Search results

1

QSAR study of the DPPH· radical scavenging activity of coumarin derivatives and xanthine oxidase inhibition by molecular docking

100%

Razo-Hernández R., Pineda-Urbina K., Velazco-Medel M., Villanueva-García M., Sumaya-Martínez M., Martínez-Martínez F., Gómez-Sandoval Z.

Open Chemistry

|

2014

|

vol. 12

|

issue 10

1067-1080

EN

A Quantitative Structure-Activity Relationship (QSAR) of coumarins by genetic algorithms employing physicochemical, topological, lipophilic and electronic descriptors was performed. We have used experimental antioxidant activities of specific coumarin derivatives against the DPPH· radical molecule. Molecular descriptors such as Randic Path/Walk, hydrophilic factor and chemical hardness were selected to propose a mathematical model. We obtained a linear correlation with R2 = 96.65 and Q LOO2 = 93.14 values. The evaluation of the predictive ability of the model was performed by applying the Q ASYM2, $\hat r^2 $ and Δr m2 methods. Fukui functions were calculated here for coumarin derivatives in order to delve into the mechanics by which they work as primary antioxidants. We also investigated xanthine oxidase inhibition with these coumarins by molecular docking. Our results show that hydrophobic, electrostatic and hydrogen bond interactions are crucial in the inhibition of xanthine oxidase by coumarins.

2

Antioxidant capacity of crude extracts containing carotenoids from the berries of various cultivars of Sea buckthorn (Hippophae rhamnoides L.)

100%

Kruczek M., Świderski A., Mech-Nowak A., Król K.

|

2012

|

vol. 59

|

issue 1

135-137

EN

Comparative analysis of antioxidant capacity was performed using FRAP and DPPH methods on extracts containing carotenoids acquired from fruits of Sea buckthorn. The examination included nine varieties of Sea buckthorn growing in the comparative cultivation. Conducted analysis allowed to compare the antioxidant capacity with carotenoids content measured with spectrophotometric and HPLC methods. Three of the examined cultivars indicating high antioxidant activity in both, FRAP and DPPH methods, also revealed highest ('Aromatnaya') and high ('Botanicheskaya', 'Arumnyj') total carotenoids content in HPLC analysis.

3

Dietary intake of specific phenolic compounds and their effect on the antioxidant activity of daily food rations

100%

Koch W., Baj T., Kukula-Koch W., Marzec Z.

Open Chemistry

|

2015

|

vol. 13

|

issue 1

EN

The determination of phenolic acids’ and flavonoids’ content in daily food rations (DFRs) of a selected group of male and female students and the development of chromatographic conditions is the primary goal of the study. The presence of 7 phenolic components were confirmed in the prepared extracts from all diets reconstructed within a period of 3 years. The highest concentrations were determined for hesperidin (124 and 55.6 mg for women and men, respectively), naringin (47.6 mg in female and 37 mg in male diets) and chlorogenic acid (19.7 and 19.8 mg for women and men). The antioxidant potential of the daily food rations, measured with a DPPH test, was higher for women (range 47.1‒78.8%) than for men (range 34.5‒78.0%) and was found to strongly correlate with the total phenolics content of the samples (Folin-Ciocalteu test) (correlation coefficient 0.90).

4

Comprehensive evaluation of biogenic amines and related drugs’ antiradical activity using reactive 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical

100%

Sârbu C., Casoni D.

Open Chemistry

|

2013

|

vol. 11

|

issue 5

679-688

EN

A comprehensive study of biogenic amines and related drugs as free radical scavengers and potential antioxidants was carried out using the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH·). The results of the effect of test duration and the relative concentration on the ability of the compounds to scavenge the DPPH· were investigated and discussed. The antiradical activity of amines was compared with the activity of some reference antioxidants (phenols, phenolic acids, flavonols and other antioxidants). Some particular insights related to the mechanism of reactivity toward the DPPH· were investigated by carrying out kinetic studies in methanol for different relative concentrations. According to the obtained results, catecholamines and especially their related drugs (D-dopa, adrenalone, S-(−)-carbidopa and isoprenaline) showed a fast reactivity towards DPPH· and the highest antiradical activity which increased in a concentration-dependent manner. Moreover, catecholamines proved to be more powerful scavengers than ascorbic and caffeic acids even at low concentrations while their related drugs (D-dopa, adrenalone and S-(−)-carbidopa) showed higher antiradical activity than gallic acid for all of the investigated concentrations. [...]

