Comparative Assessment of Phytochemical Content and Antioxidant Activities in Different Parts of Pyrus ussuriensis Cultivars

Pyrus ussuriensis, also known as Ussurian pear, is a deciduous tree from the Rosaceae family. This study examined the phytochemical profiles and antioxidant activities of different parts (1-year-old stem, 2-year-old stem, and leaves) of Pyrus ussuriensis Maxim. and P. ussuriensis var. ovoidea. The analysis included measurements of total polyphenol content (TPC), total flavonoid content (TFC), and evaluations of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical scavenging activities. Quantitative analyses were conducted using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC/UV). The analysis with one-way ANOVA indicated significant differences in TPC and TFC across tissues, with the stems exhibiting the highest TPC and the leaves showing the highest TFC in both P. ussuriensis and P. ussuriensis var. ovoidea. Among the examined structures, the stems exhibited the highest TPC, whereas the leaves exhibited the highest TFC in both P. ussuriensis and P. ussuriensis var. ovoidea. P. ussuriensis var. ovoidea displayed stronger antioxidant activity than P. ussuriensis. LC-MS/MS detected 18 phytochemicals, with chlorogenic acid being the most abundant, especially in leaf extracts, as confirmed using HPLC/UV analyses. This cultivar-based comparison highlights a tissue-specific distribution of bioactive compounds, with leaves primarily contributing to high flavonoid content and stems to polyphenolic content. Collectively, these findings provide valuable insights into the rich phytochemical diversity and antioxidant potential of P. ussuriensis cultivars, highlighting their versatility in various fields.