Platelet-activating factor Paf inhibitory activity of xanthones and aporphinoid alkaloids : structure-activity relationships

Ibrahim Jantan, . and Juriyati Jalil, . and Iftikhar Ahmad Abdul Rafi, . (2001) Platelet-activating factor Paf inhibitory activity of xanthones and aporphinoid alkaloids : structure-activity relationships. [Proceedings Paper]

Nine xanthones and seven aporphinoid alkaloids isolated from three Guttiferae species and Aromadendron elegans Blume respectively were investigated for their inhibitory effects on platelet-activating factor PAF binding to rabbit platelets using H-PAF as a ligand. Structure-activity analysis of the xanthones revealed that 2-3-methylbut-2-enyl-1 3 5-trihydoxyxanthone macluraxanthone 1 3 5-trihydroxy-6 6'-dimethylpyrano2' 3':6 7-4-1 1-dimethylprop-2-enylxanthone 6-deoxyjacareubin and 2-3-methylbut-2-enyl-1 3 5 6-terahydroxyxanthone showed strong inhibition with IC50 values of 4.8 11 21 29 and 44.0 micro M respectively. The prenyl group at C-2 the dimethylprop-2-enyl group at C-4 and the hydroxyl group at C-5 are all beneficial to the binding of xanthones to the PAF receptor. Of the aporphinoid alkaloids tested --N-acetylanonaine 1-N-acetyl-N-methylaminoethyl-3 4 6-trimethoxy-7 hydroxy-phenanthrene and predicentrine showed strong inhibition of PAF receptor binding with IC50 values of 52.4 38.6 and 29.8 micro M respectively. The results suggested that methoxyl groups at C-9 and C-10 play an important role in binding of the alkaloids to the receptor but the coplanar conformation of the oxoaporphines and the dehydroaporphine was not preferable in binding to the receptor. The results revealed that xanthones and aporphinoid alkaloids can represent new classes of natural PAF receptor antagonists.

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Abstract

Nine xanthones and seven aporphinoid alkaloids isolated from three Guttiferae species and Aromadendron elegans Blume respectively were investigated for their inhibitory effects on platelet-activating factor PAF binding to rabbit platelets using H-PAF as a ligand. Structure-activity analysis of the xanthones revealed that 2-3-methylbut-2-enyl-1 3 5-trihydoxyxanthone macluraxanthone 1 3 5-trihydroxy-6 6'-dimethylpyrano2' 3':6 7-4-1 1-dimethylprop-2-enylxanthone 6-deoxyjacareubin and 2-3-methylbut-2-enyl-1 3 5 6-terahydroxyxanthone showed strong inhibition with IC50 values of 4.8 11 21 29 and 44.0 micro M respectively. The prenyl group at C-2 the dimethylprop-2-enyl group at C-4 and the hydroxyl group at C-5 are all beneficial to the binding of xanthones to the PAF receptor. Of the aporphinoid alkaloids tested --N-acetylanonaine 1-N-acetyl-N-methylaminoethyl-3 4 6-trimethoxy-7 hydroxy-phenanthrene and predicentrine showed strong inhibition of PAF receptor binding with IC50 values of 52.4 38.6 and 29.8 micro M respectively. The results suggested that methoxyl groups at C-9 and C-10 play an important role in binding of the alkaloids to the receptor but the coplanar conformation of the oxoaporphines and the dehydroaporphine was not preferable in binding to the receptor. The results revealed that xanthones and aporphinoid alkaloids can represent new classes of natural PAF receptor antagonists.

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Item Type:	Proceedings Paper
Additional Information:	Perpustakaan Sultan Abdul Samad Universiti Putra Malaysia 43400 UPM Serdang Selangor Malaysia. QD415 A1N277 2000
AGROVOC Term:	GUTTIFERAE
AGROVOC Term:	PLATELETS
AGROVOC Term:	ALKALOIDS
AGROVOC Term:	RABBITS
AGROVOC Term:	MALAYSIA
Geographical Term:	MALAYSIA
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:27
URI:	http://webagris.upm.edu.my/id/eprint/15922

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