Received 15 September 1993; accepted 3 June 1994

Transcription

1 ELSEVIER Pharmaceutica Acta Helvetiae 70 (1995) Y HARM ACEUTICA ACTA HELVETIAE Procedures influencing the yield and the quality of the essential oil from juniperus communis L. berries Pashalina S. Chatzopoulou, Stavros T. Katsiotis * Department of Pharmaceutics, School of Pharmacy, Aristotle Uni~lersity of Thessaloniki, 54006, P.O. Box 1589, Thessaloniki, Greece Received 15 September 1993; accepted 3 June 1994 Abstract The investigation on the influence of the distillation time on integral and comminuted juniper berries performed with the classic hydrodistillation and the simultaneous distillation-extraction method showed that: (a) it is not possible to completely obtain the essential oil from the integral berries (0.30% yield) and that the yield from the comminuted plant material was increasing in the first three hours of distillation ( %); (b) the ratio of the three main constituent groups liberated, i.e. monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpenes, depends on the isolation method as well as the distillation time applied to the juniper berries. Keywords: Juniperus communis L. berries; Essential oil; Simultaneous distillation- extraction; Influence of isolation time; Comminution of plant material 1. Introduction Changes in the composition of an essential oil can be caused by environmental factors, such as the soil or climate in which the plants are grown, and by different harvesting methods or distillation techniques. The isolation and concentration techniques normally used may well alter the quantitative as well as the qualitative composition of the obtained essential oil relative to the composition of the compounds present in the plant material. This paper presents the results from the analysis of the volatile compound composition of the mature Junipems communis L. berries by using (a) the simultaneous distillation-extraction technique, and (b) by the classic method of distillation, considering the influence of the isolation time parameter on the quality and yield of the obtained volatile constituents and determining the isolation rate of the volatile constituents in the distillates. * Corresponding author. 2. Experimental procedures 2.1. Plant material The plant material (berries samples) was collected from wild growing Juniperus communis L. shrubby trees on the Olympus mountain at an altitude of 1300 m. The berries after separation from the needles and the branches were stored in a freezer at -20 C. The experimental design included the percentage determination of the essential oil yield, as well as the quality of the essential oils from (a) integral berries, and (b) from comminuted plant material Isolation and yield of the essential oil Hydrodistilla tion The essential oil percentage yield determination of the berries resulted by using the European Pharmacopoeia apparatus (Clevenger-type) and after 3 performances in an relative standard error S,,, of 50.05%. The berries were subjected to hydrodistillation after /95/$09.50 O 1995 Elsevier Science B.V. All rights reserved SSDZ (95)OOO26-7

2 248 P.S. Chatzopoulou, S. T. Katsiotis /Pharmaceutica Acta Heluetiae 70 (1995) drying until a moisture content of 25% (Chatzopoulou et al., 1988a). The plant material was kept in liquid N, for 30 min and then was comminuted in a closed type mill with a degree of comminution of 1 mm as suggested from preliminary studies on the conditions under which the plant material has to be processed (Chatzopoulou et al., 1988b). Samples of 20 g of comminuted berries with 340 ml of deionized water were distilled for 1 to 6 hours (as requested in each experiment condition) at distillation rate of ml/min (Katsiotis, 1989). The lighter-than-water, slightly yellow and limpid, oils were dried over anhydrous Na,SO, and stored in sealed containers under refrigeration ( - 20 C) Simultaneous distillation-extraction method A simultaneous distillation-extraction procedure was employed using an apparatus similar to that of Likens-Nickerson (Likens et al., 1964) and of Maarse (Maarse et al., 1970). The distiilator return arm for the extracting solvent was 1 crn higher than the distillator return arm for the aqueous phase and the glass tube of 1.7 and 1.1 cm O.D. Before starting a run, the U-tube separator section of the apparatus was charged with 3 ml of water and 2 ml of n-pentane. A 15 g sample of pulverized berries - treated in the same way as for the distillation - was placed into a 500 ml round-bottomed flask containing 340 ml (Katsiotis, 1989) of deionized water. To the solvent flask 100 ml of n-pentane were added. Both flasks were placed in thermomantles connected with a thyristor in order to maintain a constant distillation rate. The distillation-extraction was run for totally 6 h. Every exactly one hour period the run was stopped and a flask with new n-pentane (80 ml) was mounted replacing the former. Distillation time was evaluated after the first distilled drops of each distillation-extraction period. The enriched quantity of n- pentane was evaporated to 2 ml under mild vacuum in an ice/water bath Gas-liquid