Abstract:
Moringa oleifera L. is a plant of nutritional and medicinal interest, very widespread
through the tropical and subtropical areas. The present work aims to study the effect of
different methods of drying of leaves of M. oleifera (free air, sun, oven and freeze-dried)
on the content of phenolic compounds and the antioxydant and antibacterial activities. The
extraction, carried out by maceration, gave extraction yields which differ according to the
drying modes, vary from 23 to 28%. The phytochimic sifting showed a composition varied
from secondary metabolites. The contents of phenolic compounds were determined, they
vary according to the method of drying, where the extract of the leaves dried by drying
oven reveals a higher content compared to the other extracts (contents of: polyphenols,
flavonoïdes, condensed tannins are of 54.57 µg EAG/mg; 185 µg ER/mg;154 µg EC/mg of
extract respectively). The antioxydant activity is evaluated by three tests: DPPH, ABTS
and FRAP. The extract from the leaves dried by oven presented the best radical scavenging
activity IC50 of 5616.78 and 2961.58 µg/ml respectively in the tests of the DPPH and the
ABTS, and a reduction of the iron of 30.88 µg EAA/ml of extract. The antibacterial
activity was evaluated by the method of diffusion in solid medium where all the extracts
with various concentrations are active against two bacteria only; the extract of the leaves
dried by oven has the best inhibiting activity opposite with the stock Pseudomonas
aeruginosa with a diameter of 14.90 mm (12 mg/ml). The extract of the leaves dried by the
free air presents the zone of the highest inhibition against the bacterium Streptococcus sp.
(9.87 mm) whereas no effect of the four extracts was observed against the two other two
strains (Staphylococcus aureus and Escherichia coli .
