Phytochemical screening, antimicrobial activity investigation, and multivariate spectroscopic data analysis of Leucas deflexa Hook. f.

Abstract

Traditional medicine refers to health practices, approaches, knowledge, and beliefs that combine plant, animal, and mineral medicines used alone or in combination to treat, diagnose, and prevent disease or maintain health. However, the misuse of these traditional medicines results in overdose, unknown use of suspect or counterfeit herbal medication, toxic concentrations in traditional medication therapies, and unintentional injuries caused by unqualified practitioners. Leucas deflexa Hook f. is one of the most common plant species used to treat eye remedies, diarrhea dysentery, bacterial, fungal, and viral infections. However, the to best of our information there is no report about phytochemical screening, spectroscopic characterization, and antimicrobial activity on plant leaves. This study aims to test the phytochemical constituents and characterization of Leucas deflexa Hook leaf extract. f. using ultraviolet-visible (UV-Vis) spectroscopy, Fourier Transform Infrared spectroscopy, and Principal Component Analysis. Various extracts of petroleum ether, chloroform, acetone, and methanol have been prepared from the leaves based on the polarity of the solvent using the maceration method. The disc diffusion method was used to evaluate the antibacterial activities of extracts against four bacterial strains. The results of the qualitative phytochemical screening and UV-Vis spectroscopy analysis revealed the presence of essential metabolites, including alkaloids, saponins, steroids, and terpenoids. The FTIR results also indicate the presence of alkanes, alcohols, carbonyl group, carboxylic acids, aromatic, amines, and phenols in different Leucas deflexa hook f extracts. The chloroform, Petroleum ether, and methanol extracts showed good antibacterial activity against Staphylococcus auras and Escherichia coli with inhibition zones of 7-13mm, while that of ciprofloxacin is 15-17mm. PCA analysis of FTIR accounted for 99.99% of the variance in the data representation. The molecular structures revealed through our experimental results indicate the potential use of the plant for possible antibacterial agent development, mainly to produce synthetically improved therapeutic agents. The bioactivity results from the leaves of Leucas deflexa Hook. f. provides scientific justification for the traditional medicinal uses of this ethno-remedy, which is an essential step towards its acceptance and development as an alternative therapeutic agent.