chromatography The essential oil samples, as well as the fractions obtained by LSC, were analyzed by gas chromatography, using a gas chromatograph Hewlett-Packard 5890 Series 11, equipped with one injection port and a two-channel system of columns and respective flame ionization detectors connected to a chromatographic integrator (Hewlett-Packard 3396 Series I1 Dual Channel). Two fused-silica columns of different polarity were used: (a) Durabond-DB 1, and (b) DB-Wax both of 60 m X 0.25 mm with a film thickness of 0.25 pm (J&W Scientific Inc., Rancho Cordova, CA, USA). Oven temperature: 45-22WC (3.5"C/rnin); carrier gas: nitrogen, 140 kpa; injection temperature: 220 C; detector temperature: 30WC. Routinely the analyses were carried out by injecting three times 0.5 p1 of the extract or the dissolved essential oil in n-pentane (1:20). The percentage composition results were computed from the GC peak areas without applying correction factors. The relative standard deviations per peak averaged k 0.01% and %, respectively Gas chromatography and mass spectrometry A GC-MS was also applied, using a 60 m X mm I.D. fused-silica CP-Wax 52 CB column, film thickness 0.25 pm (Chrompack Nederland BV) and a gas chromatograph Packard 438 A interfaced with a Finnigan MAT Ion Trap Detector (software version 3.0) Finnigan Mat, San Jose, CA, USA). Oven temperature: C (3"C/min); carrier gas: helium (pressure 200 kpa); splitting ratio 1:40; scan time, 1 s. Table 1 Composition of the essential oil (%) after distillation of comminuted Juniperus communis berries Compounds Hours a-thujene a-pinene Carnphene Sabinene a-pinene Myrcene a-Terpinene p-cyrnene Limonene ,8-cine01 l0.y-terpinene Linalool trans-Sabinene hydrate 13. Borneo Terpinene a-Terpineol p-cubebene p-caryophyllene a-Humulene Germacrene D y-Cadinene

3 P.S. Chatzopoulou, S.T. Katsiotis /Pharn~aceutica Acta Heluetiae 70 (1995) Results and discussion The winning of the essential oil from the integral juniper berries resulted rather difficult; even after 6 h of distillation the yield remained only 0.30% v/w. Though, the comminution of the berries was considered indispensable; as a matter of fact, the comminuted juniper berries through the three first hours of distillation presented an increasing yield of the obtaining oii ( % v/w); further results on this item - methods, equipments and degree of comminution - are imminent to be published. In Table 1 are shown the percentages of the main components of the essential oil obtained by distillation (Chatzopoulou et al., 1993) of the comminuted berries and for distillation time 1-6 h. The monoterpene hydrocarbons presented a gradient decrease (53.2% of the first h) while the distillation time was extended to six hours (23.0% in the 6th hour). On the contrary, the total amount of sesquiterpenes raised from 40.6% in the first hour to 69.8% in the 6th hour (Fig. 1). As far it concern the oxygenated monoterpenes, seemed to increase through the distillation period from 1-6 h. This increase is rather negligible though losses had occurred, probably, because of their solubility. These compounds are considerably water-dissolved and probably were partially redissolved in the separation part of the distillation apparatus returning back to the First h Second h Third h Folth h Filth h Sixth h Oxygenated terpenes Monoterpene Sesquiterpenes hydrocarbons Fig. 1. Percentage variation of the monoterpene hydrocarbons, oxygenated terpenes and sesquiterpenes after distillation from 1-6 h. Table 2 9% Compositio~i of the essential oil after the simultaneous distillation-extraction of the comminuted Juniperus comrnunis berries Con~pounds I. a-thujene 2. a-pinene 3. Camphene 4. Sabinene 5. P-Pinene 6. Myrcene 7. a-terpinene 8. p-qmene 9. Limonene + 1,8-cine y-terpinene 11. Linalool 12. trans-sabinene hydrate 13. Borneo1 14. Terpinene a-terpineol 16. P-Cubebene 17. P-Caryophyllene 18. a-humulene 19. Germacrene D 20. y-cadinene Hours flask, and moreover, presumably because of the extended period of distillation (Koedam et al., 1979b). The simultaneous distillation-extraction offered a more reliable acquisition rate of these constituents. The previous global results are confirmed by this method (Table 2), as far as concerns the two main groups of the monoterpenes hydrocarbons (obtained mainly in the first and second hour of the procedure) and of the sesquiterpenes (presenting an increase of the total percentage after the second hour to the 5th) Fig. 2. Significant differences among the two methods were recorded in the oxygenated constituents percentages. From the first and second stages in the simultaneous distillation-extraction the percentage amounts of several oxygenated monoterpenes (borneol, terpinene-4-01, a-terpineol) were much higher than in the classic distillation method. Remarkable is also that the highest amount of the constituents was delivered in the fraction from the first procedure period (8.3%), whereas in the fifth hour only 0.9% was obtained (Fig. 3). For the compounds a-terpinene and y-terpinene presenting a higher percentage yield in the distillation method the results from the simultaneous distillation-

