Chromone C-glucosides and a new triterpene fatty acid diester from Cameroonian propolis extracts with anticonvulsant activity in chemical models of seizures

Abstract

Three secondary metabolites: 5,7-dihydroxy-2-methylchromone-6-C-β-D-glucopyranoside (compound 1); 5,7-dihydroxy-2-methylchromone-8-C-β-D-glucopyranoside (compound 2); and 1″-eicosanyl-3β-longispinogenin heptadecanedioate (compound 3) were isolated from propolis n-hexane and ethyl acetate extracts. Their structures were elucidated on the basis of 1D and 2D nuclear magnetic resonance (NMR) experiments. Compounds 1 and 2 were found for the first time in propolis. Compound 3 is a new triterpene fatty acid diester. All compounds were tested for their anticonvulsant activity on pentylene tetrazole, 4-aminopyridine, and pilocarpine-induced seizures and death. Compound 1 protected 80% (P < 0.01) and 100% (P < 0.001) of mice against seizures and death induced by pentylenetetrazole (PTZ). Compound 2 protected 60% (P < 0.05) of mice against tonic-clonic seizures in the pilocarpine test. Compounds 1 and 2 protected mice against seizures induced by PTZ and pilocarpine (PILO) and increased the latency to seizures. Compound 3 protected 80% of mice against convulsions and 100% of mice from death induced by PTZ, 4-Aminopyridine (4-AP), and PILO. Compounds 1, 2, and 3 may be psychoactive agents with potential anticonvulsant properties. Key words: C-glucoside, propolis, chromone, triterpene fatty acid esters, anticonvulsant activity, chemical models of seizures.