Garlet, T. M. B. et al 200
Vol. 4, N.3: pp. 200-206, August, 2013 ISSN: 2179-4804
Journal of Biotechnology and Biodiversity
Production and chemical composition of Mentha x piperita var. citrata (Ehrh.) Briq. essential oil regarding to different potassium concentrations in the hydroponic solution
Tânea Maria Bisognin Garlet1,*, Dalva Paulus2, Rejane Flores 3
ABSTRACT
This work aimed to evaluate the production of fresh and dry mass of leaves, stems and aerial parts, and the content
and quality of lemon mint (Mentha x piperita var. citrata) essential oil as a result of four potassium (K) concentrations (276, 414, 552 and 690 mg.L-1) under hydroponic solutions. The experiment was carried out in the
hydroponic NFT (Nutrient Film Technique) system. Leaves were separated and weighted to determine the fresh mass and part of them was used to extract oil in a Clevenger apparatus. The analysis of the oil chemical composition was performed in a gas chromatograph fitted with a mass spectrometer. The estimated concentration
for the maximum fresh mass production of the leaves corresponded to 384 mg.L-1 K. The greatest K concentration
proportionated an increase in essential oil content and yield per plant, but decreased linalool and linalyl acetate in
the oil. Under the conditions the experiment was carried out, in order to obtain an adequate quantity of leaves for a higher essential oil yield per plant and linalool and linalyl acetate accumulus, the K concentration of 414 mg.L-1 is
recommended in the hydroponic solution for the cultivation of lemon mint.
Key-words: Mint, Lamiaceae, hydroponic cultivation, linalool, linalyl acetate, medicinal plant.
Produção e composição química do óleo essencial de Mentha x piperita var. citrata (Ehrh.) Briq. em relação as concentrações de potássio na solução hidropônica
RESUMO
Este trabalho objetivou avaliar a produção de massa fresca e seca de folhas, hastes e parte aérea, o teor e a qualidade
do óleo essencial de hortelã-limão (Mentha x piperita var. citrata), em função de quatro concentrações de potássio (276, 414, 552 e 690 mg.L-1) em soluções hidropônicas. O experimento foi conduzido no sistema hidropônico NFT
(Nutrient Film Technique). As folhas foram amostradas e pesadas para determinação da massa fresca e uma alíquota utilizada para extração do óleo, em Clevenger. A análise da constituição química do óleo foi realizada em cromatógrafo gasoso acoplado a espectrômetro de massa. A concentração estimada para máxima produção de massa
fresca de folhas correspondeu a 384 mg.L-1 de K. A maior concentração de K estudada proporcionou aumento no teor e no rendimento de óleo essencial por planta, porém diminuiu a quantidade de linalol e acetato de linalila presentes no óleo. Nas condições em que o experimento foi conduzido, para obtenção de rendimento de folhas
adequado ao maior rendimento de óleo essencial por planta e ao acúmulo de linalol e acetato de linalila, recomenda- se a concentração de 414 mg.L-1 de K na solução hidropônica para o cultivo de hortelã-limão.
Palavras-chave: Hortelã, Lamiaceae, cultivo hidropônico, linalol, acetato de linalila, planta medicinal. *Author for correspondence.
1,*Department of Animal Science and Biological Sciences, Federal University of Santa Maria, Independence Avenue, 3751, Code 98300-000, Palmeira das Missões, RS – Brazil, taneagarlet@gmail.com
²Department of Horticulture, Federal Technological University of Paraná (UTFPR), Dois Vizinhos, PR, Brazil.
3Department of Biological Sciences, Federal Institute Farroupilha, 97420-000, São Vicente do Sul, RS, Brazil. J. Biotec. Biodivers. v. 4, N.3: pp. 200-206, Aug. 2013
https://doi.org/10.20873/jbb.uft.cemaf.v4n3.garlet
Garlet, T. M. B. et al 201
INTRODU CTION
The genus Mentha (Lamiaceae) includes 25
species and some hybrids with essential oils rich in monoterpenes, which are accumulated in glandular trichomas, especially in leaves and flowers. To this
morphologic variability corresponds a wide chemical diversity which is reflected in a varied
number of essential oils commercially obtained (Kokkini 1992).