4 250 P.S. Chatzopoulou, S. T. Katsiotis / Pharrnaceutica Acta Helvetiae 70 (1995) Fifth h xygenated Terpenes [7 Monoterpene Oxygenated Terpenes Sesquiterpenes Hydrocarbons Fig. 2. Percentage variation of the three groups of constituents during the simultaneous distillation-extraction from 1-5 h. extraction showed that they are obtained in the first and second hour. Their increased presence in the essential oil obtained from the distillation has to be assigned in partial rearrangement probably of sabinene to these compounds and to terpinene-4-01 that has been observed to occur often (Baxter et al., 1978; Clark et al., 1977; and Taskinen, 1976). The influence of the distillation duration was investigated in the case of the integral juniper berries too. The essential oil yield even after eight hours of distillation was only 0.35%. Table 3 features the results from Sirr.uk. DistillationlExtraction Hydrodistillation Hydrodistillation Simult. DistillationIExtraction Fig. 3. Variation of the oxygenated compounds after the simultaneous distillation-extraction and the hydrodistillation from 1-6 h. I Table 3 % Composition of the essential oil after the simuitaneous distillation-extraction of the integral Juniperus cornrnunis berries Compound Hours a-thujene a-pinene Camphene Sabinene P-Pinene Myrcene a-Terpinene p-cymene Limonene l,8-cineol 10. y-terpinene Linalool trans-sabinene hydrate Borneo Terpinene a-terpineol P-Cubebene 17. P-Caryophyllene 18. a-humulene Germacrene D y-cadinenr the simultaneous distillation-extraction of the integral berries over a period of six hours. From the obtained data was pointed out a quite different oil quality from integral and comminuted plant material. The terpene hydrocarbons were already obtained in high percentages in the first period of the distillation (52.7%) and finally their total amount raised at 82.4% in the sixth hour, presenting an increase of 56.2%, as far it concerns the integral plant material; in contrast, a reduction of their percentage was observed from the comminuted material (Fig. 4). Singular exception, the monoterpene sabinene that after the third hour was obtained in less amounts, due, as it was mentioned before, to partial rearrangements in a- and y-terpinene - observed also by Koedam and colleagues (Koedam and Looman, 1980, and Koedam et al., 1981) - occurring in extended distillation times. The most significant differences were observed in the case of the oxygenated monoterpenes and the sesquiterpenes. The first represented only a small amount (8.3%) in the total percentage of the obtaining constituents from the comminuted berries, while the oil from integral berries resulted in high percentages

5 P.S. Chatzopoulou, S.T. Katsiotis /Pharrnaceutica Acta Heluetiae 70 (1995) (26.4% for the first hour of distillation). On the contrary, the sesquiterpenes were obtained just in the amount of 1.35% only after the sixth hour (Table 3). Protracting the distillation time, the total amount of the oxygenated monoterpenes were decreased to 14.5% in the sixth hour, presenting a drop of 82.5%, with the result that the proportion of monoterpene hydrocarbons vs. oxygenated monoterpenes from 2:l in the first hour achieved a ratio of 7:l in the sixth (Fig. 5). The above results, as far as the very low essential oil yield from the integral berries indicated the necessity of a further treatment of the plant material in order to isolate the constituents that probably were not liberated even after a six-hour distillation period. After the six hours of simultaneous distillation-extraction, the berries remained for 30 min in liquid N, and subsequently were comminuted - the whole plant material passed through a sieve of 1 mm (Chatzopoulou, 1992)- and distilled (for conditions, see Section 2) ex novo for an additional five hours (i.e., eleven hours in total). Just after the first additional hour (total distillation time 7 h), the yield of the essential oil was 1.05% verifying the impossibility of the essential oil acquisition from the integral berries. Apparently the essential oil was not easily liberated from the plant tissue in which it occurs, because of the morphology of the tissues surrounding it. This fact suggests the necessity of this plant material being comminuted. The analysis First h Second h Third h Forlh h Fifth h Sixth h I 0 Integral Comminuted I Fig. 4. Percentage variation of the monoterpene hydrocarbons after simultaneous distillation-extraction of integral and comminuted juniper berries. First h Second h Third h Forth h Fifth h Sixth h ---[I-- Monoferpene hydrocarbons -.