Isolation of antimicrobial peptides from seed harvester ant, Trichomyrmex scabriceps (Mayr) (Hymenoptera: Formicidae) and their antimicrobial assay

Antimicrobial peptides (AMPs) are used to treat many infectious diseases. Nowadays, AMPs enjoy special attention due to their novel mode of action and kill various pathogens such as fungi, bacteria and viruses. Among insects, the ant genus can provide a potential antimicrobial peptide against various microorganisms. In the present study, AMPs compounds were isolated and purified from the ant species Trichomyrmex scabriceps using reversed-phase high performance liquid chromatography (RP-HPLC). The extract from abdomen showed the highest protein content (4.60 µg/µl) compared to head and thorax. The HPLC profile of the abdomen showed 14 different peaks, of which the peaks eluting at the 6th, 8th, 17th and 23rd minutes had a higher intensity. The number of peaks was comparatively lower in the extracts from the head and thorax. The antimicrobial activity of the head, thorax and abdomen extracts of ants was evaluated against Gram-positive Staphylococcus aureus (MTCC 3160) and Gram-negative Escherichia coli (MTCC 2692) bacterial strains. Among the extracts tested, the abdomen alone exhibited a distinct zone of inhibition against E. coli (176.98 ± 3.36 mm2). However, the extracts of the head and thorax showed no zone of inhibition. In addition, none of the extracts showed a zone of inhibition against S. aureus. To our knowledge, this is the first report observed AMPs in T. scabriceps ant and their antimicrobial property against these bacterial strains.