Abstract:
Plant extracts have long constituted a natural source of antimicrobial compounds. Antimicrobial
plant products have gained special interest because of the resistance to antibiotics that
microorganisms have been acquiring. The present study aimed to evaluate the In-vitro synergistic
antibacterial activity of Impatiens tinctoria subsp. Abyssinica and Momordica foetida schumach
leave against some selected clinical and standard pathogenic bacteria. In this study methanol,
chloroform, and acetone extract of I.tinctoria A. and M.foetida antimicrobial activity alone and
synergistic effect were evaluated against three gram-negative bacteria E.coli (ATCC35218),
P.aeruginosa (ATCC 27853), and S.typhimurium (ATCC 13331) and one gram-positive bacteria
S. aureus (ATCC 43300) and the clinical isolates of S.aureus, and E. coli. The dried plant parts
(tuber and leaves) extracted using the three solvents: Methanol, Acetone, and chloroform for 72
hr, and the agar well diffusion method used to test the plant parts for antibacterial activity. The
minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were
performed using two-fold broth dilution methods and then consequently done by agar culturing
the MIC broth tubes that didn’t show bacterial growth. This investigation showed that the extracts
of I.tinctoria, M.foetida alone, and their synergistic effect variously inhibited the growth of the test
bacteria. The chloroform extraction synergistic effect recorded the maximum inhibition zone
diameter 19.33±1.55 mm on S.typhimurium (ATCC 13331). There was no antibacterial activity in
any plant extracts against clinical isolates E.coli. Extracts effectively inhibited tested bacterial
growths as low as MIC values (15.6µg/ml). Lowest MBC values extracts were (31.25µg/ml).The
gram-positive bacteria S.aureus (ATCC 43300) and the gram-negative bacteria S.typhimurium
(ATCC 13331) were extracts that are more susceptible to all solvents. E.coli (clinical isolate) were
more resistant and did not show any inhibition to all extracts in both plants. The synergistic activity
of these two plant’s chloroform extract enhanced adjacent to the other solvent extracts. The overall
antibacterial activity of acetone M.foetide leaves and I.tinctoria tuber was better in comparison to
other solvent extracts. These plant extracts demonstrated may serve as a source for novel
antibacterial drug discoveries. Further studies should be conducted on the antibacterial activities
of both plants
