Determination of antioxidant capacity in some foods by oxygen radical absorbance capacity (ORAC)

Oxygen radical absorbance capacity (ORAC) assay has been applied to determine the Hydrophilic – ORAC index in food. The method measures antioxidant scavenging activity against peroxyl radical induced by 2,2′-azobis(2-amidino-propane) dihydrochloride (AAPH) at 37ºC, used fluororescein as the fluorescent probe. The antioxidant capacity is measured by assemssing the fluorescence decay curve (AUC) of the sample as compared to that of the blank in which no antioxidant is present. Results expressed in ORAC units, equivalent to micromole Trolox per 100 grams sample (Trolox equivalent). The method was shown with high selectivity, a wide linear range, from 5 to 50µM Trolox with linear coefficient R2 = 0.9987. The recovery from 93.2% to 104.4% and repeatability (RSD) was less than 6.60%. The limits of detection and quantitation were 5 and 10µM Trolox, respectively. The method has been applied to determine of H-ORAC index in 65 samples including vegetables, fruits, vegetable products and health supplements with content ranging from 720 µM TE/100g to 310878 µM TE/100g.

Two New Acylated Sucroses From the Roots of Canna indica L. and Their Antioxidant Activity

Two new acylated sucroses, (6- O-axetoxyl)- β-d-fructofuranosyl-(2→1)-(6- O-feruloyl- α- d-glucopyranoside (1) and (6- O-axetoxyl)- β-d-fructofuranosyl-(2→1)-(6- O-( E)- p-coumaroyl- α- d-glucopyranoside (2), and four known compounds, 2-(3′,4′-dihydroxyphenyl)-1-propanol-4′- O-[4′′′-hydroxy-3′′′,5′′′-dimethoxybenzoyl-(→6′′)- β-d-fructofuranoside (3), tryptophol glucoside (4), corchonoside C (5), and 2-hydroxy-5-(2-hydroxyethyl)phenyl β-d-fructofuranoside (6), were isolated from the roots of Canna indica L. (Cannaceae). Their structures were determined by extensive analysis of HR-ESI-MS, 1D, and 2D NMR spectral data, as well as by comparison of these with those reported in the literature. Antioxidant activity of compounds 1-6 were evaluated by peroxyl radical absorbance capacity assay. Compounds 1 and 3 neutralized high amounts of peroxyl radical. At a concentration of 1 µM, their ORACROO* values were 3.07 ± 0.15 and 4.27 ± 0.30, respectively, many times greater than that of trolox, which was used as an internal standard. At 10 µM, the peroxyl radical absorbance capacity of compounds 1 and 3 exhibited equivalents to 15.60 ± 0.22 and 24.91 ± 0.43 times the net protection by 1 µM of trolox.

Dysregulation of Catalase by a Sulphamoylated Estradiol Analogue Culminates in Antimitotic Activity and Cell Death Induction in Breast Cancer Cell Lines

Recent findings revealed that 2-ethyl-17-oxoestra-1,3,5(10)-trien-3-yl sulfamate (ESE-one) induces antiproliferative activity and cell rounding dependent on the generation of superoxide anion, hydrogen peroxide and peroxyl radical. In the current study, the role of these reactive oxygen species was assessed in the activity exerted by ESE-one on cell cycle progression, mitochondrial membrane potential and cell death induction in breast tumorigenic cells. The influence of ESE-one was also investigated on superoxide dismutase and catalase activity. ESE-one induced a time-dependent accumulation of cells in the G1 phase and G2/M phase that is partially impaired by tiron and trolox and N,N′-dimethylthiourea suggesting that superoxide anion, hydrogen peroxide and peroxyl radical are required for these effects exerted by ESE-one. Flow cytometry data in MCF-7 cells demonstrated that tiron decreased depolarization of the membrane potential in ESE-one exposed cells, indicating that superoxide anion plays a role in the depolarization effects induced by ESE-one. Spectrophotometry data showed that ESE-one decreased catalase activity in both cell lines. This study contributes towards pertinent information regarding the effects of an in silico-designed sulfamoylated compound on antioxidant enzymes leading to aberrant quantities of specific reactive oxygen species resulting in antimitotic activity culminating in the induction of cell death in breast cancer cell lines.