The gut microbiota of insects is composed of a wide range of microorganisms which produce bioactive compounds that protect their host from pathogenic attack. In the present study, we isolate and identify the fungus Chrysosporium multifidum from the gut of Hermetia illucens larvae. Extract from C. multifidum culture broth supernatant showed moderate activity against a strain of methicillin-resistant Staphylococcus aureus (MRSA). Bioguided isolation of the extract resulted in the characterization of six α-pyrone derivatives (1–6) and one diketopiperazine (7). Of these compounds, 5,6-dihydro-4-methoxy-6-(1-oxopentyl)-2H-pyran-2-one (4) showed the greatest activity (IC50 = 11.4 ± 0.7 μg/mL and MIC = 62.5 μg/mL) against MRSA.

The gut microbiota of insects contains a wide range of organisms that protect them against the attack of pathogens by releasing various types of bioactive compounds. In the present study, we report the isolation and identification of the fungus Chrysosporium multifidum as a component of the microbiota from the larval gut of Hermetia illucens. Extract from the broth culture of C. multifidum showed moderate activity on a strain of methicillin-resistant Staphylococcus aureus (MRSA). The bioguided isolation of the extract resulted in the characterization of six α-pyrone derivatives (1-6) and one diketopiperazines (7), among them 5,6-dihydro-4-methoxy-6-(1-oxopentyl)-2H-pyran-2-one (4) showed the best activity (IC50 = 11.4 ± 0.7 µg/ml and MIC = 62.5 μg/ml).