Mentha x piperita var. citrata (Ehrh.) Briq., known as lemon mint or bergamot mint, is erroneously
nominated Mentha citrata (Harley and Brigthon
1977). This species produces a type of essential oil which contains 84-90% linalool and linalyl acetate,
characteristic acyclic components, in contrast to
other species of the genus Mentha which contain menthol, menthone, carvone, limonene and
pulegone as majoritary cyclic components (Murray and Lincoln 1970). Commercially, Mentha essential oils and their constituents are widely
applied in the food, cosmetics, fragances, tobacco
and medicine industries. Essential oils world production is estimated to be from 110,000 to 120,000 t/year (Kothari 2005).
From this amount, 22,000 t come from Mentha
species, and 20,000 for the obtainment of oils rich in menthol and menthone, 2,000 for oil rich in
carvone and 200 for oil rich in linalool and l inalyl acetate (Sant Sanganeria 2005). Linalool is one of
the monoterpenes more often used in perfumes and it is estimated that it is present in 60-90% of the
cosmetics available in the market (Cal and
Kryzyzaniak 2006). High contents of linalool and linalyl acetate in the essential oil are important
under the economical point of view. These scents take part in the composition of cosmetic products,
such as facial creams, body lotions, fragrance in creams, deodorants, perfumes, shampoos, bath
products, gels, soaps and hair sprays. They m ay
also be used in non-cosmetic products such as detergents and cleaning products (Letizia et al. 2003a; Leticia et al. 2003b) and in medicines.
As it happens for other economically important characteristics, mineral nutrients are also
fundamental for plant growth and essential oil production and may be provided to soil cultivated plants as well as to hydroponic cultivated ones. The water enriched with nutrients of the hydroponic solutions, combined to the controlled environment of the greenhouses, allows a faster
growth in relation to soil cultivation, shortening the productive cycle and increasing productivity (Santos 2000). Potassium (K) is among the
essential nutrients to the plants and, in spite of being abundant in the tissues, does not make part of any organic component. Potassium interferes in
several physiological processes like enzymatic
activation, opening and closing of stomata, photosynthesis, cellular extension, translocation of
photosynthates to growing regions, resistance to diseases and better efficiency in the use of water
(Marschner 1995).
The wide utilization of essential oils and their constituents have motivated some agronomic
studies of Mentha species. In hydroponic cultivation of Mentha arvensis, Paulus et al. (2004)
obtained an oil content of 0.60% in nutritive solution containing 299 mg.L-1 K, while Maia et al.
(2001) obtained the best content (1.45%) in a solution with 468 mg.L-1 K, demonstrating that the
nutritive solutions for the species should be more concentrated in K. Garlet et al. (2007a) and Garlet
et al. (2007b), working with M. x gracilis concluded that the increase in K concentration in
the hydroponic solutions negatively affected the growth and phytomass accumulation in Mentha plants, but proportionated increase in essential oil production per plant. The authors suggest
concentrations of 276 and 414 mg.L-1 K to favor
plant growth and oil content in the studied species. This research aimed to evaluate the production of
fresh and dry mass, the content and quality of
Mentha x piperita var. citrata (Ehrh.) Briq. essential oil testing four potassium concentrations
in hydroponic solutions.
MATERIAL AND METHODS
Plant material and growing conditions for the experiment
Lemon mint (Mentha x piperita var. citrata (Ehrh.) Briq.) was used in this study. The experiment was carried out at the experimental area of the Phytotechny Department of the Universidade Federal de Santa Maria (UFSM), Rio Grande do Sul State, Brazil, using the nutrient film technique
(NFT). Plants were grown in a 250 m2 greenhouse,
using a polyvinyl chloride plastic (PVC) 200 µm thickness to cover the greenhouse and to close the laterals and doors.
Lemon mint plantlets were produced from matrixes
cultivated in soil (Garlet et al. 2007a). Exsiccate of the species is found deposited at the Herbarium of
the University of Cruz Alta, RS (UNICRUZ), under number 1079, after determination performed
J. Biotec. Biodivers. v. 4, N.3: pp. 200-206, Aug. 2013
Garlet, T. M. B. et al 202
by Dr. Ray Harley, of the Royal Botanic Gardens, Kew, England. A complete randomized block design with five plots was used, using three plants
per plot. Four K concentrations (276, 414, 552 and 690 mg.L-1) in the hydroponic solutions were
studied, and were calculated based on previous
studies with Mentha arvensis L. by Paulus et al. (2004), and the cultivation methodology described
by Garlet et al. (2007b).
