Supercritical CO2 extraction of the main constituents of Lovage (Levisticum officinal Koch.) essential oil in model systems and overground botanical parts of the plant
This document summarizes research on the extraction of constituents from lovage (Levisticum officinale Koch.) using supercritical CO2. Specifically, it investigated the solubility of two main lovage constituents, α-terpinyl acetate and 3-n-propylidene phthalide, in supercritical CO2 using model systems. The solubility of both compounds was found to depend on CO2 pressure and temperature, with higher pressures and temperatures generally increasing solubility. α-Terpinyl acetate was found to have greater solubility than 3-n-propylidene phthalide. The research aims to optimize supercritical CO2 extraction parameters to recover specific constituents from lovage.
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Supercritical CO2 extraction of the main constituents of Lovage (Levisticum officinal Koch.) essential oil in model systems and overground botanical parts of the plant
2. 52 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
grown in Lithuania has also been studied pre- aldehydes, and phenolic compounds) due to their
viously, and it was found that the content of higher vapor pressure, lower polarity and smaller
phthalides in the essential oil from roots was molecular mass [17].
64–80%, leaves 25%, and stems 14.5% [2]. CO
2
extraction has been used successfully for
Therefore, lovage root essential oil is the product the fractionation of plant extractives, e.g. jasmine
of highest commercial value. According to [18] and tuberose [19] concretes, lavender essential
Lawrence [3], the world production of lovage root oil and waxes [20], dearomatization of antioxidant
and seed oil in 1984 was 500 kg and 300 kg, rosemary extracts [21], removal of terpene in citrus
respectively. Information about the commercial oil [22].
production of essential oil from lovage stems or It can be concluded that there are several SFE
leaves was not available in the surveyed literature. parameters, which should be optimized in the
The roots of lovage can be harvested at the separation of a particular fraction from a complex
second or third year of plant cultivation, while it mixture, such as lovage oil. Our study was an
is possible to collect the seeds in the second year attempt to investigate the possibilities of supercriti-
of cultivation. An average yield of lovage roots cal CO
2
extraction in recovering the main lovage
and seeds in Lithuania is 9–10.5 ton he−1 and constituents from natural plant material and
0.2–0.4 ton he−1, respectively [4]. The overground model systems.
parts of lovage (leaves and stems) can be harvested
few times per season, their harvesting and handling
(e.g. cleaning, drying) are more simple and cheaper
as compared with harvesting and handling of
lovage roots. Therefore, the investigation of the
2. Materials and methods
possibility of obtaining an essential oil from the
green botanical parts of lovage possessing similar
2.1. Materials
composition to the oil isolated from the roots is
of interest and commercial importance.
The seeds and leaves of lovage (Levisticum
The extraction of flavors and fragrances with
officinale Koch.) were collected from the experi-
compressed CO
2
was comprehensively reviewed
mental garden of the Lithuanian Institute of
and described by Moyler [5,6], Moyler and
Horticulture in September 1996. The samples were
coworkers [7,8], Meileres and Nikolov [9], and
harvested manually, dried at 30°C in a ventilated
Stahl et al. [10]. However, information about
drying oven and stored in double layer paper bagslovage extraction by CO
2
in sub- and/or supercriti-
at ambient temperature and protected from lightcal state was not found in the surveyed literature.
until further analysis. The samples were groundThis method has been used with some other
before extraction by a Knifetec 1095 Sample MillUmbelliferae family plants, e.g. coriander, angelica
(Tecator) machine, in 20 s time.[11,12], caraway [13,14], anise [15], celery and
The volatile constituents were isolated fromcoriander [16].
lovage leaves and stems by hydrodistillation in aIt is known that the components of essential oils
Clevenger type apparatus during 3 h. The yield ofare soluble in dense CO
2
at relatively low fluid
essential oil was 1.18±0.06 ml 100 g−1.pressures. Essential oils are usually complex mix-
The solvents and chemicals were obtained fromtures consisting of substances with different volatil-
the following sources: carbon dioxide, 99.99%ity and/or polarity. For a successful isolation of a
purity, from Alfax, Sweden; 3-n-propylideneparticular fraction from such mixtures, the solubil-
phthalide, from LabKemi (Lancaster); (±)-a-terpi-ity of the compounds to be separated in the dense
nyl acetate (~95% by GC), from Fluka;gas should differ as much as possible. Monoterpene
(+)-limonene, from Sigma; Celite 545, 20–45 mm,hydrocarbons exhibit higher solubility in dense
from Kebo lab (PROLABO, France); cyclohexane,CO
2
than the other ordinary essential oil compo-
nents (e.g. terpene and sesquiterpene alcohols, extra purity (>99%), from Merck (Germany).
