Variation in Phenolic, Flavonoid, and Antioxidant Content of Rosa × hybrida Based on Flower Organs and Color: The Basis for Pruning Biomass Valorization

Abstract

Hybrid rose plants are not only valuable as floriculture commodities, but also have the potential to be a source of bioactive compounds. In cultivation activities, leaves and stems from pruning are often not fully utilized, so a scientific basis is needed to select the most promising biomass and to develop a simple extraction process. This study analyzed total flavonoids, total phenolics, and antioxidant capacity in red, pink, white, and purple flowers, stems, and leaves of Rosa × hybrida Schleich. We extracted fresh samples by infusion in distilled water at 90 °C for 15 minutes. Total flavonoids were determined by AlCl3 complexation and expressed as mg QE/g FW; total phenolics were determined with Folin–Ciocalteu as mg GAE/g FW; while antioxidant capacity was measured by DPPH and the Modified Phenanthroline Method (MPM) as mg AAE/g FW. The highest flavonoids were found in purple stems (37.046 ± 17.557 mg QE/g FW), the highest phenolics in pink flowers (20.286 ± 1.704 mg GAE/g FW), the highest DPPH in purple leaves (10.928 ± 1.227 mg AAE/g FW), and the highest MPM in purple stems (7.762 ± 3.111 mg AAE/g FW). DPPH and MPM were highly correlated in flowers, stems, and leaves (r = 0.997–0.999). These findings suggest that vegetative biomass, especially purple rose stems and leaves, should be prioritized for the development of aqueous extracts and the valorization of pruning biomass. This study is a laboratory proof of concept; economic impact, community adoption, safety, and product performance still require further pilot testing. Potential contribution to the Sustainable Development Goals (SDGs):SDG 3: Good Health and Well-BeingSDG 12: Responsible Consumption and Production