Spectrum-effect relationship between UPLC fingerprints and melanogenic effect of Ruta graveolens L.

A total of 29 batches of R. graveolens were used in this study, their fingerprints were obtained by ultra-performance liquid chromatography (UPLC) and their melanogenesis activities were evaluated. The common peaks were identified by quadrupole-orbitrap high-resolution mass spectrometry (Q-Orbitrap-HRMS). Eleven coumarins, six alkaloids, three flavonoids, three phenolic acids, and four other compounds were found. The spectrum-effect relationships between R. graveolens' chemical fingerprints, the melanin synthesis, and tyrosine's activation activities were established through chemometrics methods which in detail principal component analysis (PCA), gray correlation analysis (GRA), bivariate correlation analysis (BCA) and orthogonal partial least squares analysis (OPLS). The results showed that P18 (bergapten), P22 (isoimperatorin), P15 (kokusaginine), P7 (rutin), P12 (psoralen), and P13 (graveolinine) were relevant to intracellular melanin synthesis activity and tyrosinase activity. Among them, P18 (bergapten), P15 (kokusaginine), and P12 (psoralen) were validated with good melanogenesis activities. This study provides a research basis for future quality control and medicinal application of R. graveolens.