Abstract:

A dynamic microwave-assisted extraction (DMAE) approach was established for the extraction of scutellarin from Scutellaria barbata. The overall extraction process was monitored by online measuring the UV absorbance of the extract. The extraction conditions were optimized using orthogonal experimental design. The content of scutellarin was offline analyzed by HPLC. The detection and quantification limits of scutellarin obtained were 0.28 mg/L and 0.93 mg/L, respectively. The withinday and betweenday precisions (RSD) were 1.7% and 3.6%, respectively. The mean recovery of scutellarin was 98.3%.
The DMAE was compared with Soxhlet extraction and pressurized MAE (PMAE) respectively. The results show that the dynamic method is superior to PMAE in preventing analyte degradation, and also to soxhlet extraction in the reduction of time and solvent required. It is more important that the extraction process can be visually observed by UV online monitoring.

Key words: online monitoring; , dynamic microwaveassisted extraction, UV spectroscopy, Scutellaria barbata, scutellarin