title: New vasorelaxant indole alkaloids, villocarines A-D from Uncaria villosa.
abstract: Villocarines A-D (1-4), four new indole alkaloids have been isolated from the leaves of Uncaria villosa (Rubiaceae) and their structures were elucidated by 2D NMR methods and chemical correlations. Villocarine A (1) showed vasorelaxation activity against rat aortic ring and showed inhibition effect on vasocontraction of depolarized aorta with high concentration potassium, and also inhibition effect on phenylephrine (PE)-induced contraction in the presence of nicardipine in a Ca(2+) concentration-dependent manner. The vasorelaxant effect by 1 might be attributed mainly to inhibition of calcium influx from extracellular space through voltage-dependent calcium channels (VDC) and/or receptor-operated Ca(2+)-channels (ROC), and also partly mediated through the increased release of NO from endothelial cells and opening of voltage-gated K(+)-channels.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hoshi University, Shinagawa-ku, Tokyo, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Matsuo
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Okamoto
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Zaima
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hirasawa
authors.forename: Intan Safinar
authors.initials: IS
authors.lastname: Ismail
authors.forename: Nordin Hj
authors.initials: NH
authors.lastname: Lajis
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Morita
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000737:chemistry / Q000378:metabolism; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects; D026121:Indole Alkaloids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D009569:Nitric Oxide / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry; D024642:Potassium Channels, Voltage-Gated / Q000378:metabolism; D051381:Rats; D032070:Uncaria / Q000737:chemistry*; D014665:Vasodilator Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D026121:Indole Alkaloids; D024642:Potassium Channels, Voltage-Gated; D014665:Vasodilator Agents; D009569:Nitric Oxide; D002118:Calcium