Discovering the main "reinforce kidney to strengthening Yang" active components of salt Morinda officinalis based on the spectrum-effect relationship combined with chemometric methods

Morinda officinalis, a well-known traditional herbal medicine in China, is used to treat deficiency of kidney-yang syndrome. Although this medicine has the property of "reinforcing kidney to strengthening Yang," the chemical constituents responsible for this effect remain to be elucidated. Here, we aimed to identify the main active compounds responsible for reinforcing kidney to strengthening Yang, based on spectrum-effect relationships combined with chemometrics. We used the UPLC-diode array detection method to establish the chromatography fingerprint of M. officinalis. Hydrocortisone-induced and adenine-induced kidney-yang deficiency patterns were established to evaluate the efficacy of M. officinalis. Serum triiodothyronine, free thyroxine, thyrotropin, testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, corticotropin-releasing hormone, and adrenocorticotropic hormone levels were determined as pharmacodynamic indices. Analytic hierarchy process was used to determine the weight of each index to the total pharmacodynamic contribution. Lastly, the spectrum-effect between the fingerprint and the pharmacological effects were established using grey relational analysis and partial least squares. Our findings indicated that peaks 1, 2, 3, 5, 6, 7, 8, 9, 11, 13, 15, 17, and 20 might represent the main components that positively correlated to the total effect, of which four were identified by comparison with reference standards. The identified components were monotropein (peak 1), deacetyl asperulosidic acid (peak 3), asperulosidic acid (peak 8), and asperuloside (peak 9). Our results suggest that the "reinforce kidney to strengthening Yang" effects were attributable to the combined effects of the multiple chemical components of M. officinalis and provide a valuable method to identify the active "reinforce kidney to strengthening Yang" components of M. officinalis and establish the quality control of M. officinalis.