|
Abstract
|
Curcumin has a wide spectrum of biological
and pharmacological activities including anti-inflammatory,
antioxidant, antiproliferative, antimicrobial and anticancer
activities. Complexation of curcumin with metals
has gained attention in recent years for improvement of
its stability. In this study, the effect of gallium curcumin
and gallium diacetylcurcumin on the structure, function
and oxidative stability of horseradish peroxidase (HRP)
enzyme were evaluated by spectroscopic techniques. In
addition to the enzymatic investigation, the cytotoxic
effect of the complexes was assessed on bladder, MCF-7
breast cancer and LNCaP prostate carcinoma cell lines by
MTT assay. Furthermore, antibacterial activity of the complexes
against S. aureus and E. coli was explored by dilution
test method. The results showed that the complexes
improve activity of HRP and also increase its tolerance
against the oxidative condition. After addition of the complexes,
affinity of HRP for hydrogen peroxide substrate
decreases, while the affinity increases for phenol substrate.
Circular dichroism, intrinsic and synchronous fluorescence
spectra showed that the enzyme structure around the
catalytic heme group becomes less compact and also thedistance between the heme group and tryptophan residues
increases due to binding of the complexes to HRP. On the
whole, it can be concluded that the change in the enzyme
structure upon binding to the gallium curcumin and gallium
diacetylcurcumin complexes results in an increase
in the antioxidant efficiency and activity of the peroxidise
enzyme. The result of anticancer and antibacterial activities
suggested that the complexes exhibit the potential for
cancer treatment, but they have no significant antibacterial
activity.
|