Purpose: To study the effect of interaction between methanol leaf extract of
Spondias mombin
and
amoxicillin on diarrheagenic
Escherichia coli
(DEC).
Methods: Cold methanol extraction of
Spondias mombin leaf and its phytochemical screening were
carried out. Isolated, characterized and identified strains of enterotoxigenic
E. coli (ETEC),
enteroinvasive
E. coli (EIEC), and enterohemorrhagic
E. coli (EHEC) from watery stool, mucoid bloody
stool and watery bloody stool of diarrheal patients, respectively, were confirmed and typed by
conventional and molecular methods. The minimum inhibitory concentration (MIC) and ½ MIC at which
the extract and amoxicillin interacted were determined.
Results: Spondias mombin extract showed remarkable antibacterial activity at extract concentration of
50 - 200 mg/mL with a mean zone of inhibition (MZ) ≥ 11.1 and activity index (AI) of 0.8 - 1.1. MIC of
12.5 mg/mL was observed for both ETEC and EIEC while it was 6.25 mg/mL for EHEC. The extract
showed synergistic interaction at various concentrations (50 – 200, 12.5 and 6.25 mg/mL, respectively)
with amoxycillin against ETEC, EHEC and EIEC. Synergy across a wide range of concentrations
compared favourably with the ½ MIC and MIC of both extract and amoxycillin for ETEC. The extract
contained moderate levels of alkaloids, flavonoids and tannins, as well as a lot of saponins, and low
levels of phenol. The activity of the extract of
Spondias mombin compares well with that of amoxicillin
with AI ≥ 1 in some cases.
Conclusion: A synergistic interaction between the leaf extract of
S. mombin and amoxicillin confirms
the extract as potential antibacterial agent but further studies are required to ascertain this.
