Docking of Phytoconstituents of Cynodon dactylon on NS2B NS3 protease domain of Dengue virus

The extracts of CD have been found to exhibit potent antiviral activity against white spot syndrome virus (WSSV), Vaccinia virus and chikungunya virus.43,44 Molecular docking analysis of selected phytoconstituents from CD against WSSV structural protein VP26 has also been reported.45 In the present study, CD owing to its rich phytochemical profile was explored for potential against NS2B -NS3 dengue viral target by molecular docking studies.The molecules with lowest docking energy and interaction with essential amino acids have been identified. Briefly the protein preparation was done by preprocessing the structures for assignment of bonds and bond orders, addition of hydrogens, filling in missing loops or side chains, capping uncapped termini, adjusting bonds and formal charges for metals, and correcting mislabeled elements, removing water molecules, removing unwanted chains and optimization of hydrogen bonded structures followed by refinement. The DENV NS2B- NS3 protease is important for viral replication with conserved and significant motifs including- the catalytic triad (H51, D75, and S135) and the oxanion hole (G133, T134, S135) which may be well explored in antiviral research.46 The lowest binding energy solutions included isoorientin, luteolin, triglochinin, and apigenin with binding energy of -30.4214, -29.4214, -29.0361, - 26.2859 Kcal/mol respectively. The phytoconstituents of CD- iso-orientin and apigenin bound to S135 through hydrogen bond interactions with bond distance of less than 2AO units stating their interaction with the catalytic traid of the serine protease NS2B- NS3.