Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation

Show simple item record Motlhatlego, Katlego Ellena Abdalla, Muna Ali Leonard, Carmen M. Eloff, Jacobus Nicolaas McGaw, Lyndy Joy 2021-03-02T08:53:56Z 2021-03-02T08:53:56Z 2020-11
dc.description.abstract BACKGROUND: Diarrhoea is a major health issue in both humans and animals and may be caused by bacterial, viral and fungal infections. Previous studies highlighted excellent activity of Newtonia buchananii and N. hildebrandtii leaf extracts against bacterial and fungal organisms related to diarrhoea-causing pathogens. The aim of this study was to isolate the compound(s) responsible for antimicrobial activity and to investigate efficacy of the extracts and purified compound against bacterial biofilms. METHODS: The acetone extract of N. buchananii leaf powder was separated by solvent-solvent partitioning into eight fractions, followed by bioassay-guided fractionation for isolation of antimicrobial compounds. Antibacterial activity testing was performed using a broth microdilution assay. The cytotoxicity was evaluated against Vero cells using a colorimetric MTT assay. A crystal violet method was employed to test the inhibitory effect of acetone, methanol: dichloromethane and water (cold and hot) extracts of N. buchananii and N. hildebrandtii leaves and the purified compound on biofilm formation of Pseudomonas aeruginosa, Escherichia coli, Salmonella Typhimurium, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus. RESULTS: Myricetin-3-o-rhamnoside (myricitrin) was isolated for the first time from N. buchananii. Myricitrin was active against B. cereus, E. coli and S. aureus (MIC = 62.5 μg/ml in all cases). Additionally, myricitrin had relatively low cytotoxicity with IC50 = 104 μg/ml. Extracts of both plant species had stronger biofilm inhibitory activity against Gram-positive than Gram-negative bacteria. The most sensitive bacterial strains were E. faecalis and S. aureus. The cold and hot water leaf extracts of N. buchananii had antibacterial activity and were relatively non-cytotoxic with selectivity index values of 1.98–11.44. CONCLUSIONS: The purified compound, myricitrin, contributed to the activity of N. buchananii but it is likely that synergistic effects play a role in the antibacterial and antibiofilm efficacy of the plant extract. The cold and hot water leaf extracts of N. buchananii may be developed as potential antibacterial and antibiofilm agents in the natural treatment of gastrointestinal disorders including diarrhoea in both human and veterinary medicine. en_ZA
dc.description.department Paraclinical Sciences en_ZA
dc.description.librarian pm2021 en_ZA
dc.description.sponsorship Medical Research Council of South Africa, National Research Foundation and University of Pretoria en_ZA
dc.description.uri en_ZA
dc.identifier.citation Motlhatlego, K.E., Abdalla, M.A., Leonard, C.M. et al. 2020, 'Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation', BMC Complementary Medicine and Therapies, vol. 20. no. 1, art. 358, pp. 1-10. en_ZA
dc.identifier.issn 2662-7671 (online)
dc.identifier.other 10.1186/s12906-020-03139-4
dc.language.iso en en_ZA
dc.publisher BioMed Central en_ZA
dc.rights © The Author(s). 2020 Open Access, This article is licensed under a Creative Commons Attribution 4.0 International License. en_ZA
dc.subject Newtonia en_ZA
dc.subject Fabaceae en_ZA
dc.subject Diarrhoea en_ZA
dc.subject Cytotoxicity en_ZA
dc.subject Biofilm formation en_ZA
dc.subject Antimicrobial activity en_ZA
dc.subject Bacterial biofilms en_ZA
dc.subject Purified compound en_ZA
dc.subject Extracts en_ZA
dc.title Inhibitory effect of Newtonia extracts and myricetin-3-o-rhamnoside (myricitrin) on bacterial biofilm formation en_ZA
dc.type Article en_ZA

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