Glucokinase activity enhancement by cellulose nanocrystals isolated from jujube seed: A novel perspective for type II diabetes mellitus treatment (In vitro)

Abstract

Cellulose nanocrystals (CNCs) were extracted from jujube seeds by the exertion of sulfuric acid hydrolysis procedure initially and thus, utilizing the alkaline and bleaching treatments. The resultant materials were identified after each stage of treatment. In the following, we performed morphological researches by the usage of field diffusion scanning electron microscopy (FESEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). In addition, the spherical forms of synthesized CNCs were observed with a diameter of 27 nm throughout the FESEM images, while displaying a value of 27.37 nm as well due to TEM micrographs. The obtained Zeta potential displayed a reasonable negative surface charge for CNCs. In conformity to the outcomes of TEM and FESEM, the results of AFM revealed the fine dispersion and spherical form of cellulose nano-particles. Thermogravimetric analysis (TGA) was performed to assess the thermal stability of CNCs, provided by the usage of jujube seeds, and it was suggested by the outcomes that this factor is affected mainly through the induced dehydration by sulphate groups. The obtained spectra from Fourier transform infrared (FTIR) spectroscopy displayed the gradual ejection of non-cellulosic materials (lignin and hemi-cellulose) and determined the affiliation of resulting samples to cellulose species. Jujube and CNC seed crystallization was also investigated through X-ray diffraction (XRD) analysis, which was indicative of the high crystalinity of 87.21%. According to the results of energy dispersive x-ray diffraction (EDX), CNCs contained 0.74 wt% sulfur impurity next to the company of other main components, while the evaluation of CNCs cytotoxicity did not show any cytotoxic effect. The synthesized novel CNC from jujube seed was screened by using an in vitro assay to measure the increases in glucokinase (GK) activity that was stimulated by the glucose concentration of 10 mM. According to the results, this substance proved to be capable of acting as a potent activator for GK. The Ksv values obtained from fluorescence quenching for GK-glucose and GK-glucose-CNC were 4.98 × 103 M−1 and 8.95 × 103 M−1, respectively. Spectral results revealed the conformational changes in GK upon interaction with glucose-CNC with higher binding affinity than to glucose. The circular dichroism spectroscopy indicates that the secondary structure of GK is changed in the presence of glucose and glucose-CNC.