Separation Of Chlorogenic Acid From Green Coffee Beans And The Extract Antioxidant Activity In Vitro

Coffee contains various active compounds, and showed to possess antibacterial, antiviral, allaying tiredness, antioxidant activities, etc. Chlorogenic acid is one of the most important active compounds in Green coffee beans, which was normally obtained by column chromatography in traditional methods.In order to explore preparation of chlorogenic acid, an effective and simple method was developed in our works. Effects of pH value, extraction solvent, dosage of activated carbon and decolorization on purification of chlorogenic acid from coffee bean was investigated, the results were showed following:Coffee was extracted with95%ethanol by ultrasonic-assisted method at28℃in1hour for five times to give extract residue in23.3%yield.This residue was dispersed in water and extracted with petroleum ether repeatedly, then aqueous phase was extracted repeatedly by mixed solvent (ethyl acetate:ethanol=10:1, V/V) in pH3to offer light phase solution.This light phase solution was treated with activated carbon3times (dosage of activated carbon was0.01g·mL-1), and then concentrated to give crude chlorogenic acid. The crude chlorogenic acid was crystalized in ethyl acetate-ethanol and ethyl acetae-methol systems repeatedly to give chlorogenic acid in purity of98.8%. High-speed countercurrent chromatography (HSCCC) applied to the isolation of chlorogenic acid from ethyl acetate fraction of green coffee beans was investigagted too. Solvent system which consisted of methanol-ethyl acetate-ammonium sulfate-water (3.2:3:1:7, V/V/m/V) was used and heavy phase solution as mobile phase and light phase solution as stattionay phase. When rotation at800r·min-1with flow rate2mL·min-1in25℃, retaining time of chlorogenic acid was236～296min.Antioxidant activities of coffee extract were investigated with methods of scavenging activity against DPPH free radicals, ferric reducing ability and scavenging activity against nitric oxide free radicals. Extracts obtained coffee beans under different baking temperature showed obvious defferent results. Baked under150℃for1hour, coffee bean gave extract with most antioxidant activities. Four fractions which obtained from residue in aquoues extracted with organic solvents showed different antioxidant activities. Ethyl acetate fraction and n-buthanol fraction revealed higher antioxidant activity than petroleum ether fraction and water fraction.