DPPH radical scavenging assay

Storage period (Days) Eugenol content (mg/g cookie) Phenolic content (mg gaUic acid equivalent/g cookie) IC50 of DPPH radical scavenging assay ( xg/ml)... 

DPPH radical scavenging assay, 4113 DPX. See Disposable pipette extraction (DPX)... 

This methodology was used to extract bioactive polysaccharides (PNSPs) from seeds of Pharbitis nil, an annual climbing herb belonging to the family Convolvulaceae. The chemical analysis of PNSPs showed contents of sugar, uronic acid and proteins of 83.6 1.61, 21.8 1.25 and 16.4 0.88% (w/w), respectively. The antioxidant activity of PNSPs was evaluated in-vitro by using ABTS and DPPH radical scavenging assays. At a concentration of 5 mg/mL, PNSPs exhibited values of radical inhibitions of 100% and 89.6% in ABTS and DPPH assays, respectively [123]. 

Damasius, J., P. R. Venskutonis, V. Kaskoniene, and A. Maruska. 2014. Fast screening of the main phenolic acids with antioxidant properties in common spices using on-line HPLC/UV/DPPH radical scavenging assay. Analytical Methods 6(8) 2774-2779. 

Table I shows the results of a DPPH radical-scavenging assay on each of the whole-cranberry extracts prepared by Mediods 1 and 2. For whole cranberries, the highest antioxidant activity was observed in ethyl acetate extracts prepared by both methods, with an IC50 value of 0.033 mg/mL for the ethyl acetate extract prepared by Method 2. The ethyl acetate fraction was about twice as effective at radical scavenging as the whole-berry extract (IC50 = 0.078 mg/mL). Kinetics of these reactions were slow compared to the standard. Vitamin E for all cranberry extracts, radical scavenging occurred over a period of approximately one hour as compared to several minutes for vitamin E.

Table I. Comparative antioxidant activities of extracts of whole cranberries measured by a DPPH radical-scavenging assay...

Abstract Recently, we have investigated Aconitum cochleare Woroschin and obtained three new alkaloids cochleareine, acoleareine from the aerial parts of the plant and cochleareinine from the roots. Cochlearenine exhibited antioxidant activity against DPPH free radical scavenging assay. The cardio active effect of has also have been studied on isolated heart preparations. 

Muller L, Frohlich K, Bohm V. Comparative antioxidant activities of carotenoids measured by ferric reducing antioxidant power (FRAP), ABTS bleaching assay (aTEAC), DPPH assay and peroxyl radical scavenging assay. Food Chemistry. 2011 129 139-148... 

Fungus Epicoccum sp. was isolated from the marine brown alga Fucus vesiculosus. From the cultivated fungus, a new secondary metabolite 4,5,6-trihydroxy-7-methylphthalide 336 (epicoccone) was found. 336 was found to be potently active, showing 95% DPPH radical scavenging effects at 25 pg mL. It also inhibited the peroxidation of linolenic acid in the TEARS assay (62 % inhibition at 37 pg mL ). 

In our own study on H. diffusa using chemical-based assays such as the ferric thiocyanate (FTC), thiobarbituric acid (TBA), and diphenylpicrylhydrazyl (DPPH) radical-scavenging methods [31], we found that both quercetin 3-0-/ -glucopyranoside (21) and quercetin 3-O- -rutinoside (22) inhibited linoleic acid peroxidation and also exhibited good DPPH radical-scavenging properties (87-88%) which was comparable to vitamin C (93%). We also found asperuloside to be inactive in both assays. 

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