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Proteases from pyloric caeca extract of three fish species including brownstripe red snapper (Lutjanus vitta), bigeye snapper (Priacanthus tayenus) and threadfin bream (Nemipterus marginatus) were comparatively studied. The extracts from bigeye snapper and threadfin bream exhibited the highest hydrolytic activities toward casein, alpha-N-benzoyl-DL-arginine-p-nitroanilide and alpha-N-rho-tosyl-L-arginine methyl ester at pH 8.0 and 60 degrees C and pH 8.5 and 55 degrees C, respectively. The extract of brownstripe red snapper showed the optimal pH and temperature of 8.0 and 60 degrees C with all substrates used except the optimal temperature was 65 degrees C when casein was used. All proteases were strongly inhibited by soybean trypsin inhibitor (SBTI) and N-rho-tosyl-L-lysine chloromethylketone (TLCK) and partially inhibited by N-tosyl-L-phenylalanine chloromethylketone for all substrates tested, suggesting that trypsin-like proteases were the major enzymes. Substrate-gel activity staining of 40-60% ammonium sulfate (AS) fraction revealed that major activity bands were observed with molecular mass of 24, 22 and 20 kDa for brownstripe red snapper, bigeye snapper and threadfin bream, respectively. Those activity bands were partially inhibited by SBTI and TLCK. AS fraction was further used to produce gelatin hydrolysate from the skin of brownstripe red snapper with different degrees of hydrolysis (DH). Hydrolysate with DH of 15% exhibited the highest DPPH and ABTS radical scavenging activities and ferric reducing antioxidant power (p<0.05). Therefore, the extract from pyloric caeca could be used to produce the gelatin hydrolysates possessing antioxidative activities.
Comp Biochem Physiol B Biochem Mol Biol 2008 Dec
PMID:Comparative study on the proteases from fish pyloric caeca and the use for production of gelatin hydrolysate with antioxidative activity. 1879 44

The anti-proliferative activity of hesperetin, hesperidin, neohesperidin and rutin was evaluated on human hepatoma cell lines (Hep G2) and correlated to their antioxidant activity. The results obtained showed strong anti-proliferative effects of hesperidin and neohesperidin, considerably higher than the other two additives. Hesperetin induced caspase-3 activation, release of LDH and endogenous accumulation of putrescine. Cell cycle distribution seems to indicate that the inhibitory effects of polyphenols on cell growth could be due to G0/G1 block, and activation of apoptotic pathway in the presence of hesperetin. Our results underline also that the glycone forms show reduced scavenging activity against DPPH, but present a remarkable inhibition of cell proliferation and low cytotoxicity.
Mol Cell Biochem 2009 Jan
PMID:Influence of L-rhamnosyl-D-glucosyl derivatives on properties and biological interaction of flavonoids. 1898 44

Recent clinical and experimental data showed the involvement of reactive oxygen species/nitrogen species (ROS/RNS) in many human pathophysiological conditions. Antioxidant activity of the aqueous (ARA) and ethanolic extracts (ARE) of Asparagus racemosus (AR) root were evaluated in a series of in vitro assays including ROS generation in chemicals and biological model systems. The dose-dependent ARA and ARE extracts showed the scavenging activity against DPPH (IC50 = 60.7 and 52.5 microg/ml), nitric oxide (IC50 = 141.9 and 63.4 microg/ml), superoxide (IC50 = 221 and 89.4 microg/ml), hydroxyl (IC50 = 318.7 and 208.8 microg/ml) and ABTS.+ (IC50 = 134.5 and 71.9 microg/ml) radicals. The antioxidant capacity of ARA and ARE were assessed for their reducing power using FRAP (Ferric Reducing antioxidant power) and potassium ferricyanide reducing methods as well as free radical scavenging capacity by TEAC (Trolox Equivalent Antioxidant Capacity) method. ARA and ARE extracts were also found to be effective at suppressing lipid peroxidation induced by Fe2+/ascorbate system in rat liver mitochondrial preparation (IC50 = 511.7 and 309.2 microg/ml, respectively). Further, ARA and ARE root extracts significantly decreased (P < 0.05) copper-mediated human LDL oxidation by prolongation of lag phase time with decline in oxidation rate, maximal yield of conjugated dienes, lipid hydroperoxides and malondialdehyde concentrations. The addition of ARA and ARE root extracts to human serum significantly reduced (P < 0.05) the formation of lipid peroxidation in medium. Trolox, alpha-tocopherol and mannitol were tested similarly to compare their antioxidant activities. In conclusion, antioxidant activity of ARE as compared to ARA extract is more effective which act as hydrogen donors, metal ion chelators, reducing agents, radical scavengers and anti-lipid peroxidative. These effects are attributed to the high amount of lipophilic phenolics content of ARE root extract.
Cell Mol Biol (Noisy-le-grand) 2009 Feb 25
PMID:Suppression of reactive oxygen species and nitric oxide by Asparagus racemosus root extract using in vitro studies. 1926 91

