Preparation of water-soluble nanocurcumin with enhanced superoxide scavenging activity

Abstract

Abstract Background: Curcumin, a curcuminoid derived from turmeric (Curcuma longa), has been extensively studied for various bioactivities. However, its limited water solubility and sensitivity to light restrict its therapeutic applications. In recent years, researchers have been exploring ways to enhance the properties of curcumin. In the current investigation, curcumin was transformed into its nanoform by utilizing d-glucose in an aqueous phase at room temperature, creating water-soluble nanocurcumin. Since this study focuses on altering the architecture of the curcumin sphere, it has been examined explicitly for antioxidant activity through well-defined in vitro assays. Materials and Methods: Nanocurcumin was synthesized through the conversion of curcumin using d-glucose. The zeta potential of nanocurcumin was measured to assess its water solubility. The orientation of curcumin in its nanoform was confirmed through ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence. High-resolution transmission electron microscopy (HR-TEM) was employed to provide evidence of its potential assembly. At the same time, Fourier-transform infrared (FTIR) analysis was conducted to discern alterations in peaks and stretches indicative of the transition to the nanoform. The prepared nanocurcumin was examined for superoxide and free radical scavenging activities, given curcumin’s well-known antioxidant properties. Results: The zeta potential measurement of nanocurcumin yielded a mean value of −53.4 mV. The nanoform orientation of curcumin was confirmed through UV–Vis spectroscopy, revealing a shift in the maximum absorption from 450 to 430 nm. Photoluminescence analysis, conducted with excitation at a wavelength of 478 nm, recorded a significant 5.01-fold increase in fluorescence intensity, from 193.6 to 971.8 a.u., accompanied by a slight shift in the emission maxima peak. HR-TEM was done, and various field images have been taken. Some images illustrated the probable assembly of curcumin into a spherical nanoform with a shell-like structure embedded inside the glucose sphere. Fourier-transform infrared analysis indicated alterations in some peaks and stretches due to the transition to the nanoform. Upon examination of the prepared nanocurcumin for superoxide and free radical scavenging activity, a noteworthy enhancement in superoxide scavenging activity was observed, increasing from 21.42 ± 5.01% in the native form to 69.94 ± 5.84% in the nanoform at a concentration of 10 µg/mL of curcumin. Conversely, a slight reduction in free radical scavenging activity was noted, decreasing from 55.57 ± 5.16% in native curcumin to 47.43 ± 6.83% in the nanoform at the same concentration. Conclusion: The water-soluble curcumin synthesized in this study can be regarded as an advanced molecule with the potential to address diseases mediated by oxidative stress effectively.