A renewal of interest in plant derived drugs has led to an increased need for efficient extraction methods. Hypericum perforatum L. contains several groups of bioactive compounds with noteworthy pharmacological activity. Extraction of hypericins (hypericin and pseudohypericin), flavonoids (hyperocid, rutin and quercitrin) and hyperforin from ''H. perforatum'' using direct sonication was investigated and compared with conventional maceration, indirect sonication, Soxhlet extraction and accelerated solvent extraction.
The diffent obtained extracts were first analyzed for the total amount of the extraction and subsequently for single components.
Picture of ''Hypericum perforatum L.''
Total extract content and concentration of the secondary metabolites of all extracts was investigated. Solvent extraction of plant material leads to innumerable organic compounds within the extracts. Thus, identification and correct quantification of bioactive substances is a difficult task requiring highly selective and sensitive analytical methods. Liquid chromatography coupled with mass spectrometry promises both, separation of the analytes from the interfering matrix and very selective detection.
Direct sonication yielded the highest number of active compounds. The compound quantities increased with increasing of ultrasonic power (direct sonication) from 40 W to 60 W. Soxhlet extraction gave better results than ASE. However, significantly longer extraction times are necessary in Soxhlet extraction. Comparison of ASE and Soxhlet extraction with conventional maceration revealed that the active compound contents were higher using the former two, partly because of the higher temperatures used, which result in accelerated diffusion through the plant material. Comparison of the data indicates that direct sonication is more effective than indirect sonication because the cavitation effect is stronger, thus causing intensive mass transfer.
The main conclusion of this report is that direct sonication could be a powerful tool for extraction of pharmacological useful compounds from ''H. perforatum''.
LC/MS/MS chromatograms of constituents of a plant extract
Alexander von Humboldt Foundation