Antioxidant Activity Evaluation in a Series of Heterocyclic Compounds Derived from 1,8-Diaminonaphthalene

From (2,3-dihydro-1H-perimidin-2-yl)-phenyl, the substitution of OH group in ortho or para position on the phenyl ring, allows us to synthesize the studied compounds. These three compounds have been characterized by conventional spectroscopic methods (NMR and MS). The interest of this work is to review the antioxidant activity of our compounds. The antioxidant activity screening carried out according to FRAP and DPPH methods revealed significant anti-free radical properties for compounds 1 and 2 even at low concentrations. In contrast to the compound 2, compound 3 for which the OH group is substituted in para position has the lowest activity in both cases. Therefore the para position seems to be the least sensitive position to increase the antioxidant activity of this pharmacophore.

In vitro antioxidant activities of ethanol extract from Enhalus acoroides (L.F.) Royle

Objective:To search for new sources of safe and inexpensive antioxidants,the leaf,root and rhizome of Enhalus acoroides(E.acoroides) were screened for the first time for their antioxidant activities.Methods:Samples of leaf,root and rhizome from E.acoroides were tested for total phenolic content,proanthocyanidins and in vitro antioxidant activity in terms of total antioxidant assay,DPPH assay and FRAP assay.Results:The leaf sample was found to have high levels of phenolic(0.323±0.028 mg TAE/g) and proanthocyanidins(0.570 0±0.000 3 mg TAE/g) when compared to root and rhizome.The leaf samples exhibited higher total antioxidant activity (11.770±0.026 mg Ascorbic acid equivalent/g),higher percentage of DPPH radical scavenging activity(25.76±0.04) and higher reducing power(18.060±0.073) in terms of mg GAE/g.In addition, there was a significant correlation between total phenolic content and total antioxidant activity (R^2=0.923),DPPH assay(R^2=0.509).FRAP assay(R^2=0.994).Similarly,significant correlation was found between the proanthocyanidin and total antioxidant activity(R^2=0.977),DPPH assay (R^2=0.464) and the FRAP assay(R^2=0.998).Conclusions:These results suggested that E.acoroides have strong antioxidant potential.Further study is necessary for isolation and characterization of the active antioxidant agents,which can be used to treat various oxidative stress-related diseases.

A Comparative Study of Antioxidant Activities between Fresh and Dry Mushrooms in the Genera <i>Cantharellus</i>and <i>Afrocantharellus</i>from Tanzania

Cantharellus and Afrocantharellus mushrooms are widely consumed in both fresh and dry forms. However, their antioxidant and whether their values changing with drying processes are not known. This study establishes their values and the effect of sun drying on their quality and quantity. Methanolic extracts of five Cantharellus and two Afrocantharellus species were investigated. The investigation used (1,1-diphenyl-2-picrylhydrazyl radical) DPPH as a substrate to determine radical scavenging abilities. Further quantitative analyses for carotenoids, flavonoid, total phenolic compounds and vitamin C content were done using spectrophotometric assay at 515 nm. Comparatively, fresh mushroom had higher vitamin C and Lycopene contents than their dry counterparts with β-carotene. Flavonoid and phenolic compounds were higher in dry forms than those in their fresh counterparts. Radical scavenging ability also varied with fresh forms depicting higher activity compared to dry forms. The variation was low in Afrocantharellus species (0.8% and 0.99%) while it was higher in Cantharellus species (24.12% and 7.52%). The highest ability was observed in fresh forms of Cantharellus pseudocibarius (EC50 50 = 0.4 mg/ml) was from dry form of Cantharellus rufopunctatus. This shows that studied mushrooms are rich in antioxidants and their quality and quantities are affected differently in both forms. Both dry and fresh mushrooms are potential sources of natural antioxidants. The portrayed high scavenging ability by these mushrooms envisages promoting them into potential nutraceutics.

The Application of Novel Electrochemical Approach to Antioxidant Activity Assay of Metal Porphyrins with Bulky 3,5-Diisobornyl-4-hydroxyphenyl Moieties

The complexes of biogenic metals (Zn2+,Cu2+,Co2+,Mn3+,Fe3+) based on meso-tetra(3,5-diisobor- nyl-4-hydroxyphenyl)porphyrin 1 were synthesized. The electrochemical behavior of these com-pounds was studied using cyclic voltammetry (CV) and rotating disk electrode (RDE) techniques. The antioxidant activity of complexes was estimated by means of the electrochemical assay based on the hydrogen atom transfer reaction to the stable radical 2,2’-diphenyl-1-picrylhydrazyl (DPPH). The RDE method was applied for this process monitoring. It was shown that the efficiency of the metal complexes (Cu2+,Co2+,Mn2+,Ni2+,Fe3+) is practically the same order as that of free base porphyrin 1. However the Zn2+ complex demonstrates significantly higher antioxidant activity, and the stoichiometry of the reaction was determined as σ = 4. The results demonstrate that porphyrin macrocycle can directly affect the antioxidant properties of 2,6-diisobornylphenol.

