Study on stability of components and antioxidative activity of a γ-ray irradiated herb

This study was performed to investigate the stability of components and antioxidative activities of a gamma irradiated herb, Astragalus Membranaceus Bunge (AMB). The chemical components of gamma-irradiated and non-irradiated AMB were analyzed by HPLC, and their antioxidative activities were also evaluated in scavenging of DPPH radical and inhibition of lipid peroxidation. For HPLC analysis, calycosin, a major component, was isolated as a standard material, and EtOAc fractions were prepared from irradiated (10 kGy) and non-irradiated AMB. HPLC profile of the two EtOAc fractions showed almost same pattern. One major peak was detected during retention times (tR) at 15.07 min in irradiated sample, and at 15.09 min in non-irradiated sample, compared with calycosin (15.11 min). In the experiment of antioxidative effects, gamma-irradiated and non-irradiated samples also showed the same level of EDA value and lipid peroxidation inhibitory activity. These results suggest that chemical components and biological activities of AMB were not affected by gamma irradiation