Pharmacological Valorization of Saffron Stigmas (<I>Crocus sativus</I> L.): Green Ultrasonic Processing and Molecular Docking Analysis of Antioxidant Bioactives

Abstract

Saffron (Crocus sativus L.) is a valuable source of bioactive molecules renowned for their health benefits. However, efficient extraction of phenolic compounds using conventional techniques remains challenging. This study aimed to optimize ultrasound-assisted extraction (UAE) conditions for saffron stigmas using a Box–Behnken design. UAE parameters were optimized to maximize total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity [Ferric reducing antioxidant power (FRAP)] under different conditions. Three parameters were investigated: extraction time, solvent-to-material ratio, and solvent (ethanol/water) concentration. TPC, TFC, and FRAP were determined using standard spectrophotometric methods. In addition, in silico pharmacokinetic properties of selected bioactive compounds from saffron were analysed using the ADMELab platform. Molecular docking of the selected compounds was performed against two antioxidant-related targets: human tyrosinase (PDB ID: 5M8O) and human peroxiredoxin 5 (PRDX5) (PDB ID: 1H2D) using Aotodock toolkit. The best extraction conditions were identified as 15 min, 30 mL/g, 80% ethanol for TPC (32.15 mg GAE/g DW) and TFC (93.55 mg QE/g DW), and 45 min, 30 mL/g, 80% ethanol for antioxidant activity (EC₅₀ = 0.37 mg/mL), with desirability values > 99.9%. Regression models demonstrated high predictive reliability (R² = 0.96-0.97), confirming the higher efficiency of UAE compared with maceration and decoction. Furthermore, in silico studies revealed favourable pharmacokinetic properties for crocetin, picrocrocine, crocin-4, and safranal, and molecular docking highlighted a strong binding affinity of crocin-1 with antioxidant-related targets. Overall, UAE proved to be a robust and predictive strategy for optimizing saffron phenolic extraction, reinforcing its antioxidant and bioactive potential.