- Oxygenated terpenes Fig. 5. Percentage variation of the monoterpene hydrocarbons and oxygenated terpenes during the simultaneous distillation-extraction of the integral berries. of the first hour's sample and of the others (of each hour till the fifth distillation hour adding up to a total of 11 h of distillation time) gave the results shown in Table 4. These data show that even if the total amount of hydrocarbons gradually increased during the first six hours of distillation of the integral berries, nevertheless a rather high amount failed to be recovered. This is easily demonstrated by the presence of a high percentage of hydrocarbons in the first fraction of the subsequent procedure. On the other hand, the amount of the oxygenated compounds present showed that they were almost totally recovered during the simultaneous distillation-extraction of the integral berries. On the contrary, the sesquiterpene hydrocarbons were found in extremely low percentages even after six hours of distillation-extraction of the integral berries. However, after the comminution and the subsequent distillation they were found present in higher percentages- a fact that underlines the difficulty of these compounds to be obtained from the integral plant material. Throughout the additional distillation for five more hours (totalling the 11 h distillation time), the yields of the constituents varied in the same way as during the

6 252 P.S. Chatzopoulou, S.T. Kafsiotis /Pharmaceufica Acta Helvetiae 70 (1995) Table 4 Partial percentage composition of the obtained essential oil after 1-5 h distilllation from comminuted Juniperus comrnmis berries that previously as integral plant material has been submitted to Simultaneous distillation extraction for 6 houri Compounds 1. a-thujene 2. a-pinene 3. Camphene 4. Sabinene 5. p-pinene 6. Myrcene 7. a-terpinene 8. p-cymene 9. Limonene + 1,8-cine y-terpinene 11. Linalool 12. trans-sabinene hydrate 13. Borneo1 14. Terpinene a-terpineol 16. p-cubebene 17. p-caryophyllene 18. a-humulene 19. Germacrene D 20. y-cadinene Hours (total duration) distillation of the comminuted plant material (Table 1). A gradient decrease of the terpene hydrocarbons was observed, along with a significant steep increase of the sesquiterpenes from 20.0% to 66.3% in the fifth hour - an increase of 229% - while the oxygenated monoterpenes remained almost constant (2.0%). 4. Conclusions The results of the present investigation on the influence of the distillation time on integral and comminuted juniper berries performed with the classic hydrodistillation and the simultaneous distillation-extraction method may be concluded by the following remarks: (1) The isolation of the volatile compounds is achieved at different rate and presents a different physicochemical pattern depending on whether integral or comminuted plant material is processed. From integral berries it is almost impossible to obtain the sesquiterpene compounds, existing in a substantial percentage of the juniper essential oil. Contrarily, the oxygenated monoterpenes are obtained apparently in high percentages, because of: (a) the lack of sesquiterpenes, and (b) the incomplete winning of the monoterpene hydrocarbons (as deduced from the subsequent comminution and following distillation). (2) During the distillation of the integral berries the phenomenon of 'hydrodiffusion' prevails (first described by Von Rechenberg, 1910). Under the influence of hot water in the distillation flask, the oxygenated compounds are better purged, since these are more water-soluble than the monoterpene hydrocarbons and the sesquiterpenes. However, upon further distillation of the integral berries the influence of the volatility becomes more pronounced and significant resulting in an increasing fraction of the low-boiling monoterpene hydrocarbons (Fig. 5). These observations are in complete accordance also with Koedam et al. in their studies on plant materials such as ajowan, caraway, coriander, cumin, Anethum graveolens (Koedam et al., 1979a), Abies X arnoldiana (Koedam et al., 1980) and with Morin et al. (1985) in their study of the distillation time effect on Larlandula angustifolia. (3) The sesquiterpenes - as lesser water soluble than the oxygenated compounds and found among the constituents of the higher boiling point fractions in the essential oil - are obtained only in small quantity, even after long distillation periods. However, their weighty presence in the oil from the comminuted plant material indicates that they are enclosed in different sites of the plant cell (Croteau and Loomis, 1972; Mettal et al., 1988; Bernard-Dagan et al., 1979) and that they are released only after the comminution facilitating their acquisition. Furthermore, a prolonged distillation time results in an increase of their yield. (4) Finally it should be mentioned that in the comminuted plant material the constituents of the essential oil are released much easier from the plant tissue in which they are enclosed; a rather large amount of them occurred in the oil structures of the plant cells that are enclosed in the inner part of the berry and after grinding they are released faster. The constituents are found in direct contact with water and steam and the low-boiling point compounds (mostly consisting of monoterpene hydrocarbons) are released without delay as a result of their relatively high volatility. In this case, volatility prevails upon 'hydrodiffusion'. In the following distillation stages of the comminuted berries, the portion of monoterpene hydrocarbons in the fractions declines, though their higher percentage was obtained previously, with an attendant increase in the sesquiterpene amounts.