3. 53E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
2.2. Model systems with celite the experiments with recycling of CO
2
. The CO
2
flow was 0.025 kg min−1 at 50–55 bar pressure.
The amount of extracted constituents wasCelite 545 and pure chemicals or oil were mixed
in proportions of 3:1. The ratio was selected experi- weighed using precision balances (Mettler AE 163,
readability 0.01 mg, Mettler Instrumente AG,mentally to avoid cohesion between the sample
being extracted and the celite, thereby minimizing Switzerland). The solubility of chemical com-
pounds was assessed by dividing the yield of thethe amount of absorbent used.
compound in the extract by the amount of CO
2
passed through the sample.2.3. Apparatus
A schematic diagram of the experimental appa- 2.4. GC conditions
ratus used in this study is shown in Fig. 1. A
MILTON ROY pump (MILROYAL B-C) was GC analyses were carried out on a Varian Model
3400 capillary gas chromatograph (Varianused for CO
2
extraction at temperatures of 40 and
50°C and in the pressure range 80–350 bar. The Associates, Walnut Creek, CA) equipped with FID
connected to a Vista 420 integrator (Varianexperiment was performed with and without
recycling of CO
2
. Associates, Walnut Creek, CA) and fused silica
capillary column, Supelco SPB-5 (30 m, 0.25 mmA 7 ml capacity vessel with glass wool on the
top and bottom of the extractor was used for the i.d., 25 mm film thickness). The oven temperature
was programmed from 60 to 260°C at 5°C min−1non-recycling experiments. The CO
2
flow was
0.25 l min−1 at atmospheric pressure. The samples and kept at 260°C for 20 min. The temperature of
the on-column injector was raised from 60 toof 3-n-propylidene phthalide were collected after
passing 3, 5, 7, 10, 15, 25 and 40 l of expanded 260°C at 200°C min−1 and kept at 260°C for
5 min. The flow rate of the helium carrier gas wasCO
2
through the sample. The conditions of the
experiments with (±)-a-terpinyl acetate were the 2.0 ml min−1.
same, except that the amount of CO
2
passed
through the sample was 25 l instead of 40 l. The
extracts were collected in the 5 ml test tubes, which 3. Results and discussion
were immersed in ethanol bath at −5°C.
Vessels of 47, 200 and 1000 ml, with glass wool 3.1. Dynamics of the recovery of 3-n-propylidene
phthalide and a-terpinyl acetate from the modelon the top and bottom of the extractor, and two
separators (200 ml capacity each) were used for systems
3-n-Propylidene phthalide, a-terpinyl acetate,
limonene and b-phellandrene are the most abun-
dant components in lovage essential oil. The solu-
bility of limonene in dense CO
2
was studied earlier
by Stahl and Gerard [17]. So far as the properties
of b-phellandrene are similar to those of limonene
(both are monocyclic monoterpene hydrocarbons),
only 3-n-propylidene phthalide and a-terpinyl ace-
tate were studied in our work.
