Bioguided chemical study of Boswellia dalzielii Hutch. (Burseraceae) for antibacterial agents and a new glucopyranoxylmethoxybenzyle

Abstract

Stem barks of Boswellia dalzielii are used traditionally for the treatment of various bacterial infections. A bioassay guided fractionation of the MeOH-CH₂Cl₂ (1/1, v/v) stem barks extract led to the isolation of fourteen compounds 1–14, identified based on spectroscopic data. Dalzienoside (1) is reported here for the first time. The broth microdilution method was used to evaluate the antibacterial activity of the crude extract, fractions and compounds against six bacterial strains. The crude extract exhibited moderate antibacterial activity with MIC of 250 μL/ml; two fractions showed significant activities with MICs ranging from 7.8 to 125 μg/ml, while α-boswellic acid (2), β-boswellic acid (3), acetyl-11-keto-β-boswellic acid (4) from these fractions exhibited strong activities with MIC value of 3.125 µg/mL against Staphylococcus aureus, Salmonella typhi, Enterobacter cloacae, Streptococcus pneumonia and Pseudomonia aeruginosa. This study gives insight into the antibacterial constituents of the stem bark of B. dalzielii and justifies its use in ethnomedicine.

Graphical Abstract

Keywords:

• Antibacterial
• bioguided
• Boswellia dalzielii
• Burceraceae
• dalzienoside

Acknowledgements

Catherine Tegasne and Gilbert Deccaux Wabo Fotso Kapche are grateful to the University of Yaoundé I and the University of Bielefeld for the cooperation, the Departments of Chemistry of the Universities of Bielefeld and Botswana for NMR and Mass spectra analysis.

Disclosure statement

The authors declare they have no conflict of interest.

Additional information

Funding

This work was supported by the Yaoundé-Bielefeld Bilateral Graduate School Natural Products with Anti-parasite and Anti-bacterial Activity (YaBiNaPA) project, financially supported by Deutscher Akademischer Austauschdienst (DAAD) [grant number 57316173], the Network for Analytical and Bio-assay Services in Africa (NABSA) and the Organization for the Prohibition of Chemical Weapons (OPCW) through a three month travel grant to the Department of Chemistry-University of Botswana.