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Ultrasonics Sonochemistry 8 (2001) 299±301 www.elseviernl/locate/ultsonch The extraction of rutin from ¯ower buds of Sophora japonica L. Paniwnyk *, E. Beaufoy, JP Lorimer, TJ Mason School of Natural and Environmental Sciences, Coventry University, Coventry CV1 5FB, UK Abstract The eciency of extraction of rutin from Sophora japonica is improved by ultrasound but is dependent on the solvent employed. Rutin is a compound with antioxidant activity and aqueous solvents appear to be unsuitable for ultrasonic extractions due to the formation of free radicals from the insonation of the solvent. The application of ultrasound to methanolic extraction gave a signi®cant reduction in extraction time and an increase in maximum yield Ó 2001 Elsevier Science BV All rights reserved Keywords: Rutin; Extraction; Ultrasound; Antioxidant 1. Introduction Renewed interest in plant derived drugs has led to an increased need for ecient extraction methods. The aim of this study was to compare
conventional and ultrasonic methods for the extraction of the ¯avonoid, rutin (Fig. 1) from the dried ¯ower buds of the Chinese Scholar Tree (Sophora japonica) [5]. Flavonoids are products of secondary metabolism in plants and are of interest to the pharmaceutical and food industries because of their reported antioxidant activity [1]. Such compounds can interact with free radicals and so prevent the damage which radicals might otherwise cause to cell membranes and biological molecules such as DNA. Ultrasound has been shown to aid extraction in a number of plant materials by signi®cantly reducing extraction times and increasing maximum extraction yields. An example is the extraction of helicid, a Chinese medicine used in the treatment of fatigue and listlessness, from the dried seeds of Helicid erraticum using aqueous ethanol [2]. Conventional extraction is usually performed at re¯ux temperature of 80°C for 2 h. Ultrasonic at 40°C resulted in a yield increase of 50% in the shorter
time of 1 h. Studies on the eect of ultrasound on the extraction of the main components of sage (Salvia ocinalis) showed that cineole, thujone and borneol could be extracted better when sonicated [3]. Many other examples have been reviewed recently [4]. * Corresponding author. E-mail address: l.paniwnyk@coventryacuk (L Paniwnyk) This observed enhancement of extraction of organic compounds by ultrasound is attributed to the phenomenon of cavitation produced in the solvent by the passage of an ultrasonic wave. During the rarefaction cycle of the sound wave cavitation bubbles are produced which ®ll with solvent vapour. During the compression cycle the bubbles and the gas within them are also compressed resulting in a signi®cant increase in temperature and pressure. This ®nally results in the collapse of the bubble with a resultant Ôshock waveÕ passing through the solvent and enhanced mixing occurring. Ultrasound also exerts a mechanical eect, allowing greater penetration of
solvent into the plant body. This, coupled with enhanced mass transfer and signi®cant disruption of cells, via cavitation bubble collapse, has the eect of releasing cell contents into the bulk medium. Ultrasound may also produce some chemical eects due to the production of free radicals within the cavitation bubbles. Sonication of water results in the formation of highly reactive hydroxyl radicals which can combine to form hydrogen peroxide which may or may not be bene®cial to the extraction process itself. 2. Results and discussion Conventional extraction methods using dilute aqueous alkali and methanol as solvents were compared with ultrasonic extractions in the same solvents. In aqueous extractions ultrasonic methods were found to give reduced yields when compared with conventional methods as shown in Fig. 2 1350-4177/01/$ - see front matter Ó 2001 Elsevier Science B.V All rights reserved PII: S 1 3 5 0 - 4 1 7 7 ( 0 0 ) 0 0 0 7 5 - 4 300 L. Paniwnyk et al /
