Phytochemical Characterization and Assessment of Crude Extracts from Justicia adhatoda for Phytotoxic and Cytotoxic Activity

Background. The aim of the study was to investigate the cytotoxicity, phytotoxicity, and proximate and phytochemical analysis of methanolic extracts of the leaves of Justicia adhatoda. Methods. Methanolic leaf extract of J. adhatoda was screened for phytotoxic activity by using root length inhibition and seed germination assays. Cytotoxic activity was calculated using brine shrimp lethality bioassay. Plant extracts were also investigated for their proximate composition. The presence of several phytochemicals was tested by employing different methods. Results. Decrease in seed germination and root length, 62.67% and 83.11%, was proportional to the increasing concentration of the methanolic extract of the plant. Cytotoxicity assay results indicated that the methanolic extract possessed significant cytotoxic potential with an LC-50 of 217 mu g/ml. Proximate analysis revealed that the leaves of J. adhatoda contain 9.4% moisture, 90.6% dry matter, 19.25% crude protein, 4.5% crude fat, 8.0% crude fiber, and 11.5% total ash. Conclusion. Methanolic extracts of J. adhatoda leaves showed significant cytotoxic effects and may have potential use in medicine. The J. adhatoda foliar extract shows good inhibitory effects against seed germination and root growth. Therefore, it might be used as soil additive in crops to control weeds. Further research is required to detect and isolate phytotoxins from the plant that might replace synthetic herbicides with eco-friendly herbicides.