Callus culture, phytochemical analysis and antioxidant and cytotoxic effects of marjoram (Origanum majorana)

Background and aim Oxidative stress plays an essential role in the pathogenesis of several chronic diseases, including cancer, diabetes, and multiple sclerosis. Phenolic compounds are a group of plant-derived antioxidants used to treat or prevent cancer. Marjoram is an aromatic and medicinal plant found in Mediterranean countries and is used in traditional medicine. The aim of this study was to produce callus cultures, determine the in vitro antioxidant activity, total phenol and flavonoid contents, and evaluate the cytotoxic effects of marjoram extracts. Materials and methods Leaf, root, and stem explants were cultured in medium supplemented with different concentrations of 2,4-dichlorophenoxyacetic acid to induce callus formation. Antioxidant activity was evaluated using a 1,1-diphenyl-2-picrylhydrazyl assay. Total flavonoid and phenolic contents were measured using colorimetric assays. An MTT assay was used to estimate the cytotoxic effects of the extracts on a hepatocellular carcinoma cell line. Results and conclusion Leaf explants were the most promising for callus induction. The highest frequencies of callus induction were obtained with 2,4-D at 0.25 mg/L for leaf and root explants and 0.5 mg/L for stem explants. The maximum amount of extractable phenolic and flavonoid compounds was observed in the acetone extracts. The acetone extracts had higher cytotoxic effects than the methanol extracts, but there was no significant difference in antioxidant activity. These findings support the potential of marjoram as a resource for antioxidant and anticancer agents, and provide sufficient scientific background to isolate and purify bioactive compounds for further applications.