|
Phytochemical compounds
and antimicrobial activity of three medicinal plants (Alchornea
hirtella, Morinda geminata and
Craterispermum laurinum) from Sierra Leone
Lahai Koroma1
and Basil N. Ita2*
1Department
of Basic Sciences, Eastern Polytechnic, Kenema, Sierra
Leone.
2Department
of Chemistry, University of Uyo, Uyo Nigeria.
*Corresponding author. E-mail:
basil_ita@yahoo.com.
Accepted 7 July, 2008 |
|
Petroleum
ether, acetone, ethanolic and aqueous crude extracts of
various plant organs of Alchornea hirtella,
Morinda geminata and Craterispermum
laurinum used in Sierra Leone exhibited variable degree
of antimicrobial activity against four bacterial species.
Compared with the standard drug ciprofloxacin, the extracts
exhibited low to moderate antibacterial activity. Generally,
the tested microorganisms were resistant to the petroleum
ether and acetone extracts. The aqueous extract of the stem
bark of M. geminata was sensitive to
Streptococcus pyogenes (61% inhibition) and leaf extract
of A. hirtella inhibited the growth of Proteus
vulgaris (56%). Ethanolic crude extract of the stem bark
of C. laurinum and M. geminata were
particularly sensitive to S. pyogenes; moderate
activity was also demonstrated by the stem bark of C.
laurinum against Escherichia coli. MIC values
indicated that the ethanolic extract showed significant
microbiostatic action against S. pyogenes and
Staphylococcus aureus (MIC 0.8 – 2 mg/ml), whereas the
other strains were more resistant (MIC >2 mg/ml).
Phytochemical evaluation revealed moderate to high contents
of flavonoids, alkaloid and saponins in the ethanolic
extract.
Key
words:
Antimicrobial activity, medicinal plants, phytochemical
constituents. |
