scholarly journals Antioxidant Activity in Supramolecular Carotenoid Complexes Favored by Nonpolar Environment and Disfavored by Hydrogen Bonding

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 625
Author(s):  
Yunlong Gao ◽  
A. Ligia Focsan ◽  
Lowell D. Kispert
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Oxidation Potential ◽  
Supramolecular Complexes ◽  
Factors Affecting ◽  
Oxidation Potentials ◽  
Polar Environment ◽  
Donor Acceptor ◽  
Quench Singlet Oxygen ◽  
Effect Of Polarity

Carotenoids are well-known antioxidants. They have the ability to quench singlet oxygen and scavenge toxic free radicals preventing or reducing damage to living cells. We have found that carotenoids exhibit scavenging ability towards free radicals that increases nearly exponentially with increasing the carotenoid oxidation potential. With the oxidation potential being an important parameter in predicting antioxidant activity, we focus here on the different factors affecting it. This paper examines how the chain length and donor/acceptor substituents of carotenoids affect their oxidation potentials but, most importantly, presents the recent progress on the effect of polarity of the environment and orientation of the carotenoids on the oxidation potential in supramolecular complexes. The oxidation potential of a carotenoid in a nonpolar environment was found to be higher than in a polar environment. Moreover, in order to increase the photostability of the carotenoids in supramolecular complexes, a nonpolar environment is desired and the formation of hydrogen bonds should be avoided.

UJI AKTIVITAS ANTIOKSIDAN FRAKSI N-HEKSAN DAUN AFRIKA (Vernonia amygdalina Del.) DENGAN METODE DPPH

2020 ◽  
Vol 5 (2) ◽  
pp. 250-257
Author(s):  
Nurul Fatimah ◽  
◽  
Reksi Sundu
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Activity ◽  
Free Radicals ◽  
Ethanolic Extract ◽  
Ethanol Extract ◽  
Hexane Fraction ◽  
Phytochemical Screening ◽  
Vernonia Amygdalina ◽  
Tropical Africa ◽  
Ic50 Value

Free radicals and reactive species are widely believed to contribute to the development of several diseases by causing oxidative stress and eventually oxidative. Vernonia amygdalina (Astereacea) is a small shrub or tree between 1 and 5m high growing throughout tropical Africa. Plants are generally known as bitter leaves is well cultivated and is a general market for merchandise in several countries. The purpose of this study was to determine the antioxidant activity of hexane fraction from ethanol extract od Frican leaves (Vernonia amygdalina Del.). The method used in this study was the DPPH (1,1-Diphenil-2-Picrylhydrazyl) method. The result of phytochemical screening showed that ethanolic extract of African leaves contained a composition of secondary metabolites of alkaloids, flavonoids, tannins, steroids/triterpenoids and saponins. The antioxidant activity of the extract of n-hexane fraction was classified as very weak with an IC50 value of 317.98 ppm.

Effects of Doping on the Electrochemical and Electrical Properties of Poly(2,5-di(2-thienyl)pyrrole)

1999 ◽  
Vol 64 (8) ◽  
pp. 1357-1368 ◽  
Author(s):  
Enric Brillas ◽  
José Carrasco ◽  
Ramon Oliver ◽  
Francesc Estrany ◽  
Víctor Ruiz
Keyword(s):  
Mass Spectrometry ◽  
Fast Atom Bombardment ◽  
Oxidation Potential ◽  
Ethanolic Solution ◽  
Pt Electrode ◽  
Reversible Process ◽  
Oxidation Potentials ◽  
Lower Productivity ◽  
Polymeric Chains ◽  
Linear Molecules

