrogen (38.0 mg/dL) as well as a concomitant decrease in kidney antioxidant indices in control rats as against the normal rats. However, diets supplemented with 0.5 and 1.0% sorghum straw dye significantly reversed the plasma creatinine and the kidney antioxidant indices to near normal levels.

DISCUSSION AND CONCLUSION

The study suggests that dietary inclusion of sorghum straw dye as colorants could protect against oxidative stress and cisplatin-induced nephrotoxicity.

Development of a fluorescent probe for measurement of peroxyl radical scavenging activity in biological samples

In antioxidant activity testing, it has been argued that assays capable of measuring the inhibitive action against the biologically relevant peroxyl radicals (ROO(•)) from a controllable source are preferable in terms of simulating physiological conditions because ROO(•) is the predominant free radical found in lipid oxidation in foods and biological systems. A new fluorescent probe, p-aminobenzoic acid (PABA), was developed for selective measurement of peroxyl radical scavenging (PRS) activity of biological samples, in view of the fact that the existing PRS assays are quite laborious and require the application of strictly optimized conditions. The earlier probe, β-phycoerythrin, of a similar PRS assay of wide use, oxygen radical absorbance capacity (ORAC), varies from lot to lot of production, undergoes photobleaching, and interacts with polyphenols via non-specific protein binding, while the current probe, fluorescein, undergoes undesired fluorescence (FL) quenching and side reactions. The developed technique is based on the fluorescence decrease of the PABA probe (within an optimal time of 30 min) because of its oxidation by ROO(•), generated from the thermal dissociation of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). In the absence of the scavenger, ROO(•) reacted with the probe, generating non-fluorescent products, and caused a decrease in PABA fluorescence, whereas the ROO(•) scavenger resulted in a fluorescence increase because of the inhibition of the probe oxidation by ROO(•). Thus, the fluorescence increment of intact PABA is proportional to the ROO(•) scavenging activity of samples. The linear range of relative fluorescence intensity versus the PABA concentration was in the interval of 0.5-5.0 μM. Assay precision and accuracy were assessed by analyzing two spiked homogenates of liver and kidney at clinically relevant concentrations with 97-105% recovery and 2.3% interday reproducibility. The proposed method was successfully applied to assay the ROO(•) scavenging activity of some amino acids, plasma and thiol-type antioxidants, and albumin, with the latter showing the strongest activity with respect to both ORAC and developed PABA methods. On the other hand, the original ORAC method suffers a limitation from protein thiols in total radical-trapping antioxidant parameter (TRAP) calculations, and inconsistent results have been reported by various researchers for ORAC values of thiols, such as vastly differing values for glutathione and zero value for cysteine.

Novel optical fiber reflectometric CUPRAC sensor for total antioxidant capacity measurement of food extracts and biological samples

A novel fiber optic sensor was developed for screening the total antioxidant capacity (TAC) based on the use of cupric-neocuproine (Cu(II)-Nc) immobilized onto a Nafion cation-exchange membrane with reflectance spectrometric measurement. The reflectance change associated with the formation of the highly colored Cu(I)-Nc chelate on the membrane as a result of reaction with antioxidants was measured at 530 nm by using a miniature reflectance spectrometer. The calibration graph of trolox (TR) was linear with a slope of 3.40 × 10(3) L mol(-1) mm(-1). The limit of detection (LOD) and limit of quantification (LOQ) for TR in the reflectometric cupric reducing antioxidant capacity (CUPRAC) method were found as 0.53 and 1.76 μM, respectively. The trolox equivalent antioxidant capacities (TEAC) of various antioxidant compounds using the proposed method were comparable to those of the main CUPRAC assay. This assay was validated through linearity, additivity, precision, and recovery. The developed reflectance sensor was used to screen the TAC of some commercial fruit juices and mice tissue homogenates without preliminary treatment. The method is rapid, inexpensive, versatile, and nonlaborious, uses stable reagents on the sensor, and enables the in situ estimation of antioxidant capacity of food extracts and biological samples.

Inhibitory effect of aqueous extract of different parts of unripe pawpaw (Carica papaya) fruit on Fe²⁺-induced oxidative stress in rat pancreas in vitro

CONTEXT

Carica papaya L. (Caricaceae) is widespread throughout tropical Africa; it is cultivated for its fruits and it is eaten in various ways.

OBJECTIVE

This study sought to investigate the inhibitory effect of the aqueous extract of different parts of unripe pawpaw fruit on Fe²⁺-induced lipid peroxidation in rat's pancreas in vitro.

MATERIALS AND METHODS

The aqueous extract of the unripe pawpaw fruit parts; peel (PG), seed (SG), flesh (FG), flesh with peel (FPG) and a combination of equal amount of all parts (CG) were prepared, the total phenolic content and the antioxidant activities of the extracts were then evaluated using various spectrophotometric methods.

RESULT

PG had the highest total phenol content (1.24 mg GAE/g), flavonoid content (0.63 mg QUE/g), reducing power (7.07 mg AAE/g) and Fe²⁺ chelating ability while the SG had the highest 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability. Furthermore, all the extracts caused a significant decrease (p < 0.05) in the malondialdehyde contents in the pancreas with SG (IC₅₀ = 4.25 mg/mL) having the highest inhibitory effect on Fe²⁺-induced lipid peroxidation.

