Superoxide Anion Scavenging Effect of Coumarins

1996 ◽  
Vol 24 (01) ◽  
pp. 11-17 ◽  
Author(s):  
Wen-Shin Chang ◽  
Chun-Ching Lin ◽  
Shu-Chuan Chuang ◽  
Hsuch-Ching Chiang
Keyword(s):  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Superoxide Anion ◽  
Folk Medicine ◽  
Ortho Position ◽  
Scavenging Activity ◽  
Percent Inhibition ◽  
Scavenging Effect ◽  
Hydroxy Groups ◽  
Phenolic Hydroxy

The superoxide scavenging effects of fifteen coumarins were tested on the xanthine-xanthine oxidase-cytochrome C system. The results showed that fraxetin(10) displayed the strongest activity, and its percent inhibition at 100, 10 and 1 μM were 100, 100 and 53.13% respectively. Esculetin(4) showed the second strongest activity resulting in percent inhibition at 100 and 10 μM were 87.16 and 52.38% respectively. Both fraxetin(10) and esculetin(4) have been isolated from the plant, Fraxinus bungeana DC (Oleaceae) which has been used in folk medicine as an analgesic and anti-inflammatory medicine. It seems that two phenolic hydroxy groups in the ortho position in the molecule of coumarins play an important role in scavenging activity.

Researches on the Structure and Antioxidant Activity of Apigenin-La (III) Complex

2013 ◽  
Vol 781-784 ◽  
pp. 1138-1143
Author(s):  
Feng Qiu Wen ◽  
Lang Sheng Pan ◽  
Lei Lei
Keyword(s):  
Thermal Analysis ◽  
Antioxidant Activity ◽  
Free Radicals ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Superoxide Anion Radical ◽  
Scavenging Activity ◽  
Scavenging Effect ◽  
Pyrogallic Acid ◽  
Better Than

La (III) complex with apigenin was synthesized and characterized by UV, IR, 1HNMR and thermal analysis. The scavenging activity of the complex on superoxide anion radical (O2-·) and hdroxyl radical (·OH) was also investigated by improved pyrogallic acid way and ortho-oxybenzoic acid way. The results show that the complex had remarkable scavenging effects on O2-· and ·OH, and its scavenging effect on free radicals was better than apigenin.

Pterin-6-aldehyde, an Inhibitor of Xanthine Oxidase, Has Superoxide Anion Radical Scavenging Activity

1997 ◽  
Vol 233 (2) ◽  
pp. 447-450 ◽  
Author(s):  
Koji Watanabe ◽  
Toshiyuki Arai ◽  
Hiroko Mori ◽  
Shin-ichi Nakao ◽  
Toshinori Suzuki ◽  
...  
Keyword(s):  
Xanthine Oxidase ◽  
Superoxide Anion ◽  
Anion Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Superoxide Anion Radical ◽  
Scavenging Activity

In Vitro Studies on the Radical Scavenging Activity of Hulless Barley Pigment

2011 ◽  
Vol 183-185 ◽  
pp. 145-150 ◽  
Author(s):  
Tao Zhao ◽  
Hong Yang ◽  
Yong Feng Li ◽  
Jing Li Xu ◽  
Mao Qun Yu
Keyword(s):  
Superoxide Anion ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Antioxidant Vitamin ◽  
Scavenging Activity ◽  
Dpph Radical ◽  
Hulless Barley ◽  
Scavenging Effect ◽  
Test Concentration

In the present study, the in-vitro scavenging activities of hydroxyl, superoxide anion and DPPH radical of hulless barley pigment were studied. The results indicated that hulless barley pigment had excellent radical scavenging activity which was equivalent to the standard antioxidant, vitamin C. It was found that the radical scavenging effect of hulless barley pigment is gradually strengthened along with the increasing of concentration. In the range of test concentration, the maximum scavenging rate of the pigment to hydroxyl, superoxide anion and DPPH radical was 92.9%, 90.6% and 88.3% and the IC50was 4.2, 5.0 and 1.6 mg/L, respectively. Moreover, the scavenging velocity of hulless barley pigment was examined. It was observed that the radical scavenging activities of hulless barley pigment also increased with reaction time. These results suggested that colored hulless barley can be used for a new source of natural pigment with antioxidant activity.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

