Sappanin-type homoisoflavonoids from Scilla nervosa inhibits acetylcholinesterase enzyme: a combined in silico and in vitro approach

Alzheimer's disease is among the major health challenges that currently attract the attention of health care givers and drug discovery and development experts worldwide. This study investigated the acetylcholinesterase inhibitory activity of sappanin-type homisoflavonoids isolated from the inter-bulb surface of Scilla nervosa. Molecular docking, molecular dynamics simulation, ADMET and in vitro studies were performed to identify the hit molecules, understand their binding mode and interaction, druggability and establish their inhibitory potentials against acetylcholinesterase enzyme. The hit compounds 5, 2, 1 and 4 were identified as the hit molecules through the molecular docking. The molecular dynamics simulation and MM-PBSA analysis showed the hit homoisoflavonoids established stability and good binding affinity against the acetylcholinesterase enzyme. Also, 5 elicited the best inhibitory activity followed by 2, 1 and 4 in the in vitro experiment. Furthermore, the selected homoisoflavonoids exhibit interesting drug likeness and pharmacokinetic properties as drug candidate. The results suggest further investigations towards the development of the phytochemicals as possible acetylcholinesterase inhibitors.Communicated by Ramaswamy H. Sarma.

Analysis of Homoisoflavonoids in Caesalpinia digyna by HPLC-ESI-MS, HPLC and Method Validation

The roots of Caesalpinia digyna have been reported to contain gallic acid derivatives and minor homoisoflavonoids, but HPLC-ESI-MS and HPLC analyses of the homoisoflavonoids were challenging due to their low concentration in the roots. Separation and identification was accomplished by HPLC-ESI-MS and further elaborated for quantification using a C18 column with detection at 330 nm. A gradient mobile phase consisting of methanol and water (0.1% acetic acid) was used. The developed HPLC method showed good linearity (r2≥0.998), high precision (RSD<5%) and a good recovery (99.3-104.5%) of the compounds. The lowest detection limit was 0.75 ng and the method was found to be robust. All the validation parameters were found to be within the permissible limits and, therefore, the developed method is accurate and reliable for the quality control of C. digyna and other Caesalpinia species. This is the first report of sample preparation on Diaion HP-20 resin and characterization of homoisoflavonoids by HPLC-ESI-MS, extended by extensive quantitative HPLC analysis of homoisoflavonoids in C. digyna roots and method validation.