Abstract
The methanol extract of the leaves of Garcinia nervosa var. pubescens King, which showed strong inhibitory effects on platelet-activating factor (PAF) receptor binding, was subjected to bioassay-guided isolation to obtain a new biflavonoid, II-3,I-5, II-5,II-7,I-4',II-4'-hexahydroxy-(I-3,II-8)-flavonylflavanonol together with two known flavonoids, 6-methyl-4'-methoxyflavone and acacetin. The structures of the compounds were elucidated by spectroscopic methods. The compounds were evaluated for their ability to inhibit PAF receptor binding to rabbit platelets using ³H-PAF as a ligand. The biflavonoid and acacetin showed strong inhibition with IC₅₀ values of 28.0 and 20.4 µM, respectively. The results suggest that these compounds could be responsible for the strong PAF antagonistic activity of the plant.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Biflavonoids / chemistry
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Biflavonoids / isolation & purification
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Biflavonoids / pharmacology*
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Blood Platelets / drug effects
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Blood Platelets / metabolism
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Flavones / chemistry
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Flavones / pharmacology
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Garcinia / chemistry*
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Inhibitory Concentration 50
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Plant Extracts / chemistry
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Plant Leaves / chemistry
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Platelet Activating Factor / antagonists & inhibitors*
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Platelet Aggregation / drug effects
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Platelet Aggregation Inhibitors / metabolism
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Platelet Aggregation Inhibitors / pharmacology
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Platelet Membrane Glycoproteins / antagonists & inhibitors*
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Platelet Membrane Glycoproteins / metabolism
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Rabbits
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Receptors, G-Protein-Coupled / antagonists & inhibitors*
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Receptors, G-Protein-Coupled / metabolism
Substances
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Biflavonoids
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Flavones
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Plant Extracts
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Platelet Activating Factor
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Platelet Aggregation Inhibitors
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Platelet Membrane Glycoproteins
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Receptors, G-Protein-Coupled
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platelet activating factor receptor
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acacetin