Lipid and Phenolic Constituents from Seeds of Hypericum perforatum L. and Hypericum tetrapterum Fr. and their Antioxidant Activity |
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| Authors: | Miriam Heinrich Peter Lorenz Rolf Daniels Florian C. Stintzing Dietmar R. Kammerer |
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| Affiliation: | 1. WALA Heilmittel GmbH, Department of Analytical Development & Research, Section Phytochemical Research, Boll/Eckw?lden;2. Department of Pharmaceutical Technology, University of Tübingen, Tübingen |
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| Abstract: | Seeds of Hypericum perforatum and H. tetrapterum were extracted with dichloromethane and methanol and investigated by chromatographic and mass spectrometric methods. Both species yielded a fatty oil fraction amounting to 30.5% and 18.0% of the seed weight, respectively. Linoleic acid (C18:2n‐6) was shown to be the predominant fatty acid constituent. Moreover, xanthone derivatives, i.e. tetrahydroxyxanthones (THX), xanthone‐glycosides and xanthone‐sulfonates, were assigned in methanolic extracts. For structure elucidation, one representative xanthone, namely 1,3,6,7‐THX, was synthesized and analyzed via HPLC‐DAD/MSn and GC/MS. Total THX contents were quantitated applying a validated HPLC‐DAD method, resulting in 1.25 g/kg (H. perforatum) and 0.27 g/kg (H. tetrapterum), respectively. Moreover, the free radical scavenging capacity of the methanol extracts was tested using the DPPH antioxidant assay. Both, H. perforatum (IC50 = 8.7 mg/l) and 1,3,6,7‐THX (IC50 = 3.0 mg/l), exhibited good DPPH free radical scavenging activity compared to Trolox (IC50 = 6.6 mg/l). |
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| Keywords: | Antioxidants Fatty acids St. John's wort Seeds Xanthone derivatives |
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