The electropolymerization of 2,5-di(2-(thienyl)pyrrole) (SNS) on a Pt electrode from ethanolic solution with LiClO4 or LiCl as electrolyte has been studied by cyclic voltammetry (CV) and chronoamperometry (CA). In both media, a quasi-reversible process has been indicated by CV, reversing the scan at low oxidation potentials. Under these conditions, reducible positive charges formed in both oxidized polymers are compensated by the entrance of anions from solution. Elemental analysis reveals that polymers generated at a low oxidation potential by CA contain a 21.03% (w/w) of ClO4- or a 9.56% (w/w) of Cl-. The poly(SNS) doped with Cl- presents higher proportion of reducible positive charges, higher polymerization charge and lower productivity. A much higher electrical conductivity, however, has been found for the poly(SNS) doped with ClO4-. Both polymers are soluble in DMSO, acetone and methanol. The dimer, trimer, tetramer and pentamer have been detected as soluble and neutral linear oligomers by mass spectrometry-fast atom bombardment. The analysis of polymers by infrared spectroscopy confirms the predominant formation of linear molecules with α-α linkages between monomeric units. A condensation mechanism involving one-electron oxidation of all electrogenerated linear and neutral polymeric chains is proposed to explain the SNS electropolymerization.

PROSPECTS FOR USING ASTRAGALUS ONOBRYCHIS AS A SOURCE OF NATURAL ANTIOXIDANTS

2021 ◽  
pp. 47-53
Author(s):  
Pozdnyakovа Т.А. ◽  
Kuleshovа Е.S. ◽  
Bubenchikov R.A.
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Chemical Interaction ◽  
Raw Materials ◽  
Natural Antioxidants ◽  
The Body ◽  
Plant Raw Materials ◽  
Total Antioxidant ◽  
Promising Source ◽  
The Relationship

The predominance of synthetic and genetically modified foods in the diet of a modern person often leads to disruption of natural metabolic processes and the accumulation of toxic free radicals in the body, which provokes the development of various diseases. Natural antioxidants from medicinal plants can help maintain health and stop the processes of peroxidation. In our opinion, Аstragalus onobrychis can become a promising source of natural antioxidants. The aim of this study was to establish the antioxidant activity in extracts from the herb Astragalus onobrychis. In order to obtain objective and reliable results during our research, we used two methods: the method of titrimetry and spectrophotometry of free radicals. The titrimetric method is based on the chemical interaction between an oxidizing agent (potassium permanganate) and natural antioxidants present in extracts from plant raw materials, since they exhibit the properties of reducing agents. The spectrophotometric method makes it possible to assess the value of antioxidant activity and the duration of the reaction by assessing the interaction of 2,2-diphenyl-1-picrylhydrazil with plant antioxidants. To establish the relationship between the antioxidant activity and the presence of phenolic compounds in the plant, the content of flavonoids and hydroxycinnamic acids in the herb Astragalus onobrychis was determined. As a result of the studies, the total antioxidant activity of extracts from the herb Astragalus onobrychis was established and it was revealed that its value depends on the type of extractant used, since this factor is associated with the content of various groups of natural antioxidants in the extraction. The data obtained indicate the prospects of using the herb Astragalus onobrychis as a source of natural antioxidants.

Mechanochemical Treatment of Quercetin and Curcumin to Obtain Eutectic Mixtures with High Antioxidant Activity

CrystEngComm ◽  
2021 ◽  
Author(s):  
Richard Fernando D'Vries ◽  
Valentina Renza-Diaz ◽  
Martin emilio Gonzalez ◽  
Kriss Dayhana Pantoja
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Biological Systems ◽  
Mechanochemical Treatment ◽  
Natural Antioxidant ◽  
Eutectic Mixtures ◽  
High Antioxidant Activity ◽  
The Creation

Quercetin and curcumin are well-known natural antioxidant molecules used to prevent the malignant effect caused by free radicals on biological systems. This work addressed the creation of eutectic mixtures from...