DISCUSSION AND CONCLUSION

This protective effect of the extracts on Fe²⁺-induced lipid peroxidation in rat pancreas could be attributed to their phenolic compounds and, the possible mechanism may be through their antioxidant activities. However, the effect of combination of different parts of unripe pawpaw fruit in equal amount (w/w) on the inhibition of Fe²⁺-induced lipid peroxidation in rat pancreas exhibited additive properties.

Effects of yam peel extract against carbon tetrachloride-induced hepatotoxicity in rats

The phenolic acid and flavonoid profiles in yam peel extract were determined by HPLC. Quercetin, hesperidin, and apigenin were predominant components in yam peel extract. Male Wistar rats were orally treated with yam peel extract (100.02, 266.72, and 433.42 mg/kg) or silymarin (200 mg/kg) daily, with administration of CCl4 (1 mL/kg, 20% CCl4 in olive oil) twice a week. Yam peel extract for 8 weeks significantly reduced the impact of CCl4 toxicity on the serum markers of liver damage, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The overall potential of the antioxidant system was significantly enhanced by the yam peel extract supplements as the plasma and hepatic thiobarbituric acid reactive substances (TBARS) levels were lowered, whereas the hepatic superoxide dismutase (SOD) and catalase (CAT) activities and glutathione peroxidase (GSH-Px) protein level were elevated. Yam peel extract decreased the level of nitric oxide (NO) production, tumor necrosis factor-alpha (TNF-α), and nuclear factor-kappa B (NF-κB) in CCl4. These results point out that yam peel extract can inhibit lipid peroxidation, enhance the activities of antioxidant enzymes, and decrease the TNF-α/NF-κB level, nitric oxide production, and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions. Therefore, it was speculated that yam peel extract protects rats from liver damage through its anti-inflammation capacity.

Hepatoprotective effects of mushrooms

The particular characteristics of growth and development of mushrooms in nature result in the accumulation of a variety of secondary metabolites such as phenolic compounds, terpenes and steroids and essential cell wall components such as polysaccharides, β-glucans and proteins, several of them with biological activities. The present article outlines and discusses the available information about the protective effects of mushroom extracts against liver damage induced by exogenous compounds. Among mushrooms, Ganoderma lucidum is indubitably the most widely studied species. In this review, however, emphasis was given to studies using other mushrooms, especially those presenting efforts of attributing hepatoprotective activities to specific chemical components usually present in the mushroom extracts.

Aqueous extracts of two varieties of ginger (Zingiber officinale) inhibit angiotensin I-converting enzyme, iron(II), and sodium nitroprusside-induced lipid peroxidation in the rat heart in vitro

Ginger has reportedly been used in folk medicine for the management and prevention of hypertension and other cardiovascular diseases. Therefore, this study sought to investigate the inhibitory effect of aqueous extracts of two varieties of ginger on a key enzyme linked to hypertension (angiotensin I-converting enzyme [ACE]), and on pro-oxidants [Fe(2+) and sodium nitroprusside (SNP)] which have been shown to induce lipid peroxidation in the rat's isolated heart in vitro. Aqueous extracts (0.05 mg/mL) of red ginger (Zingiber officinale var. Rubra) and white ginger (Zingiber officinale Roscoe) were prepared and the ability of the extracts to inhibit ACE along with Fe(2+)- and SNP-induced lipid peroxidation was determined in rat's heart in vitro. Results revealed that both extracts inhibited ACE in a dose-dependent manner (25-125 μg/mL). However, red ginger extract (EC50=27.5 μg/mL) had a significantly (P<.05) higher inhibitory effect on ACE than white ginger extract (EC50=87.0 μg/mL). Furthermore, incubation of the rat's heart in the presence of Fe(2+) and SNP caused a significant increase (P<.05) in the malondialdehyde (MDA) content of the heart homogenates, while the introduction of the ginger extracts (78-313 μg/mL) caused a dose-dependent decrease in the MDA content of the stressed heart homogenates. This suggests that the possible mechanism through which ginger exerts its antihypertensive properties may be through inhibition of ACE activity and prevention of lipid peroxidation in the heart. Furthermore, red ginger showed stronger inhibition of ACE than white ginger. Additionally, it should be noted that these protective properties of the ginger varieties could be attributed to their polyphenol contents.

Antioxidant and Hepatoprotective Properties of Tofu (Curdle Soymilk) against Acetaminophen-Induced Liver Damage in Rats

The antioxidant and hepatoprotective properties of tofu using acetaminophen to induce liver damage in albino rats were evaluated. Tofus were prepared using calcium chloride, alum, and steep water as coagulants. The polyphenols of tofu were extracted and their antioxidant properties were determined. The weight gain and feed intake of the rats were measured. The analysis of serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) activities and the concentrations of albumin, total protein, cholesterol, and bilirubin were analyzed. The result reveals that the antioxidant property of both soluble and bound polyphenolic extracts was significantly higher in all tofus, but the steep water coagulated tofu was recorded higher. Rats fed with various tofus and acetaminophen had their serum ALP, ALT, AST, and LDH activities; total cholesterol; and bilirubin levels significantly (P < 0.05) reduced, and total protein and albumin concentrations increased when compared with basal diet and acetaminophen administered group. Therefore, all tofus curdled with various coagulants could be used to prevent liver damage caused by oxidative stress.

