Abstract
South African indigenous plants have been predominantly studied for their antibacterial abilities, overlooking their antipathogenic and antivirulence (also known as antiquorum sensing) potential. Hence, this study explored the selected medicinal plants as possible agents capable of interfering with bacterial growth, quorum sensing and biofilm formation and identified their respective bioactive compounds. Ten medicinal plants were extracted with varied solvents. Melianthus comosus (dichloromethane, aqueous and methanol), Pelargonium sidoides (aqueous) and Vachellia karroo (aqueous and methanol) extracts showed potent minimum inhibitory concentration values ranging from 0.19 to 0.78 mg/ml against the tested bacterial pathogens: Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli. Reduced violacein production (up to 38.34%) in Chromobacterium violaceum was noted for Melianthus comosus, Plectranthus ecklonii and Pelargonium sidoides extracts. Treatment of five MDR bacterial pathogens with active extracts for anti-adhesion and biofilm development showed up to 66.34 and 31.82% inhibitory effects, respectively. Chemical characterization of active extracts revealed compounds such as α-D-glucopyranoside, methyl, linalool, octadecanoic acid and hexadecanoic acid. The biological assays validated the tested plant extracts as having antibacterial and antipathogenic potentials that could be used against multidrug resistant bacteria. Key words: Antibacterial activity, biofilm inhibition, chemical characterization, multidrug resistance, phytochemicals, quorum sensing inhibition.
Highlights
Multidrug-resistant (MDR) pathogens progressively develop within the public and health care system, creating a menace worldwide (Karunanidhi et al, 2018)
Methanolic solvent had the highest yields from Pelargonium sidoides (35.9%), Acokathera oppositifolia (27.1%) and Artemesia afra (25.7%), while aqueous solvent extracted the highest yields from Aloe arborescens (31.5%), Artemesia afra (24.3%) and Melianthus comosus (21.1%)
The present study revealed that the leaf parts of M. comosus, P. ecklonii and P. sidoides exert bacteriostatic and/or antipathogenic activities against C. violaceum which may promote the possibility of the plant's defense mechanism against diverse bacterial invasions
Summary
Multidrug-resistant (MDR) pathogens progressively develop within the public and health care system, creating a menace worldwide (Karunanidhi et al, 2018). MDR is usually caused by a build-up of genes with every coding developing resistance to a single drug on R plasmids (Neuenschwander, 2009). The increased rate of MDR bacteria is elicited due to the bacterial proficiency in efflux pump use, expelling diverse, structurally unrelated compounds from the cell, conferring resistance to an extensive choice of antibiotics (Tang et al, 2014). These MDR bacteria are known to develop biofilms and contribute towards bacterial pathogenicity by triggering genes that regulate their virulence reducing the potency of antibiotics (Guzzo et al, 2020). Pathogenic bacteria exhibit resistance to many antibiotic classes; the discovery of novel antipathogenic drugs or plant-based antibiotics other than those isolated from microbes continues (Munita and Arias, 2016)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