A series of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy synthetic chromone derivatives was evaluated for their DPPH free radical scavenging activities. A training set of 30 synthetic chromone derivatives was subject to three-dimensional quantitative structure-activity relationship (3D-QSAR) studies using molecular field analysis (MFA). The substitutional requirements for favorable antioxidant activity were investigated and a predictive model that could be used for the design of novel antioxidants was derived. Regression analysis was carried out using genetic partial least squares (G/PLS) method. A highly predictive and statistically significant model was generated. The predictive ability of the developed model was assessed using a test set of 5 compounds (r(2) (pred) = 0.924). The analyzed MFA model demonstrated a good fit, having r(2) value of 0.868 and cross-validated coefficient r(2) (cv) value of 0.771.
Int J Mol Sci 2008 Mar
PMID:3D-QSAR investigation of synthetic antioxidant chromone derivatives by molecular field analysis. 1932 46

Litchi fruit pericarp tissue is considered an important source of dietary phenolics. This study consisted of two experiments. The first was conducted to examine the effects of various extraction temperatures (30, 40, 50, 60, 70 and 80 degrees C) and pH values (2, 3, 4, 5 and 6) on the extraction yield of phenolics from litchi fruit pericarp. Extraction was most efficient at pH 4.0, while an extraction temperature of 60 degrees C was the best in terms of the combined extraction yield of phenolics and the stability of the extracted litchi anthocyanins. The second experiment was carried out to further evaluate the effects of various temperatures (25, 35, 45, 55 and 65 degrees C) and pH values (1, 3, 5 and 7) on the total antioxidant ability and scavenging activities of DPPH radicals, hydroxyl radical and superoxide anion of the extracted anthocyanins. The results indicated that use of 45-60 degrees C or pH 3-4 exhibited a relatively high antioxidant activity. The study will help improve extraction yield of phenolics from litchi fruit pericarp and promote better utilization of the extracted litchi anthocyanins as antioxidants.
Int J Mol Sci 2008 Jun
PMID:Effects of various temperatures and pH values on the extraction yield of phenolics from litchi fruit pericarp tissue and the antioxidant activity of the extracted anthocyanins. 1932 6

This study reports the effect of Spilanthes acmella Murr. extracts on phenylephrine-induced contraction of rat thoracic aorta as well as their antioxidant activity. Results show that the extracts exert maximal vasorelaxations in a dose-dependent manner, but their effects are less than acetylcholine-induced nitric oxide (NO) vasorelaxation. Significant reduction of vasorelaxations is observed in both N(G)-nitro-l-arginine methyl ester (l-NAME) and indomethacin (INDO). In the presence of l-NAME plus INDO, synergistic effects are observed, leading to loss of vasorelaxation of both acetylcholine and the extracts. Similarly, the vasorelaxations of the extracts are completely abolished upon the removal of endothelial cells. This demonstrates that the extracts exhibit vasorelaxation via partially endothelium-induced NO and prostacyclin in a dose-dependent manner. Significantly, the ethyl acetate extract exerts immediate vasorelaxation (ED(50) 76.1 ng/mL) and is the most potent antioxidant (DPPH assay). The chloroform extract shows the highest vasorelaxation and antioxidation (SOD assay). These reveal a potential source of vasodilators and antioxidants.
Int J Mol Sci 2008 Dec
PMID:Vasorelaxant and antioxidant activities of Spilanthes acmella Murr. 1933 Jan

