ABSTRACT
Alzheimer's disease (AD) is multi-factorial disorder characterized by impaired memory and cognition deficit. AD is characterized by impaired cholinergic transmission, extracellular amyloid beta deposits, neurofibrillary tangles and oxidative stress. A multi-target directed ligand (MTDL) approach is required to devise a therapeutic strategy against AD. In the present study, Asparagus racemosus aqueous extract was chosen, as it possess abundant medicinal properties including nootropic effect mentioned in ancient Ayurvedic texts. Moreover, its secondary metabolite sarsasapogenin (SRS) was also selected for this multi-target study for the very first time. The current study demonstrated that sarsasapogenin significantly inhibits key enzymes involved in pathogenesis of AD which are acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), BACE1 and MAO-B in a concentration dependent manner. SRS also exhibited anti-amyloidogenic, anti-oxidant and neuroprotective effects by in vitro studies. The IC50 values of SRS is 9.9⯵M and 5.4⯵M for AChE and BuChE respectively. SRS also significantly inhibited Aß42 fibrillization up to 68% at 40⯵M concentration as compared to control. TEM visualization showed Aß aggregates as short and scattered fibril clearly indicating SRS significantly inhibited peptide nucleation and fibril formation. Furthermore, the SRS was found to exert neuroprotective effect on PC12 cells against Aß42 and H2O2-mediated cytotoxicity. The cell survival was 62% and 69% against Aß42 and H2O2-mediated cytotoxicity, respectively. SRS also inhibited monoaminoxidase-B (MAO-B) and BACE1 enzymes in concentration dependent manner. Molecular docking studies indicated that SRS binds to the catalytic sites of multiple targets (AChE, BuChE, Aß42, BACE1, and MAO-B) in a significant manner that might having disease-modifying effects. Thus SRS is acting as suitable lead and can be utilised as MTDL compound for factors implicated in AD.
Subject(s)
Alzheimer Disease/drug therapy , Antioxidants/pharmacology , Asparagus Plant/chemistry , Enzyme Inhibitors/pharmacology , Neuroprotective Agents/pharmacology , Spirostans/pharmacology , Acetylcholinesterase/metabolism , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/metabolism , Animals , Antioxidants/chemistry , Antioxidants/isolation & purification , Aspartic Acid Endopeptidases/antagonists & inhibitors , Aspartic Acid Endopeptidases/metabolism , Biphenyl Compounds/antagonists & inhibitors , Butyrylcholinesterase/metabolism , Cell Survival/drug effects , Electrophorus , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/isolation & purification , Horses , Humans , Ligands , Monoamine Oxidase/metabolism , Neuroprotective Agents/chemistry , Neuroprotective Agents/isolation & purification , Oxidative Stress/drug effects , PC12 Cells , Picrates/antagonists & inhibitors , Rats , Spirostans/chemistry , Spirostans/isolation & purificationABSTRACT
The global ophthalmic formulations (OFs) market is expanding dramatically with the approval of new drug formulations for a variety of ophthalmic indications by competent authorities in various countries. In India, the Central Drug Standards Control Organization (CDSCO) and Indian Pharmacopoeia Commission (IPC) are making efforts for approval and setting the standards for OFs, respectively. In fulfillment of the requirements of the Drugs and Cosmetics Act of 1940, the IPC is publishing an official book of standards for drugs known as the Indian Pharmacopoeia (IP). There are 44 ophthalmic active pharmaceutical ingredients (APIs) and combinations approved by CDSCO as of 2011; the IP 6th edition (2010) prescribes the quality standards monographs for 41 ophthalmic APIs and formulations. The IP monograph of OFs also includes description, identification, impurities, assay, and specific tests. In addition, the IPC is publishing the National Formulary of India (NFI), which covers 23 OFs for the diagnosis and treatment of various eye diseases. Both the IP and NFI play a significant role in monitoring and improving the safety and efficacy of medicines, with specific emphasis on OFs.
