Isolation and Structural Elucidation of Allantoin a Bioactive Compound from Cleome viscosa L.: A Combined Experimental and Computational Investigation

Allantoin, a crystalline compound was isolated from the methanolic extract of Cleome viscosa and it was reported for first time from this plant. The structure of Allantoin was elucidated by single crystal XRD and it was further confirmed through FTIR and ESI-MS spectroscopy techniques. It was crystallized in monoclinic crystal system with the space group P2i/c. Electronic structure characterization of the isolated Allantoin was done through density functional theory calculation. The atomic charges, dipole moment, frontier molecular orbital and the electrostatic potential map of the molecule in the gaseous phase and in the active site have also been analyzed. The optimized geometry was used for molecular docking to identify the possible binding mode. Furthermore, the in vitro antibacterial activity of the isolated Allantoin against Gram-positive and Gram-negative bacteria was evaluated. Maximum Inhibitory Concentrations (MIC) of isolated Allantoin results showed 4 μg/mL for B. subtilis and 8 μg/mL for S. aureus, E. coli and K. pneumoniae.