Fig. 1. Schematic drawing of the SFE equipment (with recircu- The results of the investigation of the effect of
lation, 1–15; without recirculation, 1–11, 15–17): 1, gas tube; CO
2
flow rate at 250 bar pressure and 40°C on the
2, shut-off valve; 3, gas filter; 4, ethanol bath, −22°C; 5, pump;
recovery of a-terpinyl acetate from the matrix
6, relief valve; 7, pressure meters; 8, shut-off valve; 9, extractor;
showed that the rate of CO
2
flow was not very10, water bath; 11, micrometering valve; 12, separators; 13,
important in the recovery process. Slightly smallerextract removal valves; 14, manual relief valves; 15, flow meter;
16, test tube (7 ml); 17, ethanol bath, −5°C. and slower recovery of a-terpinyl acetate was
4. 54 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
noticed at a flow rate of 25 ml min−1. The total cal CO
2
is shown in Fig. 3. Here, the highest
solubility of a-terpinyl acetate occurs when therecovery of the compound after passing 15 l of
CO
2
at a flow rate of 50–300 ml min−1 was close pressure of CO
2
is increased above 200 bar. At
such conditions, 0.065 to 0.08 g of a-terpinyl ace-to 90% of the added amount. Most likely, some
part of the substance was lost due to possible tate can be dissolved in 1 g of CO
2
. When the
pressure of CO
2
was maintained at 80, 100 andcondensation on the walls of tubes or strong
absorption on the celite. A flow rate of 150 bar, the solubility dropped to approximately
0.045 g g−1 CO
2
.200 ml min−1 was used in further experiments to
perform the process in a possibly shorter time. The solubility of 3-n-propylidene phthalide in
supercritical CO
2
at 40°C (Fig. 4) was found toWhen the flow rate was increased to
300 ml min−1, some reduction in recovery was be lower than that of a-terpinyl acetate at the
same conditions: from 0.017 to 0.05 g g−1 CO
2
.noticed. Possibly at this flow rate the conditions
for CO
2
penetration into celite granules were less The lowest solubility of 3-n-propylidene phthalide
was observed at 80 and 100 bar CO
2
, the highestfavorable, and/or some part of the compound was
entrained out of the test tube together with CO
2
. at 250–350 bar. However, the difference in solubil-
ity between 3-n-propylidene phthalide andThe effect of CO
2
pressure on the dynamics of
the recovery of a-terpinyl acetate was also studied a-terpinyl acetate at 40°C is not sufficient for the
efficient separation of these compounds from theirat 40°C. Here about 15 l of CO
2
was sufficient to
extract approximately 90% of the compound at all mixtures.
So far as a-terpinyl acetate was proved to beextraction pressures. However, the rate of the
process was slower at 80, 100 and 150 bar as highly soluble in supercritical CO
2
, the amount of
CO
2
in further experiments was decreased to 25 l.compared with higher pressure conditions. It seems
that by increasing the density of supercritical As shown in Fig. 5, this amount was sufficient to
recover 90–97% of the compound for all of theCO
2
from 0.4–0.75 g cm−3 (80–150 bar) to
0.85–0.95 g cm−3 (200–350 bar), it is possible to extraction pressures used at 50°C. Again, it was
confirmed that the rate of extraction depends onimprove the extraction efficiency. The rate of
recovery was slightly lower at 300 bar compared the pressure: the best result being obtained at
350 bar. For example, at this pressure, 5 l of CO
2
with 200, 250 and 350 bar, and this finding is
rather difficult to explain. recovered more than 60% of the constituent,
whereas at 80 bar, the recovery was only slightlyThe effect of CO
2
pressure on the dynamics of
the recovery of 3-n-propylidene phthalide at 40°C above 20%. The effect of the increased extraction
temperature from 40 to 50°C on the a-terpinyl(Fig. 2) was more significant when compared with
a-terpinyl acetate. Again, the rate of recovery was acetate recovery was not significant.
The effect of a relatively small increase in tem-considerably lower at CO
2
pressures of 80 and
100 bar. In this case 40 l of the supercritical fluid perature (from 40 to 50°C) has caused considerable
changes in the process of extraction of 3-n-propyli-was necessary to recover about 90% of the chemi-
cal, whereas only 15 l of CO
2
was required to dene phthalide, especially at lower pressures
(Fig. 6). Only a few per cent of the compoundextract almost the same amount of the compound
from the matrix at 150, 250 and 300 bar pressure. was isolated at 80 bar pressure and 50°C with 40 l
of CO
2
, whereas at the same pressure and 40°CThe reason for this is that 3-n-propylidene phthal-
ide is less soluble at low densities (0.35– the recovery was close to 90% (Fig. 2). The effec-
tiveness of the extraction at 100 bar was also0.5 g cm−3) of CO
2
. The curve obtained at the
highest pressure, i.e. 350 bar, yielded 80% recovery considerably lower. It seems that for the solubility
of 3-n-propylidene phthalide in low density fluidfor 15 l of CO
2
, however, further extraction (with
the remaining 25 l of CO
2
) at this pressure almost CO
2
some kind of critical temperature point lies
in the region between 40 and 50°C.did not increase the yield of 3-n-propylidene
phthalide. The solubility of a-terpinyl acetate at 50°C
(Fig. 7) was found to be lower than that at 40°C.The solubility of a-terpinyl acetate in supercriti-
5. 55E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
Fig. 2. Dynamics of the extraction of 3-n-propylidene phthalide at different CO
2
pressures, temperature 40°C.