Inhibitory Effect of Aqueous Extract of Stem Bark of Cissus populnea on Ferrous Sulphate- and Sodium Nitroprusside-Induced Oxidative Stress in Rat's Testes In Vitro

Cissus populnea are plants associated with a myriad of medicinal uses in different parts of the world and are good sources of carotenoids, triterpenoids, and ascorbic acid. The antioxidant properties and inhibitory effect of water extractible phytochemicals from stem bark of C. populnea on FeSO₄ and sodium nitroprusside- (SNP-) induced lipid peroxidation in rat testes were investigated in vitro. The results revealed that the extract was able to scavenge DPPH radical, chelate Fe²⁺ and also had a high reducing power. Furthermore, the incubation of the testes tissue homogenate in the presence of FeSO₄ and SNP, respectively, caused a significant increase in the malondialdehyde (MDA) contents of the testes. However, the aqueous extract of the stem bark of C. populnea caused a significant decrease in the MDA contents of both Fe²⁺ (EC₅₀ = 0.027 mg/mL) and SNP- (EC₅₀ = 0.22 mg/mL) induced lipid peroxidation in the rat testes homogenates in a dose-dependent manner. The water extractible phytochemicals from C. populnea protect the testes from oxidative stress and this could be attributed to their high antioxidant activity: DPPH-scavenging ability, Fe²⁺-chelating and -reducing power. Therefore, oxidatively stress in testes could be potentially managed/prevented by this plant.

Deep hypothermia protects against acute hypoxia in vivo in rats: a mechanism related to the attenuation of oxidative stress

There is growing interest in using hypothermia to prevent hypoxic damage in clinical and experimental models, although the mechanisms regulated by hypothermia are still unclear. As reactive oxygen and nitrogen species are the main factors causing cellular damage, our objective was to study the scope of hypothermia in preventing hypoxia-induced oxidative damage. We analysed systemic and hepatic indicators of oxidative stress after an acute hypoxic insult (10% oxygen in breathing air) in normothermic (37°C body temperature) and hypothermic conditions (22°C) in rats. Exposure to hypoxia resulted in tissue damage (aspartate aminotransferase increased from 54.6 ± 6.9 U l(-1) in control animals to 116 ± 1.9 U l(-1) in hypoxia, and alanine aminotransferase increased from 19 ± 0.8 to 34 ± 2.9 U l(-1)), oxidative stress (nitric oxide metabolites increased from 10.8 ± 0.4 μM in control rats to 23 ± 2.7 μM in hypoxia, and thiobarbituric reactive substances increased from 3.3 ± 0.2 to 5.9 ± 0.4 nm) and antioxidant consumption (reduced/oxidized glutathione ratio changed from 9.8 ± 0.3 to 6.8 ± 0.3). In contrast, when hypothermia was applied prior to hypoxia, the situation was reversed, with a reduction in aspartate aminotransferase (from 116 ± 1.9 in hypoxic animals to 63 ± 7.8 U l(-1) in animals exposed to hypothermia followed by hypoxia), alanine aminotransferase (from 34 ± 2.9 to 19 ± 0.9 U l(-1)), oxidative stress (nitric oxide metabolites decreased from 23 ± 2.7 to 17.8 ± 1.9 μM and thiobarbituric acid-reactive substances decreased from 5.9 ± 0.4 to 4.3 ± 0.2 nm) and antioxidant preservation (reduced/oxidized glutathione ratio changed from 6.8 ± 0.3 to 11.1 ± 0.1). Hypoxia induced a decrease in liver enzymatic antioxidant activities even during hypothermia. Both treatments, hypoxia and hypothermia, produced a similar increase in hepatic caspase-3 activity. In conclusion, hypothermia prevented the tissue damage and oxidative stress elicited by hypoxia. Our results provide new evidence concerning the protective mechanism of hypothermia in vivo.

Characterization of the antioxidant properties of phenolic extracts from some citrus peels

This study sought to determine the distribution of free and bound phenolics in some Nigerian citrus peels [orange (Citrus sinensis), grapefruit (Citrus paradisii) and shaddock (Citrus maxima)] and characterize the antioxidant properties. The free phenolics were extracted with 80% acetone, while the bound phenolics were extracted from the alkaline and acid hydrolyzed residue with ethyl acetate. Free phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability than the bound phenolic extracts, except in orange peels where the bound phenolic extracts had significantly higher (P < 0.05) DPPH* scavenging ability. Bound phenolics from orange peels had the highest ABTS* scavenging ability (6.09 mmol./TEAC g) and ferric reducing antioxidant properties (FRAP) (71.99 mg/GAE 100 g), while bound phenolics from shaddock peels had the least ABTS* scavenging ability (1.35 mmol./TEAC g) and FRAP (2.58 mg/GAE 100 g) . Bound phenolics from grapefruit peels had the highest OH* scavenging ability (EC50 = 3.8 mg/ml), while bound phenolics from shaddock peels had the least (EC50 = 16.1 mg/ml). The phenolics chelated Fe(2+) and inhibited malondialdehyde production in rat's pancreas in a dose-dependent manner. The additive and/or synergistic action of the free and bound phenolics could have contributed to the observed medicinal properties of the peels; therefore, the high antioxidant properties of the free and bound phenolic extracts from orange peels could be harness in the formulation of nutraceuticals and food preservatives.

