International Journal of Science, Engineering and TechnologyAuthors: Ruchi Upadhya, Varun Jain
Abstract: Background: Adhatoda vasica Nees (Acanthaceae), commonly known as Vasaka, is an important medicinal plant extensively used in traditional Ayurvedic and Unani systems for the treatment of respiratory disorders. The therapeutic efficacy of the plant is largely attributed to the presence of quinazoline alkaloids, particularly vasicine and vasicinone. Objective: The present investigation aimed to isolate and characterize alkaloidal constituents from the methanolic leaf extract of A. vasica using chromatographic and spectroscopic techniques. Methods: Dried leaf powder was extracted with methanol by maceration, followed by acid–base fractionation to obtain alkaloid-enriched fractions. Preliminary screening was performed using thin-layer chromatography (TLC) and Dragendorff’s reagent. Isolation of alkaloids was achieved through silica gel column chromatography and preparative TLC. Structural characterization of the isolated compounds was carried out using UV–Visible spectroscopy, FT-IR, mass spectrometry (MS), and NMR analyses. Results: Methanolic extraction yielded an alkaloid-rich fraction that exhibited positive Dragendorff’s test. TLC profiling revealed multiple alkaloidal constituents with distinct Rf values. Chromatographic purification afforded a major alkaloidal fraction (SA-2), obtained as a pale-yellow amorphous powder with a melting point of 311–315°C. High-resolution mass spectrometry displayed a molecular ion peak at m/z 270.24. FT-IR analysis indicated characteristic absorption bands corresponding to hydroxyl, aromatic C–H, carbonyl, and olefinic functionalities. UV spectra showed absorption maxima at 280 and 443 nm. Spectral data were consistent with quinazoline alkaloid derivatives reported from A. vasica. Conclusion: The developed extraction and purification strategy effectively isolated alkaloidal constituents from A. vasica leaves. Spectroscopic evidence confirmed the presence of bioactive quinazoline alkaloids, supporting the medicinal significance of the plant and its potential for pharmaceutical applications.
