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...

1,1-dipheny-2-picrylhydrazyl (DPPH) scavenging activities of the 80% methanolic leaf extracts of three cultivars (small leaf, SL; big leaf, BL; thin leaf, TL) of Mai-Men-Dong (Liriope spicata L.) are analyzed by spectrophotometry. The concentrations required for 50% inhibition (IC 50 ) of DPPH radicals were 81.08, 96.97, and 53.78 μg/mL, respectively. The methanolic extracts were further partit...

To explore the free radical scavenging properties of crude ethanolic extract of galls, bark, leaves, roots of Pistacia integerrima and its subsequent solvent fractions viz., n-hexane, chloroform, ethyl acetate and methanol against 1, 1-diphenyl-2-picrylhydrazyl (DPPH) stable. In vitro DPPH based free radical was employed using querceitin as standard antioxidant while methanol as negative contro...

Purpose: To improve the aqueous solubility of phloridzin by complexing it with hydroxypropyl-βcyclodextrin (HP-β-CD). Methods: The complex of phloridzin with HP-β-CD was prepared by freeze-drying method. The physicochemical properties of the complex were investigated by ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), differential scanning calorimetry (DSC) and x-ray diffracto...

We investigated the inhibition of advanced glycation endproduct (AGE) activity using the fluorescence characteristics of fractions and compounds from Corni Fructus. Corni Fructus extract and its iridoid glycoside components showed low inhibitory activities as well as the AGE inhibitor aminoguanidine. However, a low molecular weight polyphenol, 7-O-galloyl-D-sedoheptulose, and an antioxidant, tr...

At present, it is widely-known that free radicals are the causes of illness such as cancers, coronary heart disease, Alzheimer’s disease and aging. One method of protection from free radical is the consumption of antioxidant-containing foods or herbs. Several analytical methods have been used for qualitative and quantitative determination of antioxidants. This project aimed to evaluate antioxid...

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...

New potent antioxidants conjugating the catechol (=pyrocatechol; pyrCat) group to two N-termini of modified double-stranded tyrosine residues were synthesized and showed radical scavenging activity with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH radical, DPPH˙) as a free radical model, second-order rate constants for the DPPH˙ scavenging reaction, and the results from electron spin resonance (...

Radical scavenging and antioxidant activities of nine flavonoids previously isolated from the aerial parts of Chenopodium bonus-henricus L. were established using DPPH and ABTS free radicals as well as inhibition of lipid peroxidation in a linoleic acid system by the ferric thiocyanate method. Patuletin glycosides, compounds 1, 2 and 7 showed the highest DPPH (85.78%, 85.59%, 86.07%) and ABTS a...