Antioxidant and inhibitory activities of thioflavanones against nitric oxide production

The antioxidant and suppressive activities of thioflavanone derivatives against production of nitric oxide were investigated. Thioflavanone derivatives were prepared with methoxy, methyl, nitro, hydroxyl, chloro, and fluoro substituents at different positions. 3′-Hydroxythioflavanone with a hydroxy group at the 3′-position of thioflavanone had a 15–43× higher antioxidant activity than unmodified thioflavanone. Among thioflavanones, 3′-nitrothioflavanone and 3′-hydroxythioflavanone showed increased inhibitory activities against nitric oxide (NO) production, compared to unmodified thioflavanone in a lipopolysaccharide stimulated culture of macrophages cells. 3′-Hydroxy-thioflavanone with a functional group at the 3′-position is a potent antioxidant with an increased inhibitory activity against NO production, compared to unmodified thioflavanone compounds.     

大米鲊海椒抗氧化活性及其对肝脏脂质过氧化的影响

以总还原力最高发酵时间15d和ORAC最高发酵时间60d大米鲊海椒为样品,研究大米鲊海椒DPPH·清除率、BSA氧化抑制率、红细胞溶血和对肝脏脂质过氧化的影响。结果显示,发酵15d样品DPPH·清除率优于发酵60d样品;发酵15d样品对蛋白质氧化损伤有较好的保护作用,但发酵60d有潜在促BSA氧化的作用;发酵15d和60d样品均有抑制肝脏脂质过氧化和较好的抗细胞溶血作用,且发酵15d样品优于发酵60d样品;相关分析显示样品总酚含量与抑制肝脏脂质过氧化显著正相关(P0.01),与抑制BSA氧化和细胞溶血负相关。表明单独用化学抗氧化方法评价食物抗氧化能力不太全面,在化学抗氧化研究基础上,结合对红细胞溶血以及对蛋白质和肝脏脂质过氧化的影响能更客观判断食物的抗氧化能力。     

Relationship between dietary retinol and alpha-tocopherol and lipid peroxidation in rat liver cytosol.

The effects of retinol and alpha-tocopherol-deficient and supplemented diets on the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) in rat liver have been studied. Physiological lipoperoxidation (LPO) was observed in liver cytosol of control rats (TBARS = 0.315 +/- 0.034 nmol of MDA equivalents/mg of liver cytosolic proteins). In retinol-deficient diets there was a decrease in retinolaemia and the absence of retinol in liver cytosol while cytosolic TBARS increased significantly (P less than 0.001). Vitamin E was not found in cytosolic fractions, except in alpha-tocopherol-supplemented diet rats. alpha-Tocopherol-deficient diets induced an absence of vitamin E in the serum and cytosolic TBARS were increased compared to controls (P less than 0.001). Supplementation of the diet with retinol and alpha-tocopherol or both in combination induced a significant decrease in liver cytosolic TBARS (P less than 0.001). Finally the combination of low dietary supplementation with retinol and alpha-tocopherol (ten times the normal diet each) induced the maximum anti-LPO effect.     

Antioxidant activities of aged oat vinegar in vitro and in mouse serum and liver

BACKGROUND: The present study focused on the antioxidant activities of aged oat (Avena sativa L.) vinegar. The antioxidant activities of oat and vinegar have been proved by many previous research studies. It should be noted that oat vinegar, as a novel seasoning, has antioxidant activity. RESULTS: Oat vinegar showed stronger radical scavenging activities, reducing power, and inhibition of lipid peroxidation than rice vinegar. The concentrations of polyphenols and flavonoids in oat vinegar were higher than those in rice vinegar. Ethyl acetate extract of oat vinegar possessed the most varieties of phenolic acids and showed the strongest antioxidant activity compared with ethanol and water extracts. At suitable doses of oat vinegar, the malondialdehyde value was decreased, activities of superoxide dismutase and glutathione peroxidase were promoted, and hepatic damage induced by ⁶⁰Co γ‐irradiation was ameliorated in aging mice. CONCLUSION: Oat vinegar manifested antioxidant activity which was stronger than that of rice vinegar in vitro and the same as that of vitamin E in vivo. Copyright © 2010 Society of Chemical Industry     

