SYNTHESIS AND BIOCHEMICAL STUDIES ON SULFATED MONOMERS OF LOW MOLECULAR WEIGHT LIGNINS

Anticoagulants are used as the first line therapy for management and prevention of thrombotic disorders. Thrombin and factor Xa have been the prime targets for regulation of the coagulation cascade. In this work, a small library of 17 benzofuran derivatives were synthesized and screened against thrombin and factor Xa. The derivatives that displayed inhibitory potential were docked on the exosite-II of factor Xa using a docking protocol that was developed in our research group. These compounds were based on the β-5 structural unit found in the oligomer -\u27CDSO3‘, which was prepared in our lab and was found to inhibit both thrombin and factor Xa by an exosite-II mediated allosteric disruption of the catalytic triad.The results revealed that these β-5 like derivatives are inhibitory against thrombin and factor Xa, although their potency is weak. Thrombin and factor Xa appear to recognize different structural features suggesting a significant selectivity in recognition. Furthermore, a slight preference for the benzofuran scaffold was observed with factor Xa. Probing the mechanism of inhibition using Michaelis-Menten kinetics reveal that these compounds display uncompetitive inhibition of these proteases and the mechanism of inhibition is allosteric. Docking of these compounds on factor Xa were done using GOLD (Genetic algorithm for ligand docking) and the results, explain the observed inhibition profile. The computed docked poses also give an idea of the residues on the exosite-II of factor Xa critical for inhibition. The molecules studied here are radically different in terms of structure and mechanism of inhibition from any other ligand described in literature. This represents an opportunity to discover novel molecules with a possibly different pharmacological and toxicological profile