Loganic acid

All reagents used in this work were at least of analytical reagent grade and used as received. SFE experiments were performed using CO₂ and ethanol as modifier. Solvents were purchased from Air Product and Chemicals (Allentown, PA, USA) and VWR chemicals (Radnor, PA, USA). Ottawa sand was provided by Fisher Scientific (Leicestershire, UK). Glass wool was acquired from Sigma-Aldrich (Steinhemin, Germany). LC-MS-grade acetonitrile was purchased from Fisher chemicals (Waltham, MA, USA) and double-deionized water (conductivity of <18.0 MΩ) was obtained using a Milli-Q system acquired from Millipore (Bedford, MA, USA). Formic acid was purchased from Sigma-Aldrich (Steinheim, Germany). Apigenin, loganic acid, kaempferol 3-glucoside, quercetin, and verbascoside were purchased either from Fluka, Sigma-Aldrich (Steinheim, Germany) or Extrasynthese (Genay Cedex, France).

L. citriodora was kindly provided by Monteloeder (Alicante, Spain) and their leaves were milled and stored protected from the light and moisture at room temperature. The encapsulating agents, MD (20 dextrose equivalent) and IN, were purchased by Fagron (Barcelona, Spain). Standard compounds: loganic acid, verbascoside, kaempferol-3-O-glucoside, quercetin and apigenin were provided by Sigma-Aldrich (Steinheim, Germany), Extrasynthese (Genay Cedex, Francia) orFluka (Steinheim, Germany). Additionally, water was purified by a Milli-Q system from Millipore (Bedford, MA, USA) and ethanol for extraction procedure was acquired from VWR chemicals (Radnor, PA, USA). HPLC-ESI-TOF-MS analyses were performed using Liquid Chromatography- Mass Spectrometry (LC-MS) grade acetonitrile provided by Fisher chemicals (Waltham, MA, USA) whereas formic acid was provided from Sigma-Aldrich. Extraction procedures for analytical purposes were carried out using acetic acid acquired from Sigma-Aldrich and methanol LC-MS (Fisher chemicals, Waltham, MA, USA).

Acetonitrile, formic acid, methanol, loganin, and loganic acid were purchased from Sigma-Aldrich (Steinheim, Germany). Chlorogenic, neoChlorogenic, cryptoChlorogenic, 3,5-dicaffeoylquinic acids, and luteolin- and apigenin-7-O-glucoside were purchased from Extrasynthese (Lyon, France).