Organic and conventional fertilization effects on essential oil production of Melissa officinalis L.

Stress, anxiety, and sleep disorders increased considerably in recent years, becoming prevalent diseases affecting a high percentage of the population [1]. Melissa officinalis (Lemon balm) is a medicinal and aromatic species popularly used to promote sleep, reduce stress and anxiety [2]. The medicinal properties of M. officinalis are related to the major compounds of their essential oil, just like the Citronellal, Neral and Geranial [3]. Various factors can cause qualitative and quantitative variations of these metabolites, such as seasons, plant age, circulating water amount, geographical factors, climate and stress [4]. Providing information on essential oil production is fundamental to obtain the highest essential oil production by the plant. The objective of this study was to evaluate the effects of different types of fertilization on M. officinalis major compounds production. Neral, Geranial, Citronellal were selected as the components of interest since in commercial essential oil it is recommended that they must be present as major chemical compounds [3]. The experimental design was completely randomized with three treatments: control (site soil), organic fertilization (2 t/ha of poultry manure) and conventional fertilization (30 t/ha of NPK, 6:14:8) and four repetitions. The essays were carried out in the Municipal Gardening School experimental area, in Ibirapuera Park, São Paulo, Brazil. The essential oil was extracted from its leaves using a Clevenger-type apparatus and analyzed by gas chromatography coupled to mass spectrometer (GC-MS). The compounds were identified by using reference standards from Sigma Aldrich. Statistics analysis of the data indicated that there are no significant differences between organic and conventional fertilization for no one of the three compounds while comparing with the control only organic control treatment showed significant influence on 5% level of probability for Citronellal production (Table 1).

Tab. 1: Mean of major compounds of Lemon balm essential oil submitted to different types of fertilization.

	Compounds
Treatments	Citronellal	Neral	Geranial
	Mean ± SD	Mean ± SD	Mean ± SD
Organic control	4.5a± 1.3	35.2a± 6.9	60.3a± 7.6
Organic fertilization	1.4b± 1.1	36.9a± 6.7	61.7a± 7.4
Conventional control	1.9ab± 1.2	43.7a± 4.3	53.2a± 5.4
Conventional fertilization	2.0ab± 1.0	38.9a± 4.1	59.1a± 5.1
Mean and ± SD (Standard Deviation); abWithin column, mean followed by different letters are significantly different at p ≤0.05 (Tukey's test).

Keywords: Melissa officinalis, essential oil, organic and conventional fertilization, Citronellal, Neral, Geranial, Clevenger apparatus, GC/MS.

References:

[1] Petenatti, E. M. et al. (2011). Evaluation of macro and microminerals in crude drugs and infusions of five herbs widely used as sedatives. Braz. J. Pharmacogn. 21:1144 – 1149.

[2] Sodré, A. C. B. et al. (2012). Organic and mineral fertilization and chemical composition of Lemon balm (Melissa officinalis) essential oil. Braz. J. Pharmacogn. 22(1):40 – 44.

[3] Blank, A. F. et al. (2005). Influence of harvest times and drying of leaves on the essential oil of Melissa officinalis L. cultivated in two environments. Braz. J. Med. Plan. 8(1):73 – 78.

[4] Sorensen, J. (2000). Melissa officinalis. Inter. J. Aromather. 10:7 – 17.