Lemon balm 395
purposes and as a functional food. A moderate amount of investigation on lemon
balm has been carried out to determine its medicinal effects such as antiviral,
antibacterial, antifungal, antitumour and sedative effects. For example, Sousa et al.
(2004) indicates that the essential oil of lemon balm as an antitumoural agent has a
potential for cancer treatments or prevention. The volatile oil of Lemon balm may
also be used as an anti-virus agent and contains an anti-Herpes simplex virus type 2
(HSV-2) substance (Allahverdiyev et al., 2004).
The antimicrobial properties of plants have been investigated by a number of
researchers world wide and the antimicrobial activity tests of lemon balm show that
the most powerful scavenging compounds are monoterpene aldehydes and ketones
(neral/geranial, citronellal, isomenthone, and menthone) and mono- and sesquiterpene
hydrocarbons (E-caryophyllene) (Mimica-Dukic et al., 2004). Lemon balm, among
other members of the family Labiatae, was found to be the most effective plant
against five food spoilage yeasts (Araujo et al., 2003). The essential oil of lemon
balm at 500 mg/ml completely inhibits all these yeast species and the fungitoxic
effect is attributed to citral (58.3%), which is the main component of the oil. It also
inhibits growth of some antibiotic resistant bacteria such as Staphylococcus aureus,
Salmonella choleraesuis and Klebsiella pneumoniae (Nascimento et al., 2000).
One of the potential remedies for stress-related disorders is accepted to be
consumption of the functional food, which contains a number of herbal extracts
(Hamer et al., 2005). Lemon balm has been known as a mild sedative since the
Middle Ages. Lemon balm extract is of value in the management of mild to moderate
Alzheimer’s disease (Perry et al., 1999; Akhondzadeh et al., 2003). It also affects
mood changes during acute psychological stress (Little et al., 2003). These behavioural
consequences may be attributed to some active components of the dry herba or its
essential oil (Kennedy et al., 2002) although further work is required to substantiate
efficacy in human subjects. There is no reported side effect of topical lemon balm,
but allergic reactions should be always taken into account. Consumption as tea, fresh
herba or capsule may reduce alertness and impair mental function (Kennedy et al.,
2002). Therefore anyone engaged in a job requiring alertness or driving should avoid
using lemon balm beforehand. As a result, potential side effects of lemon balm
should be considered and the patients should consult their physician before taking
this herb.
Lemon balm has traditionally been used as a folk medicine for centuries and dates
back at least 2000 years. It is used in tea for insomnia, fevers, migraine, headache,
stomach disorders, gastric complaints, hysteria, chronic bronchial catarrh, nervous
debility, toothache, earache, high blood pressure and indigestion (Herodez et al.,
2003; Uzun et al., 2004). The essential oil is used in aromatherapy for relaxation,
depression, melancholy, and nervous tension (Horrigan, 2005). Externally in salve, it
is believed to relieve symptoms of rheumatism, nerve pains, sores, acne and painful
swellings such as insect bites and stings. Dzik et al. (2004) conducted an investigation
on the effect of lemon balm on experimental burn wound healing in pigs. The experiment
showed that lemon balm is an ideal dressing in the treatment of burn in terms of relief
of pain, a lower incidence of hypertrophic scar and post-burn contracture, with low
cost and easy availability.
Synthetic antioxidants have been widely used in food products by adding them to
fats in order to retard the oxidation process, which extends shelf life of those food
products. However, the use of some synthetic antioxidants is prohibited in several
countries, as there are concerns on their possible adverse effects on human health