Article
Chemistry, Physical
S. Anitha, S. Krishnan, K. Senthilkumar, V Sasirekha
Summary: The scavenging ability of catechins (+) catechin (CT) and (-) epicatechin (ECT) on DPPH radical was experimentally investigated. Results showed that CT and ECT have a significant inhibitory effect on DPPH, with the interaction being mainly through hydrogen bonds. The study also confirmed the antioxidant potential of both CT and ECT.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Multidisciplinary
Pawel Przybylski, Adrian Konopko, Piotr Letowski, Katarzyna Jodko-Piorecka, Grzegorz Litwinienko
Summary: The reaction rates of a 2,2-diphenyl-1-picrylhydrazyl radical (dpph) with different phenols in methanol were measured to estimate the antiradical activity of phenolic compounds. The concentration of phenols was found to affect the reaction kinetics, with diluted phenols showing different kinetics compared to non-diluted solutions. This effect was explained by the ratio of [ArO-]/[ArOH], which leads to a higher contribution of electron transfer (ET) over hydrogen atom transfer (HAT) in diluted phenols. Simplified analysis of the reaction kinetics allowed for the estimation of k(ET)/k(HAT) ratios and the rate constants k(ET) for each phenol studied. These results demonstrate the importance of phenol concentration in determining the reaction mechanism and overall kinetics.
Article
Biochemistry & Molecular Biology
Elena Gerasimova, Elena Gazizullina, Sofya Kolbaczkaya, Alla Ivanova
Summary: For the first time, the use of DPPH center dot as an oxidant molecule and its detection through potentiometry have been shown. The potentiometric method allows for the determination of Nernst slope and antioxidant capacity in one experiment, making it a versatile approach for studying materials of any color.
Article
Chemistry, Physical
Yannick Ngueumaleu, Arlette Danelle Djitieu Deutchoua, Sarrah Sonita Poungoue Hanga, Rossel Wendji Liendji, Gustave Kenne Dedzo, Emmanuel Ngameni
Summary: 2,2-Diphenyl-1-picrylhydrazyl (DPPH) is a widely used free radical due to its stability, but its stability in the presence of various chemical species is not well studied. In this work, the stability of DPPH was investigated in the presence of metal cations (Cu2+ and Zn2+) and acids (HClO4 and HNO3) in acetonitrile. It was found that Cu2+ oxidized DPPH to DPPH+ while Zn2+ caused a slow disproportionation reaction. HClO4 caused a fast disproportionation of DPPH, whereas HNO3 resulted in a slower reaction. These findings suggest that the presence of other chemicals can introduce bias in evaluating the antioxidant properties of DPPH.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Biochemistry & Molecular Biology
Ikuo Nakanishi, Yoshimi Shoji, Kei Ohkubo, Shunichi Fukuzumi
Summary: The study revealed large kinetic isotope effects in the hydrogen-transfer reaction, and the isotopic difference in activation energies suggested that quantum mechanical tunneling plays a role in the reaction.
Article
Green & Sustainable Science & Technology
Chi Hou Lau, Suyin Gan, Harrison Lik Nang Lau, Lai Yee Lee, Suchithra Thangalazhy-Gopakumar, Hoon Kiat Ng
Summary: This review discusses the use of natural and synthetic additives in biodiesel. Due to the complexity and lack of research, the application of natural antioxidants in biodiesel remains uncertain. Purification and profiling of natural antioxidants, as well as further studies on their oxidation mechanisms and environmental impacts, will provide better guidance for manufacturers and end-users.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Electrochemistry
Ikuo Nakanishi, Yoshimi Shoji
Summary: This study investigated the cyclic voltammetry behavior of DPPH· solubilized with β-cyclodextrin and found that DPPH· undergoes a reversible proton-coupled reduction with the half-wave potential shifting linearly in the negative direction as solution pH increases. The cyclic voltammogram of the oxidation of DPPH· is quasi-reversible, indicating a chemical reaction of the oxidized product.
ELECTROCHEMISTRY COMMUNICATIONS
(2022)
Article
Agriculture, Dairy & Animal Science
Shiro Takeda, Abdulatef M. Ahhmed, Kazuki Sogawa, Saki Mouri, Sakurako Kaneko, Ryoichi Sakata, Wataru Mizunoya
Summary: Venison, a type of game meat, contains bioactive peptides with antioxidative properties. The study investigated the antioxidant activity of venison treated by in vitro cooking and digestion. The results showed that the digested venison had increased antioxidant activity and contained two peptides with high DPPH-RS activities.
