초록
The antifungal bioactivity potential of the organic extract of silk tree (Albizia kalkora) was investigated in the current study. The crude extracts of A. kalkora and methanol, n-hexane, chloroform, and ethyl acetate fractions were prepared. The antifungal activity of obtained fractions of A. kalkora was studied at different concentrations ranging from 0.39-50 µg/mL. Dimethyl sulfoxide (DMSO) was taken as a toxicity control, whereas thiophanate methyl (TM) as a positive control. All the fractions significantly reduced the FOL growth (methanolic: 9.49-94.93 %, n-hexane: 11.12-100 %, chloroform: 20.96-91.41 %, and ethyl acetate: 18.75-96.70 %). The n-hexane fraction showed 6.25 µg/mL MIC as compared to TM with 64 µg/mL MIC. The non-polar (n-hexane) fraction showed maximum antifungal bioactivity against FOL in comparison with chloroform, methanol, and ethyl acetate fractions. GC/MS analysis exhibited that the n-hexane fraction contained hexadecanoic acid, 9,12,15-octadecatrienoic acid, 9,12-octadecadienoic acid, bis(2-ethylhexyl) phthalate, methyl stearate, and [1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylic acid. The results of in vitro antifungal inhibition were further reinforced by molecular docking analysis. Five virulence proteins of FOL i.e., pH-responsive PacC transcription factor (PACC), MeaB, TOR; target of rapamycin (FMK1), Signal transducing MAP kinase kinase (STE-STE7), and High Osmolarity Glycerol 1(HOG1) were docked with identified phytocompounds in the n-hexane fraction by GC/MS analysis. MEAB showed maximum binding affinities with zinnimide (-12.03 kcal/mol), HOG1 and FMK1with α-Tocospiro-B (-11.51 kcal/mol) and (-10.55 kcal/mol) respectively, STE-STE7 with docosanoic acid (-11.31 kcal/mol), and PACC with heptadecanoic acid (-9.88 kcal/mol) respectively with strong hydrophobic or hydrophilic interactions with active pocket residues. In conclusion, the n-hexane fraction of the A. kalkora can be used to manage FOL.