DPPH free radical scavenging activity

Chandrasekar, D., K. Madhusudhana, S. Ramakrishna, and P. V. Diwan. 2006. Determination of DPPH free radical scavenging activity by reversed-phase HPFC A sensitive screening method for polyherbal formulations. Journal of Pharmaceutical and Biomedical Analysis 40(2) 460-464. 

FREE RADICAL SCAVENGING ACTIVITY 15.4.1 DPPH Free Radical Scavenging Activity... 

Measurement of DPPH Free Radicals Scavenge Activity... 

In the present study, carnosol, camosic acid and rosmarinic acid showed effective DPPH free radicals scavenging activity. Camosic acid, carnosol, rosmarinic acid and ursolic acid effectively inhibited pUC19 DNA strand break induced by Fenton reaction (28). The reaction of iron (II) with hydrogen peroxide is generally considered to yield the hydroxyl radicals (29). These compounds may react with and/or scavenge the hydroxyl radicals produced by Fenton reaction. 

In this study, we used a DPPH free radical scavenging activity directed identification process to pinpoint the antioxidants from the dried bark of Du-zhong and to elucidate their chemical structures as well as to compare their antioxidant capacities. 

The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) method was used to investigate the scavenging activity of tea samples. The data for DPPH free radical scavenging activity, measured as scavenging percentage at room temperature after addition of various fermented tea infiisions are presented in Figure 3. DPPH free radical scavenging activity of tea infusion inoculated with A. aceti and A. xylinum increased with incubation time up to 22.1% and 21.9%,... 

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. 

Free radical scavenging activity was assessed using the DPPH (1, 1-di-phenyl-2-picrylhydrazyl) assay as described by Harbilas et al. [22] with incubation time increased to 65 min. Briefly, 250 tiL of 100 timol/L DPPH dissolved in methanol was added to 40 p.L of extract (tested at 5 concentrations) in a microplate well. A standard curve of ascorbic acid (positive control) was included as a reference and all data were blanked against a treatment with only methanol. Absorbance was read with a microplate reader at 517 nm. The inhibitory concentration for 50% scavenging (IC50) of each extract was calculated and compared to the IC50 of the ascorbic acid standard curve. 

Xanthosoma violaceum, Araceae, widely distributed in Dominican Republic, Puerto Rico, Guatemala, and Equator, was investigated for in vitro antioxidant and free-radical scavenger activities. The fraction rich in C-glycosylflavones showed with l,l-diphenyl-2-picryl-hydrazyl radical (DPPH) test an EC50 of 11.6 pg/ml, compared with quercetin (2.3 pg/ml) and a-tocopherol (10.1 pg/ml). 

A19. Atsumi, T., Iwakura, I., Kashiwagi, Y., Fujisawa, S., and Ueha, T., Free radical scavenging activity in the nonenzymatic fraction of human saliva A simple DPPH assay showing the effect of physical exercise. Antioxid. Redox Signal. 1, 537-546 (1999). 

DPPH (l,l-diphenyl-2-picryhydrazyl) is a purple-colored stable free radical that is reduced to the yellow-colored diphenylpicrylhydrazine by free radicals. The DPPH assay measures one electron, such as hydrogen atom donating activity and hence provides a measure of free radical scavenging activity. This assay is suitable for the initial screening of multiple samples, such as plant extracts. Reaction mixtures containing test samples dissolved in DMSO and DPPH in absolute ethanol are incubated at 37°C for 30 min in a 96-well plate and absorbance measured at 515 nm. ... 

Famesylhydroquinone 330 was isolated from the mycelium of a marine-derived fungus of the genus Penicillium. This compound exhibited potent free radical scavenging activity (IC50, 12.5 pM) against the DPPH. 

Most stilbenoids possess antioxidant activities because they possess polyphenol functions in the molecules. Some of their beneficial effects, hepatoprotective action, cardiovascular protection, for instance, are in close relation to their antioxidant activities. Several models have been employed in the assay such as lipid peroxidation system, human low-density lipoprotein model, xanthine oxidase system and l,l-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging model, which is the most commonly used protocol. 

Several free radical scavenging activity tests (hydrogen peroxide, superoxide, and DPPH) have been employed to evaluate the extracts of hazelnut kernel and hazelnut by-products. This information... 

The EO of Ziziphora clinopodioid.es ssp. rigida (blue mint bush) was isolated by hydrodistillation of the dried aerial parts, which was collected during the anthesis. The main compounds are thymol and 1,8-cineole with a content of 8% and 2.7%, respectively. Different extracts were tested by the DPPH assay to determine the antioxidative activity and showed that the free radical scavenging activity of the menthol extract was superior to all other extracts. Polar extracts exhibited stronger antioxidant activity than nonpolar extracts (Salehi et al., 2005). 

Antioxidant activity of petroleum ether, chloroform, ethyl acetate and methanol extracts of Usnea pictoides lichen was determined by DPPH free radical scavenging assay and ferric reducing assay (Pavithra et al. 2013). The scavenging potential of methanol extract was higher than other extracts, and also, in ferric reducing assay, methanol extract showed stronger reducing power than other extracts. 

Brisdelli et al. (2013) investigated the effects of six lichen metabolites (diffractaic acid, lobaric acid, usnic acid, vicanicin, variolaric acid, protolichesterinic acid) on reactive oxygen species (ROS) level towards three human cancer cell lines, MCF-7 (breast adenocarcinoma), HeLa (cervix adenocarcinoma) and HCT-116 (colon carcinoma). AU tested lichen compounds did not exhibit free radical scavenging activity using the l,l-diphenyl-2-picrylhydrazyl (DPPH) assay. The lichen metabolites did not significantly increase the intracellular ROS level and did not prevent oxidative injury induced by t-butyl hydroperoxide in tested cells. 

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