Food restriction and refeeding in lambs influence muscle antioxidant status

Compensatory growth, a frequent phenomenon observed in ruminants due to seasonal variation in food availability, affects protein metabolism including protein oxidation. These oxidation processes may have an impact on animal health as well as on meat protein degradation during post mortem aging (ie meat maturation). Sixteen male lambs were randomly divided into four groups. One group was fed ad libitum (C) and one group was food-restricted to 60% of the intake of the C group (R). The last two groups were restricted similarly to the R group and refed either ad libitum (RAL) or similarly to the C group (pair-feeding) (RPF). Muscles samples were taken immediately after slaughter. The present study showed that the restriction/refeeding pattern had no effect on protein oxidation in the muscles studied (longissimus dorsi (LD), semitendinosus (ST) and supraspinatus (SP)). However, total antioxidant capacity decreased after food restriction (-51%, -43%, P < 0.01 for ST and LD muscles, respectively) and re-increased only after ad libitum refeeding. This alteration in the total antioxidant status can partially be explained by the similar pattern of change observed in the glutathione concentration of the muscles (-25%, P < 0.05 for ST muscle and NS for the other muscles). However, none of the concentrations of other water-soluble antioxidants studied (carnosine, anserine, glutathione peroxidase and superoxide dismutase) were altered during compensatory growth. This study showed that an inappropriate feeding level following a nutritional stress induced alterations in the total antioxidant status (particularly that of glutathione), which may have consequences on animal health. Other consequences of a decrease of the animal antioxidant status in vivo could be an alteration of the protein oxidation processes during meat maturation.

Attenuation of gentamycin-induced nephrotoxicity in rats by dietary inclusion of ginger (Zingiber officinale) and turmeric (Curcuma longa) rhizomes

This study sought to investigate the modulatory effects of dietary inclusion of ginger (Zingiber officinale) and turmeric (Curcuma longa) rhizomes on antioxidant status and renal damage induced by gentamycin in rats. Renal damage was induced in albino rats pretreated with dietary inclusion of ginger and turmeric (2% and 4%) by intraperitoneal (i.p.) administration of gentamycin (100 mg/kg body weight) for three days. Assays for renal damage biomarkers (plasma creatinine, plasma urea, blood urea nitrogen and plasma uric acid), malondialdehyde (MDA) content and reduced glutathione (GSH) content as well as renal antioxidant enzymes (catalase, glutathione-S-transferase (GST), glutathione peroxidase (GPx) and superoxide dismutase (SOD)) were carried out. The study revealed significant (p < 0.05) increases in renal damage biomarkers following gentamycin administration with severe alteration in kidney antioxidant status. However, pretreatment with ginger and turmeric rhizome (2% and 4%) prior to gentamycin administration significantly (p < 0.05) protected the kidney and attenuated oxidative stress by modulating renal damage and antioxidant indices. This finding therefore suggests that dietary inclusion of ginger and turmeric rhizomes may protect against gentamycin-induced nephrotoxicity and oxidative stress.

Suppression of oxidative stress by grape seed supplementation in rats

Polyphenol-rich grape seeds have a beneficial effect on human health. The present study was performed to investigate the effects of grape seeds on antioxidant activities in rats. Male Sprague-Dawley rats were randomly divided into a control diet group (C), a high-fat diet group (HF), a 5% grape seed-supplemented control diet group (G), and a 5% grape seed-supplemented high-fat diet group (HG). Dietary supplementation with grape seeds reduced serum concentrations of lipid peroxides compared with those in the C and HF groups. The hepatic level of lipid peroxides decreased significantly in the grape seed groups compared with that in the C and HF groups. Superoxide dismutase activity in the G group increased significantly compared with that in the C group. Catalase activity tended to be higher by feeding grape seeds. The grape seed diet increased glutathione peroxidase activity in the C group. Glutathione-S-transferase activity increased significantly in the G group compared with that in the C group. Hepatic content of total glutathione increased significantly in the HG group but decreased significantly in the HF group. The ratio of reduced glutathione and oxidized glutathione increased by feeding the grape seed diet. Total vitamin A concentration was significantly higher in HG group than in other groups. Liver tocopherol content of the G and HG groups was significantly higher than that of the control groups. These results suggest that dietary supplementation with grape seeds is beneficial for suppressing lipid peroxidation in high fat-fed rats.

Mammary gene expression and activity of antioxidant enzymes and concentration of the mammalian lignan enterolactone in milk and plasma of dairy cows fed flax lignans and infused with flax oil in the abomasum

The objectives of the study were to investigate the effects of dietary supplementation of flax hulls and/or flax oil on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)) in plasma and the mammary gland and the relative mRNA abundance of antioxidant genes in the mammary gland of dairy cows. A total of eight dairy cows were used in a replicated 4 × 4 Latin square design. There were four treatments: control with no flax hulls (CONT), 9·88 % flax hulls in the DM (HULL), control with 500 g flax oil/d infused in the abomasum (COFO), 9·88 % flax hulls in the DM and 500 g flax oil/d infused in the abomasum (HUFO). Plasma GPX activity tended to decrease with flax oil supplementation. Cows fed HULL had higher levels of CAT, GPX1 and SOD1 mRNA in the mammary gland and lower mRNA abundance of GPX3, SOD2 and SOD3 compared with those fed CONT. Abundance of CAT, GPX1, GPX3, SOD2 and SOD3 mRNA was down-regulated in the mammary gland of cows fed HUFO compared to those fed CONT. The mRNA abundance of CAT, GPX1, GPX3 and SOD3 was lower in the mammary gland of cows fed COFO than in the mammary gland of cows fed CONT. The present study demonstrates that flax hulls contribute to increasing the abundance of some antioxidant genes, which can contribute to protecting against oxidative stress damage occurring in the mammary gland and other tissues of dairy cows.

