Page 32 - Book of Abstracts

5 International Scientific Online Conference DOI: https://doi.org/10.15414/2021.9788055224015

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IN VITRO ASSESSMENT OF ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS
OBTAINED FROM THE LEAVES AND PSEUDOBULBS OF COELOGYNE TOMENTOSA LINDL.
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Lyudmyla Buyun , Halyna Tkachenko , Natalia Kurhaluk , Oleksandr Gyrenko ,
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Lyudmyla Kovalska
1
1 M.M. Gryshko National Botanic Garden, National Academy of Science of Ukraine, Kyiv, Ukraine;
E-mail.: buyun@nbg.kiev.ua
2 Institute of Biology and Earth Sciences, Pomeranian University in Słupsk, Poland
Although the antimicrobial activity of many orchid species, including Coelogyne species,
has been effectively established against a wide spectrum of microorganisms, bacterial drug
resistance continues to be a worldwide public health issue, thereby stimulating the search for
new alternatives with fewer side effects. The present study was aimed to determine the
antibacterial activity of Coelogyne tomentosa Lindl. against Escherichia coli strains, сlinically
important bacteria, which are indicator organisms commonly used in various projects to
monitor antibiotic resistance.
The leaves and pseudobulbs of C. tomentosa plants cultivated under glasshouse conditions
were sampled at M.M. Gryshko National Botanical Garden (Kyiv, Ukraine). Freshly sampled
leaves and pseudobulbs were washed, weighed, crushed, and homogenized in 96 % ethanol (in
proportion 1:19) at room temperature. For this study, Escherichia coli (Migula) Castellani and
Chalmers (ATCC 25922™) and E. coli (Migula) Castellani and Chalmers (ATCC 35218™) were
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used. The antimicrobial susceptibility testing was undertaken on Muller-Hinton agar by the disc
diffusion method. Inhibition zone diameters were evaluated and averaged.
The ethanolic extract obtained from leaves of C. tomentosa resulted in considerable
growth suppression of E. coli strains. Leaf extract displayed high antibacterial potency against
E. coli, i.e. the mean values of inhibition zone diameters were (17.85 ±1.25) and (13.33 ±1.12)
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mm for E. coli (ATCC 25922™) and E. coli (ATCC 35218™), respectively. Also, E. coli exhibited
similar susceptibility for the impact of the ethanolic extract obtained from pseudobulbs of C.
tomentosa. The mean of inhibition zone diameters was (16.58 ±1.03) and (15.76 ±1.24) mm for
E. coli (ATCC 25922™) and E. coli (ATCC 35218™), respectively. Moreover, the ethanolic
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extracts obtained from the leaves and pseudobulbs of C. tomentosa revealed significant
antibacterial activity against studied strains compared to control samples (96 % ethanol). A
statistically significant increase (p<0.05) in inhibition zone diameters of strain growth for E.
coli ATCC 25922™ was 202 % (leaf extracts) and 187 % (pseudobulb extracts). Likewise, a
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significant increase (p<0.05) in inhibition zone diameters for growth of E.coli ATCC 35218™
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strain was also observed (by 48 and 76 % for leaf and pseudobulb extracts, respectively).
To conclude, the present study has revealed that ethanolic extract derived from the leaves
and pseudobulbs of C. tomentosa exhibited significant antibacterial activity against E. coli. More
impressive results were observed for E. coli ATCC 25922™ and for pseudobulb extracts.
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Overall, our analysis suggests that screening of Coelogyne species for other biological activities
including antioxidant and antibacterial activities is essential and may be effective for searching
the preventive agents to be used in the pathogenesis of some metabolic and infectious diseases.

Keywords: Coelogyne tomentosa., leaves, pseudobulbs, antibacterial efficacy, disc diffusion technique,
ethanolic extracts.

Acknowledgments
This study was carried out during the Scholarship Program supported by The Visegrad Fund in the
Department of Zoology and Animal Physiology, Institute of Biology and Earth Sciences, Pomeranian
University in Słupsk (Poland). We thank The Visegrad Fund for supporting our study.

5 International Scientific Conference Agrobiodiversity for Improving the Nutrition, Health, Quality of Life and |31
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Spiritual Human Development
November 3 2021
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