Effect of Black Cumin (<i>Nigella sativa L.L.</i>L.) Seeds on Some Fluconazole-Resistant and Biofilm-Forming Genes on Strains of <i>Candida albicans strains (C1, C2, CAF2 and CAI4)</i>

Abstract

The rise in drug resistance has become a serious health issue globally; as such the world health organization has since 1981 encouraged nations on the search for phytomedicines. Nigella sativa L. extracts have been widely studied and proved effective in the treatment of both metabolic and infectious diseases. This study was carried out to determine the effect of black cumin seeds (Nigella sativa L.) at molecular level (fluconazole-resistant genes in Candida albicans’ strains). Aqueous and metabolic extracts of the N sativa were prepared, while the oil extract was obtained from herbal shop and their phytochemical contents were determined. Candida albicans strains C1 (wild type), C2 a randomly selected clinical isolate and CAI4 and CAF2 (homogenous and heterogenous URA gene deficient respectively) strains were used for this study. 28 out of 50 (56%) Candida albicans isolated from HVS of suspected PID patients and 3 laboratory strains were resistant to fluconazole. Fluconazole resistance pattern and mode of action of each extract on the different strains were studied. Genes implicated in antifungal resistance and biofilm formation in C. albicans (EGR11, MDS3 and MDR1) were amplified (PCR), and the effects of the three extracts of N. sativa on the genes were studied. The aqueous extract had the highest concentrations of the phytochemicals followed by the methanolic extract and then the oil. The aqueous and methanolic extracts were found to have fungicidal effect at 100mg/ml and 250mg/ml respectively and oil at 100% only. While the oil and some concentration of the methanolic extracts have fungistatic effects. CAI4 and CAF2strains showed resistance to all the concentrations of the aqueous and methanolic extracts. The PCR result showed variation genes implicated in stress and pathogenicity, they were modulated on exposure to the plant extracts. It is recommended that the aqueous and oil of N. sativa be used in the treatment of multidrug resistant Candida infections alongside conventional antimicrobials. More extensive study should be carried out on the effect of the seed extracts of N. sativa on CAF2 strains CAI4 strains to study then role of URA3 gene on antifungal resistanceand mutagenesis in C. albicans.