Tinctures from Pear Buds and Young Leaves at Different Developmental Stages: Changes in Polyphenol Profiles and Antioxidant Activity

Pear buds and young leaves from three pear trees (WP, CPI, and CPII) were harvested at different developmental stages from February to May. Tinctures prepared by 14-day maceration with 70% ethanol were analysed for their phenolic profiles by LC-MS and HPLC and for antioxidant activity. A total of 40 compounds were detected, including quinic acid, phenolic acids, flavonols, flavan-3-ols, arbutin, and caffeoylarbutin. The phenolic profiles of the analysed tinctures varied with harvest date and developmental stage of the plant material. Tinctures prepared from earlier developmental stages were characterized mainly by phenolic acids and flavan-3-ols, whereas those prepared from young leaves contained higher levels of flavonols. Flavan-3-ols were most abundant in tinctures from February buds. These compositional differences were also reflected in antioxidant activity, with higher activity at earlier stages associated mainly with phenolic acids and flavan-3-ols and at later stages with higher flavonol content. Overall, the analysed tinctures showed harvest-stage-related differences in phenolic composition and antioxidant activity.