Antimicrobial Activities of Extracts of Macrosphyra longistyla against Gram-Positive Oral Biofilm-Formers from School Children in Southwestern Nigeria and Toxicity Studies Using Brine Shrimps
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Date
2024-03-13
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Abstract
The world will benefit from more effective antimicrobial agents against oral
conditions arising from the actions of biofilm forming bacteria. Also, infor
mation is lacking on the oral biofilm-forming bacterial diversity in South
western Nigeria. In this study, we isolate and characterize oral biofilm pro
ducing bacteria in the oral cavities of schoolchildren in Southwestern Nigeria.
We also investigate the antimicrobial properties of Macrosphyra longistyla
extracts against the biofilm-formers and the toxicity of potent extracts. Sam
ples were obtained from 109 schoolchildren aged 4 - 14 years from Lagos,
Oyo and Osun States. Agar well diffusion technique was used in the antimi
crobial susceptibility testing. Toxicity testing was done using brine shrimps
(Artemia salina). Biofilm-formers in this study are Klebsiella sp., Streptococ
cus sp., Staphylococcus sp., and Micrococcus sp. Ethanol leaf extracts had the
highest activity against all biofilm-producing bacteria. Ethanol stem bark ex
tract, which elicited activity against Klebsiella only, was found to be less toxic
than the ethanol leaf extract. Staphylococcus showed >10 mm susceptibility to
the ethanol and aqueous extracts of Macrosphyra longistyla. Streptococcus
and Micrococcus were susceptible to the antimicrobial actions of the ethanol
ic leaf extracts. Although the ethanol extracts of the leaves had lower mini
mum inhibitory concentrations than the ethanol extracts of the stem bark,
toxicity studies showed ethanol extracts of the stem-bark to be more toxic
than the ethanol extracts of the leaves. In conclusion, ethanolic extracts of
Macrosphyra longistyla show potential as sources of antimicrobials against
gram-positive, oral biofilm-forming bacteria.
Keywords
Biofilms, Plant Extracts, Toxicity, Bacteria, Susceptibility, Antimicrobial