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Food Chemistry, Vol. 61, No. 1/2, pp. 201±206, 1998 # 1998 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0308-8146/98 $19.00+0.00
Study of the extraction of proanthocyanidins from grape seeds
Ï Â B. Pekic,ab* V. Kovac,ac E. Alonsod & E. Revillad
a Faculty of Technology, 21000 Novi Sad, Serbia Department of Pharmaceutical Engineering, 21000Novi Sad, Serbia c Department of Biotechnology, 21000 Novi Sad, Serbia d Departmento de Quimica Agricola, Geologia y Geochimica, Universidad Autonoma de Madrid, 28049 Madrid, Spain b
(Received 21 March 1997; revised version received 27 May 1997; accepted 27 May 1997) The extraction of proanthocyanidins was studied in the system ethyl acetate± water±grape seeds. It was found that, in the absenceof water, proanthocyanidins could not be practically extracted, and the increase in water content in the system up to the saturation level resulted in a substantial yield enhancement. It was also shown that ethyl acetate, with 10% of water, is capable of selectively extracting proanthocyanidins, which has not been the case with solvents used previously. This solvent mixture extracts mainly theproanthocyanidins of lower molecular masses, which are more important from a therapeutic point of view. A further increase in water content in the extraction system yielded a small increase in the yield of proanthocyanidins, but caused a decrease in selectivity of the extraction. # 1998 Elsevier Science Ltd. All rights reserved
INTRODUCTION Because of their wide spectrum of pharmacological action,plant extracts containing proanthocyanidins attract the increasing attention of both pharmacists and physicians. An important event in this respect was the discovery that these substances exhibit marked freeradical scavenger capacities (Uchida et al., 1987; Zhao et al., 1989), and that they show good bioavailability (Laparra et al., 1977). Also, there are reports of their possible use inpreventing and treating atherosclerosis (Masquelier et al., 1981; Gavinet-Jeannin et al., 1988; Ï Kovac and Pekic, 1991) and some cancerous diseases (Okuda, 1993). Included under the term `proanthocyanidins' are the polymerization products of ¯avan-3-ols to oligomers. The ¯avan-3-ol monomers, (+)-catechin and (À)-epicatechin, as well as their dimers (Table 1) are found in grape and wine, along with thetrimer (C1) containing three molecules of (À)-epicatechin bound by inter¯avan C4ÐC8 bonds (Bourzeix et al., 1986). The determination of the above catechin monomers, dimers and trimer in grape and wine has recently been Ï the subject of several reports (Boukharta, 1988; Kovac Ï et al., 1990; Kovac et al., 1995), as they are apparently responsible for the favourable action that wine exhibits
*To whomcorrespondence should be addressed. 201
on the cardiovascular system, known as the `French paradox' (Masquelier, 1982; Renaud and De Lorgenil, 1992). Proanthocyanidins from plant material for analytical and preparative purposes have been extracted with methanol (Gupta and Haslam, 1981; Staord and Cheng, 1980), ethanol (Tsai Su and Singleton, 1969; Romeyer, 1984), acetone (Michaud et al.,1971; Nonaka et al., 1982) and their mixtures with water in dierent proportions. The results of the application of these solvents cannot be correlated because of the diversity of plant material and analytical methods employed. Nevertheless, it can be concluded that the use of an acetone±water mixture as the extractant gives a better eect in proanthocyanidin extraction than other extractants used forthis purpose (Dumon, 1990). However, the use of all these extractants generally yields a signi®cant co-extraction of the concomitant substances, which makes the procedure of extract puri®cation more dicult and decreases the yield of proanthocyanidins. As far as the authors are aware, there are no literature data on the use of selective solvents for extraction of proanthocyanidins. It is known...
Food Chemistry, Vol. 61, No. 1/2, pp. 201±206, 1998 # 1998 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0308-8146/98 $19.00+0.00
Study of the extraction of proanthocyanidins from grape seeds
Ï Â B. Pekic,ab* V. Kovac,ac E. Alonsod & E. Revillad
a Faculty of Technology, 21000 Novi Sad, Serbia Department of Pharmaceutical Engineering, 21000Novi Sad, Serbia c Department of Biotechnology, 21000 Novi Sad, Serbia d Departmento de Quimica Agricola, Geologia y Geochimica, Universidad Autonoma de Madrid, 28049 Madrid, Spain b
(Received 21 March 1997; revised version received 27 May 1997; accepted 27 May 1997) The extraction of proanthocyanidins was studied in the system ethyl acetate± water±grape seeds. It was found that, in the absenceof water, proanthocyanidins could not be practically extracted, and the increase in water content in the system up to the saturation level resulted in a substantial yield enhancement. It was also shown that ethyl acetate, with 10% of water, is capable of selectively extracting proanthocyanidins, which has not been the case with solvents used previously. This solvent mixture extracts mainly theproanthocyanidins of lower molecular masses, which are more important from a therapeutic point of view. A further increase in water content in the extraction system yielded a small increase in the yield of proanthocyanidins, but caused a decrease in selectivity of the extraction. # 1998 Elsevier Science Ltd. All rights reserved
INTRODUCTION Because of their wide spectrum of pharmacological action,plant extracts containing proanthocyanidins attract the increasing attention of both pharmacists and physicians. An important event in this respect was the discovery that these substances exhibit marked freeradical scavenger capacities (Uchida et al., 1987; Zhao et al., 1989), and that they show good bioavailability (Laparra et al., 1977). Also, there are reports of their possible use inpreventing and treating atherosclerosis (Masquelier et al., 1981; Gavinet-Jeannin et al., 1988; Ï Kovac and Pekic, 1991) and some cancerous diseases (Okuda, 1993). Included under the term `proanthocyanidins' are the polymerization products of ¯avan-3-ols to oligomers. The ¯avan-3-ol monomers, (+)-catechin and (À)-epicatechin, as well as their dimers (Table 1) are found in grape and wine, along with thetrimer (C1) containing three molecules of (À)-epicatechin bound by inter¯avan C4ÐC8 bonds (Bourzeix et al., 1986). The determination of the above catechin monomers, dimers and trimer in grape and wine has recently been Ï the subject of several reports (Boukharta, 1988; Kovac Ï et al., 1990; Kovac et al., 1995), as they are apparently responsible for the favourable action that wine exhibits
*To whomcorrespondence should be addressed. 201
on the cardiovascular system, known as the `French paradox' (Masquelier, 1982; Renaud and De Lorgenil, 1992). Proanthocyanidins from plant material for analytical and preparative purposes have been extracted with methanol (Gupta and Haslam, 1981; Staord and Cheng, 1980), ethanol (Tsai Su and Singleton, 1969; Romeyer, 1984), acetone (Michaud et al.,1971; Nonaka et al., 1982) and their mixtures with water in dierent proportions. The results of the application of these solvents cannot be correlated because of the diversity of plant material and analytical methods employed. Nevertheless, it can be concluded that the use of an acetone±water mixture as the extractant gives a better eect in proanthocyanidin extraction than other extractants used forthis purpose (Dumon, 1990). However, the use of all these extractants generally yields a signi®cant co-extraction of the concomitant substances, which makes the procedure of extract puri®cation more dicult and decreases the yield of proanthocyanidins. As far as the authors are aware, there are no literature data on the use of selective solvents for extraction of proanthocyanidins. It is known...
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