Antioxidant and lipoxygenase inhibitory activities of pumpkin seed extracts

Pumpkin seeds have been implicated in providing health benefits. However their antioxidant or anti-inflammatory activity of their extracts has never been studied. Therefore, four commercially available pumpkin seeds were treated with two different extraction methodologies in order to obtain fractions with different content. The extracts were screened for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay and for their inhibitory activity against lipid peroxidation catalyzed by soybean lipoxygenase.Most extracts tested have demonstrated radical scavenging activity, which depends on their total phenolic content, with fractions rich in phenolics showing the strongest activity. On the other hand, the phenolic content of extracts does not determine their activity against lipoxygenase, as acetone and polar lipid fractions are its strongest inhibitors. The presence of molecules being able to scavenge radicals and inhibit lipoxygenase in pumpkin seeds may in part explain the health benefits attributed to them.     

Terpenoids from Stinking toe (Hymneae courbaril) fruits with cyclooxygenase and lipid peroxidation inhibitory activities

Stinking toe (Hymenaea courbaril), also called Jatoba and Kerosene tree, is a medicinal plant commonly found in the central and South American countries. In the Caribbean, Mexico and Brazil, the powdery sweet dust of its fruit is consumed for energy. The chemical examination of the yellowish sweet powder of the fruit yielded sucrose and linolenic acid as major compounds. The pods yielded the labdane diterpenoids crotomachlin (1), labd-13E-en-8-ol-15-oic acid (2), labdanolic acid (4), (13E)-labda 7, 13 dien-15-oic acid (5) and labd-8 (17), 13E- dien-15-oic acid (6), along with the sesquiterpene, spathulenol (7), as confirmed by ¹H and ¹³C NMR spectral studies. The methyl ester of labd-13E-en-8-ol-15-oic acid (3) was also characterized during the purification of compound 5. The total amount of these terpenoids in the fruit was about 0.1% (w/w) of the dried fruit. Compounds 1–5 and 7 were assayed for anti-inflammatory activity using cyclooxygenase-1 (COX-1) and -2 (COX-2) enzymes. At 100 ppm, compounds 3 and 4 showed selective COX-2 enzyme inhibition. Also, compounds 1, 2 and 5 inhibited lipid peroxidation by 46%, 48% and 75%, respectively, at 100 ppm. These compounds were isolated from this fruit and their COX and lipid peroxidation inhibitory activities are reported for the first time in this paper.     

Antioxidative activity of nitrite in metmyoglobin induced lipid peroxidation

 The antioxidative activity of nitrite in metmyoglobin (MMb)-initiated lipid peroxidation in linoleic acid emulsions was examined using oxygen consumption measurement. Nitrite decreased MMb-induced lipid peroxidation with increasing concentrations. The antioxidative effect of nitrite was independent of pH in the range 6.3–5.5, and 1% NaCl did not seem to influence the antioxidative activity of nitrite. Furthermore, nitrite reduced MMb denaturation during MMb-induced peroxidation of linoleic acid. Thermal analysis using differential scanning calorimetry showed that nitrite increased the denaturation temperature of MMb. However, direct complexation between nitrite and the iron center of MMb could not be confirmed using chromatographic methods and analysis of UV-visible spectra of mixtures of nitrite and MMb. The observed results can rather be explained by a weak reversible interaction between nitrite and MMb such as binding of nitrite at the entrance to the haem cavity protecting MMb against heat denaturation and protecting both MMb and the fatty acids against oxidative degradation. Received: 8 March 1996     

Antioxidant and nitric oxide production inhibitory activities of galacturonyl hydroxamic acid