Fig. 3. Solubility of a-terpinyl acetate (g g−1 CO
2
) at different pressures, temperature 40°C.
The maximum value of 0.07 g g−1 CO
2
was mea- 50°C temperature varied from 0 to
0.095 g g−1 CO
2
depending on the solvent pressuresured at 350 bar pressure. The lowest solubility
was recorded at 80 bar pressure — (Fig. 8). CO
2
at 350 bar was most effective; pres-
sures lower than 150 bar were ineffective. By com-0.032 g g−1 CO
2
. Some fluctuations in the depen-
dence of solubility and pressure can be observed paring the curves in Figs. 7 and 8, one can see that
at 80 bar pressure and 50°C, the solubility ofin the range 150–250 bar. The solubility of the
particular compound in CO
2
should stay constant a-terpinyl acetate is 0.032 g g−1 CO
2
; while the
solubility of 3-n-propylidene phthalide is close toafter reaching the equilibrium, however, it starts
dropping when the compound is depleted from the zero. Hence, it was assumed that such conditions
could be used for the separation of these twoextraction matrix.
The solubility of 3-n-propylidene phthalide at compounds from their mixtures.
6. 56 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
Fig. 4. Solubility of 3-n-propylidene phthalide (g g−1 CO
2
) at different pressures, temperature 40°C.
Fig. 5. Dynamics of the extraction of a-terpinyl acetate at different CO
2
pressures, temperature 50°C.
In the next series of experiments a mixture amount of solvent is given at atmospheric pres-
sure). The content of a-terpinyl acetate and 3-n-consisting of 3 g celite, 0.5 g 3-n-propylidene
phthalide and 0.5 g a-terpinyl acetate was used. A propylidene phthalide in the recovered mixture
was 82.59% and 17.41%, respectively. In the next7 ml capacity extractor was used in the equipment
set without CO
2
recirculation. The main goal of extraction step the temperature was decreased to
40°C and 59% of the added matrix constituentsthe experiment was to extract only a-terpinyl ace-
tate from the mixture at parameters in which 3-n- was recovered. An almost equal content of
a-terpinyl acetate (51.71%) and 3-n-propylidenepropylidene phthalide was not soluble.
The results of the above experiment are summa- phthalide (48.29%) was found in the obtained
extract. Finally, by passing an additional 25 l ofrized in Table 1. All of the added compounds
(20.39%) were extracted at 50°C temperature and CO
2
through the model system under the same
conditions, 11% of the mixture was recovered,80 bar pressure using 25 l (50 g) of CO
2
(the
7. 57E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
Fig. 6. Dynamics of the extraction of 3-n-propylidene phthalide at different CO
2
pressures, temperature 50°C.
Fig. 7. Solubility of a-terpinyl acetate (g g−1 CO
2
) at different pressures, temperature 50°C.
consisting of 9.54% a-terpinyl acetate and 90.46% extracted at these conditions, and this result is in
good agreement with data presented in Fig. 6. The3-n-propylidene phthalide. For all three extrac-
tions, 90.39% of the compounds (96.8% a-terpinyl yield of the recovered a-terpinyl acetate during the
second step of the extraction (61% of that addedacetate and 84.0% 3-n-propylidene phthalide) were
recovered based on the initial amounts. However, to the matrix) was also smaller than expected
according to data obtained earlier, whereas thethe result which was expected according to the
extraction dynamics curves (Fig. 5), i.e. to remove 57% of recovered 3-n-propylidene phthalide is
quite comparable to the result obtained previouslyfrom the matrix almost all the amount of a-terpinyl
acetate during the very first step of the process, for this compound (Fig. 2). It seems that extrac-
tion of some constituents from their mixtures withwas not achieved; only 0.168 g or 33.7% of the
added amount of this compound was extracted. other compounds is different compared with the
extraction process when these constituents are usedOn the other hand, only 0.036 g or 7% of the
initial amount of 3-n-propylidene phthalide was in the model matrix and extracted separately. Only
8. 58 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
Fig. 8. Solubility of 3-n-propylidene phthalide (g g−1 CO
2
) at different pressures, temperature 50°C.
after passing 75 l of CO
2
(the total amount of ble in CO
2
under these conditions, Fig. 8); the
second 200 ml capacity separator was held atsolvent applied during all three process steps) was
all the a-terpinyl acetate extracted from the matrix 20–30°C (natural chilling), 50–55 bar; while the
flow rate of the solvent was held atby CO
2
. It is difficult to explain this result within
the scope of the present study; however, one of 0.025 kg min−1.
