Lemon Balm (Melissa officinalis)
Compounds in lemon balm, such as rosmarinic acid and flavonoids, have been shown to interact with the GABAergic system, inhibiting the enzyme GABA transaminase and thus elevating GABA levels in the brain. Certain constituents also display acetylcholinesterase inhibitory activity, similar to that observed in rosemary, thereby increasing acetylcholine levels.
Literature Review
A small study in healthy young adults found that a single 1600 mg dose of lemon balm improved memory accuracy. However, it might slow down performance in timed memory tasks compared to a placebo.[i]
Another small study in patients with mild to moderate anxiety disorders revealed that taking 300 mg of a specific standardized lemon balm extract twice daily could reduce symptoms of anxiety and improve sleep.[ii]
In elderly patients with mild to moderate Alzheimer's disease, a 4-month daily regimen of lemon balm leaf extract appeared to reduce agitation and improve cognitive function when compared to a placebo. Another study in patients with mild Alzheimer's found that a 24-week regimen of lemon balm extract did not improve cognition but may have modestly improved neuropsychiatric symptoms. This study was limited by a large number of drop-outs in the placebo group.[iii]
Mechanism of Action
General: The leaves and leaf oil of lemon balm are the applicable parts. They contain various constituents such as citronellal, neral, and geranial monoterpenoid aldehydes; flavonoids like luteolin; polyphenolic compounds like rosmarinic and caffeic acids; as well as monoterpene glycosides and triterpenoids like oleanolic and ursolic acids.[iv]
Lipid effects: Animal studies have shown that lemon balm essential oil can reduce cholesterol levels, and this is attributed to the constituent geraniol, which has been shown to inhibit HMG-CoA reductase.
A meta-analysis of clinical trials regarding lipid-lowering effects suggests a modest reduction in total cholesterol levels when lemon balm is taken orally, but it did not significantly affect LDL cholesterol or triglycerides.[v]
A meta-analysis of small clinical trials in healthy patients and in patients with various disease states such as type 2 diabetes and chronic angina suggests that taking lemon balm orally may modestly reduce levels of total cholesterol, but not LDL cholesterol or triglycerides, when compared with placebo[vi].
Neurological effects: Lemon balm has been found to contain substances that might have acetylcholine receptor activity such as citronellal, neral, and geranial monoterpenoid aldehydes; flavonoids and polyphenolic compounds (including rosmarinic acid); and monoterpene glycosides. Some research suggests lemon balm might have acetylcholine receptor activity with both nicotinic and muscarinic binding properties.[vii]
Clinical research also suggests that lemon balm has calming and anxiolytic effects, which could help alleviate symptoms like palpitations.[viii]
References
[i]Kennedy DO, Wake G, Savelev S, et al. 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. 2003 Oct;28:1871-81.
[ii]Cases J, Ibarra A, Feuillère N, Roller M, Sukkar SG. Pilot trial of Melissa officinalis L. leaf extract in the treatment of volunteers suffering from mild-to-moderate anxiety disorders and sleep disturbances. Med J Nutrition Metab. 2011;4(3):211-218.
[iii]Akhondzadeh S, Noroozian M, Mohammadi M, et al. Melissa officinalis extract in the treatment of patients with mild to moderate Alzheimer's disease: a double blind, randomised, placebo controlled trial. J Neurol Neurosurg Psychiatry 2003;74:863-6.
[iv]Kennedy DO, Scholey AB, Tildesley NT, et al. Modulation of mood and cognitive performance following acute administration of Melissa officinalis (lemon balm). Pharmacol Biochem Behav 2002;72:953-64.
[v]Karimi, I., Hayatgheybi, H., Razmjo, M., Yousefi, M., Dadyan, A., and Hadipour, M. Anti-hyperlipidaemic effects of an essential oil of Melissa officinalis L. in cholesterol-fed rabbits. Journal of Applied Biological Sciences 2010;4(1):17-22.
[vi]Heshmati J, Morvaridzadeh M, Sepidarkish M, et al. Effects of Melissa officinalis (Lemon Balm) on cardio-metabolic outcomes: A systematic review and meta-analysis. Phytother Res. 2020;34(12):3113-3123.
[vii]Kennedy DO, Wake G, Savelev S, et al. 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. 2003 Oct;28:1871-81.
[viii]Alijaniha F, et al. Heart palpitation relief with Melissa officinalis leaf extract: double blind, randomized, placebo controlled trial of efficacy and safety. J Ethnopharmacol. 2015;164:378-384. doi: 10.1016/j.jep.2015.02.007. Epub 2015 Feb 11.
