In-vitro Anti-Bacterial Activity of Extracts of Euphorbia abyssinica (Desert Candle) Stem-Bark and Latex | Chapter 13 | Recent Advances in Biological Research Vol. 3
Introduction:
Plants are a limitless gift of nature to humans and they possess very
appreciative values and roles. They have stood the test of time in the life of
man since creation. All over the world, they are hugely exploited for food,
fuel, timber, medicine etc. The natural endowment of plants with numerous
metabolites and bioactive compounds makes them good sources of therapeutic
agents capable of replacing synthetic antibiotics; For example, Salversan and
Penicillin are synthetic drugs formerly used for the treatment of Syphilis and
Staphylococcus aureus infections, respectively, but which became less preferred
because these pathogens developed resistance to the drugs.
Aim:
This study was aimed at evaluating Euphorbia abyssinica (Desert Candle), a
medicinal plant extensively used in folklore medicine among the Kendem people
of South-west Cameroon for antibacterial activity and extracts analyzed for
phytochemical composition.
Study
Design: The completely randomized block design
was used and data analyzed using of two way analysis of variance. Significant
means were separated using Duncan’s New Multiple Range Test.
Place
and Duration of Study: This study was carried out in the
Department of Microbiology, University of Nigeria Nsukka, Enugu State, Nigeria,
between April 2011 and August 2012.
Methodology:
Extraction was done using absolute methanol, 50% methanol (in water) and water
as solvents. Qualitative analysis methods were used to assay the phytochemical
constituents. Agar-well diffusion, macro broth dilution and agar dilution and
time-kill assay were the susceptibility test methods adapted.
Results:
The phytochemical constituents detected were alkaloids, flavonoids, tannins,
cardiac glycosides, carbohydrates and steroids, and saponins. The 50% methanol
extract of the stem-bark was highly active against Staphyloccocus aureus,
Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa and compared
favorably with the Gentamycin control drug. The inhibition zone diameters
(IZDs) obtained with 50% methanol extract measured 23 mm for S. aureus and 19
mm for P. aeruginosa compared to 18 mm achieved with the absolute methanol
extract for both S. aureus and P.
aeniginosa. For the aqueous extract the overall IZD range of 10±1.60-13±2.16
mm. The susceptibility patterns obtained using both dilutions (agar and
macro-broth) methods were similar to that obtained with the agar diffusion
method above. S. aureus (with MIC, 10.93±1.00-; MBC, 25-mg/mL, agar dilution or
MIC, 3.9±1.60 -, MBC, 12.5-mg/mL, macro broth dilution methods, respectively).
It was considered to be the most significantly susceptible bacteria strain
tested (significant mean value 3.933), while E. coli was the least susceptible
(with MIC, 50±0.00-, MBC, 100-mg/mL, in the agar dilution; MIC, 25±0.00-, MBC,
50-mg/mL in the broth dilution and a significant mean value of 14.70). The
stem-bark extracts was also significantly more active than the latex extracts
P= .05 with significant mean values of 13.48 and 19.53 respectively. In the
time-kill assay, all (100%) the organisms tested were killed by 50% methanol
extract of E. abyssinica at concentrations equivalent to 1MIC- 4MIC.
Conclusion:
E. abyssinica extracts showed considerable antibacterial activity against the
bacterial species tested. These findings authenticate the folklore use of
Euphorbia abyssinica for broad spectrum treatment of bacterial infections. The
determination of the antimicrobial activity of Euphorbia abyssinica stem (bark
and Latex extracts) extract included the 50% methanol, absolute methanol and
aqueous extracts of these plant parts. The antimicrobial activity variously
exhibited by the 50% methanol extracts of all the two plant parts tested, is
significant. This is because it validates the popular traditional uses of
dilute alcohol concoctions of medicinal plant preparations in ethno medicinal
practice in south-West region of Cameroon. Secondly, the results indicated that
these herbs used in traditional medicine have selective antimicrobial
activities. Thus, the microorganisms which were susceptible to these extracts
are those often associated with wound and ear infections, urinary and
gastrointestinal tract infections as well as pyrexia of unknown origin. This
explains the discriminate uses of these plants in the treatment of particular
ailments. These findings provide evidence that E. abyssinica is a strong
candidate in microgram concentrations while the plant extracts were effective
in milligram concentrations. Therefore actual comparison between the control
drugs and the extracts would await isolation, purification and determination of
molar concentrations of the pure active ingredients of these plants extracts.
Author Details:
Jacqueline Ebob Tarh
Department
of Biological Sciences, Cross River University of Technology, Calabar, Nigeria.
Christian Ukwuoma Iroegbu
Department
of Biological Sciences, Cross River University of Technology, Calabar, Nigeria.
View Volume: https://doi.org/10.9734/bpi/rabr/v3
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