Investigation of antioxidant, antimicrobial and cytotoxic activities of Plantago lanceolata extract

Both traditional medicine and folk medicine make use of natural remedies with a long history of use in the treatment of diseases. A large number of bioactive secondary metabolites, both from land and sea, have been revealed using classical natural product chemistry techniques. These natural compounds have produced a number of promising new drugs. Plantago, including the Plantago lanceolata used in our study, is the dominant genus in the Plantaginaceae family and encompasses more than 400 species, with many species classified as weeds worldwide. Plantago lanceolata L. is native to the Americas, Asia, Europe, and North Africa. Today, it is cultivated in a large number of countries around the world for medicinal purposes. In this study, the antimicrobial activity of hexane and methanol extract of P. lanceolata was tested by disk diffusion method. The antimicrobial effect of 125, 250, 500, 1000 μg/disc concentrations of plant extract was investigated using Candida albicans (ATCC 10231), Pseudomonas aeruginosa (ATCC27853), Streptococcus pyogenes (ATCC12344), Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) microorganisms. The extracts did not show a significant level of antimicrobial effect. No significant antimicrobial effects were observed for both methanol and hexane extracts. Antioxidant activity experiments were performed for different concentrations (12.5, 25, 50, 100 μg/ml) of both extracts of P. lanceolata plant using DPPH and ABTS methods. While no antioxidant activity was detectable for hexane extract, approximately 40% higher antioxidant effect was observed in the DPPH test of methanol extract compared to inhibition rates of BHT at the same doses. In the cytotoxicity tests performed in the study, the cytotoxic effect of hexane and methanol extracts on Caco-2 and HT29 colon cancer cell lines was investigated. Cytotoxicity was measured using the MTT test, a widely accepted method for assessing cell metabolic activity as an indirect measure of cell health and viability. Especially at the end of the 48th and 72nd hours, a statistically significant cytotoxic effect was observed depending on the dose.