Multifunctional biological activities of water extract of housefly larvae (Musca domestica)

Many types of insects have been used as foods and protein sources. In this study, we investigated the usefulness of housefly larvae (Musca domestica) based on their amino acid composition and multifunctional biological activities. First, the utility of the amino acid composition of housefly larvae was evaluated by amino acid analysis. Notably, the housefly larvae contained sufficient amounts of all essential amino acids, and the amino acid composition was similar to that of hen eggs. Second, we prepared housefly larvae water extract (HLWE) using the decoction method and explored the biological activities of the extract for potential application of the extract as a functional food. HLWE showed significant antioxidant activity (75.4% at 5.00 mg/mL), angiotensin-I-converting enzyme (ACE) inhibitory activity (half-maximal inhibitory concentration [IC₅₀] = 0.430 mg/mL), and dipeptidyl peptidase-IV (DPP-IV) inhibitory activity ([IC₅₀] = 3.52 mg/mL). We found that the low-molecular-weight constituents (<6 kDa) in HLWE contributed to antioxidant and ACE-inhibitory activities, whereas the high-molecular-weight constituents (>6 kDa) contributed to DPP-IV inhibition. Our results suggested that housefly larvae may provide a useful source of multifunctional protein.