Abstract

Studies on curcumin, the principal element of turmeric powder, have demonstrated several biological actions such as antibacterial activity. Evaluation of new analogs or new compounds of curcumin for their antibacterial effect is interesting for researchers. In this in vitro study, we attempted to test the antibacterial activity of indium curcumin (In(CUR)₃), indium diacetylcurcumin (In(DAC)₃), and diacetylcurcumin (DAC) in comparison with curcumin. The action of these agents were examined on Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 14990), Pseudomonas aeruginosa (ATCC 27853), andEscerichia coli (ATCC 25922). Curcumin was effective against S. aureus and S. epidermidis, whereas In(DAC)₃ showed activity against S. epidermidis and P. aeruginosa. The effect of In(DAC)₃ on P. aeruginosa is an advantage. Strikingly, In(CUR)₃ exhibited antibacterial activity on all the four mentioned strains. DAC did not show antibacterial effect on any of the four test bacteria. The minimum inhibitory concentration (MIC) of curcumin was 187.5 µg/ml for S. aureus, and 46.9 µg/ml for S. epidermidis. However, the MIC of In(CUR)₃ was lower for the same bacterial strains (93.8 µg/ml for S. aureus and 23.4 µg/ml for S. epidermidis). Therefore, In(CUR)₃ was found to have more antibacterial effect than curcumin itself and could be a suitable candidate for further in vivo investigations.

Key words: Antibacterial activity, indium, curcumin, diacetylcurcumin.