Phytochemical screening, bioactive compound characterization and antimicrobial activity assay of Commelina benghalensis L. leaf

Abstract

C. benghalensis L., traditionally used for treating leprosy, fever, and snake bites. The study aimed to identify bioactive compounds, characterize essential oils, and evaluate the plant's potential as a source of therapeutic agents. Phytochemical screening was conducted on C. benghalensis leaves, followed by compound extraction. The antimicrobial activity of the leaf extract was assessed against selected human pathogens using the disc diffusion method. Antioxidant activity was evaluated using the DPPH assay. MIC, MBC, and MFC were determined using the Broth Dilution Method. The structure of the bioactive compound was determined using GC-MS, NMR and HPL. Data analysis was performed using non-parametric one-way ANOVA and Tukey's test. Methanol yielded the highest extract (23.54 g, 75.27%), followed by chloroform (5.11 g, 16.34%) and petroleum ether (2.62 g, 8.37%), reflecting the solvents' varying abilities to solubilize different phytochemicals. Qualitative phytochemical screening revealed the presence of alkaloids, tannins, flavonoids, steroids, terpenoids, saponins, phenols and coumarins aligned with the known diversity of bioactive compounds in C. benghalensis. GC-MS analysis of the essential oil identified 25 components, with five compounds as the major constituents, highlighting the potential for various applications based on these compounds' properties. Further isolation efforts using TLC and column chromatography led to the identification of 1,2-benzenedicarboxylic acid, 1,2-bis(2-ethylhexyl) ester (DEHP), a known plasticizer, confirming its presence in the plant extract. The extracts of C. benghalensis have demonstrated antibacterial activity against various bacterial strains, with inhibition zones ranged from 6±0.6 mm to 15.7±1.5 mm. The essential oil and methanol extracts were found to be the most effective. However, they have shown less effective than standard antibiotics. Furthermore, these extracts also exhibited antifungal activity against C. albicans, with inhibition zones from 8.7±1.2 mm to 16.7±3.1 mm, where the petroleum ether extract showed the highest activity. This comprehensive analysis underscores C. benghalensis's rich phytochemical profile and potential as a source of valuable bioactive compounds, warranting further investigation into its pharmacological and industrial applications.