The results of the experiments with solventthe reasons could be the interaction between com-
ponents in the matrix and with the matrix itself. recirculation (a 47 ml capacity extractor was used)
are summarized in Table 2. The measurement ofThe equipment with recirculation of the solvent
(Fig. 1) was used for additional experiments in the extract was performed after passing 5 kg of
CO
2
through the model system. The extractedorder to optimize the extraction process. The
following conditions were applied: the extractor mixture in the first separator consisted of 33.5%
a-terpinyl acetate and 66.5% 3-n-propylidenewas kept at 40°C and 250 bar (the condition which
optimized the solubility of both a-terpinyl acetate phthalide; in the second one, 76.9% a-terpinyl
acetate and 23.1% 3-n-propylidene phthalide.and 3-n-propylidene phthalide, Figs. 3 and 4); the
first 200 ml capacity separator was held at 50°C, The composition of the next model system
(Table 2, II) was based on data for lovage essential80 bar (3-n-propylidene phthalide is almost insolu-
Table 1
Recovery of a-terpinyl acetate and 3-n-propylidene phthalide from the model matrix
Composition of Extraction parameters Recovered Content of individual compound
model mixture content (%) in the recovered mixture (%)
a-terpinyl acetate 3-n-propylidene phthalide
Celite, 3 g; a-terpinyl acetate, 0.5 g; 80 bar, 50°C, 25 l of CO
2
20.39 82.59 17.41
3-n-propylidene phthalide, 0.5 g
80 bar, 40°C, 25 l of CO
2
59.00 51.71 48.29
80 bar, 40°C, 25 l of CO
2
11.00 9.54 90.46
Total recovered amount 90.39
10. 60 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
oil composition presented by Toulemonde and capacity extractor was used) are summarized in
Table 3. It should be noted that the compositionNoleau [1]. After using 10 kg of CO
2
, 30.96% of
the mixture consisting of 61.57% limonene, 16.65% of the essential oil was quite similar to the composi-
tion of model system III in Table 2 (except thata-terpinyl acetate and 21.78% 3-n-propylidene
phthalide was recovered in the first separator; the limonene was replaced by another monoter-
pene — b-phellandrene in the essential oil). A very7.05% of the mixture consisting of 90.29% limo-
nene, 7.54% a-terpinyl acetate, and 2.17% 3-n- small amount of the oil was recovered after passing
10 kg of CO
2
, however, its composition in the firstpropylidene phthalide was recovered in the second
separator. Approximately a two-fold increase in separator was completely different from that in
the initial oil. In this case, b-phellandrene andthe content of 3-n-propylidene phthalide was
found in the first separator compared with its a-terpinyl acetate constituted only 1.86% and
11.18% respectively of the total essential oil, whilecontent in the matrix.
The composition of the third model system the content of phthalide was 77.53% (12% in the
initial essential oil). The composition of the oil in(Table 2, III) was based on published data on the
composition of essential oil from lovage grown in the second separator was approximately the same
as the initial composition; showing a decrease inLithuania [2]. During this experiment the temper-
ature in the second separator was increased to the content of b-phellandrene.
It should be noted that the composition of the30–35°C and the pressure decreased to 50 bar. The
composition of the recovered mixture (19.3%) in essential oil (from overground botanical parts)
fraction obtained in the first separator was con-the first separator was similar to the percentage
composition of the components in the matrix. In siderably enriched with phthalides, which are the
main constituents of a more valuable product —the second separator, the content of a-terpinyl
acetate and 3-n-propylidene phthalide was lower lovage root essential oil [1,2]. In other words, it
can be said that by optimizing the extractionwhen compared with the composition in the initial
mixture, while the content of limonene was approx- parameters it is possible to separate a high quality
and high price fraction (resembling in its composi-imately 1.5 times higher.
The results obtained by using recirculating tion lovage root oil) from an inferior in quality
and price product — raw lovage overground mate-solvent to extract the constituents used in the
model systems show that the composition of the rial or its essential oil.