Harvesting of lemon mint
Even though it is recommended that the harvesting of Mentha species should be done at the beginning
of flowering in order to obtain higher amounts of the essential oil content (Duriyaprapan et al. 1986)
that is concentrated in the glandular trichomas of
leaves and floral calyxes (Lawrence 1992). T he harvesting of lemon mint had to be performed 56 days after transplanting, on December, before
flowering, because the intense vegetative growth caused root interlacement which occupied the
greater part of the cultivation channels volume of the NFT system, each plant reaching 116 cm height and total aerial fresh matter of 700 g. The
collected plants were separated in roots and aerial part (i.e., stems, leaves and flowers). The flowers were added to the leaves due to the presence of oil.
Roots were not evaluated because root interlacement did not allow correct separation of plants. Plants were then placed in paper bags with
forced air ventilation at 65oC until constant mass be reached, being weighted soon after.
Oil composition and chemical content determination
For oil composition and chemical content determination, four replicates of 100 g of leaves samples were hydro-distilled in Clevenger
apparatus (Simões and Spitzer 2003) for a 2- hour period. The oil obtained was separated of the water and dried with anhydrous sodium sulphate
(Na2SO4), being then weighted for the determination of estimated yield and content per
plant.
Essential oil chemical composition analysis w ere performed using a gas chromatograph fitted to a mass spectrophotometer (CG-EM Shimadzu, QP -
5000), at the Pharmacy College of the Federal University of Rio Grande do Sul (UFRGS), Porto
Alegre, Rio Grande do Sul State, Brazil. A DB- 5 molten capillary column (25 m long x 0.25 mm internal diameter and 0.25 µm film thickness) was
used; helium as carrier gas, 1 ml.min-1 flux with
split. Injector and detector temperatures were of 220oC and 250oC, respectively. The temperature of
the column was programmed to vary from 60oC to 300oC at 3oC min-1, and mass spectra were
obtained from 30 to 400 m/z. Identification of
constituents was performed comparing their respective mass spectra and retention indexes with
authentic samples and literature data (Adams 2001) and also by comparing with mass spectra
registered in data bank like NIST 12 and NIST 62 (National Institute of Standards and Technology).
The results obtained were submitted to analysis of
variance (ANOVA) and interpreted through regression analysis using F test (P<0.01 and P<0.05) to evaluate the polynomial equations.
RESULTS AND DISCUSSION
Potassium concentrations significantly influenced fresh and dry matter of leaves, stems and aerial
part (P<0.05) 56 days after transplanting. Equations were adjusted to the quadratic model. Analyzing the Figure 1 it is possible to observe
that the greater production of fresh and dry mass of leaves (328.5 and 61.5 g.plant-1) were obtained with K concentration of 414 mg.L-1. The same
effect was verified for stems fresh and dry mass (368.96 and 66.32 g.plant-1) and aerial part (696.33 and 127 g.plant-1), respectively.
For the obtainment of maximum fresh mass of leaves (329 g.plant-1) and dry mass (61.8 g.plant-1 ), the estimated K concentration was 384 mg.L-1 and 364.7 mg.L-1, respectively (equations of the Figure
1a and 1b).
On the other hand, essential oil content (%)
increased when K was added to the hydroponic solution, reaching 1.2 g for each 100 g of fresh leaves at the concentration of 690 mg.L-1 (Fig ure 2). In spite of the 690 mg.L-1 K have caused plant
growth reduction due to the smaller accumulation of fresh mass of leaves (276.8 g.plant-1), there was
a percent increase in essential oil yield of 35.5% in relation to the smaller K concentration (276 mg.L - 1), reaching 3.32 g of oil plant-1 (Table 1).
