Chemical composition and in vitro investigation of the antibacterial activity of identified compounds from fungus-growing termites Macrotermes bellicosus

The fungus growing termites’ species Macrotermes bellicosus is used in traditional medicine in Benin for the treatment of infectious and inflammatory diseases such as digestive disorders, mumps, snake bites, cough, diarrhea, dysentery, and pulmonary infection [1]. Previous in vitro studies revealed that Macrotermes bellicosus is efficient against various pathogenic microorganisms [1]. However, the determination of active compounds that contribute to the bioactivity remains unexplored. Aim of the present study was to perform a chemical profile of an ethanolic Macrotermes bellicosus extract and determine active compounds that contribute to the antibacterial activity. Chemical profile and structural elucidation of compounds were performed using a pattern recognition strategy based on ¹³C NMR. The antibacterial activity of fractions and major identified compounds from Macrotermes bellicosus was investigated using the broth microdilution method. Minimum inhibitory concentrations (MIC) were derived to characterize the antibacterial activity. Major compounds have been identified including benzohydroquinone, 2-methylhydroquinone, niacinamide, ethyl-hexopyranoside, 3,4-dihydroxyphenethyl glycol and N-[2-(3,4-Dihydroxyphenyl)ethyl]acetamide. Benzohydroquinone and methylhydroquinone exhibited an antibacterial activity against Staphylococcus aureus with an MIC of 680 μM and 100 μM respectively. Fractions containing

N-[2-(3,4-dihydroxyphenyl)ethyl]acetamide and 3,4-dihydroxyphenethyl glycol showed a growth inhibition of S. aureus with IC₅₀ of 24.04 μg/mL and 37.28 μg/mL respectively. Macrotermes bellicosus used as a traditional medicine could be a therapeutic option for infectious diseases. The study demonstrates that methylhydroquinone and benzohydroquinone are contributing to the antibacterial activity of Macrotermes bellicosus. Moreover, antibacterial activity could be observed in M. bellicosus extract fractions containing

N-[2-(3,4-dihydroxyphenyl)ethyl]acetamide and 3,4-dihydroxyphenethyl glycol.

• References

• 1 Hammoud D, Chougourou D, Vissiennon Z, Ahyi V, Nieber K, Vissiennon C. In vitro evaluation of the antimicrobial activity of fungus-growing termites Macrotermes bellicosus used in traditional medicine in Benin. Conference paper, PMIO. 2017 4. (S 01): S1-S202. DOI: 10.1055/s-0037-1608532