CAJ | 학술논문

传统的DPPH 自由基清除活性评价方法以半数清除浓度 EC50为评价指标，但 EC50随DPPH 初始加入量增加而增加，随分析体积增加而减小，因此，不同条件EC50值不具有可比性。提出以DPPH 与抗氧化剂相互反应的化学计量数比（R）作为评价DPPH 清除活性的指标，该指标只与DPPH 与抗氧化剂相互反应的化学计量关系有关，与DPPH 初始加入量和分析体积等因素无关，解决了EC50可比性差的问题。提出了测定化学计量数比（R）的光度微量滴定法，建立了利用滴定过程吸光度差（ΔA）与抗氧化剂加入量之间的滴定方程计算R值、以R计算EC50的光度微量滴定模型，并利用芦丁对模型进行验证。结果：芦丁与DPPH反应R值在1．817～1．846之间，当DPPH 加入量为1．12×10－7，2．24×10－7，4．48×10－7和6．72×10－7 mol时，分别计算得EC50值分别为1．196×10－3，2．392×10－3，4．819×10－3和7．292×10－3 mg·mL－1。在此基础上，基于文献报道的芦丁清除DPPH 条件，利用得到的芦丁R值计算出相应EC50，结果与文献报道EC50值相当。方法可比性好，样品消耗量明显降低，简单、成本低，结果可靠，为自由基清除活性评价提出了一种新的思路。
전통적DPPH 자유기청제활성평개방법이반수청제농도 EC50위평개지표，단 EC50수DPPH 초시가입량증가이증가，수분석체적증가이감소，인차，불동조건EC50치불구유가비성。제출이DPPH 여항양화제상호반응적화학계량수비（R）작위평개DPPH 청제활성적지표，해지표지여DPPH 여항양화제상호반응적화학계량관계유관，여DPPH 초시가입량화분석체적등인소무관，해결료EC50가비성차적문제。제출료측정화학계량수비（R）적광도미량적정법，건립료이용적정과정흡광도차（ΔA）여항양화제가입량지간적적정방정계산R치、이R계산EC50적광도미량적정모형，병이용호정대모형진행험증。결과：호정여DPPH반응R치재1．817～1．846지간，당DPPH 가입량위1．12×10－7，2．24×10－7，4．48×10－7화6．72×10－7 mol시，분별계산득EC50치분별위1．196×10－3，2．392×10－3，4．819×10－3화7．292×10－3 mg·mL－1。재차기출상，기우문헌보도적호정청제DPPH 조건，이용득도적호정R치계산출상응EC50，결과여문헌보도EC50치상당。방법가비성호，양품소모량명현강저，간단、성본저，결과가고，위자유기청제활성평개제출료일충신적사로。
In the present paper,the stoichiometric ratio (R)for the interreaction of DPPH radicals with the antoxidant was em-ployed as a evaluation index for DPPH radicals scavenging activity of antioxidants.This evaluation index was related only with the stoichiometric relationship between DPPH radicals and the antioxidant,not the relationship with the initial DPPH amount and the volume of sample,which could offer a solution for the problem of poor comparability of EC50 under different conditions. A novel photometric micro-titration method was proposed for the determination of the stoichiometric ratio (R)for the interreac-tion of DPPH radicals with the antoxidant.The titration equation was established based on the absorbance difference (ΔA)of DPPH radicals in the titration process and the added amount of antoxidant.The stoichiometric ratio (R)for the reaction of DP-PH radicals with the addition amount of antoxidant was determined by the titration equation obtained,while,the DPPH median elimination concentration (EC50 )of antoxidant can be calculated by the stoichiometric ratio (R).The above photometric micro-ti-tration model was verified using rutin as DPPH radicals scavenger.As experiment results,the stoichiometric ratio (R)of DPPH radicals to rutin was determined to be in the range of 1. 817~1. 846.The calculated value of EC50 was 1. 196×10-3 ,2. 392× 10-3 ,4. 819×10-3 and 7. 292×10-3 mg·mL-1 for 1. 12×10-7 ,2. 24×10-7 ,4. 48×10-7 and 6. 72×10-7 mol of the addition amount of DPPH radicals,respectively.The proposed method has better precision and reliability with smaller amount of sample than conventional method.While,the obtained stoichiometric ratio value (R)of rutin was employed to calculate the rutin median elimination concentration for DPPH (EC50 )according to the conditions as reported in the literatures,and the calculated results were consistent with that reported in the literatures.