Phytochemical Characterization and Biological Properties of Justicia adhatoda L. Leaves: An Investigation Using HPTLC and GC-MS Techniques

Abstract

The present study was undertaken to characterize the phytochemical constituents and evaluate the biological activities of Justicia adhatoda L. using different analytical approaches. Qualitative phytochemical screening indicated the occurrence of alkaloids, phenolic compounds, flavonoids, saponins, steroids, and tannins, whereas anthocyanins, glycosides, and terpenoids were not detected. Among the quantified phytoconstituents, alkaloids and flavonoids were present at relatively higher levels, with concentrations of 8.46 and 8.24 µg/mL, respectively, followed by tannins at 4.12 µg/mL.The antibacterial potential of the plant extracts was examined against selected bacterial strains, and the methanolic extract exhibited the highest inhibitory effect against Enterobacter, showing activity comparable to that of streptomycin. The antioxidant properties of the extracts were further investigated through DPPH and ABTS radical-scavenging assays. Considerable antioxidant activity was observed, particularly with the methanol and ethyl acetate fractions. Spectroscopic and chromatographic investigations using UV-Visible spectroscopy and HPTLC demonstrated characteristic absorption patterns and several prominent chromatographic peaks, indicating the presence of diverse phytochemical constituents. GC-MS profiling subsequently revealed eleven compounds, with fatty acid derivatives and terpenoid-related compounds constituting the major identified components.