In vitro and in silico studies of the antifungal properties of the bulb and leaves extracts of Drimia delagoensis Baker (Jessop)

Drimia delagoensis (D. delagoensis), a member of the Hyacinthaceae family, is commonly used for the treatment of heartwater and skin ailments by the Zulus in South Africa. In this research study, the bulb and leaves of D. delagoensis were tested for their antifungal efficacy against Aspergillus fumigatus. Eight crude extracts were further analysed to determine the volatile chemical components of the plant using one-dimensional gas chromatography coupled with the time of fight mass spectrometry. The compounds detected from GC-MS were further subjected to molecular docking study to determine prospective relationship between the analysed compounds (1–9) and the active site of the glucosamine-6-phosphate synthase. All the crude extracts were effective against A. fumigatus. However, it was observed that dichloromethane: methanol (1:1) mixture for the bulb extracts had a high minimum fungal concentration values of (7.8 µg/mL) followed by hexane (7.8 µg/mL) and ethyl acetate (7.8 µg/mL). Compounds (9Z,12Z)-9,12-Octadecadienoic acid(R)-2,3-bis[[(E)-2-methyl-2-butenoyl]oxy]propyl ester and 9-Octadecenoic acid (9Z)-,1-methyl-1,2-ethanediyl ester had higher binding affinities of − 47.69 and − 62.36 kcal/mol, respectively when compared to amphotericin B standard drug (− 44.19 kcal/mol). Furthermore, lipophilicity values for ligands, which ranged from − 11.46 to − 27.07, were more significant than those for amphotericin B (− 19.66), and this greater significance could also be ascribed to the potency of the crude extracts against A. fumigatus.