Application of cold plasma pretreatment to improve the extraction efficiency of tanshinone compounds from Salvia subg. Perovskia root

Tanshinone, a secondary metabolite derived from the medicinal plant Salvia subg. Perovskia, possesses therapeutic properties and has the potential to serve as a viable alternative to synthetic antioxidants in food industry. The primary objective of this study was to enhance the extraction efficiency of tanshinone compounds from Salvia subg. Perovskia through the utilization of various extraction techniques, such as heat reflux, ultrasonic, and microwave-hydrodistillation (MH) applying dielectric barrier discharge cold plasma as a pretreatment. Firstly, the optimum conditions of cold plasma pretreatment, ultrasonic, and microwave methods were determined at 18 kV for 1.5 min, 600 W for 25 min, and 100 W for 60 min, respectively, based on the extracted tanshinone content. The SEM analysis revealed that CP pretreatment caused notable changes in the cell walls, characterized by perforation, cracking, and the presence of cavities. The HPLC analysis identified three major components of tanshinone, including OH-CRT, CRT, and TAH-IIA, while GC-MS spectrometry detected 13 different volatile components in the extracted solutions. In conclusion, the combination of CP pretreatment with MH emerged as the most suitable method for extracting tanshinone compounds from Salvia subg. Perovskia, owing to its effective extraction capabilities, time-saving attributes, and energy efficiency. Moreover, the kinetic of tanshinone extraction through different methods were investigated using the first-order and second-order models. The statistical analysis clearly revealed that the second-order model accurately describes the tanshinone extraction process.