Chemical characterization of three Thymus species: T. herba-barona, T. pseudolanuginosus and T. caespititius
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The genus Thymus, belonging to Lamiaceae family, is rich in medicinal and aromatic species and well-known by several health promoting activities [1,2]. Despite this genus has been extensively studied, some species remain unexploited. In this study, Thymus herba-barona, Thymus pseudolanuginosus and Thymus caespititius decoctions were screened for their phenolic constituents by ultra-high performance liquid chromatography coupled to diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI-MSn) operating in negative mode.
The three aqueous extracts were rich in caffeic acid derivatives, mainly rosmarinic acid (MW 359) and its structural isomers, that accounted for 55.8 ± 2.8 mg/g in T. herba-barona and 40.2 ± 0.9 and 43.2 ± 3.2 mg/g in T. pseudolanuginosus and T. caespititius, respectively. In turn, other depsides were differently distributed in the three Thyme extracts: while dihydro-salvianolic acid B (MW 716 Da) and caffeoyl rosmarinic acid were particularly representative in T. herba-barona, salvianolic acids K ([M-H]− at m/z 555 493 359) and B ( [M-H]− at m/z 717 519 475) were found in moderate amounts in T. caespititius extract. On the other hand, T. pseudolanuginosus was clearly distinguished by its richness in the flavone luteolin-O-glucuronide ([M − H]− at m/z 461→285).
Overall, this work is an important contribution for the phytochemical characterization of these three Thymus species, which are poorly explored.
The genus Thymus, belonging to Lamiaceae family, is rich in medicinal and aromatic species and well-known by several health promoting activities [1,2]. Despite this genus has been extensively studied, some species remain unexploited. In this study, Thymus herba-barona, Thymus pseudolanuginosus and Thymus caespititius decoctions were screened for their phenolic constituents by ultra-high performance liquid chromatography coupled to diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI-MSn) operating in negative mode.
The three aqueous extracts were rich in caffeic acid derivatives, mainly rosmarinic acid (MW 359) and its structural isomers, that accounted for 55.8 ± 2.8 mg/g in T. herba-barona and 40.2 ± 0.9 and 43.2 ± 3.2 mg/g in T. pseudolanuginosus and T. caespititius, respectively. In turn, other depsides were differently distributed in the three Thyme extracts: while dihydro-salvianolic acid B (MW 716 Da) and caffeoyl rosmarinic acid were particularly representative in T. herba-barona, salvianolic acids K ([M-H]− at m/z 555 493 359) and B ( [M-H]− at m/z 717 519 475) were found in moderate amounts in T. caespititius extract. On the other hand, T. pseudolanuginosus was clearly distinguished by its richness in the flavone luteolin-O-glucuronide ([M − H]− at m/z 461→285).
Overall, this work is an important contribution for the phytochemical characterization of these three Thymus species, which are poorly explored.
