Preliminary Evaluation of the Antifungal Activity of Aqueous Curcuma longa Extract Against Selected Fungal Isolates: An Experimental and Molecular-docking Study
Ayobami Janet Adekunle
Department of Biochemistry, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Oyo State, Nigeria.
Abiodun Bukunmi Aborisade
*
Department of Biochemistry, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Oyo State, Nigeria and Department of Medical Biochemistry, Faculty of Basic Medical Sciences, Osun State University, Osogbo, Osun State, Nigeria.
Adewale Adetutu
Department of Biochemistry, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Oyo State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Fungal contamination of agricultural materials and feed is an important concern, creating interest in plant-derived preparations with potential antifungal activity. Curcuma longa contains diverse phytochemicals that have been investigated for antimicrobial properties. However, the activity of laboratory-prepared aqueous extracts against selected agricultural fungi requires experimental evaluation.
Objective: This preliminary laboratory study evaluated the in vitro antifungal activity of an aqueous C. longa extract against Aspergillus flavus, Aspergillus fumigatus and Fusarium solani and explored the predicted interactions of selected C. longa phytochemicals with trehalose-6-phosphate phosphatase (TPP) using molecular docking.
Methods: An aqueous C. longa extract was evaluated against the three fungal isolates using a mycelial-growth inhibition assay at 100 mg/mL and broth microdilution for minimum inhibitory concentration (MIC) determination. Itraconazole was used as the reference antifungal agent. Phytochemical constituents were screened using in silico approaches, and selected compounds were docked against TPP to explore potential ligand–target interactions.
Results: The aqueous C. longa extract produced measurable inhibition of all three fungal isolates, with reported inhibition values ranging from 21.0% to 54.4% and the greatest inhibition observed against F. solani. Itraconazole produced substantially greater inhibition than the plant extract. The MIC of the C. longa extract was >50 mg/mL, compared with ≤0.04 mg/mL for itraconazole. Of the phytochemicals evaluated computationally, isocurcumenol showed the most favourable predicted interaction among the selected C. longa constituents, with a docking score of −6.3 kcal/mol, compared with −7.1 kcal/mol for itraconazole.
Conclusion: The aqueous C. longa extract demonstrated measurable but comparatively modest antifungal activity against the selected fungal isolates under the experimental conditions. Molecular docking identified potentially favourable interactions between selected C. longa constituents and TPP, providing preliminary mechanistic hypotheses for further investigation. Further studies using standardised extracts, purified constituents, and broader fungal panels and experimentally validated molecular targets are warranted.
Keywords: Curcuma longa, antifungal activity, Aspergillus flavus, Aspergillus fumigatus, Fusarium solani, molecular docking