Donor-acceptor complexes formed by perfluoro-organo bromides and iodides with nitrogenous and other bases. II. Band shapes and widths in the absorption spectrum of gaseous CF3I-N(CH3)3

1971 ◽  
Vol 24 (12) ◽  
pp. 2493 ◽  
Author(s):  
A Mishra ◽  
ADE Pullin
Keyword(s):  
Vibrational Mode ◽  
Low Frequency ◽  
Molecular Complexes ◽  
Wave Number ◽  
Centrifugal Distortion ◽  
Band Shape ◽  
Gaseous Mixtures ◽  
Factors Affecting ◽  
Donor Acceptor ◽  
Vibration Rotation

The absorption band centred at c. 77 cm-1 in gaseous mixtures of CF3I and N(CH3)3 previously reported and attributed to the N-I stretching mode of the complex CF3I-N(CH3)3 has been carefully re-examined. This band is of interest as an example of a low frequency ?dissociative type? vibrational mode of a weak molecular complex. The band is asymmetric and apparently structureless with a half intensity width at room temperature of 28-30 cm-1. The width of the band may be accounted for as arising from transitions vi + vi+1 where vi is the vibrational quantum number of the N-I stretching mode with vi up to c. 10 making appreciable contribution to the intensity on the low wave-number side. Centrifugal distortion in the complex is considered. Centrifugal stretching and consequent weakening of the bond may shift the band envelope 2-3 cm-1 to lower wave numbers. Assessment of these and other factors affecting the band shape suggest that the fundamental frequency is probably c. 90 cm-1. The band shape of the vibrational mode of the complex at c. 272 cm-1 is briefly discussed. Many of the considerations presented in this paper should apply to vibration-rotation band shapes in other weak molecular complexes. Some general consequences of anharmonicity for the interpretation of the spectra of weak molecular complexes are discussed.

scholarly journals UJI AKTIVITAS ANTIOKSIDAN SPONS Stylissa sp. DENGAN MENGGUNAKAN METODE DPPH (1,1-difenil-2-pikrilhidrazil)

PHARMACON ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 419
Author(s):  
Samuel I.M. Sibarani ◽  
Adithya Yudistira ◽  
Deby A. Mpila
Keyword(s):  
Antioxidant Activity ◽  
Cell Wall ◽  
Free Radicals ◽  
Ethanol Extract ◽  
Dna Bases ◽  
Oxidation Reactions ◽  
Terrestrial Plants ◽  
Dpph Method ◽  
High Antioxidant Activity ◽  
Ethanol Extracts

ABSTRACTHabitat of sponge Stylissa sp., were under the sea and these sponges contain active compounds, which are more active than the compounds produced by terrestrial plants. Antioxidants are inhibitors of oxidation reactions due to the free radicals, which can cause weak damage to unsaturated cells, cell wall membranes, blood vessels, DNA bases, and lipid tissue, that causing disease. The study was conducted to determine the antioxidant activity of ethanol extracts  of sponge Stylissa sp., which is located on the Bangka Island, Likupang District, North Minahasa Regency. Sponge Stylissa sp., was extracted by maceration with using ethanol. Testing of antioxidant activity was carried out by the DPPH method measured by a UV-Vis spectrophotometer. The results of the study showed that ethanol extracts of sponge Stylissa sp., has antioxidant activity in each concentration and the highest at a concentration of 100 mg / L. The conclusion is a ethanol extract of sponge Stylissa sp. have high antioxidant activity with a concentration of 25 mg/L (77,40%), concentration of 50 mg/L (85,63%), concentration of 75 mg/L (88,66%), and concentration 100 mg/L (88,96%). Key words: Stylissa sp. Sponge, Antioxidant, DPPH (1,1-diphenyl-2-picrylhydrazyl) ABSTRAKHabitat dari spons Stylissa sp. terdapat di bawah laut dan spons ini mengandung senyawa aktif yang persentase keaktifannya lebih besar dibandingkan dengan senyawa-senyawa yang dihasilkan oleh tumbuhan darat. Antioksidan adalah zat penghambat reaksi oksidasi akibat radikal bebas yang dapat menyebabkan kerusakan lemah tak jenuh, membran dinding sel, pembuluh darah, basa DNA, dan jaringan lipid sehingga menimbulkan penyakit. Penelitian dilakukan untuk mengetahui aktivitas antioksidan ekstrak etanol biota laut spons Stylissa sp. yang terdapat di pulau Bangka, Kecamatan Likupang, Kabupaten Minahasa Utara. Spons Stylissa sp. ini diekstrak dengan metode maserasi menggunakan etanol. Pengujian aktivitas antioksidan ini dilakukan dengan metode DPPH yang diukur dengan alat spektrofotometer UV-Vis. Hasil dari penelitian menunjukan bahwa ekstrak etanol spons Stylissa sp. memiliki aktivitas antioksidan disetiap konsentrasi dan yang tertinggi pada konsentrasi 100 mg/L. Kesimpulan yang didapat bahwa ekstrak etanol spons Stylissa sp. memiliki aktivitas antioksidan yang tinggi dengan konsentrasi 25 mg/L (77,40%), konsentrasi 50 mg/L (85,63%), konsentrasi 75 mg/L (88,66%), dan konsentrasi 100 mg/L (88,96%). Kata Kunci : Spons Stylissa sp., Antioksidan, DPPH (1,1-difenil-2-pikrilhidrazil)

