Antimicrobial activities of Alchornea cordifolia leaf extract on Candida albican and some selected Probiotics

Abstract

The quest for novel and effective antimicrobial agents has become increasingly urgent because of the increasing threat of drug-resistant microbial pathogens. Alchornea cordifolia, a plant species widely used in traditional medicine, has been reported to possess antimicrobial properties. However, its antifungal activity and interactions with beneficial probiotic microorganisms remain poorly understood. This study aimed to investigate the antifungal efficacy of Alchornea cordifolia extracts and their bioactive components against Candida albicans and explore their interactions with probiotic microorganisms, Lactobacillus acidophilus and Sacchromyces bourdii, which are often used for control. By elucidating the antimicrobial potential and probiotic interactions of Alchornea cordifolia, this study aims to contribute to the development of innovative and sustainable solutions for the prevention and treatment of Candida albicans infections while also promoting a balanced microbiota. The crude extract was subjected to phytochemical screening. The bioactive components were isolated and purified via column chromatography and thin layer chromatography, whereas FTIR was used to analyse the functional groups present in the extract and isolated components. The extract and isolated components were further subjected to antimicrobial, minimum inhibitory concentration (MIC) and minimum fungicidal/bactericidal concentration (MFC/MBC) assays against C. albicans, S. bourdii and L. acidophilus via the agar diffusion and broth macrodilution technique. Phytochemical analysis revealed the presence of various bioactive components, including tannins, flavonoids, phenols, saponins, alkaloids, anthocyanins, cardiac glycosides, cyanogenic glycosides, oxalates, carotene and sterols. Four spots with Rf values between 0.73 and 0.75, 0.83 and 0.73, 0.87 and 0.98 and 0.32 and 0.23 assigned as components A, B, C and D, respectively, were isolated after elution with a gradient of solvents. The FTIR results of the crude extract revealed functional groups consistent with those of secondary metabolites, such as hydroxyl groups (O-H, peaks at 3812–3500 cm-1), amines (N–H stretching peaks at 3431 cm-1), alkenes (C-H stretching CH3 CH2, CH peaks at 3175–2800 cm-1), and C=C peaks at 1623 cm-1. These functional groups were identified during preliminary tests. The crude extract and components A, B, and C exhibited similar activities against Candida albicans, with inhibition zones ranging from 21 mm to 32 mm. Component C had the highest activity, with an inhibition zone of 32 mm. Component D showed moderate activity, with an inhibition zone of 26 mm. Antimicrobial activity against Sacromyces boulardii and Lactobacillus acidophilus varied among the components, with Component C showing the highest activity against Sacromyces boulardii. There was some selectivity for the pathogen rated as the crude extract ˃C ˃B = A ˃D. The crude extract and components A, B, and C had MICs of 100 µg/ml against Candida albicans. Component C had an MIC of 1000 µg/ml against Sacromyces boulardii. Component D had an MIC of 10 µg/ml against Candida albicans. The methanol crude extract and its components have shown promising antimicrobial activity against Candida albicans, making it a potential natural solution for candidiasis management. Further research will be crucial to unlock its full potential and explore its use in combination with probiotics. Keywords: Alchornea cordifolia, candidiasis, probiotics and antimicrobial