Changes in Anti-Oxidation and Sugar Degradation Enzyme Activities of Ixeris dentata NAKAI Extract with Gamma Irradiation

Abstract

This study was designed to investigate the effects of different doses of gamma irradiation on the anti-oxidative activities, sugar degradation enzyme activity, and extraction yields of Ilxeris dentata NAKAI. Physical techniques to identify irradiation, namely photostimulated luminescence, thermoluminescence and electron spin resonance, confirmed that Ilxeris dentata NAKAI was gamma-irradiated. The total phenolics content (TPC) was higher in extracts from irradiated Ilxeris dentata NAKAI than from non-irradiated (0 kGy) samples. The inhibition of DPPH radical scavenging activity by water extracts from 0 kGy and 10 kGy irradiated Ilxeris dentata NAKAI was very high at over 80% each. The inhibition of ABTS radical cation activity by the water extracts from 0 kGy and 10 kGy irradiated Ilxeris dentata NAKAI was also very high at over 99% each, at 200 μg/mL TPC concentration. The antioxidant protection factor (PF) in the water extract from 10 kGy irradiated Ilxeris dentata NAKAI showed a very high level of activity at 1.41∼3.06 PF at 50∼200 μg/mL TPC concentrations. The thiobarbituric acid reactive substances in the water extract from 10 kGy irradiated Ilxeris dentata NAKAI showed high levels of 85.22∼98.57% inhibition at 50∼200 μg/mL TPC concentration. The pancreatin α-amylase inhibitory activities were high at 38.52∼100.00% at 50∼200 μg/mL TPC concentrations of water extract with 10 kGy irradiation doses. These results suggest an enhancement of extraction yields of phenolic compounds and biological activities from Ilxeris dentata NAKAI by gamma ray irradiation at 10 kGy. Also, treatment by gamma-irradiation can be used to amplify the solubility of biologically active compounds in plants.