摘要
天然产物芸香柚皮苷(Nrt)和表没食子儿茶素没食子酸酯(EGCG)都具有抗氧化等多种生理活性,为研究两者之间的协同抗氧化效应,将Nrt与EGCG以不同物质的量比(1∶1,1∶5,1∶10)混合,做ABTS+,DPPH和FRAP 3种抗氧化分析,结果表明:相同浓度下,两者混合后对DPPH与ABTS+的清除率明显优于Nrt或EGCG单独测定时的清除率,表明Nrt与EGCG具有显著的协同抗氧化增效作用;在FRAP体系中,Nrt与EGCG并未发挥明显的协同增效作用。采用核磁共振技术(1H-NMR,DOSY,ROESY)从分子结构层面分析其机理,结果发现Nrt与EGCG形成稳定的复合物(Nrt-EGCG),该复合物导致Nrt分子中目标原子(H2′,H6′,H3′,H5′,H8,H6,H2)的化学位移值(Δδ,0.05~0.48 ppm)和在梯度磁场中的扩散系数值(ΔD,0.50~0.81)均发生明显变化,并且通过ROE信号推断出两者的结合位点与方式,即Nrt分子中的B环与EGCG分子中的G环之间是通过pi-pi相互作用或范德华力相互作用来维系复合物的稳定结构。
Narirutin（Nrt） and Epigallocatechin gallate（EGCG） are natural products with various bioactivities such as antioxidant activity. To study the synergistic antioxidant effect of the two compounds, Nrt and EGCG were mixed at mole ratio of 1∶1, 1∶5 and 1∶10 respectively, and the antioxidant activity of Nrt, EGCG, and the mixture were estimated by ABTS＋, DPPH, and FRAP assays. As a result, the ABTS＋, DPPH free radical scavenging activity of the mixture were significantly stronger than the free Nrt or EGCG, which indicated the synergistic antioxidant enhancement of Nrt and EGCG. However, there was no significant synergistic antioxidant enhancement of Nrt and EGCG in FRAP system. The mechanism was investigated by1 H-NMR, DOSY, ROESY methods at the molecular level. It was found that Nrt complexed with EGCG and the complexation caused changes in both the chemical shift（0.01 ～0.29 ppm） and the diffusion coefficient（ΔD, 0.39～1.19） of Nrt（H2′, H6′, H3′, H5′, H8, H6, H2）. The ROE signal implied that the B ring in Nrt was in proximity to G ring in EGCG, pi-pi interaction or/and van der waals force might play an important role in stable this structure.
作者
曹汝鸽
马建飞
周中凯
Cao Ruge;Ma Jianfei;Zhou Zhongkai(College of Food Engineering and Biotechnology, Tianjin University of Science ＆ Technology, Tianjin 30045)
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2018年第1期42-48,共7页
Journal of Chinese Institute Of Food Science and Technology
基金
国家自然科学基金-青年基金项目(31601477)
天津市应用基础与前沿技术研究计划项目(15JCYBJC55200)
作者简介
曹汝鸽，女，1987年出生，博士，副教授;通讯作者：周中凯E-mail：zkzhou@tust．edu．cn
