Screening active ingredients of rosemary based on spectrum-effect relationships between UPLC fingerprint and vasorelaxant activity using three chemometrics.

Rosmarinus officinalis L., rosemary, is traditionally used to treat headache and improve cardiovascular disease partly due to its vasorelaxant activity, while the vasorelaxant ingredients remain unclear. In this study, chemical spectrum-pharmacological effect relationship (spectrum-effect relationship) was utilized for efficiently discovering the main vasorelaxant ingredients of rosemary. Ten kinds of rosemary extracts were prepared by different extracting solvents and macroporous resin purification, and their chemical components were analyzed by UPLC. At the same time, the vasorelaxant activities of the 10 kinds of rosemary extracts were estimated on isolated rat thoracic aorta, and three chemometrics named partial least squares regression (PLSR), grey correlation analysis (GRA), and the least absolute shrinkage and selection operator (LASSO) were applied to construct spectrum-effect relationship between the UPLC fingerprints and vasorelaxant activity of rosemary extracts. As a result, most rosemary extracts showed dose-dependent increase in vasorelaxant activity and five kinds of ingredients, including carnosol, carnosic acid, epirosmanol methyl ether, carnosol isomer, and augustic acid were screened as vasorelaxant ingredients. Further, the vasorelaxant activities of carnosic acid and carnosol were verified. Moreover, the increase of nitric oxide (NO) and the decrease of angiotensin-II (Ang-II) were thought to contribute to the vasorelaxant activity of rosemary.