5

THE INFLUENCE OF STORAGE TEMPERATURE AND UV-IRRADIATION ON FREE RADICAL SCAVENGING PROPERTIES OF ETHANOLIC EXTRACTS OF PROPOLIS

100%

Komosińska-Vassev K., Olczyk P., Ramos P., Mencner L., Derkacz A., Waluga E., Krysik K., Olczyk K., Pilawa B.

Acta Poloniae Pharmaceutica - Drug Research

|

2018

|

vol. 74

|

issue 6

1833-1840

EN

The free radical scavenging activity of ethanolic extracts of propolis (EEP) at the concentrations of 3%, 7%, and 10% was examined. The impact of storage temperature and exposure to ultraviolet (UV) light on the interactions of extracts of propolis with the model DPPH free radicals was also determined. The quenching of an X-band electron paramagnetic resonance spectra of DPPH free radicals by the extracts stored at room temperature, heated at the temperature of 50 oC and exposed to UV-irradiation, were compared. The examined propolis ethanolic extracts revealed an antioxidative character. The storage of the samples at a higher temperature (50 oC) caused a decrease of the scavenging activity equaling to 7% and 10% EEP. UV-irradiation of the 3% EEP increased the quenching of DPPH free radical lines. The reverse effect was observed for the 7% and 10% propolis extracts. The 3% ethanolic extract of propolis is more stable for storage at 50ºC, and less than other analyzed EEP susceptible for UV-irradiation. Alterations of the antioxidative properties of the analyzed EEP and changes in the kinetics of their interactions with free radicals, indicate that 3%, 7%, and 10% propolis extracts should not be exposed to the temperature of 50 oC and UV-irradiation.

6

Determination of antiradical and antioxidant activity: basic principles and new insights

100%

Tirzitis G., Bartosz G.

|

2010

|

vol. 57

|

issue 2

139-142

EN

Although the term 'antioxidant' is used very frequently, there are problems with the definition of antioxidants and estimation of antioxidant activity. The distinction between antioxidant and antiradical activities is not always obvious. This minireview discusses critically the principles, advantages and limitations of the most frequently used methods of estimation of antiradical and antioxidant activities.

7

Antiradical Properties OF Extracts From Roots, Leaves and Fruits of Six Rumex L. Species

100%

Wegiera M., Grabarczyk P., Baraniak B., Smolarz H.

Acta Biologica Cracoviensia s. Botanica

|

2011

|

vol. 53

|

issue 1

8

Early utilization of Spirulina platensis cultivation as an antioxidant candidate in laboratory-scale closed reactor system

100%

Oktaviani D., Basri A. H., Damayanti W.

World News of Natural Sciences

|

2021

|

vol. 34

144-153

EN

Spirulina platensis is a microalga that contains a lot of secondary metabolites and is utilized as a dietary supplement. It can inhibit fat peroxidation better compared to the chemical antioxidant. Laboratory-scale closed reactor system was designed for Spirulina cultivation. This research aims to analyze identified secondary metabolite (Phytochemical contents) and the antioxidant activity or value of Inhibition Concentration 50% (IC50) of the fresh lab-scale cultivated Spirulina platensis. The antioxidant content was evaluated using DPPH method (1,1–diphenyl-2-pikrilhidrazil) on various sample concentrations as well as using Vc (Ascorbic Acid) as a positive control. The principle of hydrogen absorption by free radicals from antioxidants was demonstrated with the absorption value using a spectrophotometer at a wavelength of 517 nm. The results show that Spirulina platensis lab-scale cultivation was resulting in 5.0±0.01 g/10.0 L wet basis on the 10th day. The results show that Spirulina platensis has positive compounds of flavonoid, steroids, triterpenoids, phenolic, and saponins. Fresh Spirulina platensis has a value of IC50 647.045 ppm and Vc as a positive control has the IC50 of 2.085 ppm. The potential as a source of natural antioxidants was categorized as a very weak capacity. Therefore this study can be concluded that Spirulina platensis cultivated in Laboratory-scale has a potential to act as antioxidant candidate.

