Isolation and characterization of an antibacterial compound Bis-(2-ethylhexyl) phthalate from the fungi Penicillium digitatum

Introduction and Aim: Penicillium is a fungal antibiotic derived from Penicillium notatum. In this study, we aimed to isolate the antibacterial compound Bis-(2-ethylhexyl) phthalate from the fungi Penicillium digitatum, as well as study its antibacterial activity against the the pathogens Escherichia coli,Group B Streptococcus agalactiae, and Staphylococcus aureus. Materials and Methods: The identification of Bis-(2-ethylhexyl) phthalate-containing secondary metabolite was achieved through bioassay-guided chemical analysis of the crude extract. The structure of the compound was identified from UV spectra, IR, and GC-MS spectral data. The antimicrobial activity of Bis-(2-ethylhexyl) phthalate, isolated from the fungus Penicillium digitatum, was determined using standard methods. Results: UV, IR, and GC-MS spectroscopy confirmed the crude extract of fungi Penicillium digitatum to contain the bioactive compounds 1,2-benzenedicarboxylic acid and bis(ethylhexyl) phthalate. The MIC value of the bioactive molecule was also determined to be 32 mg/ml. The P. digitatum ethyl acetate extract showed moderate antibacterial activity against the Gram-negative bacterial isolate Escherichia coli and high activity against the Gram positive pathogens Streptococcus agalactiae and Staphylococcus aureus. Conclusion: The fungi Penicillium digitatum produces the metabolite Bis-(2-ethylhexyl) phthalate, which exhibits antibacterial activity against Gram positive and Gram-negative pathogens and hence could be used in treating infections by these bacterial pathogens.