The final experiments were performed by usingmixture in the matrix produces a significant effect
on the extraction process. For instance, when the ground leaves and stem (Table 3, II) and seeds
(Table 3, III) of lovage. The raw material was putcontent of limonene was high (70%, model II),
the extracted mixture in the first separator was into the 1000 ml extractor and extracted with 15 kg
of CO
2
. The yield of the extract in the first and insignificantly enriched in 3-n-propylidene phthalide;
however, when a-terpinyl acetate was the major the second separator was 7.17 g (1.59%) and 0.56 g
(0.13%), respectively. Phthalides were the maincompound in the initial mixture (70%, model III),
the content of 3-n-propylidene phthalide in the constituents in the volatile fraction of the first
separator (35.57%) followed by a-terpinyl acetateextract (first separator) was almost equal to its
content in the initial mixture. (26.42%). The majority of b-phellandrene was
carried to the second separator. Judging from the
extract color, a considerable amount of chlorophyll3.2. Dynamics of the recovery of essential oil of
lovage from the model system and plant raw was isolated in the first separator. Unfortunately,
we were not able to install the third separator inmaterial
the process to try to separate chlorophyll from the
extract at a pressure below 200 bar. Therefore, theFurther experiments were carried out by using
natural essential oil from overground parts of substance obtained in the first separator was
extracted again in the same apparatus withoutlovage and raw plant material. The results of the
experiments with solvent recirculation (the 47 ml using CO
2
recirculation, using the 47 ml extractor
11. 61E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
at the following parameters: 175 bar pressure, 40°C 4. Conclusions
temperature, 200 ml min−1 flow rate, 100 l CO
2
at
(1) The rate of CO
2
flow through the extractoratmospheric pressure. The yield of chlorophyll-
was not very important for the recovery offree extract was 3.01 g, phthalides (52%) and
a-terpinyl acetate from the celite matrix.a-terpinyl acetate (13.4%) being the main constitu-
(2) The solubility of a-terpinyl acetate dependsents in the extract. It should be noted that the
on the CO
2
pressure and extraction temper-yield of the crude extract obtained in the two
ature: (i) it is considerably higher at pressuresseparators from 100 g of ground plant material
of 200–350 bar compared with pressures ofwas 1.72 g, which is higher than the amount of the
80–150 bar; (ii) it is slightly higher at 40°Cessential oil, 1.18±0.06 ml [d=0.96 (leaf ) to 1.06
than at 50°C.(root)] [23]. However, after separating the chloro-
(3) The effect of CO
2
pressure and extractionphyll fraction, the yield of the extract was reduced
temperature on the solubility of 3-n-propyli-to 0.67 g 100 g−1. In general, it is observed that
dene phthalide was more significant comparedCO
2
extraction of spices yields the same extract,
with the effect of these parameters on theclose to that obtained by hydrodistillation [5]. It
solubility of a-terpinyl acetate. 3-n-is also worthwhile noting that thermally mild
Propylidene phthalide was almost insoluble inconditions yield concentrates which in their sen-
CO
2
at 80 bar and 50°C; however, reasonablesory qualities are superior to steam distillates or
solubility of this compound was obtained onlyclassical solvent extracts [17].
after increasing the pressure up to 150 bar.The seeds of lovage were extracted in the 200 ml
(4) It was found that by using a solvent circulatingextractor by using 15 kg of CO
2
(Table 3, III),
system with two separators operating at
resulting in 4.77 g of an extract consisting of
different parameters, it is possible to obtain a
17.43% b-phellandrene, 2.82% a-terpinyl acetate
phthalide enriched fraction both from the
and 28.26% phthalides obtained in the first separa-
model matrix prepared from celite and lovage
tor. A much lower amount of the extract was
essential oil and raw plant material
carried to the second separator — 0.15 g. It was
(leaves+stems and seeds).
established that the content of b-phellandrene in
(5) CO
2
extraction can be a useful process for
seeds essential oil exceeds 60% (Bylaite et al.,
obtaining lovage extract from its overground
unpublished results), therefore the result obtained
botanical parts, which resembles in composi-
in the first separator in terms of high content of tion commercially more valuable essential oil
phthalides can be considered to be quite successful. from lovage roots.
It should be observed that the total yield of the
extract (4.92%) was high compared with the yield
Acknowledgmentsof the essential oil from lovage seeds obtained by
hydrodistillation, which was from 0.8 to 1.1% [24]
The authors wish to thank Dr. M.and 1.8% [4]. Moyler [5] determined that the
Baranauskiene and Dr. P. Visˇkelis from theyields of steam distilled oil and liquid CO
2
extract
Lithuanian Institute of Horticulture for providing
from celery (Apium graveolens) seeds were almost
plant material.
equal (2.5–3.5% and 3%, respectively), whereas
from parsley (Petroselinum crispum) seeds,
2.0–3.5% of oil was distilled by steam during 5 h,
Referenceswhile 9.8% of the extract was obtained by CO
2
during 2 h of extraction at 58 bar and 20°C.
