Synergetic antibacterial activity of Vernonia auriculifera Hiern and Buddleja polystachya Fresen on selected human pathogenic bacteria

Firnus Haile; Markeshaw Tiruneh G/Medhin; Zemene Demelash Kifle; Tadesse Asmamaw Dejenie; Nega Berhane

doi:10.1016/j.metop.2022.100210

Synergetic antibacterial activity of Vernonia auriculifera Hiern and Buddleja polystachya Fresen on selected human pathogenic bacteria

Metabol Open. 2022 Sep 15:16:100210. doi: 10.1016/j.metop.2022.100210. eCollection 2022 Dec.

Authors

Firnus Haile¹, Markeshaw Tiruneh G/Medhin², Zemene Demelash Kifle³, Tadesse Asmamaw Dejenie², Nega Berhane¹

Affiliations

¹ Institute of Biotechnology, University of Gondar, Gondar, Ethiopia.
² Department of Medical Biochemistry, School of Medicine, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
³ Department of Pharmacology, School of Pharmacy, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.

Abstract

Background: Medicinal plants have been used as traditional treatments for various human diseases for many years and they are still widely practiced throughout the world. Due to the long history of the practice, medicinal plants have become an integral part of the Ethiopian culture. This study aimed to evaluate the antibacterial activities of Vernonia auriculifera Hiern and Buddleja polystachya Fresen leaf extracts and their synergistic effect against some selected human pathogenic bacteria.

Methods: Ethanol, methanol, and n-hexane crude extracts of Vernonia auriculifera, Buddleja polystachya, and a mixture of the two-plant respective of each solvent were evaluated against tested pathogenic bacteria using the agar well diffusion method; the inhibition zones were recorded in millimeters. Gentamycin was used as a positive control, while dimethyl sulfoxide served as a negative control. The minimum inhibitory concentration of the plant extracts against test bacteria was evaluated using two-fold broth dilution methods and then Minimum bactericidal concentration was determined by sub-culturing the test dilutions from minimum inhibitory concentration tubes onto fresh Muller Hinton Agar plates incubated at 37 °C for 24 h.

Results: Maximum antibacterial inhibition zone was observed on methanol extracts of synergism against S. Typhimurium (ATCC 1333) (31.00 ± 1.73 mm) while, a minimum inhibition zone was observed on methanol extract of Buddleja polystachya, against E. coli (ATCC 35218) (5.67 ± 0.57). Minimum inhibitory concentration and minimum bactericidal concentration values of the crude extracts of Vernonia auriculifera, Buddleja polystachya, and their mixture lies between (3.125%-12.5%) and (6.25%-25%) respectively. The data were analyzed using the SPSS software package version 20 for windows.

Conclusion: The present study revealed that ethanol and methanol extracts of Vernonia auriculifera and Buddleja polystachya possess significant inhibitory effects against tested pathogens and the antibacterial activity of both plants leaf extracts was greater than the activity of currently used antibiotics (Gentamycin) against some selected organisms.

Keywords: ANOVA, Analysis of variance; ATCC, American Type Cell Culture; Antibacterial; Buddleja polystachya Fresen; CFU, Colony Forming Unit; DMSO, Dimethyl Sulfoxide; MBC, Minimum Bactericidal Concentration; MDR, Multi Drug Resistance; MHA, Mueller Hinton Agar; MIC, Minimum Inhibitory Concentration; Medicinal plant; RPM, Revolution per Minute; SPSS, Statistical Package for Social Science; Synergism; Vernonia auriculifera Hiern; WHO, World Health Organization; XDR, Extremely Drug Resistant.