Biological Activities of Saussurea lappa Antioxidants Recovered by Solid–liquid, Ultrasound and Ired-Irrad®

Background: Saussurea lappa is a traditionally well-known plant appreciated for its biological activities and medicinal uses. Objective: In the present study, the recovery of antioxidants from Saussurea lappa was optimized using Response Surface Methodology (RSM). The efficiency of a newly-patented Infrared (IR) technology, Ired-Irrad®, was compared to that of the emerging ultrasound method (US) and the conventional solid liquid Water Bath (WB) extraction. Methods: The effects of time (t) and Temperature (T), mostly known to affect the extraction process, were tested on maximizing the Total Phenolic compounds Concentration (TPC) and the radical scavenging activity (AA). Response surface methodology was used for the optimization process. Results: A multiple response optimization of both time (t) and Temperature (T) was conducted, showing the best extraction conditions to be for WB: t= 43.86 min, T=33.79°C, for US: t= 65.47 min, T= 57.97°C and for IR: t= 42.5 min, T=34.19°C. The quantity of the optimally extracted polyphenols by WB, US and IR; as well as many of their bioactivities were compared. IR extraction gave the highest yield of TPC (15.3 mg GAE/g DM) followed by US (14.8 mg GAE/g DM) and lastly WB (13.9 mg GAE/g DM). The highest antioxidant and antiradical activities were also obtained by the IR treatment. The optimal IR extract inhibited the growth of Staphylococcus aureus and Escherichia coli up to 65 and 35%, respectively. Moreover, all Saussurea lappa extracts (WB, US and IR) inhibited up to 96% the production of Aflatoxin B1 (AFB1) by Aspergillus flavus. Conclusion: Our findings on the extraction of antioxidants from Saussurea lappa demonstrated that IR technology is an efficient novel method that can be used to extract the maximum yield of polyphenols, with the highest antioxidant, antiradical and antibacterial activities.