Investigation and Characterization of Novel Biologically Active Secondary Metabolites from Melissa officinalis L.

Plants have very important chemical components, known as secondary metabolites, for the pharmaceutical industry, as well as for the chemical, cosmetics, and agricultural control industries. These secondary metabolites isolated from essential oils are used to obtain the raw material or fragrance component of the drug by semi-synthesis. For this reason, plants have been used to treat many diseases in the past, and their active ingredients are still used in medicine today. Each plant, each drug, contains differences owing to their natural structure. However, making the drug obtained from a plant a standard product is important in terms of using it as a medicine in treatment. Therefore, in our study, both the characterization of secondary metabolites and the antioxidant, antimicrobial and antiproliferative potential of Melissa officinalis were investigated. β-Citral (30.900%) was the main component of the essential oil. Total phenolic and flavonoid contents of M. officinalis were found to be 923.33 μg/mL gallic acid equivalent and 1.650 μg/mL quercetin equivalent. The free radical scavenging percentage of M. officinalis was 42.17%. M. officinalis had antimicrobial activity against Enterococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Candida parapsilosis. In mouse fibroblast cells, the cell viability was found to be 87.50%, 88.235%, and 94.118% respectively, at low doses. In a human breast cancer cell line, it was observed that the cell viability at low concentrations was 77.861%, 85.40%, and 89.474% respectively. The inhibitory concentrations IC50 of M. officinalis calculated for mouse fibroblast and human breast cancer cells in the GraphPad Prism 9.1.1 program were found to be 6229 and 4417 μg/mL respectively. In conclusion, M. officinalis has high bioactive secondary metabolites such as β-citral, β-caryophyllene, 6-methyl-5-hepten-2-one, and cis-1,2-dihydroperillaldehyde, has strong antimicrobial activity, and inhibits viability on breast cancer cells. [ABSTRACT FROM AUTHOR]