Chemical constituents, total phenolic content, antioxidant activity and bactericidal effect of Dicliptera verticillate (Acanthaceae)

This study investigated the phytochemical constituents and evaluated the total phenolic content, it also determined the antioxidant and antibacterial activities of the ethanol (EtOH) extract of the whole plant of Dicliptera verticillata. The phytochemical study was carried out using repeated silica gel column chromatography followed by Sephadex LH-20 to purify the extract which afforded three known compounds: lutein (1), shikimic acid (2) and guaiacylglycerol (3). The structures of these compounds were identified after analyses of their NMR and MS data and comparison of these data with those reported in the literature. The antioxidant and antibacterial activities were evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical assay and the broth macrodilution method, respectively. The EtOH extract showed moderate antioxidant activity (63.9%; IC₅₀ 40.16 μg/mL), weak total phenolic content and had a bactericidal effect against both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Klebsiella pneumonia and Escherichia coli). This is the first report on the isolation of compounds (1–3), as well as the total phenolic content and the antibacterial and antioxidant activities of the EtOH extract of D. verticillata.