In vitro growth-inhibitory effect of medicinal plants used in Cambodian traditional medicine for treatment of diarrhoea against intestinal bacterial pathogens

Bc. Marie Koryťáková

Master's thesis

Abstract:

Infectious diarrhoea is the most widespread and serious health problem. Worldwide this malady affects up to 5 billion people per year, and in developing countries every year causes up to 10 million deaths. Especially in developing countries it is leading cause of morbidity and mortality in infants and young children. Due to the increasing antibiotic resistance is necessary to find new pathways how to face it. An opportunity are medicinal plants traditionally used in indigenous Cambodian herbal medicine that have not been examined and studied in detail yet. For this purpose, Cambodian healers use mainly roots and bark of concrete medicinal plants. The purpose of this study was to investigate the in vitro growth-inhibitory effect of plants traditionally used in Cambodian herbal medicine to cure gastrointestinal disorders, against the representatives of diarrhoea-causing bacteria. In order to assess that, the minimum inhibitory concentrations (MIC) of 12 ethanol extracts from collected 9 different species were determined against 12 intestinal pathogens. The impacts of the plant extracts on bacterial growth were evaluated by broth microdilution method. 10 out of 12 tested plant extracts showed growth-inhibitory effect against at least 1 out of 12 intestinal pathogens tested, whereas 5 plant extracts demonstrated interesting MICs. Namely, Ancistrocladus tectorius exhibited the highest antibacterial effect against Bacillus cereus (MIC = 64 μg/mL) and Listeria monocytogenes (MIC = 128 μg/mL); certain antimicrobial effects showed also Shorea siamensis against B. cereus, Escherichia coli and Salmonella enterditis (MIC = 256 μg/mL), Bauhinia malabarica against E. coli (MIC = 256 μg/mL), Melastoma dodecandrum against E. coli (MIC = 256 μg/mL), and Breynia vitis-idaea against E. coli and Salmonella typhimurium (MIC = 256 μg/mL). Additionally, antimicrobial effects of Aganoneiron polymorphum, B. malabarica, B. vitis-idaea, Lagerstroemia cochinchinensis, Melastoma saigonense and S. siamensis were tested in our study for the first time. These results suggest that A. tectorius, B. malabarica, B. vitis-idaea, M. dodecandrum and S. siamensis can be used for further research focused on identification of compounds with antibacterial effect against pathogens causing diarrhoea.

Keywords

broth microdilution method, Cambodia, plant extracts, medicinal plants, antimicrobial activity

Language used: English

Date on which the thesis was submitted / produced: 19. 4. 2021

Thesis defence

• Supervisor: prof. Ing. Ladislav Kokoška, Ph.D.

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme / field:
Tropical Agriculture / Tropical Crop Management and Ecology