Pressurized liquid extraction of oak leaf polyphenols: Solvent selection via Hansen parameters, antioxidant evaluation and monoamine-oxidase-a inhibition analysis.

This study focuses on the extraction of bioactive compounds from Quercus sideroxyla Bonpl., leaves which have been shown to possess health benefits. The extraction process was done using pressurized liquid extraction (PLE), which is efficient and preserves heat-sensitive compounds. Key factors in the process included the choice of solvents, pressure, temperature, and extraction duration. The Hansen solubility parameters analysis aided in selecting effective solvents, such as ethanol and benzyl alcohol. The extracts were found to contain phenolic compounds, flavonoids, and polyphenols with antioxidant properties. The UPLC-PDA-ESI-QqQ was employed for the precise identification and quantification of these compounds, demonstrating superior extraction of quinic acid and gallic acid at elevated temperatures. Notably, the extracts obtained through PLE exhibited significant inhibitory activity of the MAO-A enzyme, linked to neuronal and cognitive health, suggesting potential benefits in these areas.