Phytotherapy Research 2009-03-01

5-Hydroxytryptamine2A receptor binding activity of compounds from Litsea sessilis.

Lip Yong Chung, Mee Wah Lo, Muhammad Rais Mustafa, Swee Hock Goh, Zamrie Imiyabir

Index: Phytother Res. 23(3) , 330-4, (2009)

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Abstract

A 96-well microplate filtration based 5-HT(2A) receptor-radioligand binding assay was optimized and adopted to carry out a bioassay-guided fractionation of the methanol extract of the leaves of Litsea sessilis. This purification led to the isolation of two compounds identified as (+)-boldine (1) and (+)-dehydrovomifoliol (2). (+)-Boldine binds to 5-HT(2A) receptors at high concentrations with a K(i) value of 2.16 microm. However, (+)-dehydrovomifoliol showed minimal competitive inhibition on the binding of [(3)H]ketanserin to the same receptor with a K(i) value of 2.06 mm. These results suggest that (+)-boldine influences the activity of 5-HT(2A) receptors through competitive binding as an agonist or antagonist.(c) 2008 John Wiley & Sons, Ltd.