In silico screening, TLC bioautography and in vivo studies of Zanthoxylum armatum DC. (Indian Prickly Ash) extract as a potential neuroprotective agent

Zanthoxylum armatum DC., a popular spice, and folklore medicine, is widely distributed throughout the Northeastern region of India and practiced by indigenous tribes as a remedy for digestive and nervous system disorders. The study aimed to assess the neuro-protective potentiality of Zanthoxylum armatum extract through different learning and memory paradigms against scopolamine-induced cognitive impairment. For the isolation of the compounds, coarsely powdered shade-dried fruits were extracted with ethanol by the cold maceration method. In silico studies were performed for the isolated compounds. TLC bioautographic enzyme assay was developed to screen acetylcholinesterase and butyrylcholinesterase inhibition by plant extract using donepezil, a known acetylcholinesterase inhibitor. Memory retention activities of ethanolic extract (100, 200, and 400 mg/kg; p.o.) were determined in-vivo , along with an estimation of whole-brain cholinesterase and antioxidant activity. Chromatographic analysis from chloroform fraction resulted in the isolation of three bio-active phytoconstituents, and structural elucidation identified them as β-sitosterol (ZA-01), Stigmasterol (ZA-02), and Lupeol (ZA-03). In silico molecular docking studies revealed stigmasterol has the minimum binding energy with acetylcholinesterase among all the isolated bioactive. The stability of the protein-ligand complex was found satisfactory after performing molecular dynamics simulation studies. Pre-treatment with extract significantly improved transfer latency in maze tests decreased rat brain acetylcholinesterase activity, and showed antioxidant potentiality against scopolamine-induced memory impairment. The combination of neuroprotective, anticholinesterase, and antioxidant effects shown by Z. armatum extract may be what makes it a nootropic drug. These are good signs for the search for natural nootropics from Z. armatum extract. Even so, more research with extracts and isolated compounds will be needed to make the traditional uses of the plant more scientifically sound. • Zanthoxylum armatum is evaluated for its potential as neuroprotective agent. • β-sitosterol, Stigmasterol and Lupeol were isolated from the plant extract. • In silico molecular docking and molecular dynamics simulations were performed. • TLC bioautography, in vivo animal tests showed good neuroprotective action of Zanthoxylum armatum extract.