Table 1: Main studies supporting the use of Melissa officinalis in aromatherapy.

StudyMain characteristics

Ballard et al., 2002.Placebo-controlled trial, conducted on seventy-two demented resident in care facilities in the UK (seventy-one out of whom completed the trial), demonstrating that M. officinalis essential oil, applied as massage twice a day for 4 weeks, produced an improvement of agitation (according to the CMAI), without the occurrence of significant side effects.

Akhondzadeh et al., 2003.Parallel group, double-blind, randomized, placebo-controlled trial, involving aged patients (from 65 to 80 years of age) suffering from mild-moderate AD, who were given 60 drops/day of lemon balm extract. Lemon balm exerted positive effects both on cognition (according to the ADAS-cog and the CDR-SB) and on agitation as side effect at 4 months.

Dastmalchi et al., 2009.Fractionation of the crude lemon balm hydroalcoholic extract, demonstrating anticholinesterase activity of most of the fractions, that resulted in being more active than the whole extract. The constituents of the most active fractions are cis- and trans-rosmarinic acid isomers and a rosmarinic acid derivative.

Kennedy et al., 2003.Two-phase study: preliminary evaluation of the AChE inhibition and of nicotinic and muscarinic receptor-binding properties for eight samples of lemon balm dried leaves in human postmortem occipital cortex tissue and subsequent administration to 20 healthy young participants of the sample that resulted to have the highest cholinergic activity. The effects on cognition and mood were examined in a multiple-dose, multiple time-point, double-blind, placebo-controlled, balanced crossover study. The obtained data supported the cholinergic receptor-binding properties of M. officinalis and the fact that it acts on mood and cognition in a dose- and time-dependent manner.

Guginski et al., 2009.Study performed using the formalin test in mice, in which the M. officinalis extract provided a significant inhibition of both phases and inhibited in a dose-dependent manner the glutamate-induced pain. The antinociceptive effect elicited by this extract in the glutamate test was significantly attenuated by i.p. administered atropine, mecamylamine, or L-arginine but not naloxone or D-arginine, thus supporting the involvement of the cholinergic system and of the L-arginine-nitric oxide pathway. The rosmarinic acid contained in this extract appeared to contribute to its antinociceptive features.