Valorisation of hydrodistillation by-products from Damask Rose (Rosa damascena): extraction, characterization, and bioactivity of phenolic compounds with biological properties.

The present study focuses on the valorization of aqueous waste generated from the essential oil distillation of Damask rose (Rosa damascena) petals through the extraction and characterization of their bioactive compounds having potential antioxidant and anti-inflammatory properties. The aqueous waste, referred to as rose water, was subjected to liquid-liquid extraction using ethyl acetate, followed by solvent evaporation and methanol solubilization. The final extract shows a significant bioactivity, with a total phenolic content of 255.45 µg GAE/g dry extract (DE) and a total flavonoid content of 320.86 µg QE/g DE. The antioxidant capacity, assessed via the DPPH radical scavenging assay, revealed an IC50 value of 18.23 µg/mL, indicating potent activity. HPLC-DAD analysis identified key phenolic compounds, including protocatechuic acid, gallic acid, syringic acid, ferulic acid, isorhamnetin-3-O-glucoside, quercetin-3-O-rutinoside, ellagic acid, and quercetin. The extract also exhibited dose-dependent anti-inflammatory effects, as evidenced by the inhibition of nitric oxide production in LPS-stimulated RAW 264.7 macrophage cells. The valorization of rose water not only contributes to the discovery of bioactive compounds but also promotes the sustainable management of distillation by-products, reducing waste and minimizing environmental impact.