ORAC assay was developed as an analytical tool for estimating the antioxidant capacity of substances. It was an important advancement in commercially available analysis and has become a de facto standard in the natural products industry.
- The ORAC method was considered a starting spot – not a definitive endpoint – for comprehensive antioxidant analysis.
- The original ORAC method is not a universal standard – it favors certain antioxidant substances over others (e.g. anthocyanins over carotenoids) due to the use of only one free radical source (peroxyl radical).
- There now is a complementary suite of assays based on a unified ORAC chemistry that broadens the analytical scope of antioxidant testing.
This new ORAC-based suite is called ORAC 6.0. It expands the ORAC platform to measure antioxidant capacity against five primary reactive oxygen species (commonly referred to as radicals): peroxyl, hydroxyl, peroxynitrite, superoxide anion, singlet oxygen, and hypochlorite.
ORAC 6.0 substantially improves broad-spectrum antioxidant analysis and gives evidence of the diverse antioxidant potential of natural products against radicals other than peroxyl. In some instances this potential may be specialized (e.g. carotenoids vs. singlet oxygen); in other cases, there is balanced antioxidant performance against multiple radicals. Compounds such as resveratrol and standardized ingredients such as green tea extract exhibit significant broad-spectrum antioxidant capacity.
The six primary radicals all contribute to the same outcomes—oxidative damage and corresponding disease states — and have unique characteristics that need to be addressed. Like position players on a sports team, antioxidant substances have different skill sets. ORAC 6.0 measures how antioxidants perform against different radical opponents.