Synthesis of deep eutectic solvents for Xanthine oxidase inhibitors extracted from medicinal plant, Coleus aromaticus

Abstract

Deep eutectic solvents (DES), a green solvent has great concern currently with characteristics of cheap, low toxicity and biodegradable compared to ionic liquids. DESs were studied for extraction of natural xanthine oxidase inhibitors (XOI) from Coleus aromaticus which has potency to replace synthetic XOI, allopurinol possess many drawbacks in gout treatment. Choline chloride (ChCl) as hydrogen bond acceptor, glycerol (Gly) and D-glucose (Glu) as hydrogen bond donor were used in formulating DESs with different molar ratios. C.aromaticus extract by ChCl-Glu in 2:1 was found to be the best molar ratio. C.aromaticus extraction by ChCl-Glu in 2:1 exhibited (82.901±0.367) % where 7 % inhibition less effective than allopurinol (90.242±0.646) %. IC50 value of allopurinol was (3.466±0.333) μg/ml as the lowest IC50 compared to C.aromaticus (29.782±0.419) μg/ml. From the Lineweaver-Burks plot, the mode of inhibition was found to be non-competitive inhibition with Vmax and Km values of C.aromaticus and allopurinol were 79.748 Abs/min, 0.914 μM and 75.429 Abs/min, 0.041 μM respectively.