Ultrasonics Sonochemistry 8 (2001) 299±301 Fig. 1 Structure of rutin Fig. 3 Eect of ultrasound on the extraction of rutin from Sophora japonica using methanol. during sonication of methanol the extracted rutin is not degraded. 3. Experimental methods The conventional and ultrasonic methods employed are summarised as follows: 3.1 Aqueous extractions Fig. 2 Eect of ultrasound on the extraction of rutin from Sophora japonica using water. The observed reduction in extraction yield is believed to be the result of degradation of the rutin by interaction with highly reactive hydroxyl radicals formed during sonication of the aqueous solvent. The extractions were therefore carried out in methanol, a solvent which does not give rise to such a large proportion of radicals under cavitation. Experiments were performed at room temperature without allowing the temperature to rise since (a) cavitational eects are reduced as temperature is increased and (b) although the solubility of rutin
in methanol is much higher than in water over the whole temperature range the dierence is particularly signi®cant at lower temperatures. Conventional methanolic extractions gave much higher yields than aqueous extractions and the yields were further enhanced by the use of ultrasonic extraction methods as shown in Fig. 3 The higher yields obtained from conventional methanolic extractions are attributed to the much greater solubility of rutin in methanol than in water and its apparent stability to air oxidation in this solvent. The further increase in yield when ultrasound is applied is believed to be due to the disruption of cell walls by cavitational eects. Since hydrogen peroxide is not formed Ten grams of dried ¯ower buds were crushed using a pestle and mortar and mixed with water (100 cm3 ). The pH was adjusted to 6±8 using 1 M NaOH and the mixture was either boiled (for conventional extraction) or subjected to ultrasound (for ultrasonic extraction) using a 20 kHz ultrasonic
probe (Sonics and MaterialsVC600 with 0.5 in tip) at 23°C for varying lengths of time. The mixture was ®ltered and the ®ltrate was acidi®ed (pH 5±6) using 1 M HCl to precipitate the rutin and left to stand overnight. The precipitate was collected by vacuum ®ltration and dissolved in water and further puri®ed as follows. The pH was adjusted to 6±8 and the solution was boiled for 30 min. It was ®ltered under vacuum and the ®ltrate was acidi®ed and left to stand overnight. The resulting precipitate was collected by vacuum ®ltration and dried in an oven at 70°C. 3.2 Alcoholic extractions Ten grams of dried ¯ower buds were crushed using a pestle and mortar and mixed with methanol (100 cm3 ). The mixture was either re¯uxed (for conventional extraction) or subjected to ultrasound (for ultrasonic extraction) using a 20 kHz ultrasonic probe at 23°C for varying lengths of time. The mixture was ®ltered and the solvent removed using a rotary evaporator. The residue, L.
Paniwnyk et al / Ultrasonics Sonochemistry 8 (2001) 299±301 containing rutin alcoholate, was dissolved in water to convert it into the hydrated form which precipitated from solution. The mixture was extracted with diethyl ether to remove chlorophyll and the precipitate in the aqueous phase was collected by vacuum ®ltration and dried in an oven at 70°C. 301 Acknowledgements The authors thank the EC for ®nancial support (COPERNICUS research program ERB-CIPA-CT940227-1995). References 4. Conclusions In any extraction process consideration must be given to the solubility of the compound being extracted in the chosen solvent at the extraction temperature employed. In the cases of compounds with antioxidant activity, such as rutin, aqueous solvents appear to be unsuitable for ultrasonic extractions and care must be taken when employing aqueous solvents in order to avoid degradation of the sample. The application of ultrasound to the methanolic extraction of rutin from Sophora
japonica gave a signi®cant increase in maximum extraction yield. [1] J.Q Griths, CF Krewson, J Naghski, Rutin and Related Flavonoids; Chemistry, Pharmacology and Clinical Applications, Mack Publishing., Easton, Pennsylvania, 1955 [2] Y. Zhao, C Bao, TJ Mason, A study of the isolation of eective compositions from traditional Chinese medicinal plants, Ultrasonics International 91 Proceedings, Butterworths, 1991, pp. 87±90 [3] M. Salisova, S Toma, TJ Mason, Comparison of conventional and ultrasonically assisted extractions of pharmaceutically active compounds from Salvia ocinalis, Ultrason. Sonochem 4 (1997) 131±134. [4] M. Vinatoru, M Toma, TJ Mason, Ultrasonically assisted extraction of bioactive principles from plants and their constituents, In: T.J Mason (Ed), Advances in Sonochemistry, vol 5, JAI Press, ISBN 0-7623-0331-X, 1999, pp. 209±248 [5] E. Beaufoy, The extraction of rutin from Sophora japonica Using Ultrasound, M.Sc Thesis, Coventry University, 1998
