In-Vitro Antimicrobial Activity of Some Traditional Medicinal Plants on Some Food Borne Pathogens
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Date
1998-06
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Addis Ababa University
Abstract
Eleven various types of traditionally used Ethiopian medicinal plants have been screened for their
antimicrobial activity at the crude preparation level against six different bacteria, two Gram +ve
(Bacillus cereus and Siaphyloccus aureus ) and four Gram -ve (Escherchia coli, Shigella
boydii,Shigella jlexneri and Salmonella Iyphimunum). Of the tested crude preparations only two
(Rula chalepellsis alldEchinops spp.) showed antimicrobial activity against B. cereus by the agar
well-plate diffussion assay. The effects of these crude preparations were found to be heat
dependent. Eight of the tested crude preparations at various concentrations by agar dillution assay
were found to be effective in or both of the Gram positive bacteria at various concentrations, as
assessed by agar dilution assay. The l'vilC of Syzygillm guineense (0.312%) was the same for all
susceptible organisms (E. Cereus, S. aurellS, Sh. jlexneri and S. boydii). It appeared to be
bacteriocidal for S. aurellS, Sh. jlexneri and S. Boydeii). It appeared to be bactericidal for S.
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aurellS, Sh. jlexneri and S. boydii and bacteriostatic for B. cereus. All the active preparation found
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effect by agar dillution assay, were found to be stable upon heating upto 121 0 C for 15 minutes.
The l'vilC of Carum copiticm, Rula chalepensis and Artemisia (!Ira against B. cereus was 5%. It
was higher for Cymbopogon citra/us (10%) and lower for EchillOps spp.(0.625%) and Syzygillm
guineense (0.312%). The l'vilC of Vernonia amygdalana was 5%. For S. aureus the l'vilC forthe
latter two plants was the same as for B. Cereus.
Of the tested crude preparations, only Syzygium guineense appeared to bacteriocidal. The J\i[8C
was 1.25% for S. aureus and 5% for Sh. jlexneri and S. boydii. The crude preparations at the
l'vIBC killed all the population within 8 h in all the above mentioned organisms.
Broth dillution assay was conducted to assess the antimicrobial effect of the crude preparations
concentrations: Cal'1l11l copilicllm, Coriandrum salivllm, Echinops spp.at 10%; RlIta chalepensis,
Fonicu/um vulgare, Cymbopogon citratus, Vel'llonia amygdalina and Ginger officinale at 7%;
Artemisia afi'a at 5% and Lipidium sativum at 2%. The results showed that eight of the crude
preparations have reduced the final population of B. cereus by one to four log units as compared
to the control. On the other hand, ten of them were found to reduce the final population of S.
aureus. Only one of the crude preparations had retarding effect on Sh. jlexneri, and two on Sh.
boydii. None of them has inhibitory effect on E. coli and Salmonel/a Iyphimurium except
Syzygium guineese that decreased the final population of Salmonella.
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Biology