The self-prepared pectin hydroxamic acid has been reported to have antioxidant activities [Yang, S. S., Cheng, K. D., Lin, Y. S., Liu, Y. W., & Hou, W. C. (2004). Pectin hydroxamic acids exhibit antioxidant activities in vitro. Journal of Agricultural and Food Chemistry, 52, 4270–4273]. In this study, the galacturonic acid (GalA), the monomer unit of the pectin polymer, was esterified with acidic methanol (1 N HCl) at 4 °C with gentle stirring for 5 days to get galacturonic acid methyl ester which was further reacted with alkaline hydroxylamine to get galacturonyl hydroxamic acid (GalA–NHOH). The GalA–NHOH was used to test the antioxidant and antiradical activities in the comparison with GalA. The scavenging activities of GalA–NHOH against DPPH radicals (half-inhibition concentration, IC₅₀, was 82 μM), hydroxyl radicals detected by electron spin resonance (IC₅₀ was 0.227 nM in the comparison with Trolox of 0.433 μM), superoxide radicals (IC₅₀ was 830 μM) were determined. The protection activities of GalA–NHOH against hydroxyl radicals-mediated calf thymus DNA damages, linoleic acid peroxidation and peroxynitrite-mediated dihydrorhodamine 123 oxidations were also investigated. It was found that the GalA–NHOH exhibited dose-dependently antioxidant activity and few or none was found in GalA. The GalA–NHOH was used to evaluate the suppressed activity of nitric oxide (NO) productions of RAW264.7 cells in the presence of lipopolysaccharide (LPS, 100 ng/ml) as inducers. It was found that GalA–NHOH (0.02–0.1 mg/ml) could dose-dependently suppress the NO productions (expressed as nitrite concentrations) in RAW264.7 cells without significant cytotoxicity.     

Antioxidant,ACE inhibitory,and acetylcholinesterase inhibitory activities of subcritical water extract of blue mussel

Food Science and Biotechnology - Subcritical water (SCW) extract of blue mussel was prepared at 100, 200, and 300 °C for 10, 30, and 60 min, respectively, and its effect on...     

DHA对大鼠脏器、生化指标及脂质过氧化的影响

采用SD大鼠,按体重随机分为3组:对照组、DHA小剂量组(300mg/kg)、DHA大剂量组(1000mg/kg),灌胃3个月后测定各组大鼠体重、主要脏器、血液生化指标及脂质过氧化指标。结果表明:大剂量组大鼠肝脏、肾脏、睾丸的脏器系数比升高,与对照组比有显著性差异,且肝脏SOD、MDA升高,血液中TG、AST下降,ALT升高,与对照组比均有显著性差异,小剂量组血液AST也下降,呈现显著性差异,肝脏HE染色未发现透明空泡,油红染色无红色脂滴,因此未发生特异性病理改变。实验结果,DHA对大鼠无明显的毒副作用,但大剂量组生化指标显示肝脏可能发生轻微病变,结果还有待于进一步论证。     

板栗壳天然色素对油脂抗氧化作用的研究

以猪油和花生油作为底物,采用烘箱贮藏法测定油脂的 POV值,研究板栗壳天然色素对油脂的抗氧化活性,结 果表明,板栗壳色素具有一定的抗油脂氧化能力,当色素 的添加量分别为猪油和花生油质量的0.03％和0.01％时, 效果最好,而且柠檬酸与抗坏血酸对色素的抗氧化性有 协同增效作用,柠檬酸的协同作用更好,同时添加质量分 数0.005％的柠檬酸和0.03％与0.01％的色素,对猪油和花 生油的抗氧化效果可与0.02％的BHT媲美。     

The dietary effects of sodium carboxymethylcellulose in man

Following a 7-day control period, five male volunteers consumed 15 g sodium carboxymethyl-eellulose (CMC) daily for 23 days. The CMC was well tolerated with no adverse effects on any volunteer. The daily intake of CMC exceeded, by a factor of 7.5, the acceptable daily intake (ADI) recommended for cellulose and its derivatives (group ADI = 25 mg/kg body wt). The wide range of measurements made before and at the end of the test period show that the ingestion of CMC had no significant effect on any of the following: plasma biochemistry; haematological indices; urinalysis parameters; glucose tolerance; serum cholesterol, triglyceride and phospholipids; breath hydrogen and breath methane concentrations. The intestinal transit time decreased for four of the volunteers and increased for one of them. For all volunteers, faecal wet and dry weights increased substantially. Faecal bile acids increased moderately for some volunteers and more extensively for others. Faecal fat increased for four volunteers and decreased slightly for one. The excretion of neutral sterols decreased for all volunteers when calculated as μmol sterols/g dry wt of faeces. These changes are of physiological and dietary interest; they do not reflect any adverse toxicological effects resulting from the ingestion of CMC.     

