2-2--azino-di-(3-ethylbenzothiazoline)-6-sulfonic-acid and ferulic-acid

Ferulic acid (FA) is an effective chemopreventive and therapeutic agent for colorectal cancer. However, FA cannot stably reach the colon through human digestive system, and it can be grafted into oligosaccharides to improve its digestion stability. Therefore, in this study, different degrees of substitution of feruloylated oat β-glucan (FA-OβG) were prepared by grafting FA onto water soluble oat β-glucan. FA grafting changed the crystallinity and surface morphology of OβG, and the thermal stability of the FA-OβG improved. As the DS increased, the antioxidant activity of FA-OβG increased, and FA-OβG III with DS of 0.184 showed the same antioxidant activities compared to the equal amount of free FA. The FA-OβG showed higher stability under gastrointestinal and colonic conditions than free FA. Furthermore, the FA-OβG conjugates exhibited good in vitro anticancer activity against human colorectal cancer cells, while FA-OβG III showed better anticancer activity than an equal amount of free FA.

Topics: Adult; Antineoplastic Agents, Phytogenic; Antioxidants; Benzothiazoles; beta-Glucans; Biphenyl Compounds; Cell Proliferation; Colon; Coumaric Acids; Feces; Female; Fermentation; Gastric Juice; HCT116 Cells; Humans; Intestinal Secretions; Male; Picrates; Sulfonic Acids; Surface Properties; Young Adult

Topics: Anions; Antioxidants; Arabinose; Benzothiazoles; Biological Availability; Biphenyl Compounds; Cations; Coumaric Acids; Dietary Fiber; Flavonoids; Fruit; Galactose; Glucose; Hydroxybenzoates; Mannose; Micronutrients; Minerals; Opuntia; Pectins; Picrates; Plant Mucilage; Polyphenols; Polysaccharides; Rhamnose; Sulfonic Acids; Xylose

Carnosine (CAR) dipeptide was functionalized with ferulic acid (FA) as substrate using laccase from Myceliophtora thermophila as biocatalyst. The enzymatic reaction was performed in aqueous medium under mild conditions (pH 7.5, 30°C) as an eco-friendly procedure. Results showed that this enzymatic process led to the synthesis of two new derivatives (P1, P2), from the coupling between CAR and FA derived products. Conditions allowing a high production of P1, P2 derivatives were determined with an optimal ratio of (FA: CAR) of (1:1.6) at optimal time reaction of 8h. Under these optimal conditions, the coupling between CAR and FA-products was demonstrated, resulting in the decrease of -NH2 groups (almost 50%) as quantified via derivatization. Due to the presence of FA in the structure of these new derivatives, they exhibited higher hydrophobic property than carnosine. Structural analyses by mass spectrometry showed that P1 and P2 (FA-CAR) derivatives exhibited the same molecular mass (MM 770g/mol) containing one CAR-molecule and three FA-molecules but with different chemical structures. Furthermore, these derivatives presented improved antioxidant (almost 10 times) and anti-proliferative (almost 18 times) properties in comparison with CAR. Moreover, P1 derivative exhibited higher antioxidant and anti-proliferative activities than P2 derivative, which confirmed the different structures of P1 and P2. These results suggested that the oxidized phenols coupling with carnosine is a promising process to enhance the CAR-properties.

Topics: Benzothiazoles; Biocatalysis; Caco-2 Cells; Carnosine; Cell Proliferation; Chromatography, High Pressure Liquid; Coumaric Acids; Humans; Inhibitory Concentration 50; Kinetics; Laccase; Mass Spectrometry; Oxidation-Reduction; Peptides; Solubility; Spectrophotometry, Ultraviolet; Sulfonic Acids; Time Factors

Essential oils have played a prominent role in research on natural products, due to the high level of bioactive constituents, which include those derived from phenylpropanoids or terpenoids. This study aimed to evaluate the antioxidant capacity of isopentyl ferulate (IF) employing in vitro experimental models for elimination of the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS+), hydroxyl (OH) and nitric oxide (NO), as well as its capacity to electron transfer by reducing potential and inhibition of lipid peroxidation by TBARS (thiobarbituric acid reactive substances) method. In all in vitro antioxidants protocols, isopentyl ferulate showed to be potent in a concentration of 54.4 nM, presenting a percentage inhibition of 91.29±0.57, 92.63±0.28, 83.62±0.18, 77.07±0.72 and 79.51±0.32% for DPPH, ABTS+, hydroxyl, nitric oxide and TBARS level, respectively. The increase of absorbance at 700 nm in the concentrations of 3.4, 6.8, 13.6, 27.2 and 54.4 nM shows the reducing potential of IF. Similar results were obtained with Trolox (559 nM), a hydrophilic synthetic analogue of α-tocopherol, which is widely used as a standard antioxidant. The present study demonstrated that isopentyl ferulate has an antioxidant activity in vitro experimental models, suggesting that this compound could enhance the development of a new product with antioxidant properties. However, further in vivo studies are needed to assign possible implications in the treatment of diseases related with free radicals.

