Comparison of different extraction techniques for isolation of antioxidants from sweet grass (Hierochloe odorata)

Summary, in English

Strong antioxidants, 5,8-dihydroxycoumarin and 5-hydroxy-8-O-beta-D-glucopyranosyl-benzopyranone were extracted from sweet grass (Hierochloe odorata L.) by using Soxhlet (SE), microwave-assisted (MAE) and supercritical fluid carbon dioxide (SFE) extractions at different extraction schemes and parameters. One-step MAE gave the most concentrated extract with 8.15% of 5,8-dihydroxycoumarin (extract yield 0.42%). Comparable results were obtained by one-step SFE and Soxhlet extraction. A two-step extraction was applied in order to increase the concentration of active compounds. Taking into account antioxidant recovery and concentration as well the extraction time and environmental aspects, two-step SFE was considered as a preferable method. The obtained crude extract contained 20.31% of 5,8-dihydroxycoumarin and 2.18% of 5-hydroxy-8-O-beta-D-glucopyranosyl-benzopyranone. The extraction yields were 0.46 and 0.06%, respectively. First-step of SFE extraction was performed from dried herb at 35 MPa and 40degreesC with 20% of ethanol as a modifier; the second extraction step was performed from the crude extract at 25 MPa and 40degreesC.

• Author: D Grigonis; P R Venskutonis; Björn Sivik; Margareta Sandahl; Cecilia Sparr Eskilsson
• Department/s: LTH School of Engineering in Helsingborg; Centre for Analysis and Synthesis
• Publishing year: 2005
• Language: English
• Pages: 223-233
• Publication/Series: Journal of Supercritical Fluids
• Volume: 33
• Issue: 3
• Links: http://dx.doi.org/10.1016/j.supflu.2004.08.006
• Document type: Journal article
• Publisher: Elsevier
• Topic: Analytical Chemistry; Engineering and Technology
• Keywords: sweet grass; extraction (MAE); microwave-assisted; soxhlet; supercritical fluid extraction (SFE); Hierochloe odorata; antioxidants
• Status: Published
• ISBN/ISSN/Other: ISSN: 0896-8446