CONICET | Buscador de Institutos y Recursos Humanos

Melissa officinalis L., ?melisa?, is rich in terpenoids, flavonoids and cinnamic, acid derivatives, with rosmarinic acid (RA) as the main component. In order to establish a quality control assay to evaluate this phenolic acid, factors such as stability and sensitivity to high temperature, exposure to UV radiation or air oxygen, and metal ions should be considered. Thus the aim of this work was to establish a rapid and sensitive method for the analysis of RA in M. officinalis derivatives considering the RA stability. The samples consisted of teas and tinctures prepared from dried ground plant material, obtained from both cultivated herbs and others available in the local herbal shops; spray dried extracts; freeze dried extracts; pellets, coated pellets, and Melissa-based commercial products. Water extracts were both analyzed directly and mechanically dried on a Mini-spray BÜCHI Dryer 290, at inlet temperatures ranging between 90 and 140 °C, with Aerosil® as carrier, and subsequently reconstituted. For photostability studies, samples were exposed to daylight at room temperature and were stored in a refrigerator under darkness conditions; for extreme thermal stability studies, one part of each sample was placed in an oven configured at 140 ◦C and 90% of humidity for a period of time. The analytical 2-minutes run LC-MS/MS methodology was validated and applied to the above-mentioned samples. In terms of stability, spry dried extracts stored from different years did show no aging variation. However, under extreme temperature and humidity conditions, the RA concentrations drop off abruptly. In addition, greater degradation was observed in pellets without coating. On the other hand, many of the commercially available M. officinalis products did not contain the specified RA.