Wet synthesis approach afforded four new heteroleptic mononuclear neutral diamagnetic oxidovanadium(V) complexes, comprising salicylaldehyde-based 2-furoic acid hydrazones and a flavonol coligand of the general composition [VO(fla)(L-ONO)]. The complexes were comprehensively characterized, including chemical analysis, conductometry, infrared, electronic, and mass spectroscopy, as well as 1D 1H and proton-decoupled 13C(1H) NMR spectroscopy, alongside extensive 2D 1H1H COSY, 1H13C HMQC, and 1H13C HMBC NMR analyses. Additionally, the quantum chemical properties of the complexes were studied using Gaussian at the B3LYP, HF, and M062X levels on the 6-31++g(d,p) basis sets. The interaction of these hydrolytically inert vanadium complexes and the BSA was investigated through spectrofluorimetric titration, synchronous fluorimetry, and FRET analysis in a temperature-dependent manner, providing valuable thermodynamic insights into van der Waals interactions and hydrogen bonding. Molecular docking was conducted to gain further understanding of the specific binding sites of the complexes to BSA. Complex 2, featuring a 5-chloro-substituted salicylaldehyde component of the hydrazone, was extensively examined for its biological activity in vivo. The effects of complex administration on biochemical and hematological parameters were evaluated in both healthy and diabetic Wistar rats, revealing antihyperglycemic activity at millimolar concentration. Furthermore, histopathological analysis and bioaccumulation studies of the complex in the brain, kidneys, and livers of healthy and diabetic rats revealed the potential for further development of vanadium(V) hydrazone complexes as antidiabetic and insulin-mimetic agents.

The purpose of this study was to explore possible protective effects of vitamin D3 on serum glucose concentration, body weight and histopathology of pancreas and liver. Animals were divided into 3 groups: Control group (n=6), streptozotocin (STZ) group (n=6) and streptozotocin + vitamin D3 (STZ+D3) group (n=6). Rats in the STZ+D3 group starting from the 7th day of experiment were given vitamin D3 for 14 days. Glucose levels and body weight were measured on the 1, 7, 14 and 21st day of experiment. Qualitative histological analysis of pancreas and liver was done using the light microscope with a digital camera. Differences between the groups were tested by one-way analysis of variance (ANOVA) followed by Dunnett's posttest. Differences in repeated measures were tested using paired t-test. On day 14 and 21, blood glucose level in STZ+D3 group was significantly higher compared to the control group of animals but significantly lower than the glucose level registered in STZ group of rats. On day 14 and day 21, body weight in STZ rats was significantly lower compared to weight in STZ+D3 and control groups of rats. Morphological changes, such as shrinkage of islets, vacuolation of both endocrine and exocrine cells, were observed in pancreas of STZ group of animals but were nearly absent in STZ+D3 rats. Similarly, STZ+D3 group of rats showed preserved liver histoarchitecture. Obtained results suggest that vitamin D3 treatment reduces hyperglycemia, exerts beneficial effects on body weight and alleviates histopathological changes in pancreas and liver in STZ-induced diabetic rats.