Determination of antioxidant activities of berries and resveratrol

There has been growing interest in the health benefits of fruits with the emphasis on antioxidants. Berries contain considerable amounts of chemicals referred to as phenolic compounds which have been identified as an important source of antioxidants. The determination of antioxidant capabilities of various berries and resveratrol by reducing 1,1-Diphenyl-2-picrylhydrazyl (DPPH) essay was designed as an experiment for general, analytical, and introductory biochemistry laboratories. The reduced DPPH radical is colorimetrically analyzed by UV-Vis spectrophotometry to determine the IC50, which is the concentration of an antioxidant at which 50% inhibition of free radical activity is observed. This experiment acquaints students with free radicals and their scavengers, solution preparation, the extraction of a natural product, and UV-Vis spectroscopy. Unlike so many undergraduate laboratory experiments, the procedure does not utilize any toxic reagents. Students gain an understanding of the overlap among the different fields of chemistry and the concept of green chemistry.