Isolation and characterization of novel antibacterial compound from an untapped plant, Stereospermum fimbriatum

Abstract

Stereospermum fimbriatum or locally known as “Chicha” is traditionally used for itchy skin, earache, stomachache and postpartum treatments. This study was designed to evaluate the antimicrobial potential of S. fimbriatum’s stem bark against 11 pathogens and isolate its bioactive compound. Successive soxhlet extraction was conducted using n-hexane, dichloromethane (DCM) and methanol. Disc diffusion, minimum inhibitory and bactericidal concentration (MIC & MBC) assays were done to examine the antimicrobial activity. Bioassay-guided isolation was conducted on S. fimbriatum’s extract. The DCM extract of stem bark (DS) was the most potent extract followed by n-hexane extract of the stem bark (NS). A novel compound was isolated and coded as C1 which demonstrated potent antibacterial effects with the MIC values as low as 3.13 µg/mL to 6.25 µg/mL, against S. epidermidis, MRSA and S. aureus. Thus, S. fimbriatum could be a potential source of antimicrobial agents for the treatment of skin infections, specifically, MRSA.

Keywords:

• Stereospermum fimbriatum
• chicha
• antibacterial
• isolation
• angucycline

Acknowledgements

The authors would like to thank International Islamic University Malaysia (IIUM) for providing lab facilities, Universiti Teknologi MARA (UiTM) for NMR analysis and Monash University, Malaysia for LCMS/MS service. The appreciation also goes to International Scientific Participation Program (ISPP# 0026) at King Saud University, Riyadh, Saudi Arabia.

Disclosure statement

The authors confirm that this article content has no conflict of interest.

Additional information

Funding

This work was partially funded by the Research Management Centre of International Islamic University Malaysia through Research Initiative Grant Schemes for Postdoctoral Fellowship (RPDF18-005-0005).