Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/25/2010
Publication Date: 10/27/2010
Citation: Crockett, S.L., Poller, B., Tabanca, N., Pferschy-Wenzig, E., Kunert, O., Wedge, D.E., Bucar, F. 2010. Bioactive xanthones from the roots of Hypericum perforatum (common St John's Wort). Journal of the Science of Food and Agriculture. 91:428-434. Interpretive Summary: Hypericum perforatum is a perennial herb that is found in its native range distributed throughout Eurasia and that has been incorporated in the folklore and traditional medicine of people in this part of the world. The inflorescences of H. perforatum are prepared as a decoction or infusion and taken internally for sedative and tonic purposes, or applied externally as a poultice or prepared as an oil-infusion to treat sciatica, neuralgia and speed wound healing. Isolated xanthones have been tested against plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides and for anti-inflammatory activity through inhibition of COX-1, COX-2.
Technical Abstract: In contemporary western alternative medicine, extracts of the inflorescences and upper stem leaves of Hypericum perforatum L. (common St. John’s Wort; Clusiaceae) are taken orally for the treatment of mild to moderate depression and applied topically to promote wound-healing. Numerous researchers have described constituents isolated from above-ground portions of this species and chemical variation among leaves, flowers and fruits, but few reports describe the secondary metabolites found in underground structures. Anthracnose infections of H. perforatum are caused by Colletotrichum gloeosporioides, a highly virulent fungal pathogen that does considerable necrotic damage to plants and dramatically decreases crop value. Such infections have been observed to trigger the production of new secondary metabolites, specifically xanthones, in cell culture experiments. Correspondingly, bioassay-guided fractionation of dichloromethane and methanol extracts of H. perforatum root material was performed in which extracts and isolated pure compounds were tested for growth inhibition of several plant pathogenic fungi from the genera Colletotrichum, Botrytis, Fusarium and Phormopsis. In addition, fractions and isolated pure compounds were evaluated in vitro for anti-inflammatory activity through inhibition of COX-1, COX-2 and 5-LOX catalyzed LTB4-formation. Extracts were analyzed by chromatographic means (TLC, OC, HPLC) and structure elucidation performed using data from NMR and MS. This work resulted in the isolation of three xanthones, specifically 1,6-dihydroxy-5-methoxy-4’,5’-dihydro-4’,4’,5’-trimethylfurano-(2’,3’:3,4)-xanthone; 4,6-dihydroxy-2,3-dimethoxyxanthone; and cis-kielcorin, one of which possessed novel bioactivity against species of Phormopsis.