Phytochemical profiling of Laurus nobilis L. leaf extracts with direct analysis in real-time mass spectrometry and HPLC-DAD

This work focuses on the extraction and analysis of polyphenols, more precisely flavonoid aglycones, from Algerian Laurus nobilis L. leaf extracts. The extraction of these bioactive substances was carried out according to a routine method with some modifications. Two main extraction steps were carried out. Hence, the first step was to solubilize flavonoids in methanol, followed by liquid–liquid extraction using ethyl acetate. The extract thus obtained was separated into six fractions by column chromatography. The identification of constituents was carried out by high-performance liquid chromatography (HPLC)-diode array detector and by comparing the ultra-violet spectra with those of standards. Accordingly, this method allowed the identification of six flavonoids among them: kaempferol, rutin, naringenin, and methoxyflavone. Moreover, these results were compared to those obtained using direct analysis in real time, time-of-flight-mass spectrometry. This convenient analytical technique not only confirmed the HPLC identification but also allowed characterization of other compounds in the bay extracts (maltol, vanillin, safrole, vanillic acid, myristicin, valerenic acid, and rhamnetin).