conventional and ultrasonic methods for the extraction of the ¯avonoid, rutin (Fig. 1) from the dried ¯ower buds of the Chinese Scholar Tree (Sophora japonica) [5]. Flavonoids are products of secondary metabolism in plants and are of interest to the pharmaceutical and food industries because of their reported antioxidant activity [1]. Such compounds can interact with free radicals and so prevent the damage which radicals might otherwise cause to cell membranes and biological molecules such as DNA. Ultrasound has been shown to aid extraction in a number of plant materials by signi®cantly reducing extraction times and increasing maximum extraction yields. An example is the extraction of helicid, a Chinese medicine used in the treatment of fatigue and listlessness, from the dried seeds of Helicid erraticum using aqueous ethanol [2]. Conventional extraction is usually performed at re¯ux temperature of 80°C for 2 h. Ultrasonic at 40°C resulted in a yield increase of 50% in the shorter
time of 1 h. Studies on the eect of ultrasound on the extraction of the main components of sage (Salvia ocinalis) showed that cineole, thujone and borneol could be extracted better when sonicated [3]. Many other examples have been reviewed recently [4]. * Corresponding author. E-mail address: l.paniwnyk@coventryacuk (L Paniwnyk) This observed enhancement of extraction of organic compounds by ultrasound is attributed to the phenomenon of cavitation produced in the solvent by the passage of an ultrasonic wave. During the rarefaction cycle of the sound wave cavitation bubbles are produced which ®ll with solvent vapour. During the compression cycle the bubbles and the gas within them are also compressed resulting in a signi®cant increase in temperature and pressure. This ®nally results in the collapse of the bubble with a resultant Ôshock waveÕ passing through the solvent and enhanced mixing occurring. Ultrasound also exerts a mechanical eect, allowing greater penetration of
solvent into the plant body. This, coupled with enhanced mass transfer and signi®cant disruption of cells, via cavitation bubble collapse, has the eect of releasing cell contents into the bulk medium. Ultrasound may also produce some chemical eects due to the production of free radicals within the cavitation bubbles. Sonication of water results in the formation of highly reactive hydroxyl radicals which can combine to form hydrogen peroxide which may or may not be bene®cial to the extraction process itself. 2. Results and discussion Conventional extraction methods using dilute aqueous alkali and methanol as solvents were compared with ultrasonic extractions in the same solvents. In aqueous extractions ultrasonic methods were found to give reduced yields when compared with conventional methods as shown in Fig. 2 1350-4177/01/$ - see front matter Ó 2001 Elsevier Science B.V All rights reserved PII: S 1 3 5 0 - 4 1 7 7 ( 0 0 ) 0 0 0 7 5 - 4 300 L. Paniwnyk et al /
Ultrasonics Sonochemistry 8 (2001) 299±301 Fig. 1 Structure of rutin Fig. 3 Eect of ultrasound on the extraction of rutin from Sophora japonica using methanol. during sonication of methanol the extracted rutin is not degraded. 3. Experimental methods The conventional and ultrasonic methods employed are summarised as follows: 3.1 Aqueous extractions Fig. 2 Eect of ultrasound on the extraction of rutin from Sophora japonica using water. The observed reduction in extraction yield is believed to be the result of degradation of the rutin by interaction with highly reactive hydroxyl radicals formed during sonication of the aqueous solvent. The extractions were therefore carried out in methanol, a solvent which does not give rise to such a large proportion of radicals under cavitation. Experiments were performed at room temperature without allowing the temperature to rise since (a) cavitational eects are reduced as temperature is increased and (b) although the solubility of rutin