Antioxidant and inhibitory effect of red ginger (Zingiber officinale var. Rubra) and white ginger (Zingiber officinale Roscoe) on Fe(2+) induced lipid peroxidation in rat brain in vitro

Neurodegerative diseases have been linked to oxidative stress arising from peroxidation of membrane biomolecules and high levels of Fe have been reported to play an important role in neurodegenerative diseases and other brain disorder. Malondialdehyde (MDA) is the end-product of lipid peroxidation and the production of this aldehyde is used as a biomarker to measure the level of oxidative stress in an organism. The present study compares the protective properties of two varieties of ginger [red ginger (Zingiber officinale var. Rubra) and white ginger (Zingiber officinale Roscoe)] on Fe(2+) induced lipid peroxidation in rat brain in vitro. Incubation of the brain tissue homogenate in the presence of Fe caused a significant increase in the malondialdehyde (MDA) contents of the brain. However, the aqueous extract from both varieties of ginger caused a significant decrease in the MDA contents of the brain in a dose-dependent manner. However, the aqueous extract of red ginger had a significantly higher inhibitory effect on both Fe(2+)-induced lipid peroxidation in the rat brain homogenates than that of white ginger. This higher inhibitory effect of red ginger could be attributed to its significantly higher phytochemical content, Fe(2+) chelating ability, OH scavenging ability and reducing power. However, part of the mechanisms through which the extractable phytochemicals in ginger (red and white) protect the brain may be through their antioxidant activity, Fe(2+) chelating and OH scavenging ability. Therefore, oxidative stress in the brain could be potentially managed/prevented by dietary intake of ginger varieties (red ginger and white ginger rhizomes).

Effect of antioxidant activity and functional properties of Chingshey purple sweet potato fermented milk by Lactobacillus acidophilus, L. delbrueckii subsp. lactis, and L. gasseri strains

In this study, individual selected lactic acid bacteria strains Lactobacillus acidophilus (LA), L. delbrueckii subsp. lactis (LDL), and L. gasseri (LGA) were grown in Chingshey purple sweet potato (CPSP) substrate/media. CPSP is rich in anthocyanin, which possesses antioxidant activity and in vitro cell assay. The antioxidant ability and functional properties of the fermented milk were examined. High-performance liquid chromatographic (HPLC) method was used to analyze the free amino acid, organic acids, and anthocyanin content. Total phenolic compounds, scavenging effects of 1,1-diphenyl-2-picyl-hydrazyl (DPPH) radicals, and scavenging effects of superoxide anion radicals were determined to evaluate the antioxidant ability of the samples. The cell proliferation of the fermented PSP milk was evaluated by 3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyl Tetrazolium Bromide (MTT) assay. The result indicated that the antioxidant ability of the fermented CPSP milk through LA, LDL, and LGA strains was significantly higher than CPSP. The main anthocyanins present in the samples are cyanidin and delphinidin. MTT assay has revealed that incubation with both PSP and fermented CPSP milk prevented the cell death of macrophage-like RAW264.7 cells. The potential health benefit of fermented PSP milk through LA, LDL, and LGA strains makes the further application of CPSP in health food highly worthwhile.

PRACTICAL APPLICATION

(1) In our study, we have employed the γ-aminobutyric acid (GABA), organic acid contents, total phenol content, anthocyanins content, DPPH, oxygen radical absorbance capacity, superoxide dismutase activity assay, and cytotoxicity assay to assess the functional properties of fermented CPSP milk by different lactic acid bacteria. (2) Our results have revealed that the fermented CPSP milk samples possess high GABA concentrations, organic acid contents, anthocyanins contents, and antioxidant activity. This will provide potential opportunity to develop different functional food products from fermented CPSP milk. (3) The potential health benefit of fermented CPSP milk makes the further application of CPSP in health food highly worthwhile.

tert-Butylhydroquinone as a spectroscopic probe for the superoxide radical scavenging activity assay of biological samples

As a more convenient and less costly alternative to electron spin resonance (ESR) and nonspecific nitroblue tetrazolium (NBT) and cytochrome c assays of superoxide radical (SR, O(2)(•-)) detection, a novel probe, tert-butylhydroquinone (TBHQ), is introduced for SR nonenzymatically generated in the phenazine methosulfate-β-nicotinamide adenine dinucleotide (PMS-NADH) system. SR attacks both TBHQ and SR scavengers incubated in solution for 30 min where scavengers compete with TBHQ for the O(2)(•-) produced. TBHQ, but not its O(2)(•-) oxidation product, tert-butyl-1,4-benzoquinone (TBBQ), is responsive to the CUPRAC (cupric reducing antioxidant capacity) spectrophotometric assay. The CUPRAC absorbance of the ethyl acetate extract of the incubation solution arising from the reduction of Cu(II)-neocuproine reagent by the remaining TBHQ was higher in the presence of O(2)(•-) scavengers (due to less conversion to TBBQ), the difference being correlated to the SR scavenging activity (SRSA) of the analytes. With the use of this reaction, a kinetic approach was adopted to assess the SRSA of amino acids, vitamins, and plasma and thiol antioxidants. This assay, applicable to small-molecule antioxidants and tissue homogenates, proved to be efficient for cysteine, uric acid, and bilirubin, for which the widely used NBT test is nonresponsive. Thus, conventional problems of NBT assay arising from formazan insolubility and direct reduction of NBT by tested scavengers were overcome.

