Infrared‐assisted extraction coupled with high‐performance liquid chromatography for simultaneous determination of eight active compounds in Radix Salviae miltiorrhizae

In this study, a novel infrared-assisted extraction (IRAE) method, in which infrared radiation was employed to extract the active compounds from plant, was developed and coupled with HPLC for simultaneous determination of four phenolic acids and four diterpenoids in Radix Salviae miltiorrhizae (Chinese name Danshen). The extraction conditions of IRAE were optimized and the optimal conditions were as follows: extraction time of 15 min; extraction solvent of 70% v/v methanol in water solution, and solid/liquid ratio of 0.1:15 (g/mL). Chromatography was performed on a 200 mm×4.6 mm id, 5-μm particle size, C18 column. Good linearity (r>0.9994) was observed over the concentration ranges investigated, and intra-day and inter-day precision were high. Recoveries of the eight compounds were from 96.90 to 104.30% and RSD was below 2.5%. By using this novel IRAE method, with a shorter extraction time, the determined amounts of the eight active components in Danshen were comparable with or even higher than those extracted with conventional heat-reflux extraction and ultrasound-assisted extraction methods and microwave-assisted extraction. The developed IRAE method is simple, low-cost and efficient, offering a great promise for quick determination of active compounds in natural plants.