[1] B. Toulemonde, I. Noleau, Volatile constituents of lovageLachowicz et al. applied CO
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(Levisticum officinale Koch.), in: B.M. Lawrence, B.D.
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critical CO
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cultivated in Lithuania, in: K.H.C. Baser (Ed.), Proc. 13th [14] H. Kallio, K. Kerrola, P. Alhonma¨ki, Carvone and limo-
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[5] D.A. Moyler, Extraction of flavours and fragrances with Chromatographia 30 (1990) 16.
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[20] E. Reverchon, G. Della Porta, F. Senatore, Supercriticaltion of essential oils, in: B.M. Lawrence, B.D. Mookherjee,
B.J. Willis (Eds.), Flavors and Fragrances: A World CO
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[9] M.A.A. Meileres, Z.L. Nikolov, Extraction and fraction- [21] S. Lo´pez-Sebastia´n, E. Ramos, E. Iba´n˜ez, J.M. Bueno, L.
Ballester, J. Tabera, G. Reglero, Dearomatization of anti-ation of essential oils with liquid carbon dioxide, in: G.
Charalambous (Ed.), Development in Food Science 34, oxidant rosemary extracts by treatment with supercritical
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![Journal of Supercritical Fluids 15 (1999) 51–62
Supercritical CO
2
extraction of the main constituents of lovage
(Levisticum officinale Koch.) essential oil in model systems and
overground botanical parts of the plant
Egidijus Dauksˇas a, Petras Rimantas Venskutonis a,*, Bjo¨rn Sivik b
a Department of Food Technology, Kaunas University of Technology, Radvilenu pl. 19, Kaunas 3028, Lithuania
b Food Technology, Chemical Centre, University of Lund, PO Box 124, S-221 00 Lund, Sweden
Received 25 March 1998; received in revised form 10 August 1998; accepted 27 August 1998
Abstract
The effect of various fluid CO
2
parameters on the extraction process of separate flavor compounds and essential
oil of lovage was investigated in the present study. Model systems and lovage leaves, stems and seeds were used for
this purpose. It was found that the solubility of a-terpinyl acetate depends on the CO
2
pressure and extraction
temperature. This compound was more soluble at pressures of 200–350 bar as compared with pressures of 80–150 bar.
The solubility of 3-n-propylidene phthalide was more dependent on the CO
2
pressure and extraction temperature
than the solubility of a-terpinyl acetate. 3-n-Propylidene phthalide was almost insoluble in CO
2
at 80 bar and 50°C,
and finite solubility of this compound was obtained only after increasing the pressure up to 150 bar. This investigation
showed that the extraction process from the model matrix is rather complex and cannot be predicted from the
solubility data for each separate constituent. The percentage content of the main constituents in the extracts varied
over a wide range depending on their ratio in the initial mixture. By using a solvent circulating system with two
separators operating at different parameters, it was possible to obtain a phthalide enriched fraction both from the
model matrix (prepared on celite) and raw plant material (leaves+stems and seeds). © 1999 Elsevier Science B.V.
All rights reserved.
Keywords: Extraction; Levisticum officinale Koch.; Lovage; Solubility; Supercritical CO
2
1. Introduction diffusive and penetrating tendency. Volatile com-
pounds in lovage have been studied previously,
and more than 190 compounds have been reportedLovage (Levisticum officinale Koch.) is a peren-
in its roots, seed or leaf essential oil. It wasnial herbaceous plant from the Umbelliferae
determined that the chemical composition of thefamily. The essential oils from roots, seeds and
essential oil distilled from separate botanical partsleaves are used in perfume and flavor formulation.
of the plant is rather different. The most importantThe root oil is characterized by a warm spicy note,
constituents of essential oil from lovage are phthal-whilst the seeds and leaf extract impart a more
ides, which constitute more then 70% of the total
volatile oil from the roots, and about 6% from the* Corresponding author. Fax: +370 7 756647;
e-mail: rimas.venskutonis@ctf.ktu.lt seed [1]. The chemical composition of lovage
0896-8446/99/$ – see front matter © 1999 Elsevier Science B.V. All rights reserved.
