From chemical markers to quality markers: an integrated approach of UPLC/Q-TOF, NIRS, and chemometrics for the quality assessment of honeysuckle buds†
Because of the poor discovery rate of relatively effective components and elusive component-effect correlation, formulating a quality control system for Chinese herbal medicines (CHMs) has been a great challenge for quality management. In this paper, the concept of the quality marker (Q-marker) was used, and a set of integrated strategies to improve the chemical markers of the Q-markers was introduced. Two often confused CHMs, Lonicera japonica flos (LJF) and Lonicera flos (LF), which are of the same genus but different species, are illustrated to quickly evaluate their potency. Ultra-performance liquid chromatography-quadrupole/time-of-flight (UPLC/Q-TOF) with partial least squares-discriminant analysis (PLS-DA) was used to screen the chemical markers for their herbal origin identification; then, a bioactive-guided evaluation method was performed to detect the Q-markers. As a result, four NF-κB inhibitors were proposed to be representative Q-markers for the anti-inflammatories: 3-O-caffeoylquinic acid (CA), 3,5-O-dicaffeoylquinic acid (3,5-diCQA), `iamarin, and vogeloside. After the chemometrics study, near-infrared spectroscopy (NIRS) based on the distinctive wavenumber points from the Q-markers was developed for its distinction and determination capabilities by optimum siPLS-CARS analysis (OPSC). Then, the back propagating-artificial neutral network (BP-ANN) algorithm was used to clarify the non-linear relationship between the Q-markers and their integral anti-inflammation effect. Finally, convenient and reliable fast quantitative analysis and holistic bioactivity assessment patterns were established by NIRS for the quality management of honeysuckle buds. The integrated Q-marker screen and NIRS assessment strategy was suitable for a fast quality evaluation of herbal medicines and was applied to the quality control of botanical functional foods.