Phytochemical composition and anticancer potential of the endemic gold oak of Cyprus Quercus alnifolia

Quercus alnifolia , is an evergreen endemic oak, grows in the Troodos peninsula. Leaf dichromatism is a notable characteristic of this species, with young leaves showing a dark green adaxial and gold abaxial, while mature leaves have a brown abaxial (Fig. 1). The aim of the study was to investigate the phytochemical composition of young and mature leaves, along with its variation based on season (summer and winter) and collection site (three distinct altitudinal sites). In addition, the phytochemical composition and antioxidant activity of other botanical parts, such as acorns and bark, were determined. Subsequently, the anticancer properties of selected leaf extracts were examined using the MTT assay on breast (MDA-MB-231 and MCF-7), colon (HT29, HCT116), and lung cancer cell lines (H1975, A549). Additionally, the potential phytotoxic effects of the extracts were examined on a normal breast cell line MCF-12F. Phytochemical analysis revealed that leaf age is the predominant factor influencing phytochemical composition, particularly concerning total phenolics and antioxidant capacity, which were significantly higher in young compared to mature leaves. The collection season influenced flavonoid and tannin concentrations. Among the other botanical parts, fruits and young bark exhibited promising phytochemical composition. As for anti-cancer properties, the selected young leaf extracts showed a significant dose- and time-dependent reduction of cell viability in all cancer cell lines examined, while its impact on MCF-12F cells was limited. Concluding, this study highlights the significance of Q. alnifolia as a rich source of phytochemical compounds and emphasizes the potential of leaf extracts as anticancer agents. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany