Isolation, Characterization and Antifungal Evaluation of Flavonoid-Rich Fractions from Datura metel Leaves Against Candida albicans

Abstract

Background: Fungal infections caused by pathogenic microorganisms, particularly Candida albicans, have become a major global health concern due to the rapid emergence of antimicrobial resistance and reduced effectiveness of existing antifungal agents. Medicinal plants rich in bioactive phytoconstituents have gained considerable attention as potential sources of novel antifungal compounds.

Objective: The present study was undertaken to evaluate the antifungal potential of Datura metel leaf extracts and to isolate and characterize bioactive flavonoid compounds responsible for antifungal activity against Candida albicans.

Materials and Methods: Powdered leaves of Datura metel were subjected to successive solvent extraction using petroleum ether, chloroform, ethyl acetate, acetone, methanol, and hydroalcoholic solvents. Preliminary phytochemical screening was performed using standard qualitative tests. Antifungal activity of the extracts and isolated fractions was evaluated against Candida albicans ATCC No. 10231 using agar well diffusion method with fluconazole as the standard drug. Bioactive fractions were isolated by flash chromatography and characterized using FTIR, and C13 NMR spectroscopic techniques.

Results: Among all extracts, the chloroform extract exhibited maximum antifungal activity with a zone of inhibition of 18 mm at 10 mg/mL concentration, followed by ethyl acetate extract showing 16 mm inhibition. Phytochemical screening confirmed the presence of flavonoids, alkaloids, phenolic compounds, tannins, glycosides, and terpenoids in the active extracts. Flash chromatographic separation yielded fractions DCH FII, and DME FII, among which DCH FII demonstrated comparatively superior antifungal activity with MIC 62.5 µL/mL. FTIR analysis confirmed the presence of hydroxyl, aromatic, ether, and conjugated carbonyl functional groups characteristic of flavonoid compounds Further structural elucidation using C13 NMR spectroscopy confirmed the presence of aromatic and oxygenated carbon signals typical of flavonoid skeletons.

Conclusion: The present study demonstrated that Datura metel possesses significant antifungal activity due to the presence of flavonoid phytoconstituents. The chloroform extract and its isolated fractions exhibited promising antifungal potential against Candida albicans. The findings scientifically validate the traditional medicinal use of Datura metel and suggest that flavonoid-rich fractions may serve as potential natural antifungal agents for future pharmaceutical development.