Objective: To test the in vitro antiviral activity of a crude tissue extract (CTE) from the earthworm Eisenia fetida, determine any effective components in the CTE, and elucidate possible mechanisms of action.
Methods: A CTE was made by homogenizing earthworms, followed by treatment with ammonium sulfate, then thermal denaturation. Inhibition of virus-induced cytopathic effect (CPE) was used to assess antiviral activity. Chromatographic analysis was used to identify effective components in the CTE.
Results: The CTE inhibited viral CPE at non-cytotoxic concentrations. Chromatography indicated that antiviral components corresponded to three active peaks indicative of proteases, nucleases and lysozymes. For adenoviruses, reduction in viral activity occurred for 100 microg/mL CTE. The reduction in adenoviral activity for four fractions was 100%, 91.8%, 86.9%, and 94.7%. For influenza viruses, reduction in viral activity of 100%, 86.6%, 69.1% and 88.3% was observed for 37 microg/mL CTE. In addition, three active fractions mixture had stronger antiviral activity (98.7% and 96.7%) than three fractions alone. Gel electrophoresis results indicated that nucleases from E. fetida could degrade the genome of influenza viruses and adenoviruses.
Conclusion: The earthworm CTE displayed non-specific antiviral properties, possibly mediated by a combination of proteases, nucleases and lysozymes. Nucleases likely participate in the antiviral process, and degrade the genome of the virus thereby preventing further replication.