An LC/MS/MS Method for the Analysis of Furocoumarins in Citrus Oil

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.

Ecometabolomic Analysis of Wild Populations of Pilocarpus pennatifolius (Rutaceae) Using Unimodal Analyses

Studies examining the diversity of plant specialized metabolites suggest that biotic and abiotic pressures greatly influence the qualitative and quantitative diversity found in a species. Large geographic distributions expose a species to a great variety of environmental pressures, thus providing an enormous opportunity for expression of environmental plasticity. Pilocarpus, a neotropical genus of Rutaceae, is rich in alkaloids, terpenoids, and coumarins, and is the only commercial source of the alkaloid pilocarpine for the treatment of glaucoma. Overharvesting of species in this genus for pilocarpine, has threatened natural populations of the species. The aim of this research was to understand how adaptation to environmental variation shapes the metabolome in multiple populations of the widespread species Pilocarpus pennatifolius. LCMS data from alkaloid and phenolic extracts of leaf tissue were analyzed with environmental predictors using unimodal unconstrained and constrained ordination methods for an untargeted metabolomics analysis. PLS-DA was used to further confirm the chemoecotypes of each site. The most important variables contributing to the alkaloid variation between the sites: mean temperature of wettest quarter, as well as the soil content of phosphorus, magnesium, and base saturation (V%). The most important contributing to the phenolic variation between the sites: mean temperature of the wettest quarter, temperature seasonality, calcium and soil electrical conductivity. This research will have broad implications in a variety of areas including biocontrol for pests, environmental and ecological plant physiology, and strategies for species conservation maximizing phytochemical diversity.