Phytochemical and Antioxidant Variability in Some Black Mulberry, Chokeberry, and Elderberry Cultivars in Relation to Cultivar, Plant Part, and Extraction Solvent

Polyphenols and flavonoids are key bioactive compounds with significant antioxidant properties, making them crucial for human health and nutraceutical applications. However, their extraction efficiency and concentrations are influenced by multiple factors, including plant part, cultivar, and solvent selection. Therefore, this study investigated the effects of plant part, cultivar, and solvent type on the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity (ABTS and CUPRAC assays) in different extracts from black mulberry, chokeberry, and elderberry. In all three species, the leaves exhibited significantly higher phytochemical and antioxidant properties than the fruits, with an average increase of 62.8–133.4% in the TPC and 55.4–390.3% in the TFC. Among genotypes, Gümüşhacıköy Horum and Tohma Medik (black mulberry), Viking and Nero (chokeberry), and Tokat (T1) (elderberry) demonstrated the highest levels of bioactive compounds, while Şelale Karadut, Aron, and Haschberg exhibited the lowest values. Solvent selection played a crucial role, with methanol:water:HCl emerging as the most effective extraction medium, increasing the TPC by 27.5–46.3%, the TFC by 28.3–67.6%, and the antioxidant capacity (ABTS and CUPRAC) by up to 94.2% compared to water extraction. These findings indicate the significance of leaf-based bioactive compound extraction and optimized solvent selection for maximizing antioxidant yields. The results of this study also have important implications for both fruit cultivation and human nutrition, highlighting the potential of leaves as a valuable source of polyphenols and antioxidants.