9

Long Wave UV-B Radiation and Asahi SL Modify Flavonoid Content and Radical Scavenging Activity of Zea mays var. saccharata Leaves

86%

Skórska E., Grzeszczuk M., Barańska M., Wójcik-Stopczyńska B.

Acta Biologica Cracoviensia s. Botanica

|

2019

|

vol. 61

|

issue 1

10

Total Phenolic, Flavonoid Contents and Antioxidant Activities of Honey and Propolis Collected from the Region of Laghouat (South of Algeria)

86%

Bakchiche B., Habati M., Benmebarek A., Gherib A.

World News of Natural Sciences

|

2017

|

vol. 11

91-97

EN

The aim of this study was to determine total phenolic and flavonoid contents and to evaluate the antioxidant activities of two honeys and one propolis sample, collected from the region of Laghouat (South of Algeria). Total phenolic content were determined by using Folin-Ciocalteu reagent as gallic acid equivalent, while flavonoids content was assessed by means of the AlCl3 method as Rutin equivalent. Antioxidant activities of the honeys and propolis were examined by two different methods, namely, scavenging of free radical 2,2-diphenyl-1-picrylhydrazyl and reducing power. The antioxidant activities were compared with standard antioxidants such as Ascorbic acid, BHT and Trolox. The highest level of phenolic was 2385 mg Gallic acid per 100g sample, the highest level of flavonoid was 379 mg Rutin per 100g sample, while the highest protein content was 1177 mg per 100g sample, DPPH (0.026 mg/ml) and TEAC (0.0015) were detected especially in the propolis sample, indicating that it holds good antioxidant properties. A strong positive correlation was found between phenolics, flavonoids, DPPH and TEAC, indicating that in addition to total phenolic content, flavonoid and protein concentrations are good indicators of the antioxidant potential of propolis and honey.

11

Dpph Radical Scavenging Activity and Phenolic Compound Content in Different Leaf Extracts from Selected Blackberry Species

72%

Gawron-Gzella A., Dudek-Makuch M., Matławska I.

Acta Biologica Cracoviensia s. Botanica

|

2012

|

vol. 54

|

issue 2

Refine search results

QSAR study of the DPPH· radical scavenging activity of coumarin derivatives and xanthine oxidase inhibition by molecular docking

Antioxidant capacity of crude extracts containing carotenoids from the berries of various cultivars of Sea buckthorn (Hippophae rhamnoides L.)

Dietary intake of specific phenolic compounds and their effect on the antioxidant activity of daily food rations

Comprehensive evaluation of biogenic amines and related drugs’ antiradical activity using reactive 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical

THE INFLUENCE OF STORAGE TEMPERATURE AND UV-IRRADIATION ON FREE RADICAL SCAVENGING PROPERTIES OF ETHANOLIC EXTRACTS OF PROPOLIS

Determination of antiradical and antioxidant activity: basic principles and new insights

Antiradical Properties OF Extracts From Roots, Leaves and Fruits of Six Rumex L. Species

Early utilization of Spirulina platensis cultivation as an antioxidant candidate in laboratory-scale closed reactor system

Long Wave UV-B Radiation and Asahi SL Modify Flavonoid Content and Radical Scavenging Activity of Zea mays var. saccharata Leaves

Total Phenolic, Flavonoid Contents and Antioxidant Activities of Honey and Propolis Collected from the Region of Laghouat (South of Algeria)

Dpph Radical Scavenging Activity and Phenolic Compound Content in Different Leaf Extracts from Selected Blackberry Species