Mapping Cutaneous Tissue Distribution of Sesquiterpene Lactone Goyazensolide Using MALDI Imaging

Species of Lychnophora, popularly known in Brazil as “arnica-da-serra,” are widely used in topical preparations as analgesics and anti-inflammatories, in which the most commonly used species is Lychnophora ericoides Mart., Asteraceae. The studies of seasonal and circadian rhythms in L. ericoides to the production of the secondary metabolites show greater stability for phenolic constituents. On the other hand, sesquiterpene lactones from L. ericoides showed seasonal variations in their concentrations. Herbalists often report that seasonality influences the increase of lactone levels in leaves, which may have increased the allergenic potential. In the present study, we sought to develop a methodology for imaging tissues treated with solutions of the sesquiterpene lactone goyazensolide to observe skin retention using the Franz cell model. To this end, MALDI-MS parameters were optimized for imaging generation, and an LC-MS/MS protocol was used to confirm goyazensolide skin retention. The obtained data revealed that sesquiterpene lactones strongly bind to the stratum corneum of the skin.