Antioxidant enzyme activities in beef in relation to oxidation of lipid and myoglobin

Lipid- and oxy-free radical generation has been implicated in oxidative processes which occur during meat maturation but the importance of the antioxidant enzyme (AOE) activity in these processes is not known. It was shown that metmyoglobin (MetMb) % and lipofuscin content were higher in colour-unstable muscles such as psoas major (PM) and diaphragma (D) compared to longissimus lumborum (LL) and tensor fasciae latae (TFL). Although Superoxide dismutase (SOD) activity is higher post mortem in PM and D muscles than in LL and TFL muscles, catalase and glutathione peroxidase (GPx) activities were higher only in D muscle. The higher AOE activity in colour-unstable muscles such as PM and D was not sufficient to prevent increased formation of MetMb and lipofuscin in these muscles compared to LL and TFL muscles.     

Antioxidant and tyrosinase inhibitory activities of a novel chitosan–phloroglucinol conjugate

A novel chitosan–phloroglucinol conjugate was developed by conjugating phloroglucinol onto a chitosan backbone. The chitosan–phloroglucinol conjugate was characterised by ¹H nuclear magnetic resonance (NMR), and the NMR spectra confirmed the conjugation. Antioxidant and tyrosinase inhibitory activities of the chitosan–phloroglucinol conjugate were investigated. The chitosan–phloroglucinol conjugate showed strong 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), hydrogen peroxide and ABTS⁺ radical scavenging activities as well as reducing power compared with those of the unmodified chitosan (P < 0.05). The formation of malondiadehyde (MDA) as an indicator of lipid peroxidation in a linoleic acid emulsion was 30.56 μM in the absence of the chitosan–phloroglucinol conjugate after 4 days incubation, whereas MDA was 4.14 μM in the presence of the chitosan–phloroglucinol conjugate (P < 0.05). The activity was higher than that of ascorbic acid, which is currently used as a food preservative. Moreover, the chitosan–phloroglucinol conjugate inhibited 56.30% tyrosinase activity, which is responsible for browning of foods, and acted as non‐competitive inhibitor. Taken together, the chitosan–phloroglucinol conjugate may have potential for application in functional foods and/or as a food preservative.     

Antioxidant and antiacetylcholinesterase activities of five plants used as Portuguese food spices

In the present work, we report the results of a study aimed at evaluating the antiradical activity, the antioxidant activity and the acetylcholinesterase (E.C. 3.1.1.7.) inhibitory capacity of essential oils, ethanol and boiling water extracts from five aromatic herbs growing wild in Portugal and used in traditional food preparations: fennel (Foeniculum vulgare), mint (Mentha spicata), pennyroyal (Mentha pulegium), rosemary (Rosmarinus officinalis) and wild thyme (Thymus serpyllum). The water extracts of M. spicata and M. pulegium showed the highest radical-scavenging activity (DPPH test) values (IC₅₀ = 5.7 ± 0.4 and 8.9 ± 0.2 μg ml⁻¹ respectively). This activity was higher than that found with the standard antioxidant BHT. The ethanol extracts of M. spicata, T. serpyllum and F. vulgare showed the highest antioxidant activities measured by the β-carotene/linoleic acid assay, IC₅₀ = 36.9 ± 0.1, 41.2 ± 0.1 and 68.7 ± 0.1 μg ml⁻¹, respectively. The inhibition of AChE was higher in the essential oil fraction. The highest activity was found for R. officinalis with an IC₅₀ = 69.8 ± 0.1 μg ml⁻¹.     

Acetyl cholinesterase inhibitory,antioxidant and cytotoxic activity of three dietary medicinal plants

Three medicinal plants namely Trigonellafoenum-graecum, Glycinemax and Sesamumindicum were evaluated for invitro acetyl cholinesterase inhibitory activity. These plants have been selected based on their use as memory enhancing as well as their nutrient value. These plants have been consumed as nutritious food and are believed to play an important role in health-promoting. The results were expressed as IC₅₀ and the percent of inhibition of acetylcholinesterase (AchE) activity. Diphenyl picrylhydrazil (DPPH) assay and beta-carotene bleaching method were used for antioxidant studies and brine shrimp lethality test (BSL) was used for cytotoxicity assay. The obtained results showed that the G.max extract has inhibited AChE activity strongly in a dose-dependent manner (IC₅₀ = 4.69 mg/mL). The most inhibition of AChE activity was due to G.max extract (68.4%). This extract was also able to scavenge DPPH radical with IC₅₀ = 454.3 μg/mL. The G.max extract has shown the least cytotoxicity (IC₅₀ value of 1112.6 μg/mL) in BSL assay. T.foenum-graecum and S.indicum also exhibited noticeable AchE inhibition.