Development and validation of a new HPTLC-HRMS method for the quantification of a potent pancreatic lipase inhibitory lead Echitamine from Alstonia scholaris

Alstonia scholaris is an important indole alkaloid rich medicinal plant with diverse pharmacological activity. To understand the effect of extraction techniques, the stem bark sample of A. scholaris was subjected to continuous hot percolation, ultrasonic extraction, and cold maceration techniques. Continuous hot percolation technique extractive exhibited a potential pancreatic Lipase (PL) inhibitory activity and further bio-assay guided fractionation resulted in the isolation of echitamine with a PL inhibitory activity (IC₅₀ = 10.92 µM). A new validated HPTLC-HRMS method was developed for the quantification of echitamine by using a mobile phase of chloroform: methanol (80:20, v/v) with 0.04% formic acid. Echitamine content in the individual extractives were in direct correlation with the PL inhibitory activity (Pearson's r = -0.9409). The molecular docking studies further confirmed the PL inhibitory potential of echitamine. These results clearly highlight the role of echitamine as a natural product-based lead for potent PL inhibitory activity.