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Total Antioxidant Activity Screening

Free radicals and reactive oxygen species (ROS) are highly reactive molecules that are generated by normal cellular processes, environmental stresses, and UV irradiation. ROS react with cellular components, damaging DNA, carbohydrates, proteins, and lipids causing cellular and tissue injury. Excess production of reactive oxygen species can also lead to inflammation, premature aging disorders, and several disease states, including cancer, diabetes, and atherosclerosis. Organisms have developed complex antioxidant systems to protect themselves from oxidative stress, however, excess ROS can overwhelm the systems and cause severe damage.

Zen-Bio offers two screening methods for evaluating the total antioxidant activity of compounds or extracts: ABTS and ORAC antioxidant assays. Both assays can determine the total antioxidant capacity of biological fluids, cells, tissue, and naturally occurring or synthetic compounds for use as dietary supplements, topical protection, and therapeutics.

The ABTS assay measures ABTS.+ radical cation formation induced by metmyoglobin and hydrogen peroxide. Trolox [6-Hydroxy-2,5,7, 8-tetramethylchroman-2-carboxylic acid], a water soluble vitamin E analog, serves as a positive control inhibiting the formation of the radical cation in a dose dependent manner. The antioxidant activity in biological fluids, cells, tissues, and natural extracts can be normalized to equivalent Trolox units to quantify the composite antioxidant activity present. This assay measures radical scavenging by electron donation.

The ORAC (Oxygen Radical Absorbance Capacity) antioxidant assay measures the loss of fluorescein fluorescence over time due to peroxyl-radical formation by the breakdown of AAPH (2,2.-azobis-2-methyl-propanimidamide, dihydrochloride). Trolox [6-Hydroxy-2,5,7, 8-tetramethylchroman-2-carboxylic acid], a water soluble vitamin E analog, serves as a positive control inhibiting fluorescein decay in a dose dependent manner. The ORAC assay is a kinetic assay measuring fluroescein decay and antioxidant protection over time. The antioxidant activity in biological fluids, cells, tissues, and natural extracts can be normalized to equivalent Trolox units to quantify the composite antioxidant activity present. This assay measures antioxidant activity by hydrogen atom transfer.

Effects of antioxidants in ABTS assay Trolox, Sodium L-ascorbate (L-Asc),Epigallocatechin gallate (EGCG), and Gallic acid (Gallic) were tested for their antioxidant activity in the ABTS antioxidant assay.
Effects of antioxidants in ORAC assay Trolox, Sodium L-ascorbate,Epigallocatechin gallate (EGCG), and Gallic acid were tested for their antioxidant activity in the ORAC Antioxidant assay.

Ordering Information

Item#Item DescU/MPrice
CA-120ABTS Total Antioxidant AssayCall
CA-121ORAC Total Antioxidant AssayCall
CA-122Combined ABTS and ORAC Total Antioxidant Assay TestCall
Prices for contract services vary depending on number of sample numbers, special conditions, compound solubility, etc. Minimum charges will apply.
Please contact us for detailed information and a price quote on your project.

To learn more about our services, please contact our Services Team

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