392 Handbook of herbs and spices
48% of the essential oil, followed by citronellal with 39.47% and Hc b-caryophyllene
with 2.37%.
In another investigation, the percentages of the main constitutes found by Sari and
Ceylan (2002) are as follows: a-pinene (2.86), b-pinene (11.73%), linalool (2.74%),
citronella (5.86%), borneol (0.62%), neral (12.22%) and geraniol (38.13%). In addition,
fresh herb of lemon balm contains total phenolics (2253 mg/100 mg), L-Ascorbic
acid (53.2 mg/100 mg) and carotenoids (46.3 mg/100 mg) (Capecka et al., 2005).
Ivanova et al. (2005) found that lemon balm extract contains on average 1370.09 mM
total phenols and has an antioxidant capacity of 4.06 TEAC (Trolox equivalent
antioxidant capacity).
As the essential oils show complex structures, essential oil rate or its chemical
composition of lemon balm is strongly affected by several factors such as light
intensity, nutrient, temperature, cultural practices, genotype, plant part, age, harvesting
time, etc. For example, essential oil rate and tannin contents increase with increasing
light intensity from 1000 to 1500 lux (Manukyan, 2004). Similarly, the nutrient
applied to lemon balm also has a significant effect on average essential oil rate.
Another investigation showed that lemon balm under saline conditions tends to decrease
its essential oil ratio whereas it increases under drought conditions (Ozturk et al.,
2004). On the other hand, essential rate does not change significantly with plant
density and plant source used for propagation (Saglam et al., 2004). However, both
essential oil content and its components very much depend upon the harvest cut
height of lemon balm (Mrlianova et al., 2002). Average essential oil content in the
top third part is 0.39% whereas it is 0.14% in the whole aerial part. Thus, there is an
ontogenetic variation for essential oil in balm leaves (Hose et al., 1997). Caryophyllene
oxide content as a main constituent also changes depending on age and environment
(Meyer and Spiteller, 1996). Poor soils without fertilisation increase Caryophyllene
oxide content. It is also important to mention that the collection period of the plant
material changes product quality criteria such as essential oil content and components.
23.3 Cultivation and production.............................................................
There has been a growing demand for plant based medicines, health products,
pharmaceuticals, food ingredients, cosmetics, etc. Lemon balm is one of those plants
and is used in several areas. In some countries such as Turkey, Syria and the Kingdom
of Jordan, many medicinal and aromatic plants including lemon balm are collected
from the flora. Cultivation of these species should alleviate the pressure on the
wild populations and avoid their extinction. Therefore, apart from protection of
biodiversity, its cultivation is commercially attractive to companies, as providing
standard raw material in terms of quality and supply. Today lemon balm is widely
cultivated in Europe and the United States, but also grows wild along paths and
roadsides.
The plant prefers sandy and loamy fertile soils, well drained and at pH range 5 to
- It grows well in full sun, but it also grows well in partial shade. When the plants
grow in semi-shade, they produced larger leaves and habitat than those grown in
sunny condition. Lemon balm can rapidly grow at temperature range 15 to 35 ∞C and
requires 500–600 mm precipitation well distributed throughout the growing season,
otherwise it should be irrigated. It is sensitive especially to drought in the establishment
year. Once it develops a deep root system, its water requirement lessens. However, it