title: Antiplatelet and anti-inflammatory constituents and new oxygenated xanthones from Hypericum geminiflorum.
abstract: Two new pentaoxygenated xanthones, 2,3-dihydroxy-1,6,7-trimethoxyxanthone (1) and 3,6-dihydroxy-1,5,7-trimethoxyxanthone (2) were isolated from the leaf of Hypericum geminiflorum. The antiplatelet activities of the constituents, 2,6-dimethoxy-p-benzoquinone (3), gemichalcone A (4), gemichalcone B (5), and cycloartocarpin (6), of this plant, were assessed in vitro by determining their inhibitory effects on the aggregation of washed rabbit platelets induced by various inducers. The anti-inflammatory effects of 4 and 5 were assessed in vitro by determining their inhibitory effects on the chemical mediators released from mast cells and neutrophils. Of the compounds tested, 4 exhibited the most potent inhibition of platelet aggregation induced by arachidonic acid (AA) and 4 and 5 strongly inhibited the release of beta-glucuronidase and lysozyme in formyl-Met-Leu-Phe (fMLP)-stimulated rat neutrophils.
authors.affiliation: School of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China. meinch@cc.kmu.edu.tw
authors.forename: Mei-Ing
authors.initials: MI
authors.lastname: Chung
authors.forename: Jing-Ru
authors.initials: JR
authors.lastname: Weng
authors.forename: Jih-Pyang
authors.initials: JP
authors.lastname: Wang
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Teng
authors.forename: Chun-Nan
authors.initials: CN
authors.lastname: Lin
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D015550:Cell Degranulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005966:Glucuronidase / Q000378:metabolism; D006632:Histamine / Q000378:metabolism; D020902:Hypericum; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology; D008516:Medicine, Chinese Traditional; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013481:Superoxides / Q000378:metabolism; D014966:Xanthenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D044004:Xanthones
chemical_list: C452868:2,3-dihydroxy-1,6,7-trimethoxy-xanthone; C452869:3,6-dihydroxy-1,5,7-trimethoxy-xanthone; D000893:Anti-Inflammatory Agents; D010936:Plant Extracts; D010975:Platelet Aggregation Inhibitors; D014966:Xanthenes; D044004:Xanthones; D013481:Superoxides; D006632:Histamine; D005966:Glucuronidase