Abstract

Gedunin, a highly oxidized triterpenoid was obtained from hexane extractive of stem wood of Entandrophragma angolense (Welw) C. D. C. of the family Meliaceae. The gedunin was dissolved in minimum methanol at 40°C and set aside in the dark for recrystallization. Pure gedunin crystals were obtained in 0.92% yield. Methanolic alkaline hydrolysis of the gedunin afforded 7-deacetoxy-7α-hydroxygedunin potassium salt in 90.53% w/w yield. The gedunin and 7-deacetoxy-7α-hydroxygedunin potassium salt were screened againstBacillus subtilis, Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniaeusing broth microdilution assay method. 7-Deacetoxy-7α-hydroxygedunin potassium salthad minimum inhibitory concentration (MIC) of 1000 μg/ml against K. pneumoniae, 2000 μg/ml against S. aureus, and E. coli. However, B. subtilis was not susceptible to 7-deacetoxy-7α-hydroxygedunin potassium salt at 2000 μg/ml. Gedunin was not active against all the bacterial organisms tested at 2000 μg/ml.

Key words: Gedunin, synthesis, gedunin potassium salt, antibacterial, broth microdilution method.