DPPH radical scavenging reactions of protocatechuic acid and its methyl ester were investigated in various solvents. In alcoholic solvents, methyl protocatechuate rapidly scavenged more than four equivalents of the radical, whereas approximately two equivalents were consumed in aprotic solvents. Methyl, ethyl, butyl, isopropyl, and tert-butyl protocatechuates were examined for their DPPH radica...

In this study, the antioxidant properties of 80 % ethanol extracts of 16 species of plants from Jeju Island in Korea were evaluated using various antioxidant assays, including the DPPH (1,1-Diphenyl-2-pricrylhydrazyl) radical scavenging, superoxide scavenging, xanthine oxidase inhibition and hydrogen peroxide scavenging activities. Among the 16 plant extracts tested, CN-13 showed strong antioxi...

Free radicals are atoms or molecules with unpaired electrons. Many diseases are caused by free radicals. Normally, free radical formation is controlled naturally by various beneficial compounds known as antioxidants. Several analytical methods have been used for qualitative and quantitative determination of antioxidants, and each has its own specificity. This project aimed to evaluate antioxida...

In vitro antioxidant activity for 12 stannoxanes derived from Ph(3)SnCl (compounds 1-3), Ph(2)SnCl(2) (compounds 4-6), Bu(3)SnCl (compounds 7-9), and Bu(2)SnCl(2) (compounds 10-12), was assayed qualitatively by the chromatographic profile with 1,1-diphenyl-2-picrylhydrazil (DPPH) method and by two quantitative methods: the DPPH radical scavenging activity and Ferric-Reducing Antioxidant Power (...

In this study, n-butanol fraction (KBF) and aqueous fraction (KAF) isolated from methanol extract of Koelreuteria paniculata Laxm. leaves were evaluated for their antioxidant potential using (ABTS) 2, 2-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid), DPPH (2,2-diphenyl-2-picrylhydrazyl) assay, Reducing power assay and Superoxide anion radical scavenging assay. These fractions were also studi...

Moutan cortex, a widely used traditional Chinese medicine for the treatment of various diseases, is the root bark of Peaonia suffruticosa Andrews (Paeoniaceae). In this study, the crude polysaccharides (CPS), paeonol and the crude total glycosides (CTG) of moutan cortex were extracted by the multiple-stage extraction. CPS was extracted by water, paeonol was distilled by steam distillation metho...

The first 100s of reaction between gallic acid (GA) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical follows the second order reaction. The addition of zinc (Zn) significantly enhanced the rate of reaction, such that the rate constant when GA:Zn is 1:1 was significantly higher, (P<0.05), 120 ± 12 Ms as compared to 92 ± 6 Ms when zinc was absent. However, the addition of excess zinc, GA:Zn 1:2,...