Morton lentil extract attenuated angiotensin II-induced cardiomyocyte hypertrophy via inhibition of intracellular reactive oxygen species levels in vitro

The objective was to investigate whether a lentil (Morton) extract had any protective effect on cardiac hypertrophy, which is one of the most significant sequelae of cardiovascular diseases. High phenolic compounds (43.4 mg of GAE/g), including thirteen phenolic acid and two flavonoids, were detected in the acetone/water/acetic acid lentil extract. The extract showed strong antioxidant ability (105 μmol of TE/g). The effect of lentil extract on angiotensin (Ang) II-induced cardiac hypertrophy was examined. Results showed that pretreatment with lentil extract (25, 50, 100 μg/mL) significantly attenuated Ang II (0.1 μM)-induced hypertrophy by 18, 28, and 36% in rat cardiomycytes, respectively; lentil extract (12.5, 25, 50 μg/mL) attenuated Ang II (0.1 μM)-induced hypertrophy by 9, 17, and 25% in human cardiomycytes, respectively. Intracellular reactive oxygen species (ROS) levels were enhanced by Ang II treatment, and this stimulatory action was significantly attenuated (33% inhibition) by lentil extract (100 μg/mL) in rat cardiomyocytes and attenuated by 22% by 50 μg/mL lentil extract in human cardiomyocytes. In conclusion, Morton lentil extracts attenuated Ang II-induced rat and human cardiomyocytes hypertrophy via decreasing intracellular ROS levels.

A diet rich in cocoa attenuates N-nitrosodiethylamine-induced liver injury in rats

The effects of cocoa feeding against N-nitrosodiethylamine (DEN)-induced liver injury were studied in rats. Animals were divided into five groups. Groups 1 and 2 were fed with standard and cocoa-diet, respectively. Groups 3 and 4 were injected with DEN at 2 and 4 weeks, and fed with standard and cocoa-diet, respectively. Group 5 was treated with DEN, received the standard diet for 4 weeks and then it was replaced by the cocoa-diet. DEN-induced hepatic damage caused a significant increase in damage markers, as well as a decrease in the hepatic glutathione, diminished levels of p-ERK and enhanced protein carbonyl content, caspase-3 activity and values of p-AKT and p-JNK. The cocoa-rich diet prevented the reduction of hepatic glutathione concentration and catalase and GPx activities in DEN-injected rats, as well as diminished protein carbonyl content, caspase-3 activity, p-AKT and p-JNK levels, and increased GST activity. However, cocoa administration did not abrogate the DEN-induced body weight loss and the increased levels of hepatic-specific enzymes and LDH. These results suggested that cocoa-rich diet attenuates the DEN-induced liver injury.

Effect of daily fruit ingestion on angiotensin converting enzyme activity, blood pressure, and oxidative stress in chronic smokers

OBJECTIVE

This study examined whether, daily fruit (blueberries) consumption (250 g) for three weeks or acute fruit ingestion (250 g) would attenuate angiotensin converting enzyme (ACE) activity and reduce oxidative stress in chronic cigarette smokers.

METHODS

Twenty subjects were recruited and randomized into fruit or control groups. Blood samples and blood pressure were obtained at baseline and then pre and one hour post when subjects returned to the lab three weeks later. To examine acute effects, the fruit group immediately ingested 250 g of blueberries after returning and at least one hour prior to the post blood draw. Plasma samples were analyzed for ACE activity, F(2)- isoprostanes and lipid hydroperoxides (LH) as measures of oxidative stress, and ferric reducing ability of plasma (FRAP) as a measure of antioxidant potential. A 2 (treatment) x 3 (time) repeated measures ANOVA was used for statistical analysis. If interaction was significant, then Student's t-tests were used to further examine this relationship. For these comparisons, a Bonferroni adjustment was made with statistical significance set at P < 0.025.

RESULTS

The pattern of change between treatments was not significant for any variable except LH (P < 0.001).

CONCLUSION

This study indicates that LH are significantly reduced by daily fruit consumption, but not affected by acute ingestion. This finding could be one way in which fruit consumption contributes to prevention of cardiovascular disease.