scholarly journals Formulation and Evaluation of Antioxidant Peel-Off Face Mask Containing Red Dragon Fruit Rind Extract (Hylocereus polyrhizus Haw.)

2020 ◽  
Vol 20 (3) ◽  
pp. 438
Author(s):  
Trasna Arman Jani ◽  
Aliefman Hakim ◽  
Yohanes Juliantoni
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Ethyl Acetate ◽  
Ethyl Acetate Extract ◽  
Face Mask ◽  
Hexane Extract ◽  
Product Evaluations ◽  
Drying Time ◽  
Dragon Fruit ◽  
Dispersive Power

Peel-Off face mask is one of the cosmetics that is used to treat skin from free radicals. Peel-off face mask can minimize the effects of free radicals because it contains antioxidant. One of the antioxidant sources is red dragon fruit’s rind (Hylocereuspolyrhizus Haw.). The aim of this study is to obtain Peel-Off face mask of red dragon fruit’s rind extract that contains anthocyanin. Red dragon fruit’s rind was macerated by ethanol 96%, ethyl acetate and n-hexane added citric acid (4:1) solvents. TLC test used Chloroform: ethyl acetate: n-butanol (5:4:1) eluent and sprayed by AlCl3. Antioxidant activity of extract was tested using DPPH (1,1-Diphenyl-2-Picryhidrazyl) method. Peel-Off face mask was made using PVA, HPMC, methyl paraben, propylparaben, propylenglycol, extract, ethanol 96% and aquadest. The rendemen of ethanol 96% extract was 9,476%, ethyl acetate extract was 0,783% and n-hexane extract was 0,631%. The results of TLC test showed yellow spots on the ethyl acetate and ethanol 96% extracts which indicated that extract contained flavonoids (anthocyanin). The results of antioxidant activity test showed that IC50 value of ethanol 96% extract was 189,7422 (AAI=0,2087), ethyl acetate extract was 196,9398 (AAI=0,2011), and n-hexane extract was 385,3664 (AAI=0,1027). The result of the product evaluations showed that all the formulas complied the product requirements such as the organoleptic, homogenity, pH, dispersive power and drying time. Peel-off face mask already meet the product requirements but further research is needed to test the product stability and activity.

scholarly journals Limpasu Pericarpium : an Alternative Source of Antioxidant From Borneo with Sequential Maceration Method

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Irfan Zamzani ◽  
Nita Triadisti
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Ethyl Acetate ◽  
Methanol Extract ◽  
Oxidation Process ◽  
Antioxidant Activities ◽  
Alternative Source ◽  
Dpph Method ◽  
Indigenous Plant ◽  
Ic50 Values

