Development of a photosensitive, high-throughput chip-based superoxide dismutase (SOD) assay to explore the radioprotective activity of herbal plants

Appropriate pharmacological interventions and modalities are needed to protect humans against the deleterious effects of ionizing radiation. We disclose a rapid chip-based approach to elucidate the radioprotective/antioxidant potential of herbal plants using a photodiode array (PDA) microchip system. Red light absorption property of nitroblue tetrazolium (NBT) formazan was applied to chip-based superoxide dismutase (SOD) activity measurements of six herbal plant extracts in a high-throughput manner. SOD activities obtained via gel-based assays were in line with the data obtained through the chip-based assay and hence validated our approach. Compared to amifostine, all the tested herbal plant extracts, except apricot kernel, demonstrated greater radioprotective properties. Among the tested herbal extracts, pueraria root showed the highest antioxidant/radioprotective activity and can be considered a preferred radioprotector candidate. Low standard deviations and high statistical confidence obtained during the assay prove the sensitivity and consistency of this approach. The developed approach has several advantages (simplicity, rapidness and portability) over existing methods and can be applied to high-throughput screening of the radioprotective properties of various unexplored plants species.