in methanol is much higher than in water over the whole temperature range the dierence is particularly signi®cant at lower temperatures. Conventional methanolic extractions gave much higher yields than aqueous extractions and the yields were further enhanced by the use of ultrasonic extraction methods as shown in Fig. 3 The higher yields obtained from conventional methanolic extractions are attributed to the much greater solubility of rutin in methanol than in water and its apparent stability to air oxidation in this solvent. The further increase in yield when ultrasound is applied is believed to be due to the disruption of cell walls by cavitational eects. Since hydrogen peroxide is not formed Ten grams of dried ¯ower buds were crushed using a pestle and mortar and mixed with water (100 cm3 ). The pH was adjusted to 6±8 using 1 M NaOH and the mixture was either boiled (for conventional extraction) or subjected to ultrasound (for ultrasonic extraction) using a 20 kHz ultrasonic
probe (Sonics and MaterialsVC600 with 0.5 in tip) at 23°C for varying lengths of time. The mixture was ®ltered and the ®ltrate was acidi®ed (pH 5±6) using 1 M HCl to precipitate the rutin and left to stand overnight. The precipitate was collected by vacuum ®ltration and dissolved in water and further puri®ed as follows. The pH was adjusted to 6±8 and the solution was boiled for 30 min. It was ®ltered under vacuum and the ®ltrate was acidi®ed and left to stand overnight. The resulting precipitate was collected by vacuum ®ltration and dried in an oven at 70°C. 3.2 Alcoholic extractions Ten grams of dried ¯ower buds were crushed using a pestle and mortar and mixed with methanol (100 cm3 ). The mixture was either re¯uxed (for conventional extraction) or subjected to ultrasound (for ultrasonic extraction) using a 20 kHz ultrasonic probe at 23°C for varying lengths of time. The mixture was ®ltered and the solvent removed using a rotary evaporator. The residue, L.
Paniwnyk et al / Ultrasonics Sonochemistry 8 (2001) 299±301 containing rutin alcoholate, was dissolved in water to convert it into the hydrated form which precipitated from solution. The mixture was extracted with diethyl ether to remove chlorophyll and the precipitate in the aqueous phase was collected by vacuum ®ltration and dried in an oven at 70°C. 301 Acknowledgements The authors thank the EC for ®nancial support (COPERNICUS research program ERB-CIPA-CT940227-1995). References 4. Conclusions In any extraction process consideration must be given to the solubility of the compound being extracted in the chosen solvent at the extraction temperature employed. In the cases of compounds with antioxidant activity, such as rutin, aqueous solvents appear to be unsuitable for ultrasonic extractions and care must be taken when employing aqueous solvents in order to avoid degradation of the sample. The application of ultrasound to the methanolic extraction of rutin from Sophora
japonica gave a signi®cant increase in maximum extraction yield. [1] J.Q Griths, CF Krewson, J Naghski, Rutin and Related Flavonoids; Chemistry, Pharmacology and Clinical Applications, Mack Publishing., Easton, Pennsylvania, 1955 [2] Y. Zhao, C Bao, TJ Mason, A study of the isolation of eective compositions from traditional Chinese medicinal plants, Ultrasonics International 91 Proceedings, Butterworths, 1991, pp. 87±90 [3] M. Salisova, S Toma, TJ Mason, Comparison of conventional and ultrasonically assisted extractions of pharmaceutically active compounds from Salvia ocinalis, Ultrason. Sonochem 4 (1997) 131±134. [4] M. Vinatoru, M Toma, TJ Mason, Ultrasonically assisted extraction of bioactive principles from plants and their constituents, In: T.J Mason (Ed), Advances in Sonochemistry, vol 5, JAI Press, ISBN 0-7623-0331-X, 1999, pp. 209±248 [5] E. Beaufoy, The extraction of rutin from Sophora japonica Using Ultrasound, M.Sc Thesis, Coventry University, 1998
Jellemzően a vállalkozás beindítása előtt elkészített tanulmány, de készülhet már meglévő vállalkozás esetében is. Az üzleti tervezés egy olyan tervezési módszer, amely keretet a cég céljainak eléréséhez. Írásunk módszertani útmutatóként szolgál azoknak, akik érdeklődnek az üzleti tervezés iránt.