Topics: Benzothiazoles; Biphenyl Compounds; Coumaric Acids; Free Radical Scavengers; Hydroxyl Radical; Nitric Oxide; Oxidation-Reduction; Picrates; Sulfonic Acids; Thiobarbituric Acid Reactive Substances

Black rice bran contains phenolic compounds of a high antioxidant activity. In this study, the 40% acetone extract of black rice bran was sequentially fractionated to obtain 5 fractions. Out of the 5 fractions, ethyl acetate fraction was subfractionated using the Sephadex LH-20 chromatography. The antioxidant activity of phenolic compounds in the extracts was investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical assay, 2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulfonic acid) (ABTS) radical cation assay, reducing power. The subfraction 2 from ethyl acetate fraction had the highest total phenolic contents (TPC) (816.0 μg/mg) and the lowest EC50 values (47.8 μg/mL for DPPH radical assay, 112.8 μg/mL for ABTS radical cation assay, and 49.2 μg/mL for reducing power). These results were 3.1, 1.3, and 2.6 times lower than those of butylated hydroxytoluene (BHT), respectively. At a concentration of 100 μg/mL, the antioxidant activity and TPC of various extracts was closely correlated, with correlation coefficients (R(2) ) higher than 0.86. The major phenolic acid in subfraction 2 was identified as ferulic acid (178.3 μg/mg) by HPLC and LC-ESI/MS/MS analyses. Our finding identified ferulic acid as a major phenolic compound in black rice bran, and supports the potential use of black rice bran as a natural source of antioxidant.

Topics: Antioxidants; Benzothiazoles; Biphenyl Compounds; Chromatography; Chromatography, High Pressure Liquid; Coumaric Acids; Dextrans; Hydroxybenzoates; Indicators and Reagents; Oryza; Phenols; Picrates; Plant Extracts; Sulfonic Acids; Tandem Mass Spectrometry

A comparative analysis of ethanol extracts from peel, pulp and seed of Prunus persica var. platycarpa (Tabacchiera peach) was done. The total phenol, flavonoid and carotenoid content as well as the antioxidant properties by using different in vitro assays (DPPH, ABTS, FRAP, Fe-chelating, β-carotene bleaching test) were evaluated. Pulp extract was subjected to liquid chromatography-electrospray-tandem mass spectrometry (HPLC-ESI-MS/MS). Gallic acid, protocatechuic acid, protocatechualdehyde, chlorogenic acid, p-coumaric acid, and ferulic acid were identified as main constituents. Pulp extract was characterized by the highest total phytonutrients content and exhibited the highest antioxidant activity in all in vitro assays (IC(50) values of 2.2 μg/mL after 60 min of incubation by using β-carotene bleaching test and 2.9 μg/mL by using Fe-chelating assay). Overall, the obtained results suggest that P. persica var. platycarpa displays a good antioxidant activity and its consumption could be promoted.

Topics: Antioxidants; Benzaldehydes; Benzothiazoles; beta Carotene; Biphenyl Compounds; Catechols; Chlorogenic Acid; Chromatography, High Pressure Liquid; Coumaric Acids; Fruit; Gallic Acid; Humans; Hydroxybenzoates; Oxidation-Reduction; Picrates; Plant Extracts; Propionates; Prunus persica; Seeds; Species Specificity; Sulfonic Acids; Tandem Mass Spectrometry