DNA damage by reactive species is associated with susceptibility to chronic human degenerative disorders. Anthocyanins are naturally occurring antioxidants, that may prevent or reverse such damage. There is considerable interest in anthocyanic food plants as good dietary sources, with the potential for reducing susceptibility to chronic disease. While structure-activity relationships have provided guidelines on molecular structure in relation to free hydroxyl-radical scavenging, this may not cover the situation in food plants where the anthocyanins are part of a complex mixture, and may be part of complex structures, including anthocyanic vacuolar inclusions (AVIs). Additionally, new analytical methods have revealed new structures in previously-studied materials. We have compared the antioxidant activities of extracts from six anthocyanin-rich edible plants (red cabbage, red lettuce, blueberries, pansies, purple sweetpotato skin, purple sweetpotato flesh and Maori potato flesh) using three chemical assays (DPPH, TRAP and ORAC), and the in vitro Comet assay. Extracts from the flowering plant, lisianthus, were used for comparison. The extracts showed differential effects in the chemical assays, suggesting that closely related structures have different affinities to scavenge different reactive species. Integration of anthocyanins to an AVI led to more sustained radical scavenging activity as compared with the free anthocyanin. All but the red lettuce extract could reduce endogenous DNA damage in HT-29 colon cancer cells. However, while extracts from purple sweetpotato skin and flesh, Maori potato and pansies, protected cells against subsequent challenge by hydrogen peroxide at 0 degrees C, red cabbage extracts were pro-oxidant, while other extracts had no effect. When the peroxide challenge was at 37 degrees C, all of the extracts appeared pro-oxidant. Maori potato extract, consistently the weakest antioxidant in all the chemical assays, was more effective in the Comet assays. These results highlight the dangers of generalising to potential health benefits, based solely on identification of high anthocyanic content in plants, results of a single antioxidant assay and traditional approaches to structure activity relationships. Subsequent studies might usefully consider complex mixtures and a battery of assays.
Int J Mol Sci 2009 Mar
PMID:Dietary protection against free radicals: a case for multiple testing to establish structure-activity relationships for antioxidant potential of anthocyanic plant species. 1939 39

The objective of this study was to verify the effect of the organochalcogen 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on some parameters of oxidative stress in human serum. Serum of volunteers were incubated for 30 min in the presence or absence of 1, 10, or 30 microM of 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one and oxidative stress was measured. First, we tested the influence of the compound on 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) radical-scavenging and verified that the organotellurium did not have any antioxidant properties. The organochalcogen was capable to enhance TBARS but the compound was not able to alter carbonyl assay. Furthermore, the organochalcogen provoked a reduction of protein thiol groups measured by the sulfhydryl assay. Moreover, the organotellurium enhanced the activity of catalase and superoxide dismutase, inhibited the activity of glutathione peroxidase and did not modify the glutathione S-transferase activity. Furthermore, nitric oxide production and hydroxyl radical activity were not affected by the compound. Our findings showed that this organochalcogen induces oxidative stress in human serum, indicating that this compound is potentially toxic to human beings.
Mol Cell Biochem 2009 Dec
PMID:Effect of in vitro exposure of human serum to 3-butyl-1-phenyl-2-(phenyltelluro)oct-en-1-one on oxidative stress. 1955 24

The effects of genetic, pre-harvest (season of harvest, spear diameter, spear portion and spear tip color) and post-harvest factors (storage and domestic preparation practices, e.g., peeling and cooking) on total phenolic, flavonoid and ascorbic acid content of white asparagus spears and their correlation with antioxidant capacity (DPPH and FRAP) were studied. Results showed that genetic material was important for the total phenolic content but not season of harvest, spear diameter or storage. Violet spear tips and apical spear portions showed the largest amount of total phenolics. Peeling did not affect total phenolics in fresh asparagus, whereas it reduced their content in stored asparagus, while cooking resulted in an increase in both fresh and stored asparagus. However, the soluble extract of total phenolics and flavonoids were minor and the missing significance of phenolics and flavonoids in antioxidant capacity of white asparagus spears depends on these small amounts.
Int J Mol Sci 2009 Dec 16
PMID:Effects of genetic, pre- and post-harvest factors on phenolic content and antioxidant capacity of white asparagus spears. 2005 75

Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, was obtained using acetone-water (1:1; v/v) as the mobile phase. Phenolic compounds present in the crude extract and its fractions demonstrated antioxidant and antiradical activities as revealed from studies using a beta-carotene-linoleate model system, the total antioxidant activity (TAA) method, the DPPH radical-scavenging activity assay, and a reducing power evaluation. Results of these assays showed the highest values when tannins (fraction 2) were tested. For instance, the TAA of the tannin fraction was 5.85 micromol Trolox eq./mg, whereas the crude extract and fraction 1 showed 0.68 and 0.33 micromol Trolox eq./mg, respectively. The content of total phenolics in fraction 2 was the highest (290 mg/g); the tannin content, determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g, was 129. There were 24 compounds identified in the crude extract using an HPLC-ESI-MS method: quercetin diglycoside, catechin, digallate procyanidin, and p-hydroxybenzoic were the dominant phenolics in the extract.
Int J Mol Sci 2009 Dec 23
PMID:Antioxidant activity of a red lentil extract and its fractions. 2005 84


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