title: Diethylstilbestrol and tetrahydrochrysenes are calcium channel blockers in human platelets: relationship to the stilbene pharmacophore.
abstract: The effects of compounds with the stilbene pharmacophore [diethylstilbestrol (DES), DES derivatives, tetrahydrochrysene (THC), and THC derivatives] were examined for their ability to inhibit thrombin-induced Ca(2+) influx in human platelets. DES derivatives (DES dimethyl ether, DES dipropionate, dienestrol, and hexestrol) had lower inhibitory activity than DES. Esterification of DES with the bulky monobenzyl group eliminated inhibitory activity. Unsubstituted THC diol had the lowest inhibitory activity in the series of the THC derivatives bearing substituents in the 5,11 positions. These derivatives, either diethyl or dipropyl, cis or trans, were potent inhibitors of thrombin-induced [Ca(2+)](i) elevation (near 100% inhibition at 10 microM). Therefore, stilbene pharmacophore having bulk out of the plane of the double bond (from the twisting of the two aromatic rings or from addition of all substituents) seems to be requirement for the inhibitory activity. Free hydroxyl groups are also required for inhibitory activity, most likely for hydrogen bonding, since trans-diethyl tetrahydrochrysene dimethyl ether was inactive. Compounds bearing ethyl substituents (DES and THC derivatives) inhibited thrombin-induced release of calcium from the endoplasmic reticulum. These compounds also inhibited thapsigargin-induced Ca(2+) influx. This result implies that these compounds also block store-operated Ca(2+) influx directly, as well as internal Ca(2+) release. Compounds without ethyl substituents (trans-resveratrol, genistein, daidzein, and THC diol) only inhibited calcium influx into platelets.
authors.affiliation: Division of Pharmacology, Department of Physiological Sciences, Eastern Virginia Medical School, P.O. Box 1980, 700 Onley Road, Norfolk, VA 23501, USA.
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Dobrydneva
authors.forename: Roy L
authors.initials: RL
authors.lastname: Williams
authors.forename: John A
authors.initials: JA
authors.lastname: Katzenellenbogen
authors.forename: Paul H
authors.initials: PH
authors.lastname: Ratz
authors.forename: Peter F
authors.initials: PF
authors.lastname: Blackmore
mesh_terms: D000328:Adult; D001464:Barium / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002911:Chrysenes / Q000737:chemistry / Q000494:pharmacology*; D004054:Diethylstilbestrol / Q000737:chemistry / Q000494:pharmacology*; D005260:Female; D016257:Fura-2 / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D017136:Ion Transport / Q000187:drug effects; D007476:Ionophores / Q000737:chemistry / Q000494:pharmacology; D007529:Isoflavones / Q000737:chemistry / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D015394:Molecular Structure; D048789:Phytoestrogens; D028321:Plant Preparations / Q000737:chemistry / Q000494:pharmacology; D015539:Platelet Activation / Q000187:drug effects; D013324:Strontium / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002911:Chrysenes; D007476:Ionophores; D007529:Isoflavones; D048789:Phytoestrogens; D028321:Plant Preparations; D001464:Barium; D019284:Thapsigargin; D004054:Diethylstilbestrol; D013917:Thrombin; D002118:Calcium; D016257:Fura-2; D013324:Strontium