Rhizoma Atractylodes macrocephala (AM) has been used in Traditional Chinese Medicine (TCM) for about 2,000 years. In the study, we firstly determined the antioxidant levels of five AM extracts by •OH-scavenging, •O2−-scavenging, Fe2+-chelating, Cu2+-chelating, DPPH·-scavenging, and ABTS+·-scavenging assays. After measurement of the chemical contents in five AM extracts, we quantitatively analyzed the correlations between antioxidant levels and chemical contents. It was observed that total phenolics and total flavonoids had significant positive correlations with antioxidant levels (R = 0.685 and 0.479, respectively). In contrast, total sugars and total saponins presented lower correlations with antioxidant levels (R=−0.272 and 0.244, respectively). It means that antioxidant activity of AM should be attributed to total phenolics (including phenolic acids and flavonoids), and not total sugars and total saponins. Further analysis indicated that phenolic acids exhibited higher R values with radical-scavenging assays (R=0.32–1.00), while flavonoids showed higher R values with metal-chelating assays (R=0.86 and 0.90). In conclusion, AM exerts its antioxidant effect through metal-chelating, and radical-scavenging which is via donating hydrogen atom and donating electron. Its metal-chelating may result from flavonoids, while its radical-scavenging can be attributed to phenolic acids, especially caffeic acid, ferulic acid, and protocatechuic acid.

Topics: Atractylodes; Benzothiazoles; Biphenyl Compounds; Caffeic Acids; Copper; Coumaric Acids; Drugs, Chinese Herbal; Flavonoids; Free Radical Scavengers; Hydroxybenzoates; Hydroxyl Radical; Iron; Liquid-Liquid Extraction; Oxidants; Picrates; Rhizome; Sulfonic Acids; Superoxides

The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigöl) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigöl ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH(•), ABTS(•+), DMPD(•+), and O(•-)(2) radical scavenging activities, H(2)O(2) scavenging activity, ferric (Fe(3+)) and cupric ions (Cu(2+)) reducing abilities, ferrous ions (Fe(2+)) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α-tocopherol, pyrogallol, p-hydroxybenzoic acid, vanillin, p-coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high-performance liquid chromatography and tandem mass spectrometry (LC-MS-MS). The results clearly show that p-coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.

Topics: Antioxidants; Ascorbic Acid; Benzaldehydes; Benzothiazoles; Chromatography, High Pressure Liquid; Coumaric Acids; Ecotype; Ellagic Acid; Fruit; Gallic Acid; Hydrogen Peroxide; Hydroxybenzoates; Plant Extracts; Polyphenols; Propionates; Pyrogallol; Rosaceae; Sulfonic Acids; Tandem Mass Spectrometry

Dietary polyphenols are beneficial to human health by exerting various biological effects. Ferulic and caffeic acids are hydroxycinnamic acid derivatives widely distributed in plant-derived food products. Studies indicate that some dietary compounds may have concentration-dependent antioxidant or prooxidant activities. The present study concerns such activities of ferulic and caffeic acids. They have concentration-dependent antioxidant effects in terms of inhibition of lipid peroxidation and reactive oxygen species-scavenging after 2,2'-azobis-amidinopropane dihydrochloride-induced damage in mouse liver microsomes and splenic lymphocytes respectively. They also show differential scavenging of nitric oxide, superoxide and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid radical (ABTS*(+)). In DPPH (1,1-diphenyl picrylhydrazyl) assay above 20 μM the absorbance start increasing due to the formation of an unknown adduct which has a shoulder at 517 nm. However, in Fenton reaction, above 5 μM, they behave as prooxidants and the possible mechanisms responsible for their prooxidant property may be related to their ferric reducing ability. These findings may have significant health implications where these natural compounds are being used/consumed.

Topics: Amidines; Animals; Antioxidants; Benzothiazoles; Biphenyl Compounds; Caffeic Acids; Coumaric Acids; Ferric Compounds; Free Radical Scavengers; Hydroxyl Radical; In Vitro Techniques; Lipid Peroxidation; Male; Mice; Microsomes, Liver; Nitric Oxide; Oxidants; Picrates; Reducing Agents; Sulfonic Acids; Superoxides

Pale malts were prepared using standard and rapid kilning regimes that differed in the temperature and moisture profiles in the kiln. Samples were taken over the last 9 h of kilning, that is, at 18, 20, 22, 25, and 27 h. Antioxidant activity, assessed by redox potential, scavenging of the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS*+), and ferric reducing/antioxidant power (FRAP), increased at moisture levels below 6.7% for both regimes. The 27 h malt exposed to the rapid regime (moisture content of 4.8%) had a higher activity than the 27 h standard regime sample (moisture content of 4.8%). None of the malts scavenged oxygen. Pro-oxidant activity profiles were different for the malts obtained using each regime and, at 27 h, the rapid procedure gave malt with higher activity. Levels of (+)-catechin and ferulic acid (the most abundant phenolic compounds identified) generally increased as the moisture content of malt fell below 6.7%. Differences in antioxidant and pro-oxidant activities of the 27 h malts are partly attributed to the Maillard reaction, as evidenced by lower L* and higher b* values and higher levels of Maillard-derived flavor compounds, in the sample obtained by the rapid procedure. Levels of lipid-derived flavor compounds were significantly higher after 27 h of kilning using the rapid procedure.

