Anatomic and Phytochemical Investigation of Herbal Tea Bags Sold as Lemon Balm (Melissa officinalis L.) in the Market

Melissa officinalis L., an ethnobotanically valuable plant, has been used for the treatment of several diseases since ancient times. However, different plants with the same name are sold instead of lemon balm in markets that sell herbal products in Türkiye. For this purpose, 15 different brands of tea bags in crushed form, sold as lemon balm (Melissa officinalis L.) in markets, were analyzed. The total phenolic, flavonoid, and antioxidant capacities of the hydroalcoholic extracts of these tea samples along with the stomatal structure were investigated. Additionally, chemical compositions and rosmarinic acid contents were determined by the high-performance thin-layer chromatography method. Among the samples examined, S1, S2, S9, and S12 tea samples were found to meet the eligibility criteria. The leaves of these samples had diacytic stomata and the rosmarinic acid ratio in their phytochemical composition was over 2%. Furthermore, caffeic acid was detected in these samples.