Browsing by Author "Olsen, John Elmerdahl"

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    Bacteriostatic and haemolytic activities of extracts and compounds of commiphora swynnertonii
    (Research Journal of Pharmacognosy, 2023) Msengwa, Zaituni; Credo, David; Mafuru, Magesa; Mwesongo, James; Mabiki, Faith Philemon; Mwang’onde, Beda John; Mtambo, Madundo Mkumbukwa; Kusiluka, Lughano Jeremy; Mdegela, Robinson Hammerthon; Olsen, John Elmerdahl
    Background and objective: Commiphora swynnertonii (Pax) is used in traditional medicine to treat infectious diseases. Previous studies have reported antimicrobial activity of this plant; however, the activity of compounds that are present in extracts of this plant has not been thoroughly documented. Likewise, the primary mode of action (bactericidal or bacteriostatic) and the possible toxicity on red blood cells have not been reported. Methods: Extracts of leaves, whole root, root bark, root wood, whole stem, stem bark and stem wood, were produced using hexane, dichloromethane, methanol and water. Cold and hot extraction methods were employed. Antibacterial activity of extracts was tested against selected medically important Gram-positive and Gram-negative bacteria by growth inhibition, minimum inhibitory concentrations and time kill assays. Moreover, haemolytic activity against sheep red blood cells was determined in vitro. Results: The hexane extracts of whole root and root bark, methanol extracts of root wood, and dichloromethane extracts from the leaves of C. swynnertonii inhibited the growth of S. aureus. MIC values for the extracts and compounds, indicated moderate activity against Gram-positive bacteria (Staphylococcus aureus, Streptococci species and Enterococci species) while the activity against Gram-negative bacteria (Escherichia coli, Klebsiella species, Pseudomonas aeruginosa, Salmonella species, Shigella sonnei and Yersinia enterocolitica) was weak. Time kill profiles showed the extracts have bacteriostatic activity against S. aureus, and low haemolytic effect, except for extracts of whole root and leaves at the concentration of 1000 μg/mL. Conclusion: Extracts of C. swynnertonii showed bacteriostatic activity against Gram-positive bacteria with low toxicity on red blood cells.
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    In-vitro assessment of antibacterial effects of combined crude extracts of s. glaucescens and c. swynnertonii with antibiotics
    (Academic Journals, 2023) Ochollah, Mary George; Mabiki, Faith Philemon; Kusiluka, Lughano Jeremy Moses; Mdegela, Robinson Hammerthon; Olsen, John Elmerdahl
    Currently, there is an upsurge of bacterial resistance in single-drug treatment regimens. This has stimulated a growing interest in research and development of new antibacterial agents containing several ingredients as one of the means to combat bacterial resistance. Herb-antibiotic combination therapy is one of the reported effective treatment regimens to combat antimicrobial resistance. This study was aimed to assess antibacterial effects of combined crude extracts of Synadenium glaucescens and Commiphora swynnertonii with antibiotics. In this study, three standard antibiotic drugs namely, ciprofloxacin, ampicillin and erythromycin in combination with crude extracts from S. glaucescens and C. swynnertonii were screened for antibacterial effects against two Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis and three Gram-negative bacteria Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. Broth microdilution technique was used to determine the Minimum Inhibitory Concentration (MIC) while Fractional Inhibitory Concentration (FIC) indices were calculated from MIC values of combined extracts to determine the combination effects. Synergism was observed when ciprofloxacin was combined with all tested crude extracts against E. coli (ΣFIC of 0.02), combination of ciprofloxacin with extract from root barks of C. swynnertonii (ΣFIC of 0.5) against S. aureus, root barks of Synadenium glaucescens (ΣFIC of 0.1) against S. aureus and combination of ampicillin with all tested crude extracts (ΣFIC of 0.03-0.1) against E. faecalis. Moreover, antagonism was observed between the combinations of ampicillin and erythromycin with all tested crude extracts against Gram-negative bacteria (ΣFIC of 4-8). Therefore, the combinations which demonstrated synergism may be promising alternatives for the treatment of infectious diseases caused by E. coli, S. aureus and E. faecalis. However, in the future, toxicity studies for combinations which demonstrated synergism are recommended.