| In vitro | Therefore, major CHAs were isolated from three major instant coffee brands, confirmed and quantified using HPLC and NMR spectroscopic methods. Then, their antioxidant activities and protective effects on H2O2-induced apoptosis in PC-12 cells were investigated using radical scavenging, mitochondrial membrane potential and caspase assays. In the coffee samples, three major CHAs (3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 5-O-caffeoylquinic acid) and some minor CHAs (3-O-Feruloylquinic acid, 4-O-feruloylquinic acid, 5-O-feruloylquinic acid, 3,5-O-dicaffeoylquinic acid, 3,4-O-dicaffeoylquinic acid, and 4,5-O-dicaffeoylquinic acid) were detected. The three major CHAs were further isolated and their chemical structures were confirmed using NMR spectroscopic techniques. Also, the amounts of the three major CHAs were individually quantified using a HPLC method. At the concentration of 10 μM, all three major CHAs quenched DPPH and/or xanthine oxidase-generated radical species by 21-51% (P < 0.014). They also inhibited H2O2-induced mitochondrial membrane depolarization and caspase-9 activation by 27% (P < 0.034) and 50% (P < 0.05), respectively[1] |
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