title: Stereochemistry and biological activities of constituents from Cynanchum taiwanianum.
abstract: The stereochemistry of new acetophenones, cynandione B-D (2-4), isolated from Cynanchum taiwanianum, elucidated by computer modelling calculation and NOESY spectrum. It establishes the absolute configurations of cynandiones B-D (2-4) as 7R; 7"S, 7S; 7"S and 7R; 7"R, respectively. Cynandione B (2) strongly inhibited the release of beta-glucuronidase and lysozyme in formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated rat neutrophils in a concentration-dependent manner with IC50 values of 1.5 +/- 0.2 and 1.6 +/- 0.2 microM, respectively. 2,5-Dihydroxyacetophenone (6) strongly inhibited the aggregation of washed rabbit platelets induced by arachidonic acid in a concentration-dependent manner with an IC50 value of about 4.8 microM. In human citrated platelet-rich plasma, 2,5-dihydroxyacetophenone (6) inhibited the secondary phase, but not the primary phase, of aggregation induced by adrenaline and ADP. These results suggest that the antiplatelet effect of 2,5-dihydroxyacetophenone (6) is due to inhibition of the formation of thromboxane A2.
authors.affiliation: School of Pharmacy, Kaohsiung Medical College, Taiwan.
authors.forename: C N
authors.initials: CN
authors.lastname: Lin
authors.forename: P L
authors.initials: PL
authors.lastname: Huang
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
authors.forename: S H
authors.initials: SH
authors.lastname: Day
authors.forename: H C
authors.initials: HC
authors.lastname: Lin
authors.forename: J P
authors.initials: JP
authors.lastname: Wang
authors.forename: Y L
authors.initials: YL
authors.lastname: Ko
authors.forename: C M
authors.initials: CM
authors.lastname: Teng
mesh_terms: D000098:Acetophenones / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects; D003094:Collagen / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology; D008958:Models, Molecular; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology; D010946:Plants, Medicinal; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013481:Superoxides / Q000378:metabolism
chemical_list: D000098:Acetophenones; D010975:Platelet Aggregation Inhibitors; D013481:Superoxides; D000244:Adenosine Diphosphate; D003094:Collagen; D004837:Epinephrine