African Journal of Biotechnology Vol. 6 (6), pp. 777-786, 19 March 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Synthesis and neuropharmacological activity of some quinoxalinone derivatives

G. Olayiwola¹, C. A. Obafemi²* and F. O. Taiwo²

¹Department of Clinical Pharmacy, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.

²Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria.

*Corresponding author. Tel: (234)8034753605.  E-mail: adeyemi01@yahoo.com.

Accepted 15 September, 2006

Eight quinoxalinone derivatives were synthesized and investigated for some neuropharmacological effects (analgesia, sedation, convulsion, anxiety, memory and psychosis) in mice and rats. In the CNS depressant activity, N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide is the most active, while the other compounds appear variously dose-dependent. Only three of the compounds showed anxiolytic effect, with N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide showing the highest activity at 2.5 mg/kg. At the dose of 30 mg/kg, 6-nitro-1,4-dihydroquinoxaline-2,3-dione showed a better anxiolytic effect in mice than diazepam (dose: 1 mg/kg), while 1,2,3,4-tetrahydro-quinoxaline-2,3-dione (dose: 25 mg/kg) showed a comparative effect to diazepam. 6-Chloro-1,4-dihydro-quinoxaline-2,3-dione and N,N-dibenzyl-2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonamide showed significant anticonvulsant action. None of the compounds showed any analgesic or antido-paminergic effect. The LD₅₀ (24 h) calculated for the compounds were between 74 and 160 mg/kg i.p.

Key words: Quinoxalin-2-ones, quinoxaline-2,3-diones, sedative effect, anticonvulsant activity, anxiolytic activity.