Topics: Antioxidants; Benzothiazoles; Catechin; Chromatography, High Pressure Liquid; Coumaric Acids; Desiccation; Edible Grain; Flavonoids; Free Radical Scavengers; Hot Temperature; Maillard Reaction; Oxidants; Oxidation-Reduction; Phenols; Plant Extracts; Polymers; Sulfonic Acids; Time Factors

The optimal conditions for catalysis by the peroxidase isolated from leaves of African oil palm tree (AOPTP) have been determined. The pH optimum for oxidation of the majority of substrates studied in the presence of AOPTP is in the interval of 4.5-5.5. A feature of AOPTP is low pH value (3.0) at which the peroxidase shows its maximal activity toward 2,2;-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS). Increasing the buffer concentration changes the AOPTP activity, the degree of the effect depending upon the chemical structure of the substrate. Under optimal conditions of AOPTP catalysis, the values of second order rate constant characterizing efficiency of enzymatic oxidation of substrates have been calculated. It was shown that among 12 peroxidase substrates studied, ABTS and ferulic acid are the best substrates for AOPTP. The results show that substrate specificities of AOPTP and royal palm tree peroxidase are similar, but different from substrate specificity of other plant peroxidases.

Topics: Arecaceae; Benzothiazoles; Buffers; Catalysis; Coumaric Acids; Hydrogen-Ion Concentration; Kinetics; Oxidation-Reduction; Peroxidase; Substrate Specificity; Sulfonic Acids; Trees

Steady-state and transient-state analysis of Coprinus cinereus peroxidase, CIP (identical to Arthromyces ramosus peroxidase), was used to characterize the kinetics of the three fundamental steps in heme peroxidase catalysis: compound I (cpd I) formation, cpd I reduction, and compound II (cpd II) reduction. The rate constant k1 for cpd I formation determined by transient-state analysis is (9.9 +/- 0.6) x 10(6) M-1 s-1. The k1 determined by steady-state analysis is (8.8 +/- 0.6) x 10(6) M-1 s-1 in the presence of ferulic acid and (6.7 +/- 0.2) x 10(6) M-1 s-1 in the presence of ABTS. The value of k1 is constant from pH 6 to 11. However, at low pH the value of k1 decreases, corresponding to titration of an enzyme group with a pKa of 5.0. Titration of this group is also detected from cyanide-binding kinetics. Furthermore, titration of this group is linked with marked spectroscopic changes unique to CIP. We ascribe these changes to protonation of proximal His183. A very low pKa is proposed for distal His55 in the resting state of CIP. The rate constants, k2 for cpd I and k3 for cpd II reduction, are very large for both ferulic acid and 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS). For ferulic acid, transient-state kinetic analysis shows that the values of k2 and k3 are identical at pH 5-6, and the ratio k2/k3 increases to 10 at pH 10. The similar magnitude of k2 and k3 is unusual for a peroxidase. Both k2 and k3 decrease with increasing pH, and both are influenced by two ionizations: one with a pKa value near 7, assumed to reflect the protonation of His55; and the other with pKa of 9.0 +/- 0.7 for k2 and 8.8 +/- 0.4 for k3, perhaps reflecting the phenol-linked deprotonation of ferulic acid. Steady-state analysis at pH 7.0 gave k2k3/(k2 + k3) = (2.2 +/- 0.1) x 10(7) M-1 s-1 for ferulic acid, and (2.0 +/- 0.7) x 10(7) M-1 s-1 for ABTS and revealed a unimolecular step with ku = 1500 s-1, ascribed to slow ABTS radical product release. From transient-state results at pH 7, the values of k2 and k3 were found to be identical also for ABTS. A mechanism for cpd I and II reduction involving distal histidine and arginine is proposed.

Topics: Benzothiazoles; Coprinus; Coumaric Acids; Hydrogen Peroxide; Hydrogen-Ion Concentration; Kinetics; Peroxidase; Sulfonic Acids