In Vitro Inhibitory Effect of Rubraxanthone Isolated from Garcinia parvifolia on Platelet-Activating Factor Receptor Binding

Ibrahim Jantan; Mazura Md Pisar; Muhammad Sum Idris; M. Taher; Rasadah Mat Ali

doi:10.1055/s-2002-36343

Planta Medica, Table of Contents

Planta Med 2002; 68(12): 1133-1134
DOI: 10.1055/s-2002-36343

Letter

In Vitro Inhibitory Effect of Rubraxanthone Isolated from Garcinia parvifolia on Platelet-Activating Factor Receptor Binding

Ibrahim Jantan¹ , Mazura Md. Pisar¹ , Muhammad Sum Idris² , M. Taher² , Rasadah Mat Ali³

¹Department of Pharmacy, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
²Department of Chemistry, Universiti Teknologi Malaysia, Johor Bahru, Malaysia
³Medicinal Plant Division, Forest Research Institute Malaysia, Kepong, Malaysia

Abstract

Rubraxanthone and isocowanol isolated from Garcinia parvifolia Miq. were investigated for their inhibitory effects on platelet-activating factor (PAF) binding to rabbit platelets using ³ H-PAF as a ligand. Rubraxanthone showed a strong inhibition with IC₅₀ value of 18.2 μM. The IC₅₀ values of macluraxanthone, 6-deoxyjacareubin, 2-(3-methylbut-2-enyl)-1,3,5-trihydroxyxanthone, 2-(3-methylbut-2-enyl)-1,3,5,6-tetrahydroxyxanthone and 1,3,5-trihydroxy-6,6′-dimethylpyrano(2′,3′:6,7)-4-(1,1-dimethylprop-2-enyl)-xanthone were also determined for comparison. In the course of our study on structure-activity relationship of xanthones, the results revealed that a geranyl group substituted at C-8 was beneficial to the binding while a hydroxylated prenyl group at C-4 resulted in a significant loss in binding to the PAF receptor.

Full Text

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Ibrahim Jantan, PhD

Department of Pharmacy

Faculty of Allied Health Sciences

Universiti Kebangsaan Malaysia

Jalan Raja Muda Abdul Aziz

50300 Kuala Lumpur

Malaysia

Phone: +603-40405331

Fax: +603-26983271

Email: ibj@medic.ukm.my