Investigating In Vitro Antibacterial Activities of Medicinal Plants Having Folkloric Repute in Ethiopian Traditional Medicine

Abstract

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.

Antibacterial and Antifungal Activities of Ethiopian Medicinal Plants: A Systematic Review

“…Records from as far back as the fifteenth century detail traditional medical practices and remedies obtained from oral tales, early medico-religious manuscripts, and traditional pharmacopeia ( Jima and Megersa, 2018 ). The antimicrobial activities of these traditional medicinal plants are based on their secondary metabolites such as alkaloids, terpenoids, flavonoids, tannins and glycosides ( Sisay et al, 2019 ).…”

Antimicrobial activity of leaf extracts of Euphorbia paralias L. and Melilotus sulcatus Desf. against some pathogenic microorganisms

“…The agar well diffusion assay has been used in this research because it is more sensitive than the agar disc diffusion assay (Valgas et al, 2007). Many studies have shown that extracts obtained from the Euphorbia and Melilotus genera inhibit the growth of different microorganisms at various concentrations (Annapurna et al, 2004;Singh & Kumar, 2013;Sonju et al, 2017;Sisay et al, 2019). Other studies on the species of genus Euphorbia and Melilotus have confirmed the efficacy of the methanolic extracts compared with the aqueous extracts.…”

Comparison of the Effect of Phenylalanine Arginine Beta Naphthylamide (PAβN) and Curcumin on Minimum Inhibitory Concentration of Aminoglycosides on Pseudomonas aeruginosa Clinical Isolates

“…Increasing drug resistance has led researchers to try to find alternative or complementary herbal medicines to inhibit the growth of these pathogens, and many studies have been conducted in this area. A study by Sisay et al (2019) showed that the extract of Myrtus significantly reduces the growth inhibitory zone diameter of P. aeruginosa in laboratory (28). The results of another study carried out by Chakotiya et al (2016) on Glycyrrhiza glabra exhibited the effective role of this plant's extract on inhibiting the growth of P. aeruginosa clinical isolates (29).…”