Structural and Quantitative Analysis of Three C-Glycosylflavones by Variable Temperature Proton Quantitative Nuclear Magnetic Resonance

Quantitative nuclear magnetic resonance is a powerful tool in drug analysis because of its speed,precision,and efficiency. in present study,the application of variable temperature proton quantitative nuclear magnetic resonance (vt-1h-qnmr) for the calibration of three c-glycosylflavones including orientin,isoorientin,and schaftoside as reference substances was reported. since there was conformational equilibrium due to the restricted rotation around the c(sp3)-c(sp2) bond in c-glycosylflavones,the conformational behaviors were investigated by vt-nmr and verified by molecular mechanics (mm) calculation. the vt-1h-qnmr method was validated including the linearity,limit of quantification,precision,and stability. the results were consistent with those obtained from mass balance approach. vt-1h-qnmr can be deployed as an effective tool in analyzing c-glycosylflavones. © 2017 jing liu et al.