Antioxidant and inhibitory effects of aqueous extracts of Salvia officinalis leaves on pro-oxidant-induced lipid peroxidation in brain and liver in vitro

The present study sought to determine the antioxidant activity and protective ability of water-extractable phytochemicals from Salvia officinalis leaves (strongly aromatic leaves used in flavoring cooked foods) on lipid peroxidation induced by some pro-oxidants in rat brain and liver homogenates in vitro. Aqueous extracts of the leaves were prepared, and the ability of the extract to inhibit 25 microM FeSO(4)- and 7 microM sodium nitroprusside-induced lipid peroxidation in isolated rat brain and liver was determined. Subsequently, the ascorbic acid content, total phenol content, reducing power, Fe(II) chelating, and .OH radical scavenging ability of the extracts were determined as indices of antioxidant activity. The results of the study revealed that the extract inhibited malondialdehyde (MDA) production in basal and pro-oxidant-induced lipid peroxidation in the brain and liver in a dose-dependent manner. The percentage induction of lipid peroxidation by Fe(II) and sodium nitroprusside was higher in the brain than the liver; however, the level of inhibition of MDA production in the brain was significantly (P < .05) higher than the liver. The ascorbic acid (10.3 +/- 2.5 mg/g) and total phenol (7.6 +/- 1.2 mg/g) contents of the leaves were high; likewise, the aqueous extract had high reducing power and Fe(II) chelating ability but low .OH radical scavenging ability. This antioxidant and protective effect of this leaf could be harnessed in the management and prevention of degenerative diseases associated with oxidative stress.

Changes in Polyphenols Distribution and Antioxidant Activity during Fermentation of Some Underutilized Legumes

The effect of fermentation on the polyphenol distribution and antioxidant activity of four underutilized legumes [Cajanus cajan L. Millsp (Pigeon pea), Vigna subterranea L. Verdc (Bambara groundnut), Sphenostylis stenocarpa Harms (African yam bean), and Phaseolus vulgaris L. (Kidney bean)] were investigated. The beans were cooked (12 h), soaked in boiled water (12 h), dehulled, and then cooked again (2 h). The cotyledons were drained, wrapped in jute sacks and left to ferment at 37°C (4 days) to produce condiments. The distribution of free and bound phenolic compounds in the fermented and unfermented beans was determined; thereafter the free radical scavenging ability, reducing power, and the ability of the free and bound phenolic compounds of the fermented and unfermented beans to inhibit lipid peroxidation were determined. The results of the study revealed that fermentation caused a significant increase (p<0.05) in the free soluble phenol content of the legumes, while there was a significant decrease (p<0.05) in the bound phenol content of the legumes. Free soluble phenol from both the fermented and unfermented legumes had a significantly (p<0.05) higher reducing power (except C. cajan), free radical scavenging ability (except C. cajan) and inhibition of lipid peroxidation than bound phenolic extract. However, free soluble phenolic compounds from the fermented beans had a significantly higher (p<0.05) reducing power, free radical scavenging ability, and inhibition of lipid peroxidation than free soluble phenols from unfermented beans. Hence, it was concluded that, fermentation could increase the free soluble phenolic content of the underutilized legumes tested and consequently enhance the antioxidant activities of the legumes; fermented V. subterranea was found to be the most promising condiment with antioxidant activity.

Hot Pepper (Capsicum spp.) protects brain from sodium nitroprusside- and quinolinic acid-induced oxidative stress in vitro

One practical way through which free radical-mediated neurodegenerative diseases could be prevented is through the consumption of food rich in antioxidants. The ability of aqueous extracts of ripe and unripe Capsicum annum, Tepin (CAT) and Capsicum chinese, Habanero (CCH) to prevent lipid peroxidation induced by sodium nitroprusside and quinolinic acid in rat brain in vitro is assessed in this study. The aqueous extract of the peppers were prepared (1 g/20 mL). Incubating rat brain homogenates with pro-oxidant (7 microM sodium nitroprusside [222.5%] and 1 mM quinolinic acid [217.4%]) caused a significant increase (P < .05) in lipid peroxidation in rat brain homogenates. However, the aqueous extract of the peppers (4.2-16.8 mg/mL) caused a significant decrease (P < .05) in the lipid peroxidation in a dose-dependent manner. However, unripe CAT (92.5-55.2%) caused the highest inhibition of sodium nitroprusside-induced lipid peroxidation, while unripe CCH caused the least inhibition (161.0-102.1%). Furthermore, unripe CAT and CCH peppers had a significantly higher (P < .05) inhibitory effect on quinolinic acid-induced lipid peroxidation in rat brain than the ripe pepper (CAT and CCH). Therefore, the protection of the brain tissues by hot pepper depends on the total phenol content in sodium nitroprusside-induced lipid peroxidation, while ripening would reduce the protective properties of hot pepper against quinolinic acid-induced lipid peroxidation. However, unripe CAT has the highest protective properties against sodium nitroprusside- and quinolinic acid-induced lipid peroxidation in rat brain.

