In vitro and in silico study of the anti-hyperuricemia and anti-xanthine oxidase activity of some natural extracts and pure molecules

Abstract

With lifestyle changes, gout has become common; excessive consumption of red meat and seafood can lead to hyperuricemia and then acute gout attacks. Recently, new strategies have been applied; using natural products and some approved synthetic products to treat the disease. We aim to evaluate in vitro and in silico, the inhibition activity with kinetics of four vitamins like: vitamin C, vitamin E, vitamin D3, and vitamin B9, three purified molecules: (harmaline and harmine) from Peganum harmala L., (hispidin) from Inonotus hispidus (Bull.) P.Karst., and two extracts: flavonoids (CEAE) and alkaloids (CAE) from Cupressus sempervirens L., to bovine milk xanthine oxidase (BXO), molecular docking using GOLD was done to explain the mechanism of action related to its inhibition and the pharmacokinetics (PK) parameters were checked to confirm their safety using preADMET 2.0 servers, the best-ranked inhibitors were chosen based on the approved PK properties and the best PLPchem score generated by GOLD. The results show that BXO have a Km value of 163.55 µM with Vmax of 37 U, the tested compounds present an important inhibition activity to BXO with an IC50 of 34.10 ± 0.21 µM (vitamin B9), 36.68 ± 1.50 µM (vitamin E), 39.01 ± 0.02 µM (vitamin C), and 100.28 ± 0.33 µM (vitamin D3), 48.52 ± 1.76 µM (harmine), 39.72 ± 0.32 µM (hispidin), and 51.00 ± 1.00 µM (harmaline), 3.52 ± 0.04 µg/ml (CAE), and 8.46 ± 1.98 µg/ml (CEAE), compared to the control (allopurinol with 32.03 ± 0.73 µM). The kinetic study shows that vitamins were noncompetitive inhibitors with Ki values of 12 ± 1.41 µM (vitamin C), 29 ± 1.06 µM (vitamin E), 15 ± 1.76 µM (vitamin B9), and 20 ± 0.71 µM (vitamin D3), the purified molecules were non-competitive inhibitors such as harmaline (Ki = 11 ± 2.12 µM) and harmine (Ki = 2.5 ± 0.00 µM), while hispidin (Ki = 3.5 ± 0.00 µM) was a competitive inhibitor. The in-silico results show that lignan rhamnoside, hispidin, and vitamin E were the best inhibitors model with approved PK; the other molecules were saved as moderate to weak inhibitors with suitable PK properties. Eventually, the tested inhibitors could be significant in drug discovery, especially in treating gout; therefore, drug development, including clinical trials, should be done with these promising results. Keywords: Bovine xanthine oxidase, Vitamins, Hispidin, Harmine, ADMET, GOLD, Gout.