7 P.S. Chatzopodou, S. T. Katsiotis / Pharmaceutica Acta Helvetiae 70 (1 995) Acknowledgements The authors are grateful to Mrs. A. Looman for valuable technical assistance in the GC-MS analysis of the sample. References Baxter, R.L., Laurie, W.A. and McHale, D. (1978) Transformations of monoterpenoids in aqueous acids. Tetrahedron 34, Bernard-Dagan, C., Carde, J.P. and Gleizes, M. (1979) Etude des composts terpeniques au cours de la croissance des aiguilles du Pin maritime: comparison de donn6es biochimiques et ultrastructurales, Can. J. Bot. 57, Chatzopoulou, P. (1992) Study of the Juniperus communis berries improvement of the treatments, of the winning and the analysis of the obtaining essential oil. Ph.D. Dissertation, School of Pharmacy, Aristotle University of Thessaloniki, Greece. Chatzopoulou, P. and Katsiotis, T.S. (1988) Influence of different processing on the plant material of fructus Juniperus communis on the yield and the quality of the obtained essential oil. 19th lnternational Symposium on Essential Oils and Other Natural Substrates, Greifensee, Switzerland, Abstracts L-9. Chatzopoulou, P. and Katsiotis, T.S. (1993) Study of the essential oil from Juniperus communis 'berries' (cones) growing wild in Greece. Planta Med. 59, Chatzopoulou, P., Katsiotis, T.S. and Georgakopoulos, P.P. (1988) Preliminary study of the composition of the Juniperus communis L. essential oil. Influence of dryness on the yield. Acta of 4th Panhelleriic Pharmaceutical Congress, Athens, pp Clark, B.C., Powell, C.C. and Radford, T. (1977) The acid catalyzed cyclization of citral. Tetrahedron 33, Croteau, R. and Loomis, W.D. (1972) Biosynthesis of monoterpenes and sesquiterpenes in pepermint from mevalonate-2.'" *. Phytochemistry 11, Katsiotis, T.S. (1989) Study of different parameters influencing the composition of hydrodistilled sweet fennel oil. Flav. Fragr. J. 4, Koedam, A. and Looman, A. (1980) Effect of ph during distillation on the composition of the volatile oil from Juniperus sabina. Planta Medica Suppl. pp Koedam, A,, Scheffer, J.J.C. and Baerheim Svendsen, A. (1979) Comparison of isolation procedures for essential oils. I. Dill. Chem. Mikrobiol. Techno]. Lebensm. 6, 1-7. Koedam, A,, Scheffer, J.J.C. and Baerheim Svendsen, A. (1979) Comparison of isolation procedures for essential oils. 11. Ajowan, caraway, coriander, cumin. 2. Lebensm. Unters. Forsch. 168, Koedam, A,, Scheffer, J.J.C. and Baerheim Svendsen, A. (1980) Monoterpenes in the volatile leaf of Abies X arnoldiana Nitz. J. Agric. Food Chem. 28, Koedam, A., Scheffer, J.J.C. and Baerheim Svendsen, A. (1981) Comparison of isolation procedures for essential oils. IV. Leyland cypress. Perf. Flav. 5, Likens, S. and Nickerson, G. (1964) Detection of certain hop oil constituents in brewing products. Proc. Am. Brew. Chem Maarse, H. and Kepner, R.E. (1970) Changes in composition of volatile terpenes in Douglas Fir needles during maturation. J. Agr. Food Chem. 18, Mettal, U., Boland, W., Beyer, P. and Kleinig, H. (1988) Biosynthesis of monoterpene hydrocarbons by isolated chromoplasts from daffodil flowers. Eur. J. Biochem. 170, Morin, P., Gunther, C., Peyron, L. and Richard, H. (1985) Etude des phtnomhes physico-chimiques intervenant lors du procedt d'hydrodistillation. Bul. Soc. Chim. Fr. 5, Taskinen, J. (1976) The acid catalyzed reaction of some monoterpene alcohols in aqueous ethanol. Int. Flavours Food Addit. 7, Von Rechenberg, C. (1910) Theorie der Gewinnung und Trennung der Aetherischen Oele durch Destillation. Selbstverlag von Schimmel and Co., Miltitz bei Leipzig, 423 pp.