Growth inhibitory properties of extracts prepared from selected Leptospermum and Melaleuca species against a panel of pathogenic bacteria

Mpala, Lindiwe Nomathemba; Chikowe, Getmore Rumbudzai; Cock, Ian Edwin

doi:10.5530/pc.2016.4.4

Cited by 5 publications

(5 citation statements)

References 43 publications

(39 reference statements)

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“…These were tentatively associated with stronger and weaker potentials for mediating antibiosis against faecal microorganisms within biofilters, respectively. All species demonstrating high antimicrobial scores ( n = 11 species) belonged to the family Myrtaceae (tested genera: Callistemon, Leptospermum and Melaleuca ), a family comprising species recognised for their significant production of antimicrobial oils [50, 65, 89] (listed in Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

Rise of the killer plants: investigating the antimicrobial activity of Australian plants to enhance biofilter-mediated pathogen removal

2019

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Background Biofilters are soil-plant based passive stormwater treatment systems which demonstrate promising, although inconsistent, removal of faecal microorganisms. Antimicrobial-producing plants represent a safe, inexpensive yet under-researched biofilter design component that may enhance treatment reliability. The mechanisms underlying plant-mediated microbial removal in biofilters have not been fully elucidated, particularly with respect to antimicrobial production. The aim of this study was therefore to inform biofilter vegetation selection guidelines for optimal pathogen treatment by conducting antimicrobial screening of biofilter-suitable plant species. This involved: (1) selecting native plants suitable for biofilters (17 species) in a Victorian context (southeast Australia); and (2) conducting antimicrobial susceptibility testing of selected plant methanolic extracts (≥ 5 biological replicates/species; 86 total) against reference stormwater faecal bacteria ( Salmonella enterica subsp. enterica ser. Typhimurium , Enterococcus faecalis and Escherichia coli ). Results The present study represents the first report on the inhibitory activity of polar alcoholic extracts from multiple tested species. Extracts of plants in the Myrtaceae family, reputed for their production of antimicrobial oils, demonstrated significantly lower minimum inhibitory concentrations (MICs) than non-myrtaceous candidates ( p < 0.0001). Melaleuca fulgens (median MIC: 8 mg/mL; range: [4–16 mg/mL]) , Callistemon viminalis (16 mg/mL, [2–16 mg/mL]) and Leptospermum lanigerum (8 mg/mL, [4–16 mg/mL]) exhibited the strongest inhibitory activity against the selected bacteria ( p < 0.05 compared to each tested non-myrtaceous candidate). In contrast, the Australian biofilter gold standard Carex appressa demonstrated eight-fold lower activity than the highest performer M. fulgens (64 mg/mL, [32–64 mg/mL]). Conclusion Our results suggest that myrtaceous plants, particularly M. fulgens , may be more effective than the current vegetation gold standard in mediating antibiosis and thus improving pathogen treatment within biofilters. Further investigation of these plants in biofilter contexts is recommended to refine biofilter vegetation selection guidelines. Electronic supplementary material The online version of this article (10.1186/s13036-019-0175-2) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Rise of the killer plants: investigating the antimicrobial activity of Australian plants to enhance biofilter-mediated pathogen removal

2019

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“…Indeed, the ability of plant extracts to block the growth of pathogenic bacteria has become a focus of substantial recent study. [1][2][3][4][5] Much of the research into traditional medicinal plant use has focused on Asian, [6][7][8] African, [9][10][11] Middle Eastern [12][13][14] and South American 15 plants. However, despite the potential of plants to provide us with useful pharmaceutical agents, the field is still relatively poorly studied.…”

Section: Introductionmentioning

confidence: 99%

An Examination of the Antioxidant Capacity, Antibacterial Activity and Toxicity of Commercial Kale and Spirulina Powders

Blanc¹,

Cock²

2021

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Introduction:The development of antibiotic resistant bacteria has resulted in treatment failure for the current antibiotic regimen against many bacteria. A corresponding decrease in the development of new antibiotic therapies has highlighted the urgent need for the discovery of new antibiotics. An examination of 'superfoods' is an attractive option due to the high antioxidant capacities and beneficial secondary compounds reported in many 'superfoods'. This study was undertaken to test kale and spirulina extracts for the ability to inhibit the growth of a panel of bacterial pathogens of human importance. Methods: Commercially sourced kale and spirulina powders were extracted and tested for antimicrobial activity using modified disc diffusion and liquid dilution MIC methods. Toxicity was evaluated using an Artemia franciscana nauplii bioassay. Results: The methanolic and aqueous extracts of kale and spirulina displayed noteworthy growth inhibitory activity against P. mirabilis. The aqueous spirulina extract was a particularly good inhibitor of P. mirabilis, with MIC values as low as 220μg/mL. In contrast, all extracts were ineffective or of low inhibitory activity against all other bacteria tested. All extracts were non-toxic in the Artemia nauplii bioassay, confirming their suitability as natural antibacterial therapies. Conclusion: These studies indicate that aqueous kale and spirulina extracts are promising inhibitors of P. mirabilis growth and may be useful in the prevention and treatment of rheumatoid arthritis, as well as other diseases caused by that bacterium.

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“…Indeed, the ability of plant extracts to block the growth of pathogenic bacteria has become a focus of substantial recent study. [1][2][3][4][5] Much of the research into traditional medicinal plant use has focused on Asian, [6][7][8] African, [9][10][11] Middle Eastern [12][13][14] and South American 15 plants. The recent establishment of bacterial pathogens that are either extremely (XDR) or totally resistant (TDR) to common clinically used antibiotics 16 has resulted in the need to develop new and effective antibiotic chemotherapies.…”

Section: Introductionmentioning

confidence: 99%

Davidsonia pruriens F. Muell. Fruit and Leaf Extracts Lack Antibacterial and Antifungal Activity

Mpala¹,

Chikowe²,

Cock³

2020

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Introduction: High antioxidant levels have been linked with multiple therapeutic properties, including antibacterial activity. Therefore, high antioxidant plant preparations are good targets for antibacterial testing. D. pruriens has high antioxidant capacity although it is yet to be tested for the ability to inhibit the growth of bacterial pathogens. Methods: The ability of D. pruriens fruit and leaf extracts to inhibit the growth of a panel of bacterial and fungal pathogens was investigated by disc diffusion assay. Toxicity was examined using the Artemia franciscana nauplii bioassay. Results: All D. pruriens fruit and leaf extracts were completely ineffective at inhibiting the growth of gram-positive and gram-negative panels of bacteria, as well as fungi. The extracts were non-toxic in the Artemia bioassay following 24 h exposure. Conclusion: Despite their high antioxidant capacity, D. pruriens fruit and leaf extracts were completely ineffective bacterial and fungal growth inhibitors. However, these extracts may have other therapeutic properties and testing against protozoa, virus and tumour cells is required.

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Growth inhibitory properties of extracts prepared from selected Leptospermum and Melaleuca species against a panel of pathogenic bacteria

Cited by 5 publications

References 43 publications

Rise of the killer plants: investigating the antimicrobial activity of Australian plants to enhance biofilter-mediated pathogen removal

Rise of the killer plants: investigating the antimicrobial activity of Australian plants to enhance biofilter-mediated pathogen removal

An Examination of the Antioxidant Capacity, Antibacterial Activity and Toxicity of Commercial Kale and Spirulina Powders

Davidsonia pruriens F. Muell. Fruit and Leaf Extracts Lack Antibacterial and Antifungal Activity

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