Reducing power: the measure of antioxidant activities of reductant compounds?

Cheng, Zhiyong; Li, Yuanzong

doi:10.1179/135100004225005994

Cited by 24 publications

(17 citation statements)

References 34 publications

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“…As it is known from the literature, caffeic acid has a higher antioxidant capacity as compared to cinnamic and coumaric acids. This behaviour is also observed in Fig.…”

Section: Resultsmentioning

confidence: 96%

Antioxidising activity of cinnamic acid derivatives against oxidative stress induced by oxidising radicals

Santos¹,

Vieira

2013

J. Phys. Org. Chem.

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Cinnamic acid and its derivatives react with hydroxyl radical (HO ), in neutral medium, to give hydroxylation products, whether on the benzene ring or on the exocyclic chain, and decarboxylation products. The latter compounds are also obtained after oxidation of the same substrates by the SO 4 À radical anion. Evidence was provided for the protecting effects afforded by cinnamic acid and hydroxylated derivatives against oxidative reaction mediated by HO . By using adenine as a model compound, the results obtained suggest that the high protective effect is due to an antioxidising cascade process.

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“…As it is known from the literature, caffeic acid has a higher antioxidant capacity as compared to cinnamic and coumaric acids. This behaviour is also observed in Fig.…”

Section: Resultsmentioning

confidence: 96%

Antioxidising activity of cinnamic acid derivatives against oxidative stress induced by oxidising radicals

Santos¹,

Vieira

2013

J. Phys. Org. Chem.

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“…Furthermore, the antioxidant capacity of the studied extracts was evaluated in terms of reducing power using CUPRAC and FRAP assays. Several factors governed the reducing potential of antioxidants, namely their ionization potentials, spin distribution of the radical cations and the bond dissociation energy of the phenolic O-H bond [36]. With CUPRAC assay, 1 g of methanolic twig extract exhibited a remarkably high Trolox equivalent value (1336.88 mg TE) followed by aqueous twig (1082.00 mg TE).…”

Section: Resultsmentioning

confidence: 99%

Untargeted Metabolomic Profiling, Multivariate Analysis and Biological Evaluation of the True Mangrove (Rhizophora mucronata Lam.)

et al. 2019

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Currently, there is a renewed interest towards the development of plant-based pharmacophores. In this work, 16 extracts prepared from the leaves, twigs, roots and fruits of a hydro-halophyte, Rhizophora mucronata Lam. (Family: Rhizophoraceae), were studied for possible antioxidant activity and the phenolic profiles established. Thereafter, enzymatic inhibitory activities (α-amylase, α-glucosidase, tyrosinase, acetyl- (AChE), butyrylcholinesterase (BChE), lipase, and elastase) were assessed. The total phenolic, flavonoid, phenolic acid, tannin, flavanol and triterpenoid content were estimated using standard assays. An untargeted metabolomics-based approach, based on ultra-high-pressure liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-QTOF-MS) followed by multivariate statistics, was then used to comprehensively profile and describe the phenolics present. UHPLC-QTOF-MS allowed for putatively annotating 104 phenolic acids, 103 flavonols, 94 flavones, 71 anthocyanins, 66 tyrosols, 29 lignans, 15 alkylphenols and 10 stilbenes in the extracts. Nine strains (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Methicillin-resistant Staphylococcus aureus (MRSA), Salmonella enteritidis, Sarcina lutea, Proteus mirabilis, Bacillus cereus and Candida albicans) were then used to investigate the antimicrobial properties. The methanolic twig extract exhibited significant reducing potential towards Cu (II)/Cu (I) and Fe (III)/Fe (II) (1336.88 ± 15.70 and 710.18 ± 21.04 mg TE/g, respectively) and was the most potent DPPH radical scavenger (807.07 ± 6.83 mg TE/g). Additionally, the methanolic twig extract showed significant inhibition against most targeted enzymes. Anti-microbial results showed that all extracts were active against MRSA. Multivariate analysis demonstrated that the phenolic profile of ethyl acetate extracts and leaves were the two most discriminative parameters in terms of solvents and organs, respectively. The present findings indicated that R. mucronata may be further explored for the management/prevention of oxidative stress, neurodegenerative complications and hyperpigmentation.

