Antimicrobial activities of fungus comb extracts isolated from Indomalayan termite (Macrotermes gilvus Hagen) mound


Abstract

Incorporating antimicrobial components into food packaging materials can prevent microbial contamination. Fungus combs could be an alternative source of natural antimicrobial agents. In this study, n-hexane, ethyl acetate, methanol, and water extracts were obtained from fungus combs isolated from Indomalayan termite (Macrotermes gilvus Hagen) mound. Their antibacterial and antifungal activities against food spoilage microorganisms including Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Aspergillus flavus, and Aspergillus niger were evaluated by Kirby–Bauer disc diffusion and microdilution. Results showed that ethyl acetate extract formed the largest diameter inhibition zone for all tested bacteria and fungi, exhibited antibacterial activity against all tested bacteria with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.39 and 0.78 mg/mL, respectively, and suppressed A. flavus and A. niger with an MIC value of 0.78 mg/mL. This extract contained guaiacol and syringol, which were predicted as the main antimicrobial components in fungus comb. n-Hexane extract only inhibited Gram-positive bacteria. S. aureus ATCC 25923 was the most sensitive to all the extracts, and A. flavus was more sensitive than A. niger. All these fungus comb extracts exhibited antimicrobial activity against E. coli ATCC 25922, P. aeruginosa ATCC 27853, S. aureus ATCC 25923, A. flavus, and A. niger. This study revealed that fungus comb extracts, especially ethyl acetate, could be considered as a new antimicrobial agent.

 

Keypoints

  • Ethyl acetate extract from fungus combs exhibited high antimicrobial activity against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 2785, Aspergillus flavus FNCC 6181, and Aspergillus niger FNCC 6114.
  • Ethyl acetate extract from fungus combs contained phenolic compounds such asguaiacol and syringol, which are predicted as the main antimicrobial substances.
  • Staphylococcus aureus ATCC 25923 was the most sensitive against n-hexane, ethyl acetate, methanol, and water extracts from fungus comb



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