Recent insight in the phytochemistry and bioactivity of organic Melissa officinalis L. essential oil from Transylvania

Lemon balm is an aromatic plant from the family Lamiaceae, and a source of essential oil (EO) having a higher market value compared to other species of this botanic family. It is more expensive due to the low extraction rate, and it is distinguished by the pleasant citrus-like aroma. Although there have been works on lemon balm, regional quality variations remain poorly represented in the scientific literature, and this study provides a perspective in this regard, with emphasis on potential use in the food industry. We explored the composition, FT-IR particularity and the bioactivity (antimicrobial and cytotoxic) for a traceable and authentic Melissa officinalis EO obtained from an organic crop from Transylvania, Romania. Microscopic analysis of the plants indicated that density of peltate glandular trichomes was significantly higher on leaves of lateral branches compared to those from main stems, proving these are recommended for fresh use in foodstuffs. The EO profile was given mainly by monoterpenes and sesquiterpenes. The functional groups displayed characteristic peaks on the FT-IR spectrum that might be useful for comparing and authenticating EOs. Biologic activity screening demonstrated that EO was more effective against pathogenic bacterial strains while having a milder effect against beneficial lactic acid bacteria (Lactiplantibacillus plantarum), suggesting compatibility with food matrixes. A cytotoxic assay on cancer cell lines (Caco-2, T47D-Kbluc) supports the potential phytotherapeutic properties but with ranging effectiveness. EO from locally grown plants added to food products can increase their “regional” character, improve shelf life while having health-promoting properties, providing an excellent approach as a natural alternative to synthetic additives and food preservatives while supporting local sources.