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“…The MICs increased 2.5-fold (from 8 g/ml to 20 g/ml) in the presence of ascorbic acid and Ͼ30-fold (from 8 g/ml to Ͼ250 g/ml) in the presence of glutathione, compared to that of the controls ( Table 2), suggesting that the protective effect against streptomycin is more pronounced with glutathione than with ascorbic acid. The enhanced protective effect seen with glutathione might be due to the dependence of the protective ability of the given antioxidant on its reducing power (6) or to the contribution of glutathione metabolism proteins involved in detoxification pathways in prokaryotes (23). We also investigated whether this antioxidant-mediated protection phenomenon is specific to MG1655 or whether it can be seen across diverse E. coli K-12 strains.…”

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confidence: 99%

Effects of Glutathione and Ascorbic Acid on Streptomycin Sensitivity of Escherichia coli

Goswami

Mangoli

Jawali

2007

Antimicrob Agents Chemother

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We examined the effects of antioxidants and the role of reactive oxygen species (ROS) on the antibacterial action of aminoglycosides in Escherichia coli. We concluded that reduced streptomycin sensitivity in the presence of glutathione and ascorbic acid is not due to the antioxidant-mediated scavenging of ROS.Aminoglycosides like streptomycin, gentamicin, etc., are highly potent, broad-spectrum antibiotics (15), crucial for the treatment of various infections and prophylaxes in special situations. The mechanism of antibacterial action of aminoglycosides is not completely understood. However, it has been established that these antibiotics act primarily by impairing bacterial protein synthesis through binding to the 30S ribosomal subunit (5,9,15).Recent studies have shown that some antibiotics stimulate the induction of reactive oxygen species (ROS) in different bacterial species (1, 2). Redox cycling of some of the antibiotics affects the formation of ROS during the oxidation process (4). We have recently established the involvement of ROS in the antibacterial action of ciprofloxacin (13). Since two of the major side effects of the aminoglycosides, ototoxicity and nephrotoxicity, are believed to be mediated through ROS (15), the role of ROS in their antibacterial actions is worth investigating.The aim of the present study was to investigate whether antioxidants alter the aminoglycoside sensitivity of E. coli and, if they do, to further identify the role of ROS in the antibacterial action of aminoglycosides. This was undertaken by supplementing the growth medium with antioxidants and by introducing mutations in genes whose products are known to reduce the steady-state level of ROS in the cell, namely, Mnsuperoxide dismutase (sodA), catalases (katE and katG), and alkylhydroperoxide reductase (ahpCF). The effects of multicopy sod genes on streptomycin sensitivity were also examined, and the changes in ROS levels in the presence of these antibiotics were measured using the nitroblue tetrazolium (NBT) reduction method.The bacterial strains and plasmids used in this study are listed in Table 1. The preparation and handling of the antioxidant solutions, microbial-culture growth conditions, and antibiotic susceptibility-testing methods were essentially the same as those previously described by Goswami et al. (13).The effects of antioxidants on the streptomycin sensitivity of E. coli strain MG1655 were analyzed by the antibiotic disk diffusion method. Reduction in the zone of inhibition around the antibiotic disk indicated that the presence of 10 mM glutathione or ascorbic acid in the growth medium reduced the sensitivity of MG1655 cells to streptomycin (Fig. 1). However, other antioxidants, such as histidine and mannitol, which act as specific scavengers for singlet oxygen ( 1 O 2 ) and hydroxyl radicals ( ⅐ OH), respectively, did not alter the streptomycin sensitivity, even at 25 mM concentrations (data not shown), suggesting that 1 O 2 and ⅐ OH are not involved in the antibacterial action of streptomycin. In order to q...

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Reducing power: the measure of antioxidant activities of reductant compounds?

Cited by 24 publications

References 34 publications

Antioxidising activity of cinnamic acid derivatives against oxidative stress induced by oxidising radicals

Antioxidising activity of cinnamic acid derivatives against oxidative stress induced by oxidising radicals

Untargeted Metabolomic Profiling, Multivariate Analysis and Biological Evaluation of the True Mangrove (Rhizophora mucronata Lam.)

Effects of Glutathione and Ascorbic Acid on Streptomycin Sensitivity of Escherichia coli

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