title: Effects of different extraction methods and conditions on the phenolic composition of mate tea extracts.
abstract: A simple and rapid HPLC method for determination of chlorogenic acid (5-O-caffeoylquinic acid) in mate tea extracts was developed and validated. The chromatography used isocratic elution with a mobile phase of aqueous 1.5% acetic acid-methanol (85:15, v/v). The flow rate was 0.8 mL/min and detection by UV at 325 nm. The method showed good selectivity, accuracy, repeatability and robustness, with detection limit of 0.26 mg/L and recovery of 97.76%. The developed method was applied for the determination of chlorogenic acid in mate tea extracts obtained by ethanol extraction and liquid carbon dioxide extraction with ethanol as co-solvent. Different ethanol concentrations were used (40, 50 and 60%, v/v) and liquid CO₂ extraction was performed at different pressures (50 and 100 bar) and constant temperature (27 ± 1 °C). Significant influence of extraction methods, conditions and solvent polarity on chlorogenic acid content, antioxidant activity and total phenolic and flavonoid content of mate tea extracts was established. The most efficient extraction solvent was liquid CO₂ with aqueous ethanol (40%) as co-solvent using an extraction pressure of 100 bar.
authors.affiliation: Department of Pharmacy, Medical Faculty, University of Novi Sad, Serbia. nevenagrujic@hotmail.com
authors.forename: Nevena
authors.initials: N
authors.lastname: Grujic
authors.forename: Zika
authors.initials: Z
authors.lastname: Lepojevic
authors.forename: Branislava
authors.initials: B
authors.lastname: Srdjenovic
authors.forename: Jelena
authors.initials: J
authors.lastname: Vladic
authors.forename: Jan
authors.initials: J
authors.lastname: Sudji
mesh_terms: D002726:Chlorogenic Acid / Q000737:chemistry / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D025924:Chromatography, Supercritical Fluid; D000431:Ethanol / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification*; D030019:Ilex paraguariensis / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification*; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification*; D018515:Plant Leaves / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry
chemical_list: D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D012997:Solvents; D002726:Chlorogenic Acid; D000431:Ethanol