Antioxidant and hepatoprotective properties of polyphenol extracts from Telfairia occidentalis (fluted pumpkin) leaves on acetaminophen induced liver damage

In this study the antioxidant and hepatoprotective properties of free and bound polyphenols from Telfairia occidentalis (darkish green leafy vegetable popularly used in soup and folk medicine for the management of many diseases in Nigeria) leaves were compared. Free soluble polyphenols were extracted with 80% acetone, while the bound polyphenols were extracted from the acid and alkaline hydrolyzed residue of the leaf from free soluble polyphenols using ethyl acetate. The total phenol, DPPH free radical scavenging ability and reducing property were determined; subsequently the ability of the extracts to prevent acetaminophen (megadose) induced liver damage in rats were also assessed. Change in serum Glutamate Oxaloacetate Transaminase (GOT), Glutamate Pyruvate Transaminase (GPT), alkaline phosphatase (ALP), albumin, total protein and bilirubin were also determined. The results of the study revealed that the free soluble polyphenols content in the vegetable were significantly higher (p<0.05) than the bound polyphenols. Also, the free soluble polyphenols had a significantly higher antioxidant activity as typified by their higher reducing Power (0.28 OD700) and free radical scavenging ability (83.3%) than the bound polyphenols [reducing power (0.22 OD700), free radical scavenging ability (66.6%)]. Daily intubation of wistar strain albino rat's with 100 mg/mL/day for 7 days caused a significant increase (p<0.05) in serum alkaline phosphatase (ALP), Glutamate Oxaloacetate Transaminase (GOT) and Glutamate Pyruvate Transaminase (GPT), while there was no significant change (p>0.05) in serum bilirubin, albumin, globulin and total proteins in the rats. However, simultaneous intubations of some of the rat with 10 mg or 20 mg mL(-1) of T. occidentalis leaf extract (free soluble or bound polyphenols) along side with the acetaminophen caused a significant decrease (p<0.05) in serum ALP, GOT and GPT (except those intubated with bound polyphenols). Free soluble polyphenols had higher protective effect on the liver than the bound polyphenols; however there action were not dose-dependent. It could be inferred that both soluble free and bound polyphenols extracts of T. occidentails leaf have antioxidant and hepatoprotective properties, however soluble free polyphenols had significantly higher antioxidant and hepatoprotective properties than the bound polyphenols.

Tropical green leafy vegetables prevent garlic-induced hepatotoxicity in the rat

Garlic (Allium sativum) is popularly consumed because of its role in the treatment and management of several diseases. However, unregulated and chronic intake of garlic can cause damage to cells through the production of free radicals. This study was carried out in order to assess the ability of some tropical green leafy vegetables (Telfairia occidentalis, Solanum macrocapon, Corchorus olitorius, Baselia alba, Cnidoscolus acontifolus, Amarantus cruentus, and Ocimum gratissimum) to prevent garlic-induced hepatotoxicity in rats. Wistar strain albino rats were fed diet containing 4% garlic along with or without 40% green leafy vegetable supplement for 14 days. Thereafter, the feeding trial was terminated, the serum of the blood was prepared, and the liver, spleen, intestine, and organ were isolated for gross pathological investigation. The results of the study revealed that there was a significant increase (P < .05) in serum glutamate-oxaloacetate transaminase (SGOT) and glutamate-pyruvate transaminase (SGPT) of the albino rats fed diet containing 4% garlic supplement when compared with the rats fed the basal diet without garlic and vegetable (40%) supplement. However, there was a significant decrease (P < .05) in the serum total protein and albumin levels in those rats. Conversely, there was a consistent significant decrease (P < .05) in the SGOT and SGPT of the rats fed diet containing garlic (4%) and T. occidentalis (40%) and C. acontifolus (40%) supplement compared with those rats fed diet containing garlic (4%) supplement, while there were no consistent significant decrease in those rats fed diet with garlic (4%) alongside with 40% of other leafy vegetables (S. macrocanum, C. olitorius, B. alba, A. cruentus, and O. gratissimum). An increase in serum level of total protein and albumin was also observed in the rats fed T. occidentalis and C. acontifolus. Thus, T. occidentalis and C. acontifolus proved to be better vegetables in preventing garlic-induced hepatotoxicity compared with the other vegetables used in this study.

A diet rich in dietary fiber from cocoa improves lipid profile and reduces malondialdehyde in hypercholesterolemic rats

OBJECTIVE

The potential hypolipidemic effect of a new cocoa product rich in dietary fiber (DF) naturally containing antioxidant polyphenols (cocoa fiber [CF]) was studied in a rat model of dietary-induced hypercholesterolemia.

METHODS

For 3 wk animals were fed normal, cholesterol-free diets or diets supplemented with cholesterol to evoke hypercholesterolemia. Control diets contained 10% cellulose as DF, and test diets were supplemented with 165 g of CF per kilogram (providing 10% DF). Lipid profile, total antioxidant capacity, and malondialdehyde were measured in serum in addition to the activity of the antioxidant enzymes catalase, glutathione reductase, glutathione peroxidase, and superoxide dismutase and concentrations of glutathione and malondialdehyde in the liver.

RESULTS

Hypercholesterolemia and hypertriglyceridemia were established as a consequence of the cholesterol-rich diets. CF showed an important hypolipidemic action, returning triacylglycerol levels in hypercholesterolemic animals to normal values. The hypocholesterolemic effect was also patent, reducing total and low-density lipoprotein cholesterol, yet basal values were not attained. Decreased lipid peroxidation in serum and liver as a consequence of CF intake was patent not only in hypercholesterolemic but also in normocholesterolemic animals. No apparent effects on serum total antioxidant capacity or on the activity of antioxidant enzymes and hepatic levels of glutathione were observed. These effects might be attributed to the high DF content of CF and to the natural presence of antioxidant polyphenols.

CONCLUSION

The consumption of CF with a hypercholesterolemic diet improved the lipidemic profile and reduced lipid peroxidation, suggesting that CF might contribute to a reduction of cardiovascular risk.