Abstract
An Alkanna orientalis leaf and flower extract inhibited the growth of
Staphylococcus aureus, a pathogen that causes an estimated
478 000 hospitalizations in the US annually. Bioassay-guided fractionation
of A. orientalis resulted in isolation of the flavonoid sarothrin
(5,7,4′-trihydroxy-3,6,8-trimethoxyflavone), which inhibited the growth of
Mycobacterium smegmatis (MIC 75 µM) and S. aureus (MIC
> 800 µM), and possessed efflux pump inhibitory activity. This is the
first report of antimicrobial or efflux pump inhibitory activity of
sarothrin, and of its presence in A. orientalis. Our findings suggest
that the effectiveness of A. orientalis extracts is due to a
combination of multiple constituents, including sarothrin.
Key words
Alkanna orientalis
- Boraginaceae - antimicrobial - efflux inhibition
