title: Stability studies on trans-rosmarinic acid and GC-MS analysis of its degradation product.
abstract: The stability of trans-rosmarinic acid (trans-RA, an important phenolic compound with anti-oxidant, anti-inflammatory, anti-bacterial, and anti-viral properties) exposed to different stress conditions (daylight, higher temperatures, different solvents, and humidity) was investigated. Gas chromatography-mass spectrometry (GC-MS) was used to analyse the degraded samples, and structural identification of degradation products was assigned based upon MS fragmentation pattern. The GC-MS method was validated in terms of linearity, precision as repeatability, accuracy, limit of detection (LOD), limit of quantitation (LOQ) and recovery. The stability experiments were performed on pure trans-RA and on trans-RA present in commercially available rosemary extract. The cis-isomer of RA was the only degradation product. The results showed that trans-RA was readily isomerized into its cis-form within a few hours when dissolved in ethanol, methanol or tetrahydrofuran, and exposed to darkness or daylight at different temperatures. Isomerization took place to a greater extent in protic than in aprotic solvents. Trans-RA in the solid state was found to be stable for up to three months under all tested conditions. The described GC-MS method was also applied to the determination of trans-RA in eight different species of Lamiaceae family.
authors.affiliation: University of Maribor, Faculty of Chemistry and Chemical Engineering, Smetanova 17, 2000 Maribor, Slovenia. masa.islamcevic@uni-mb.si
authors.forename: Maša Islamčević
authors.initials: MI
authors.lastname: Razboršek
mesh_terms: D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002934:Cinnamates / Q000032:analysis*; D053630:Depsides / Q000032:analysis*; D000431:Ethanol / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007536:Isomerism; D057230:Limit of Detection; D000432:Methanol / Q000737:chemistry; D008956:Models, Chemical; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D000097123:Rosmarinic Acid
chemical_list: D002934:Cinnamates; D053630:Depsides; D000431:Ethanol; D005663:Furans; D000432:Methanol; D012997:Solvents; D000097123:Rosmarinic Acid; C018674:tetrahydrofuran