Electron Spin Resonance (ESR) studies on radical scavenging activity of gamma ray irradiated pepper

The properties of radicals induced in the gamma ray irradiated pepper were investigated by means of spin trapping method and CW-ESR spectroscopy. Three radicals were found in the specimens irrespective of irradiation. The representative ESR spectrum of pepper is composed of a sextet centered at g = 2.0, a singlet at the same g-value, and a singlet at g = 4.0. The first signal is attributable to a signal with hyperfine interaction of the Mn2+. The second signal is due to an organic free radical. The third signal is originate from the Fe3+. Upon irradiation, a new radical was found. The peak intensity of the irradiated pepper was almost 4 times greater than that of the non-treated pepper. The radical scavenging activity increased upon the irradiation as evaluated by the ESR spin trap method. We revealed that radicals were produced and the radical scavenging activity substantially increased by the irradiation.