Chemical Constituents Isolated from Rhododendron ungernii with Antioxidant Profile

2019 ◽  
Vol 9 (3) ◽  
pp. 238-243 ◽  
Author(s):  
Emine Dede ◽  
Nusret Genc ◽  
Mahfuz Elmastas ◽  
Huseyin Aksit ◽  
Ramazan Erenler
Keyword(s):  
Antioxidant Activities ◽  
Biological Activities ◽  
Chemical Constituents ◽  
Reducing Power ◽  
Scavenging Activity ◽  
Isolation And Identification ◽  
Reduced Pressure ◽  
Scavenging Effect ◽  
Pharmaceutical Industries ◽  
Dpph Scavenging

Background: Plant in Rhododendron genus that contains phenolic compounds has been used in traditional medicine and revealed considerable biological activities. Objective: Isolation and identification of antioxidant natural products from Rhododendron ungernii. Methods: Rhododendron ungernii Trautv. flowers were collected and dried in shade. The dried flowers were extracted with methanol for 3 days. The solvent was removed by reduced pressure to yield the extract which was subjected to column chromatography (Sephadex LH-20, C18 reversed phase column) to isolate catechin-7-O-glucoside (1), quercetin-3-O-β-galactoside (2), quercetin-3-O- β-xyloside (3), farrerol (4), myricetin (5), and quercetin (6). The structures of isolated compounds were elucidated by spectroscopic methods such as 1D-NMR, 2D-NMR, and LC-TOF/MS. DPPH scavenging effect, ABTS+ scavenging activity, and reducing power (FRAP) were performed for antioxidant assays of isolated natural compounds. Results: Isolated flavonoids displayed the outstanding antioxidant activities. Catechin-7-O-glucoside (1) and quercetin-3-O-β-galactoside (2) (IC50, 3.66 µg/mL) had the most DPPH• scavenging effect among the compounds. The highest ABTS•+ scavenging activity (IC50, 1.41 µg/mL) and reducing power effect (6.05 mmol TE/g comp) were observed for myricetin (5). Conclusion: R. ungernii extract and isolated compounds could be a promising antioxidant for food and pharmaceutical industries.

Candida antarctica lipase B-catalyzed regioselective deacylation of dihydroxybenzenes acylated at both phenolic hydroxy groups

2016 ◽  
Vol 94 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Toshifumi Miyazawa ◽  
Manabu Hamada ◽  
Ryohei Morimoto
Keyword(s):  
Candida Antarctica ◽  
Candida Antarctica Lipase B ◽  
Candida Antarctica Lipase ◽  
Primary Alcohols ◽  
Lipase B ◽  
Highly Active ◽  
Direct Acylation ◽  
Acyl Acceptors ◽  
Hydroxy Groups ◽  
Phenolic Hydroxy

Candida antarctica lipase B proved to be highly active in the deacylation of substituted hydroquinones and resorcinols acylated at both phenolic hydroxy groups. The deacylation reactions were much faster than the corresponding direct acylations of these dihydroxybenzenes catalyzed by the same lipase. More importantly, they took place generally in a markedly regioselective manner: the acyloxy group remote from the substituent was preferentially cleaved. The main or exclusive products obtained were the regioisomers of those produced through the direct acylation of the dihydroxybenzenes. In the case of alkyl-substituted hydroquinone derivatives, the regioselectivity increased with an increase in the bulk of the substituent. In the case of 4-substituted diacylated resorcinols, the 3-O-monoacyl derivatives were obtained generally as the sole products. Quite interestingly, some secondary alcohols proved to act as better acyl acceptors than the corresponding primary alcohols in these enzymatic deacylations.

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