PII S0896-8446 ( 98 ) 00123-5](https://image.slidesharecdn.com/9b40f261-1664-48c7-8456-60a1527ac40b-160414152641/85/Supercritical-CO2-extraction-of-the-main-constituents-of-Lovage-Levisticum-officinal-Koch-essential-oil-in-model-systems-and-overground-botanical-parts-of-the-plant-1-320.jpg)
![52 E. Dauksˇas et al. / Journal of Supercritical Fluids 15 (1999) 51–62
grown in Lithuania has also been studied pre- aldehydes, and phenolic compounds) due to their
viously, and it was found that the content of higher vapor pressure, lower polarity and smaller
phthalides in the essential oil from roots was molecular mass [17].
64–80%, leaves 25%, and stems 14.5% [2]. CO
2
extraction has been used successfully for
Therefore, lovage root essential oil is the product the fractionation of plant extractives, e.g. jasmine
of highest commercial value. According to [18] and tuberose [19] concretes, lavender essential
Lawrence [3], the world production of lovage root oil and waxes [20], dearomatization of antioxidant
and seed oil in 1984 was 500 kg and 300 kg, rosemary extracts [21], removal of terpene in citrus
respectively. Information about the commercial oil [22].
production of essential oil from lovage stems or It can be concluded that there are several SFE
leaves was not available in the surveyed literature. parameters, which should be optimized in the
The roots of lovage can be harvested at the separation of a particular fraction from a complex
second or third year of plant cultivation, while it mixture, such as lovage oil. Our study was an
is possible to collect the seeds in the second year attempt to investigate the possibilities of supercriti-
of cultivation. An average yield of lovage roots cal CO
2
extraction in recovering the main lovage
and seeds in Lithuania is 9–10.5 ton he−1 and constituents from natural plant material and
0.2–0.4 ton he−1, respectively [4]. The overground model systems.
parts of lovage (leaves and stems) can be harvested
few times per season, their harvesting and handling
(e.g. cleaning, drying) are more simple and cheaper
as compared with harvesting and handling of
lovage roots. Therefore, the investigation of the
2. Materials and methods
possibility of obtaining an essential oil from the
green botanical parts of lovage possessing similar
2.1. Materials
composition to the oil isolated from the roots is
of interest and commercial importance.
The seeds and leaves of lovage (Levisticum
The extraction of flavors and fragrances with
officinale Koch.) were collected from the experi-
compressed CO
2
was comprehensively reviewed
mental garden of the Lithuanian Institute of
and described by Moyler [5,6], Moyler and
Horticulture in September 1996. The samples were
coworkers [7,8], Meileres and Nikolov [9], and
harvested manually, dried at 30°C in a ventilated
Stahl et al. [10]. However, information about
drying oven and stored in double layer paper bagslovage extraction by CO
2
in sub- and/or supercriti-
at ambient temperature and protected from lightcal state was not found in the surveyed literature.
until further analysis. The samples were groundThis method has been used with some other
before extraction by a Knifetec 1095 Sample MillUmbelliferae family plants, e.g. coriander, angelica
(Tecator) machine, in 20 s time.[11,12], caraway [13,14], anise [15], celery and
The volatile constituents were isolated fromcoriander [16].
lovage leaves and stems by hydrodistillation in aIt is known that the components of essential oils
Clevenger type apparatus during 3 h. The yield ofare soluble in dense CO
2
at relatively low fluid
essential oil was 1.18±0.06 ml 100 g−1.pressures. Essential oils are usually complex mix-
The solvents and chemicals were obtained fromtures consisting of substances with different volatil-
the following sources: carbon dioxide, 99.99%ity and/or polarity. For a successful isolation of a
purity, from Alfax, Sweden; 3-n-propylideneparticular fraction from such mixtures, the solubil-
phthalide, from LabKemi (Lancaster); (±)-a-terpi-ity of the compounds to be separated in the dense
nyl acetate (~95% by GC), from Fluka;gas should differ as much as possible. Monoterpene
(+)-limonene, from Sigma; Celite 545, 20–45 mm,hydrocarbons exhibit higher solubility in dense
from Kebo lab (PROLABO, France); cyclohexane,CO
2
than the other ordinary essential oil compo-
nents (e.g. terpene and sesquiterpene alcohols, extra purity (>99%), from Merck (Germany).](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)