Validation of Sennae Folium specification grade classification based on UPLC-Q-TOF/MS spectrum-effect relationship

Sennae Folium (SF) has been consumed as a fat-reducing tea throughout the world due to its laxative effect. However, little attention has been paid to the impact of the specification grade classification on its quality. The present work aims to verify the rationality of the specification grade classification of SF and investigate the quality markers for distinction of different SF grades. Based on the use of ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) method, and with the help of molecular networking, 60 compounds of the SF extracts were tentatively identified. 22 differential compounds were screened via chemometrics for distinguishing different grades of SF, including 8 sennosides and anthraquinones, 11 flavonoids, and 3 benzophenones. The strongest lipase inhibitory activity was identified in the extract taken from the green leaves. Correlation analysis of their chemical compositions and lipase inhibitory activity indicated that SF of the green leaf contained the highest amount of sennosides and showed the strongest lipid-lowering effect. In conclusion, the combination of molecular networking and spectrum-effect relationships showed that the specification grade classification of SF according to green leaf, yellow leaf, and diseased leaf was reasonable, and sennosides could serve as quality markers for distinguishing different grades of SF.