Jeon Kyung-Im, Park Eunju, Park Hae-Ryong, Jeon You-Jin, Cha Seon-Heui, Lee Seung-Cheol
Department of Food and Nutrition, Kyungnam University, Masan, Korea.
J Med Food. 2006 Spring;9(1):42-8. doi: 10.1089/jmf.2006.9.42.
The antioxidant activities of methanolic extracts of far-infrared irradiated rice hull (FRH) and non-irradiated intact rice hull (IRH) were determined. The antioxidant effects against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide, hydrogen peroxide (H2O2), and nitric oxide radical and capacity for chelating metals. Except for H2O2 scavenging activity, FRH showed higher scavenging activity than IRH; for example, the 50% inhibitory concentration (mg/mL) values for DPPH radical scavenging of FRH and IRH were 0.067 and 0.085, respectively, as compared with 0.362 and 0.012 for butylated hydroxytoluene and alpha-tocopherol, respectively. The effect of rice hull extract on DNA damage induced by H2O2 in human lymphocytes was also evaluated by comet assay. The protective effect of rice hull extract increased as its concentration increased from 12.5 to 50 microg/mL, as indicated by DNA strand breakage decreasing from 38% to 22% with FRH and from 49% to 28% with IRH as compared with H2O2-treated positive controls. When human lymphocytes were post-incubated with rice hull extract for 30 minutes after exposure to H2O2, the protective ability of the rice hulls remained unchanged. These results suggest that methanol extracts of rice hulls possess significant ROS scavenging and metal chelating activities and protective effect against oxidative DNA damage.
测定了远红外辐照稻壳(FRH)和未辐照完整稻壳(IRH)甲醇提取物的抗氧化活性。通过测量对1,1-二苯基-2-苦基肼(DPPH)自由基、超氧化物、过氧化氢(H2O2)和一氧化氮自由基的清除活性以及金属螯合能力,评估了对活性氧(ROS)的抗氧化作用。除H2O2清除活性外,FRH的清除活性高于IRH;例如,FRH和IRH对DPPH自由基清除的50%抑制浓度(mg/mL)值分别为0.067和0.085,而丁基羟基甲苯和α-生育酚的该值分别为0.362和0.012。还通过彗星试验评估了稻壳提取物对H2O2诱导的人淋巴细胞DNA损伤的影响。稻壳提取物的保护作用随着其浓度从12.5增加到50μg/mL而增强,与H2O2处理的阳性对照相比,FRH处理组的DNA链断裂从38%降至22%,IRH处理组从49%降至28%。当人淋巴细胞在暴露于H2O2后与稻壳提取物孵育30分钟时,稻壳的保护能力保持不变。这些结果表明,稻壳甲醇提取物具有显著的ROS清除和金属螯合活性以及对氧化性DNA损伤的保护作用。