Evaluation of in vitro antioxidant, antiglycation and antimicrobial potential of indigenous Myanmar medicinal plants

Objective： Myanmar has a long history of using medicinal plants for treatment of various diseases. To the best of our knowledge there are no previous reports on antiglycation activities of medicinal plants from Myanmar. Therefore, this study was aimed to evaluate the antioxidant, antiglycation and antimicrobial properties of 20 ethanolic extracts from 17 medicinal plants indigenous to Myanmar. Methods： In vitro scavenging assays of 2,2-diphenyl-l-picrylhydrazyl （DPPH）, nitric oxide （NO）, superoxide （SO） radicals were used to determine the antioxidant activities. Folin-Ciocalteu＇s method was performed to determine the total phenolic content. Antiglycation and antimicrobial activities were detected by bovine serum albumin-fluorescent assay and agar well diffusion method. Results： Terminalia cbebula Retz. （Fruit）, containing the highest total phenolic content, showed high antioxidant activities with inhibition of 77.98% ± 0.92% 88.95% ± 2.42%, 88.56% ±1.87% and 70.74% ±2.57% for DPPH, NO, SO assays and antiglycation activity respectively. It also showed the antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coil, Pseudomonas aeruginosa and Candida albicans with inhibition zone of 19, 18, 17, 25 and 15 ram, respectively. Garcinia mangostana Linn. showed the strongest activities for SO and antiglycation assays with inhibition of 93.68% ± 2.63% and 82.37%± 1.78%. Bark of Melia sp. was the best NO radical scavenger with inhibition rate of 89.39%± 0.60%. Conclusion： The results suggest that these plants are potential sources of antioxidants with free radical-scavenging and antiglycation activities and could be useful for decreasing the oxidative stress and glycation end-product formation in glycation-related diseases.

后发酵过程中乙醇对豆豉抗氧化能力的影响

以黄豆为原材料,接种米曲霉制作豆豉,在豆豉后发酵过程中设定了不同乙醇添加量,测定了不同乙醇添加量的豆豉样品清除DPPH(2,2-diphenyl-1-picrylhydrazyl hydrate)及ABTS[2,2-’azinobis-(3-ethylbenzthia-zoline-6-sulfonic acid)]自由基能力、Fe2+螯合能力、还原能力,评价了乙醇对豆豉抗氧化能力的影响。后发酵过程中,豆豉的抗氧化能力持续增大,醇对豆豉的抗氧化能力有影响,发酵相同时间的豆豉,抗氧化能力随乙醇含量的增大而下降。

In vitro anti oxidant activity and acute oral toxicity of Terminalia paniculata bark ethanolic extract on Sprague Dawley rats

Objective:To ensure the safety and evaluate the anti oxidant activity of Terminalia paniculata(T.paniculata)ethanolic extract in Sprague Dawley rats.Methods:The solvent extracts(hexane,ethyl acetate and ethanol)of T.paniculata were subjected to phytochemical analysis and their DPPH radical scavenging activity was assayed.The oral acute toxicity was evaluated using ethanolic extract of T.paniculata.Results:Ethyl acetate and elhanolic extracts showed more phytochemicals,whereas highest DPPH scavenging activity was found in ethanolic extract.In an acute toxicity study,T.paniculata ethanolic extract was orally administered(1000 mg/kg body weight)to rats and observed for72 h for any toxic symptoms and the dose was continued up to 14 d.On the 15th day rats were sacrificed and blood samples were collected from control and test animals and analyzed for some biochemical parameters.We did not observe any behavioral changes in test groups in comparison with their controls.Also,there were no significant alterations in biochemical,hematological(hemoglobin content and blood cells count)and liver function parameters such as serum glutamate pyruvate transaminase,serum glutamate oxaloacetate transaminase,alkaline phosphatase,total proteins,albumin and bilirubin levels between T.paniculata ethanolic extract treated and normal control groups.Conclusions:Together our results demonstrated that T.paniculala ethanolic possessed potent antioxidant activity and it was safer and non toxic to rats even at higher doses and therefore could be well considered for further investigation for its medicinal and therapeutic efficacy.

Targeting biosignatures of hyperglycemia and oxidative stress in diabetes comorbid depressive rats: effectiveness of hydroethanolic extract of the whole plant of Ludwigia octovalvis

Background:The prime objective of the current research was to evaluate the whole plant hydroalcoholic extract of Ludwigia octovalvis(HLO)against hyperglycemia,and oxidative stress biomarkers in rats induced with diabetes comorbid depression,diabetes comorbid depression(streptozotocin-nicotinamide+electric footshocks).Methods:2,2-Diphenyl-1-picrylhydrazyl assay of HLO versus ascorbic acid was done.Effects of 200 and 400 mg/kg body weight/day HLO doses versus 25 mg/kg body weight/day metformin was studied through insulin,glucose,superoxide dismutase,lipid peroxidation,catalase,and behavioral assessment(forced swim and open field tests).Results:IC50 values of HLO and ascorbic acid were 33.52 and 27.86μg/mL respectively.Both the HLO doses showed intended results with respect to oxidative stress biomarkers in diabetes comorbid depression rats in comparison to metformin.Open field test showed better results for HLO in diabetes comorbid depression rats.However,hypoglycemic effects,and forced swim test performance of metformin was slightly higher than the 400 mg dose,followed by the 200 mg dose of HLO.Ethyl gallate,gallic acid,β-sitosterol,and quercetin in HLO might resulted in attenuating diabetic as well as depression biomarkers.Conclusion:Inhibition of glucosidase and lipase activity,and AMP-activated protein kinase phosphorylation might be the possible biochemical changes occurred in HLO treated rats.