Gardeniae fructus is a common neuroprotective medicinal food in China, however the extraction efficiency and mixture activities are rarely mentioned. In this study, accelerated solvent extraction (ASE) parameters were optimized by a response surface methodology to extract antioxidants from Gardeniae fructus. Neuroprotective activity was evaluated using H2O2 and amyloid-β25-35 peptide-treated PC12 cells. By comparing with three other extract methods (i.e., heated refluxing extraction (HRE), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE)), it was found that the yield (35.10%), total iridoids (27.69%), total flavonoid (6.12%) content, antioxidant activities (IC50 on DPPH, 164.46 µg/mL; FRAP value 4703.54 μmol/L), and acetylcholinesterase inhibitory ability (IC50 92.58 µg/mL) of ASE extract under the optimal condition (150 °C temperature, 10 min static time, 60% ethanol, 2 extract cycles) were significantly higher than other extract methods. The strongest ability to protect PC12 cells from damage was also present in ASE extract, as evidenced by decreasing lactate dehydrogenase and malondialdehyde levels, elevating superoxide dismutase and glutathioneperoxidase activities. Compositional analysis indicated that the extremely high crocetin level in ASE extract (1.30 μg/mg) may offer great potential. Our results indicated that ASE is a proper extraction method that could offer great potential for finding the neuroprotective ability of Gardeniae fructus for the treatment of AD.
Keywords: Gardeniae fructus; PC12 cell; accelerated solvent extraction; acetylcholinesterase inhibitory; antioxidant; characteristic compounds.