Abstract:
The stem bark of Azadirachta indica, one of the most widely distributed plants in tropical and
sub-tropical countries, is used in traditional medicine for treatment of several diseases. This
study was conducted to analyze the major phytochemicals, to evaluate the antioxidant capacities
using, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities as well as to determine the
total phenolics, and the antibacterial activities of extracts of the stem bark of A.indica. The stem
bark of this plant was extracted by successive extraction with petroleum ether, ethyl acetate and
methanol solvents. The percentage yields of methanol, ethyl acetate and petroleum ether extracts
were 4.48%, 2.75% and1.98% respectively. Qualitative phytochemical analysis of the extracts
indicated the presence of, alkaloids, flavonoids, terpenoids, and phenols, with different
concentration. The result of total phenolics content estimation in petroleum ether, ethyl acetate
and methanol crude extract was 17.87, 32.14 and 55 mgGAE/g dry samples respectively. The
DPPH radical scavenging assay result showed that methanol stem bark extract has high
antioxidant activity than ethyl acetate and petroleum ether extracts. IC
50
values were found to be
34.96 μg/mL, 50.45 μg/mL and 68.56 μg/mL in methanol, ethyl acetate and petroleum ether stem
bark extracts respectively for their antioxidant activity by DPPH assay; the lower IC
50
value
which showed that the radical scavenge activity to be effective in this solvent extract. The
antioxidant potential of the extracts increased with increasing concentration of the sample.
Growth inhibition tests against gram positive (S. aureus and S. pyrogens) and gram negative (E.
coli and K. pneumonia) bacteria showed a good result at a higher concentration in methanol and
ethyl acetate extracts.