Antibacterial and antitumor activities of melatonin hormone

Abstract

AIM: The present study aims to investigate antibacterial and antitumor activities of melatonin hormone. METHODS: In the present study, antibacterial and antitumor activities of six different melatonin hormone concentrations (0.001, 0.01, 0.1, 1, 10, 100 mg/ml) were investigated by using Kirby-Bauer microbial sensitivity assay and Agrobacterium tumefaciens-induced potato disc tumor assay. Antibacterial activity was carried out with ten different human pathogens (Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis, Escheria coli, Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens, Proteus vulgaris, Enterobacter cloacae and Klebsiella pneumoniae). RESULTS: Only 100 mg/ml of melatonin among all of the tested concentrations showed a broad antibacterial spectrum against all of the studied bacteria. P. vulgaris (inhibition zone: 13.5 mm) and S. aureus (inhibition zone: 12.5 mm) were more vulnerable to melatonin than other tested bacteria. Antitumor activities of six different melatonin hormone concentrations (0.001, 0.01, 0.1, 1, 10, 100 mg/ml) were investigated by using Agrobacterium tumefaciens-induced potato disc tumor assay. Generally, all concentrations of melatonin showed high tumor inhibition (more than 50 %). Best antitumor activity was observed with 100 mg/ml of melatonin (100 % tumor inhibition). CONCLUSIONS: These results have shown that melatonin hormone may have a therapeutical potent as an antibacterial and antitumor agent.