J. Biotec. Biodivers. v. 4, N.3: pp. 200-206, Aug. 2013
Garlet, T. M. B. et al 203
A B
Figure 1. Fresh mass of leaves (A) and dry mass of leaves (B) of Mentha x piperita var. citrata cultivated in different K concentrations in the hydroponic solution.
Chromatographic analysis identified 20 essential oil components, which in average correspond to 96.6% of the total. Quantitative differences (P<0.01 and P<0.05) were found in the chemical composition of the oil samples examined. The majoritary components found were linalool with 45 to 53.5% and linalyl acetate with 28.1 to 34 %
(Table 2).
Other components which showed significance were mircene (0.4 – 1.7%), limonene (0.2 – 0.9%), 1,8-cineol (0.1 – 0.4%), (Z)-β-ocimene (0.4 –
1.6%), (E)-β-ocimene (0.3 – 1.2%), linalyl formate (0.4 – 0.9%), germacrene D (0.8 – 1.6%) and viridiflorol (1,2 – 2.9%) (Table 2). Linalool and linalyl acetate contents in the oil were smaller (%) in the plants submitted to greater K. However, for the components mircene, limonene, 1,8- cineol, (Z)-β-ocimene, (E)-β-ocimene, linalyl formate,
germacrene D and viridiflorol, as K concentration
increased there was also an increase in their contents.
Table 1. Fresh mass yield of leaves, essential oil content and yield of Mentha x piperita var. citrata cultivated under different K concentrations in the hydroponic solution.
Maximum accumulated linalool and linalyl acetate quantity, associated to the fresh mass of leaves
Concentration (mg.L-1 )
Fresh mass of leaves (g.plant–1 )
Content (%)
Essential oil
Yield (g.plant–1 )
276 322.5 0.76 2. 45
414 328.5 0.91 2.99
552 313.3 1.05 3.29
690 276.8 1.20 3.32
CV (%) 8.86 7.90 7.90
(g.plant-1), amount (%) and essential oil yield (g.plant-1) may be obtained in K concentrations of 414 and 552 mg.L-1, being equal to 2.5 g.plant-1, a higher value in relation to those calculated for 276 and 690 mg.L-1 K concentrations, which, respectively, were 2.1 and 2.4 g.plant-1 .
The results of this study are in agreement with Garlet et al. (2007b) in works with Mentha arvensis f. piperascens Holmes, who found that the
K dosage estimated for maximum fresh leaves yield was equal to 412 mg.L-1. The essential oil
and menthol contents, on the other hand, increased with increased K concentration in the hydroponic
solution. According with Garlet et al. (2007b), the K dosage of 552 mg.L-1 proportionated greater oil yield in g.plant-1, but the best chemical
composition in menthol content was obtained with the K dosage of 690 mg.L-1 and this dosage is,
thus, recommended for the cultivation of M. arvensis f. piperascens in hydropony .
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Garlet, T. M. B. et al 204
Figure 2. Essential oil content of Mentha x piperita var. citrata cultivated under four K concentrations in the nutritive solution.
In a work with Mentha x gracilis Sole, Garlet et al. (2007c) observed that even though leaves have produced greater oil content in the K dosage of 690
mg.L-1, leaf production was reduced, resulting in a smaller oil yield per plant (2.56 g.plant-1) and its equivalent per hectare (256 kg.ha-1 ).
A high oil content itself may not be of agricultural interest since plants that produce too much oil but show low production of leaves will result in low
oil yield per area. Tuomi et al. (1991) state that the concentration of secondary metabolites used for
vegetal defense tend to present an inverse
concentration to growing taxes and, according to Croteau et al. (2000), there exists a direct relation
between photosynthates like glyceraldeid-3 - phosphate or piruvate and the biosynthesis of the terpenoids. Plants translocate substances of the primary metabolism, which could generate sugar, proteins and fat and that provide energy for the growth, to produce secondary metabolites, like the
terpenoids, as an answer to external factors which
in this study was the culture exposition to growing K concentrations. These results suggest that K affected the activity of enzymes responsible for the
biosynthesis of these terpenes constituents of the
Mentha x piperita var. citrata essential oil. Studying Mentha arvensis, Maia et al. (2001) cite
that nutrient availability in the solution may induce the enzymatic activity of the constituents of the oil
and increase menthol content and the essential oil quality.
