Study of the Anti-bacterial and Anti-tumor Effects of Calycosin

The spread of antibiotic-resistant pathogenic strains has led to growing concerns in the world. One of the solutions to overcome this global problem is to research natural compounds and find natural ones with antibacterial properties. In this research, therefore, the antibacterial effects of calycosin on some important pathogens were studied. Also, we studied the antitumor effects of calycosin on HT-29 cell line.

After preparation of calycosin, its antioxidant capacity was measured. Then, the indicated strains were prepared from the microbiology department of Tehran Medical University and were then cultured. The disk diffusion, microdilution and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium (MTT) methods were used for evaluating antibacterial activity, determining minimum inhibition concentration (MIC), studying the antitumor effects of calycosin, respectively.

Calycosin showed a strong antioxidant capacity and its IC50 for 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging was measured to be 120 μg/ml. The study of the antibacterial effects of calycosin indicated that it was more effective on gram-positive bacteria than gram-negative bacteria. The MIC of calycosin for pathogens E. coli, Shigella dysenteriae, Salmonella typhimurium, Staphylococcus aureus and Bacillus cereus was calculated to be 32, 32, 40, 26 and 28 μg/ml, respectively. To determine the synergistic effects, a concentration of 1.2 MIC of calycosin was used along with antibiotics; the results indicated the synergistic effects of antibiotics and calycosin on the studied pathogens, except for Staphylococcus aureus. Calycosin reduced HT-29 cell line viability at 2000μg/mL.

In general, it was concluded that calycosin has strong antibacterial activity on the pathogens used, especially Gram-positive bacteria Staphylococcus aureus and Bacillus cereus; besides, it has synergistic effects with antibiotics. In this field, in vivo and clinical studies are needed.