ANIMAL SCIENCE JOURNAL
(2023)
Article
Biochemical Research Methods
Yangzom Dawa, Yurong Du, Qi Wang, Chengbiao Chen, Denglang Zou, Desheng Qi, Jianbin Ma, Jun Dang
Summary: Traditional Tibetan medicine (TTM) provides valuable novel therapeutic lead molecules from natural products. This study successfully separated and identified 4 main radical scavenging compounds from the methanolic extract of Saxifraga atrata using efficient methods. The developed methodology is effective for targeted isolation of high-purity compounds and rapid identification and isolation of DPPH inhibitors from various natural products.
JOURNAL OF CHROMATOGRAPHY A
(2021)
Article
Environmental Sciences
Jiahao Liang, He Liu, Mengyao Zou, Xueqin Tao, Jiangmin Zhou, Zhi Dang, Guining Lu
Summary: In this study, the thermally activated persulfate (TAP) process was used to degrade the most toxic and representative polybrominated diphenyl ethers (PBDEs) in e-waste dismantling sites. The results showed that 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) can be completely degraded under specific conditions, and only one oxidation product of low toxicity was detected. The TAP system exhibited universality for degrading PBDEs and the degradation rate was influenced by the number of substituted bromine atoms.
Article
Chemistry, Applied
Soliyah Shafi, Syed Jasirah Andrabi, Gajendra Kumar, Parvaiz Ahmad Bhat, Aijaz Ahmad Dar, Oyais Ahmad Chat
Summary: The solubilization of butylated hydroxyanisole (BHA) in different aqueous surfactant solutions (anionic, cationic, and nonionic) was investigated to improve its solubility and assess its antiradical activity against DPPH. The results showed that the micellar encapsulation and DPPH antiradical activity of BHA were highly dependent on the surfactant structure and amount used. The study is important for identifying the optimal medium to improve solubility and antioxidant capacity of compounds like BHA, and to understand the effects of different micro-heterogeneous/multiphase environments on BHA's antioxidant capability.
JOURNAL OF SURFACTANTS AND DETERGENTS
(2023)
Article
Food Science & Technology
Yuan Cheng, Yuan Chi, Xuhao Geng, Yujie Chi
Summary: This study investigated the impact of protein oxidation on the physicochemical properties and digestibility of egg white protein (EWP). Results showed that increasing concentration of AAPH led to decreased amino acid content, protein solubility, and free sulfhydryl content in EWP, while carbonyl content doubled. The study also found that essential amino acids were particularly sensitive to oxidation, with a decrease of more than 10% after EWP oxidation by 5.0 mmol/L AAPH. Additionally, the formation of larger soluble aggregates by AAPH increased, and the digestibility of EWP decreased with higher oxidation degree, indicating reduced nutritional and biological activity of EWP.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Applied
Hyunkyung Kim, YunSik Woo, HyungSeok Choi, Mi-Ja Kim, JaeHwan Lee
Summary: The study found that 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and moisture affect the solubility and oxidative stability of antioxidants in medium-chain triacylglycerol (MCT). DOPC displays a synergistic antioxidant effect with ascorbyl palmitate in bulk oil.
Article
Food Science & Technology
Maher M. Al-Dabbas, Majd Moumneh, Hani J. Hamad, Mahmoud Abughoush, Balkees Abuawad, Bha'a Aldin Al-Nawasrah, Rawan Al-Jaloudi, Sehar Iqbal
Summary: This study evaluated the impact of different processing and preservation methods on the levels of phenolic compounds, flavonoids, and antioxidant activities of okra. The results showed that blanching and freezing had the highest retention of phenolic contents and antioxidant activities.
Article
Chemistry, Medicinal
Jan Seeger, Volker F. Wendisch, Nadja A. Henke
Summary: In this study, Corynebacterium glutamicum was engineered to produce astaxanthin by heterologous gene expression. An efficient extraction process using ethanol was established, and the optimal conditions were determined to be 90% ethanol, 60 degrees C, and a biomass-to-solvent ratio of 5.6 mg(CDW)/mL(solvent). The purified astaxanthin obtained showed high antioxidative activity.