Using a modified Sarruge solution, the authors
obtained the greatest menthol content (82.7%) in the solution with higher (468 mg.L-1) K
concentration. Valmorbida (2003), however, testing solution no 2 of Hoagland and Arnon and
varying K level, through the reduction of 50 to
75% in its concentration, did not observe effect on the chemical constitution of Mentha x piperita
essential oil.
Since leaves correspond to the active site of essential oil synthesis and accumulation in Mentha species (Lawrence 1992; Turner et al. 2000), increases in its content and quality are economically interesting aspects. The conditions of
potassium concentration increase to which Mentha
x piperita var. citrata were submitted may have provoked stimulus in enzymatic activities, altering the composition of oils and suggesting that
potassium is involved in the synthesis of these aromatic compounds, since the ion is activator of several enzymes, synthetases, oxyrreduthases , deshydrogenases, transferases, kinases and
aldolases being the outstanding ones (Marschner 1995).
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Garlet, T. M. B. et al 205
Table 2. Essential oil chemical composition (%) of Mentha x piperita var. citrata cultivated in nutrient solution wit h different potassium concentrations and respective regression equations.
Component (%) K concentration (mg.L-1 )
276 414 552 690 Equation R2 CV (%)
Mircene 0.4 0.5 1.2 1.7 y = -0.70 + 0.0034x 0.95** 31
Limonene 0.2 0.3 0.6 0.9 y = -0.273+ 0.00162x 0.95** 14
1.8-cineol 0.1 0.2 0.2 0.4 y = -0.07 + 0.00063x 0.89** 21
(Z)-β-ocimene 0.4 0.5 0.9 1.6 y = -0.60 + 0.003x 0.89** 10
(E)-β-ocimene 0.3 0.4 0.6 1.2 y = -0.39 + 0.0021x 0.83** 8
γ-terpineno tr tr tr tr - - -
Terpinolene 0.1 0.1 0.2 0.3 y = 0.17 - 44
Linalool 53.5 51.2 45.0 45 y = 59.753 - 0.02297x 0.89* 5
N-nonanol 0.4 0.4 0.4 0.5 y = 0.41 - 26
α-terpineol 3.6 3.6 4.2 4.7 y = 4.02 - 17
Linalyl formate 0.4 0.5 0.7 0.9 y = 0.003 + 0.0013x 0.97* 27
Linalyl acetate 34 33 31 28.1 y = 38.1 - 0.0136x 0.93** 26
Neril acetate 1.3 1.1 2.3 1.8 y = 1.65 ns 54
β-cariofilene 1.8 1.6 2.6 2.6 y = 2.16 ns 27
α-humulene 0.1 0.1 0.1 0.1 y = 0.11 - 27
Germacrene D 1.0 0.8 1.5 1.6 y = 0.29 + 0.0019x 0.71* 28
Elemol 0.4 0.4 0.3 0.6 y = 0.42 ns 30
Viridiflorol 1.2 1.7 2.9 2.9 y = 0.036 + 0.0044x 0.90* 32
γ-eudesmol 0.1 0.1 0.2 0.1 y = 0.12 ns 40
β-eudesmol 0.1 0.1 0.4 0.4 y = 0.23 ns 39
Total identified 99.29 96.5 95.37 95.29
** , * = significant by test F, with P<0.01 e P<0.05.respectively; ns = not significant). Tr = traces (<0.1%)
Potassium concentrations in the hydroponic
solutions altered the production of fresh mass of leaves, the content and the chemical composition
of Mentha x piperita var. citrata essential oil. The
estimated K concentration for maximum yield of fresh leaves corresponds to 384 mg.L-1. Th e maximum K (690 mg.L-1) proportionates increase
in total essential content and yield per plant, but decreases linalool and linalyl acetate quantity.
CONCLUSION
Under the conditions this experiment was carried
out, for the obtainment of an adequate amount of leaves to yield greater amounts of essential oil and
linalool and linalyl acetate contents, the K concentration of 414 mg.L-1 is recommended in
the hydroponic solution for lemon mint cultivation.
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Recebido: 13 /05/2013 Received: 05/13/20 13
Aprovado: 22 /07/2013 Approved: 07/22 /2013
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