Study of the dual biological impacts of aqueous extracts of normal and gamma-irradiated Galleria mellonella larvae

Abstract

Objectives: Galleria mellonella assimilates beeswax using many gut enzymes; however, high doses of gamma radiation have been used to eradicate such pests, affecting its life cycle. In vitro studies of irradiated extracts of G. mellonella against bacterial species as well as three tumour cell lines are demonstrated in the present study. The antibacterial and antitumour effects are compared with those of the non-irradiated Galleria mellonella larval extract. Methods: The effect of different dose levels of gamma irradiation, ranging from 2 to 8 Gy, was tested on G. mellonella lipase, protease, and acid phosphate activities. The antimicrobial activity of un-irradiated and irradiated G. mellonella larval extracts was tested against different gram-positive and gram-negative bacteria and some fungi. The antitumour action was tested against different tumour cell lines. A cytotoxicity assay was performed on normal and irradiated larval extracts against normal human lung fibroblast cells. A microscopic examination of Streptococcus mutants and HepG- 2 was performed using transmission and scanning electron microscopy. Results: Optimum results were obtained at 6 Gy, which enhanced maximum enzymatic activity. Maximum antimicrobial activity was obtained against Streptococcus mutants with MIC 31.25 mg/ml at a dose of 6 Gy. A microscopic examination depicted an apoptotic process for irradiated G. mellonella larvae with either Streptococcus mutants or HepG-2. Conclusion: The present study shows a synergistic relationship between the G. mellonella larval extract and a 6 Gy radiation dose for further biomedical applications.