Melissa officinalis, Lamiaceae
Lemon Balm is a perennial herb in the mint family, native to southern Europe and the Mediterranean region. The leaves have a refreshing lemony scent. During summer, small white flowers full of nectar appear, attracting bees, hence the genus name Melissa (Greek for ‘honey bee’). Its flavor comes from its essential oil content of citronellal (24%), geranial (16%), linalyl acetate (12%) and caryophyllene (12%).
The crushed leaves, when rubbed on the skin, are used as a repellant for mosquitos. Lemon balm is also used medicinally as a herbal tea, or in extract form.
It is also used as an anxiolytic, mild sedative or calming agent. One study has found it to be effective at reducing stress. Lemon balm extract was identified as a potent inhibitor of GABA transaminase, which explains anxiolytic effects. The major compound responsible for GABA transaminase inhibition activity in lemon balm is rosmarinic acid which is also anti-oxidant.
Lemon balm and preparations thereof also have shown to improve mood and mental performance. These effects are believed to involve muscarinic and nicotinic acetylcholine receptors. The essential oil of lemon balm is claimed to have antibacterial and antiviral properties and to be effective against herpes simplex. Its antibacterial properties have also been demonstrated scientifically, Extract of lemon balm was found to have exceptionally high antioxidant activity.
Researchers in endocrinology have investigated lemon balm and discovered that it demonstrates anti-thyrotropic activity, inhibiting Thyroid-Stimulating Hormone (TSH) from attaching to TSH receptors, hence making it of possible use in the treatment of Graves’ disease or hyperthyroidism. Lemon balm should be avoided by those on thyroid medication (such as thyroxine), as it is believed the herb inhibits the absorption of this medicine.
 Awad, Rosalie; Muhammad, Asim; Durst, Tony; Trudeau, Vance L.; Arnason, John T. (2009). “Bioassay-guided fractionation of lemon balm (Melissa officinalisL.) using anin vitromeasure of GABA transaminase activity”. Phytotherapy Research 23 (8): 1075–81. doi:10.1002/ptr.2712. PMID 19165747.
 Kennedy, D O; Wake, G; Savelev, S; Tildesley, N T J; Perry, E K; Wesnes, K A; Scholey, A B (2003). “Modulation of Mood and Cognitive Performance Following Acute Administration of Single Doses of Melissa Officinalis (Lemon Balm) with Human CNS Nicotinic and Muscarinic Receptor-Binding Properties”. Neuropsychopharmacology 28 (10): 1871–81.
 Schnitzler, P; Schuhmacher, A; Astani, A; Reichling, J (2008). “Melissa officinalis oil affects infectivity of enveloped herpes viruses”. Phytomedicine 15 (9): 734–40. doi:10.1016/j.phymed.2008.04.018. PMID 18693101.
 Dastmalchi, K; Damiendorman, H; Oinonen, P; Darwis, Y; Laakso, I; Hiltunen, R (2008). “Chemical composition and in vitro antioxidative activity of a lemon balm (Melissa officinalis L.) extract”. LWT – Food Science and Technology 41: 391–400. doi:10.1016/j.lwt.2007.03.00
 Auf’mkolk, M.; Ingbar, J. C.; Kubota, K.; Amir, S. M.; Ingbar, S. H. (1985). “Extracts and Auto-Oxidized Constituents of Certain Plants Inhibit the Receptor-Binding and the Biological Activity of Graves’ Immunoglobulins”. Endocrinology 116 (5): 1687–93. doi:10.1210/endo-116-5-1687. PMID 298535