In vitro, acidic, non-proteinaceous antifungal activities of lactic acid bacteria isolated from salad vegetables against human pathogenic Candida albicans

T.A. Bamidele, B.A. Adeniyi, S.I. Smith

 

Abstract

Background: The antagonistic abilities of lactic acid bacteria (LAB) against clinical isolates of Candida albicans are not quite widely reported and such are even scarce in Nigeria. This study therefore investigated inhibitory potentials of LAB isolated from locally grown cabbage, cucumber and lettuce against four (4) clinical isolates of C. albicans.

Methods: The cell free supernatants (CFS) generated from LAB culture filtrate was evaluated for anti-candida activity using agar well diffusion method, and the CFS-LAB pH was measured and neutralized using standard methods. The proteinaceous inhibitory metabolites were assayed for using sodium dodecylsulphate polyacrilamide gel electrophoresis (SDS-PAGE) technique. The LAB strains used were previously isolated and identified by 16S rRNA partial sequencing and their data submitted to GenBank for accessioning.

Results: The CFS of six (6) LAB strains showed varying degrees of anti-candida activity. Pediococcus pentosaceus BTA 51 from cucumber showed the widest inhibition zone of 14 mm while at neutral pH, it was 12 mm diameter. Weissella confusa BTA 20, BTA 40 isolated from cabbage and lettuce produced 10 mm and 12 mm zones of inhibition at acidic and neutral pH respectively. Lactobacillus plantarum BTA 07 from lettuce showed inhibition zone of 12 mm while L. fermentum BTA 47 and BTA 62 from cucumber showed zones of 14 mm each in acidic pH only. The SDS-PAGE did not detect any proteinaceous substances.

Conclusion: In conclusion, LAB isolated from cabbage, cucumber and lettuce produced organic acids, non proteinaceous metabolites at neutral pH, exhibiting invitro inhibitory abilities against clinical isolates of C. albicans.

Keywords: In vitro, Lactic acid bacteria, 16S rRNA, antifungal, SDS-PAGE, salad vegetables

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In vitro, acidic, non-proteinaceous antifungal activities of lactic acid bacteria isolated from salad vegetables against human pathogenic Candida albicans

Screening of selected medicinal plants for their antifungal properties

M. I. Aboh, P. Oladosu, G.O. Adeshina, B. O. Olayinka, S Olonitola, N.H. Atasie

 

Abstract

Background: The rising incidence of fungal infections has created the need for the next generation of antifungal agents, as many of the currently available ones either have adverse effects, or are not active against emerging or re-emerging fungi, leading to the fast progression of resistant strains. Objectives: This study aims at evaluating the antifungal activities of some medicinal plants used traditionally for treating skin infections in Nigeria. Methods: In vitro antifungal activities of seven indigenous plants (Leptadenia hastate, Lawsonia inermis, Hyptis suaveolens, Luffa cylindrica, Jatropha curcas, Pterocarpus erinaceous and Afromaxia laxiflora) were screened against Candida albicans ATCC 10231, Candida tropicalis ATCC 13803, clinical strains of Candida albicans, Candida tropicalis, Trichophyton rubrum, Microsporum canis and Epidermophyton floccosum using agar dilution and micro broth dilution methods. Terbinafine and fluconazole were used as reference standards for comparism. Results: The results showed that the ethanol and ethyl acetate extracts of the plants produced better antifungal effects than the hexane and water extracts. Luffa cylindrica and H. suaveolens exhibited the strongest inhibitory activity against all the fungi tested with minimum inhibitory concentration values ranging between 250 and 1000 ag/mL. Conclusion: The plants screened could serve as leads for the development of new antifungal drugs.

Key words: Antifungal, agar dilution, micro broth dilution, minimum inhibitory concentration.

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Screening of selected medicinal plants for their antifungal properties