5-Hydroxytryptamine_1A receptor binding activity of bisbenzyltetrahydroisoquinoline alkaloids from Popowia odoardi

Abstract

A 96-well filtration-based 5-HT_1A receptor-radioligand binding assay was optimized and adapted to carry out a bioassay-guided fractionation of the methanol extract of the bark of Popowia odoardi Diels (Annonaceae). This purification led to the isolation of two compounds identified as O-methyldauricine (1) and popisidine (2), which bind competitively to 5-HT_1A receptors at high concentrations with K_i values of 4.5 and 5.8 μM, with [³H]8-OH-DPAT as the radioligand. These results suggest that both of these bisbenzyltetrahydroisoquinoline alkaloids influence the activity of 5-HT_1A receptors through competitive binding as agonists or antagonists and may possess anxiolytic and anti-depressive effects.

Keywords::

• Alkaloid
• Annonaceae
• 5-hydroxytryptamine receptor
• O-methyldauricine
• Popowia odoardi
• popisidine

Acknowledgements

This project was partly supported by the Biotechnology Directorate, Ministry of Science, Technology and Innovation, Malaysia (IRPA 26-02-06-0127).

Declaration of interest: The authors alone are responsible for the content and writing of the paper.