Novel spiroindoline derivatives targeting aldose reductase against diabetic complications: Bioactivity, cytotoxicity, and molecular modeling studies.

Despite significant developments in therapeutic strategies, Diabetes Mellitus remains an increasing concern, leading to various complications, e.g., cataracts, neuropathy, retinopathy, nephropathy, and several cardiovascular diseases. The polyol pathway, which involves Aldose reductase (AR) as a critical enzyme, has been focused on by many researchers as a target for intervention. On the other hand, spiroindoline-based compounds possess remarkable biological properties. This guided us to synthesize novel spiroindoline oxadiazolyl-based acetate derivatives and investigate their biological activities. The synthesized molecules' structures were confirmed herein, using IR, NMR (1H and 13C), and Mass spectroscopy. All compounds were potent inhibitors with KI constants spanning from 0.186 ± 0.020 µM to 0.662 ± 0.042 µM versus AR and appeared as better inhibitors than the clinically used drug, Epalrestat (EPR, KI: 0.841 ± 0.051 µM). Besides its remarkable inhibitory profile compared to EPR, compound 6k (KI: 0.186 ± 0.020 µM) was also determined to have an unusual pharmacokinetic profile. The results showed that 6k had less cytotoxic effect on normal mouse fibroblast (L929) cells (IC50 of 569.58 ± 0.80 µM) and reduced the viability of human breast adenocarcinoma (MCF-7) cells (IC50 of 110.87 ± 0.42 µM) more than the reference drug Doxorubicin (IC50s of 98.26 ± 0.45 µM and 158.49 ± 2.73 µM, respectively), thus exhibiting more potent anticancer activity. Moreover, molecular dynamic simulations for 200 ns were conducted to predict the docked complex's stability and reveal significant amino acid residues that 6k interacts with throughout the simulation.

Some indazoles as alternative inhibitors for potato polyphenol oxidase.

Fresh-cut vegetables and fruits have gained attention among consumers because of their fresh appearance, lack of pollution, nutrition, and convenience. However, in fresh-cut foods, enzymatic browning is the main problem. Polyphenol oxidase (PPO) is a vital enzyme involved in the process of enzymatic browning. In this study, PPO was purified from potato using Sepharose 4B-l-tyrosine-p-aminobenzoic acid affinity chromatography and the effect of some indazoles on the enzyme was determined. The enzyme was purified with a specific activity of 52,857.14 EU/mg protein and 21.26-purification fold. Indazoles exhibited inhibitor properties for PPO with IC50 values in the range of 0.11-1.12 mM and Ki values in the range of 0.15 ± 0.04-3.55 ± 0.88 mM. Among these compounds, 7-chloro-1H-indazole was shown as the most potent PPO inhibitor (Ki : 0.15 ± 0.04 mM). Determination of the enzyme's inhibition kinetics will simplify the testing of candidate PPO inhibitors.