Effects of Ultrasound-Assisted and Direct Solvent Extraction Methods on the Antioxidant and Antibacterial Properties of Saffron (Crocus sativus L.) Corm Extract

Abstract

In this study, the response surface methodology (RSM) based on a central composite face-centered design (CCD) was used to optimize the extraction of bioactive constituents from Crocus sativus corms. The ultrasound-assisted extraction (UAE) was compared with the conventional direct solvent extraction (DSE) procedure. The optimum conditions of ethanol (80%), 48 °C and 60 min in DSE, and ethanol (80%), 37 °C, 45 min, and 37 kHz in UAE, were determined to receive extracts with maximum antioxidant activity and total phenolic content (TPC). The results showed TPC values of 89.28 and 100.39 (mg gallic acid equivalents in 100 g dry saffron corm) and total flavonoid contents (TFC) of 0.912 and 1.558 (mg quercetin equivalents in100 g dried saffron corm) for the optimized DSE and UAE extracts, respectively. The GC-MS analysis showed n-hexadecanoic acid as one of the main non-polar constituents in the saffron corm extract (39.315% and 19.015% in DSE and UAE extracts, respectively). The disc diffusion tests revealed a degree of activity of saffron corm extracts against Staphylococcus aureus at a minimum concentration of 300 mg/mL.