Antioxidants are substances that can slow down the oxidation process of free radicals. Limpasu plant (Baccaurea lanceolata (Miq) Muell. Arg), an indigenous plant of Borneo, is a natural antioxidant source. The purpose of this study was to determine the antioxidant activity of the limpasu pericarpium extract. The extraction of the limpasu pericarpium was done by maceration method using solvents with increasing polarity ranging from n-hexane, ethyl acetate, and methanol. Antioxidant activities of the three extracts were measured by the DPPH and FRAP methods. The IC50 values of n-hexane, ethyl acetate, and methanol extracts, as well as quercetin using the DPPH method were 517,45 µg/mL, 530,64 µg/mL, 10,63 µg/mL and 6,83 µg/mL, respectively. Meanwhile, the IC50 values obtained from FRAP method were 198,96 µg/mL, 190,07 µg/mL, 661,36 µg/mL, and 7,09 µg/mL, respectively. The results revealed that the methanol extract is more potent than other extracts tested for antioxidant activity.

scholarly journals Analysis of antioxidant activity, total phenolic and flavonoid contents of ethanol extract of Litsea cubeba Lour. Bark

2021 ◽  
Vol 332 ◽  
pp. 08005
Author(s):  
Aminah Dalimunthe ◽  
Dewi Pertiwi ◽  
Mahatir Muhammad ◽  
Denny Satria
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Ethanol Extract ◽  
The Body ◽  
Total Flavonoid ◽  
Total Phenolic ◽  
Antioxidant Power ◽  
Litsea Cubeba ◽  
Ferric Reducing Antioxidant Power ◽  
Phenolic And Flavonoid

Free radicals also play a role in the pathology of various degenerative diseases such as cancer, rheumatism, coronary heart disease, cataracts, and others. Free radicals can come from within the body (endogenous) and outside the body (exogenous). Litsea cubeba (Lour,) is a Lauraceae family plant which have contents volatile oils which used as antimicrobial, anticancer on breast cancer, pesticide, antideppressants, antiinflammation, antioxidant, and neuro pharmacology. The extract was prepared using water with the soxhletation method. The antioxidant activity was determined with the 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-Azinobis [3-ethylbenzothiazoline-6)-sulfonic acid] -diammonium salt (ABTS) and Ferric Reducing Antioxidant Power (FRAP) methods. Total flavonoid and total phenolic content were determined with colorimetric methods. Antioxidant activity measured as IC50 was 23.37 ± 0.42 µg/mL; 111.21 ± 0.42 and 109.01 ± 0.28 respectively. The extract was found to contain high levels of total phenolic (282.93 ± 0.33 mg GAE/g) and total flavonoid 7.49 ± 0.51 mg QE/g). The results reveal that ethanol extract of Litsea cubeba Lour. Bark has antioxidant potential. The further analysis is to isolation antioxidant compound.

scholarly journals Pengaruh Paparan Hipoksia terhadap Aktivitas Antioksidan Katalase dan Kadar Malondialdehid (MDA) pada Jaringan Hati Tikus

Jurnal BIOMA ◽  
2014 ◽  
Vol 10 (2) ◽  
pp. 27
Author(s):  
Rini Puspitaningrum ◽  
Amanda Putri Lestari ◽  
Tri Murtiati
Keyword(s):  
Antioxidant Activity ◽  
Free Radicals ◽  
Cell Membrane ◽  
Rat Liver ◽  
Catalase Activity ◽  
Liver Tissue ◽  
Hypoxia Exposure ◽  
Randomized Design ◽  
Mda Content ◽  
Key Words Catalase

Abstract content in the tissue. Hypoxia can make the formation of free radicals or reactive oxygen species (ROS) which reactive to cell membrane. Body will avoid free radicals by producing antioxidant, such as catalase enzyme. The reaction between ROS and cell membrane will form malondialdehyde (MDA). Liver is the main location of catalase. This research was aimed to know the influence of hypoxia exposure toward catalase antioxidant activity and MDA content in the rat liver tissue. This research used experiment method with fully randomized design. Based on one way Anova test (p≤0.01), it was shown that there had no average difference on catalase activity and MDA content toward length hypoxia exposure. The conclusion of this research was no influence of hypoxia exposure toward catalase activity and MDA content in rat liver tissue.   Key words: catalase antioxidant activity, hypoxia, malondialdehyde (MDA) content,rat liver tissue

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