Drug – bio-affecting and body treating compositions – Antigen – epitope – or other immunospecific immunoeffector – Conjugate or complex
Reexamination Certificate
1999-06-28
2001-05-01
Saucier, Sandra (Department: 1651)
Drug, bio-affecting and body treating compositions
Antigen, epitope, or other immunospecific immunoeffector
Conjugate or complex
Reexamination Certificate
active
06224874
ABSTRACT:
BACKGROUND OF THE INVENTION
Today, irone extracts are produced by solvent extraction or steam distillation of the rhizomes of any iris species, preferably
Iris pallida
or
Iris germanica
. After a cultivation period of 2-3 years the rhizomes are harvested and stored for 3-5 years at room temperature. During this maturation period the irones are released from their precursors (W. Krick, F. J. Marner, and L. Jaenicke, Z. Naturforsch. 1983, 38c 179-184). Then the irones are recovered by steam distillation (as iris butter) or solvent extraction (leading to a resinoid) of the powdered rhizomes leading to valuable iris materials for the flavour and fragrance industry.
This long period of maturation is cumbersome, expensive, needs extensive storage capacity and leads to the loss of part of the isomers in uncontrolled degradation reactions.
Several alternatives to this non-effective and time consuming maturation period have been proposed. In a first proposal (FR-2 620 702, 24/3/89) by Buono et al., a lipohilic extract of the iris rhizomes containing the irone precursors is oxidized with KMnO
4
in an organic solvent; in this procedure the extraction of the precursors is laborious and due to this unusual downstream processing (working-up), namely the extraction of the precursors before the oxidation, the quality of the resulting product is quite different from the traditionally preferred Iris Butter or Absolute. A reduction of the maturation period to two months has been disclosed in FR-2 653 637, 3/5/91, by Baccou et al., with a preliminary treatment of the fresh, i.e. not maturated iris rhizomes with ionizing radiation; but the claimed yields hardly reach the irone contents (<400 mg/kg dry rhizomes) obtained during maturation by a 2-3 years period of storage. Bioconversions of lipophilic extracts of the rhizomes with fungi of the genus Botryonia (EP 0 443 925; 23/8/91) by Gil et al. or with peroxidizing enzymes (EP 0 443 926; 28/8/91) by Gil et al., have been disclosed; they lead to a good conversion of the precursors but again present the disadvantage of the preliminary solvent extraction and consequently lead to a product whose quality differs from the preferred iris butter. The bioconversion of powdered iris rhizomes by bacteria of the family Enterobacteriacea in the presence of a plant cell medium (EP 0 353 683, U.S. Pat. No. 4,963,480) by Belcour et al., releases the irones from their precursors, and, after steam distillation produces an iris butter of excellent quality characterized by a high content of irones. A drawback is that the long maturation period has been replaced by a rather expensive microbiological treatment.
SUMMARY OF THE INVENTION
The present invention relates to a new process for the preparation of irones. In particular the invention relates to the treatment of iris rhizomes, parts of such rhizomes, iris extracts, plant tissues or any source of irone precursors, with nitrite salts in order to release, i.e. to form, to produce the irones.
Under irones there is to be understood a mixture of the isomers gamma-irone, cis-alpha-irone, trans-alpha-irone and beta-irone as usually found in extracts of iris species.
Under irone precursors there are to be understood compounds or any mixture of such compounds which, when treated with the nitrite, lead to irones. The use of selected clones of iris species characterized by a high content of irone precursors is preferred.
One embodiment of the invention is a process for the preparation of irones, which process includes treating iris rhizomes, parts of such rhizomes, iris extracts, iris extraction wastes, or any iris plant tissue containing precursors of irones and mixtures thereof, with an aqueous solution of a nitrite, and recovering the irones formed therefrom.
DETAILED DESCRIPTION OF THE INVENTION
Surprisingly it has now been found that the treatment, e.g. at mild temperatures, of rhizomes, e.g. powdered fresh iris rhizomes with an aqueous solution of a nitrite salt liberates, i.e. forms the irones, under mild conditions and with excellent yields. The isomeric and enantiomeric distribution of the resulting irones is identical to that obtained after a traditional maturation.
Various cations may be associated to the nitrite anion. Good results were obtained with alkali metal, alkaline earth or ammonium nitrites, e.g. with sodium nitrite, potassium nitrite, calcium nitrite, ammonium nitrite, etc. preferably sodium or potassium nitrite.
A suitable concentration of nitrite salts is from about 0.1 g/L to about 5 g/L, and, preferably from about 0.5 to about 1 g/L.
A suitable range of the ratio by weight of iris rhizome substrate to medium, i.e. the aqueous solution, is from about 1:20 to about 2:1, with about 1:5 to about 1:20 being preferred.
A suitable pH range for the treatment with aqueous nitrite solutions is from 1 to about 6, more preferably from about 2 to about 5. The preferred pH is between about 2 and about 3.
Any suitable acid, e.g. H
3
PO
4
, or other mineral acids may be used to adjust the desired pH value.
The treatment is effective at mild temperatures. Best results are obtained between ca. 10 and ca. 50° C. and preferably at ambient temperatures, e.g. between 20 and 30° C.
The time necessary to complete the generation of the irones is dependant upon the conditions of the treatment. A suitable reaction time for the process is from about 1 hour to about 5 days, with about 5 to about 36 hours being preferred.
Table 1 shows the results of a kinetic study of the production of irones by treatment of iris rhizomes with a solution of sodium nitrate at ambient temperature.
In the example, the treatment of freshly harvested rhizomes of
Iris pallida
with an initial irone content of 12 mg/kg dry rhizomes, in suspension at 100 g/L in a 0.1% solution of sodium nitrite at pH 2.5 and at a temperature of 25° C. liberates between 1200-1400 mg irones/kg dry rhizomes after 30 hours.
Rhizomes of the genera Iris (Iridacea family), parts of such rhizomes, iris wastes or extracts and more generally all plant tissues containing precursors of irones can be used. The substrate of the present invention is preferably obtained from an iris plant selected from the group consisting of
I. pallida, Lgermanica, I. florentina
, preferably
I. pallida.
The iris substrate, which is preferably taken from the plant in a vegetative, i.e. growing state, may be used fresh or shortly after harvest, e.g. in the form of:
iris rhizomes, e.g. crushed or powdered,
iris rhizome parts, iris rhizome extracts, e. g., extracts using any organic solvent dissolving the irone precursors, preferably alcoholic e.g. alkanolic, and preferably methanolic extracts,
iris wastes, i.e. the residues recovered after the industrial extraction of iris rhizomes,
plant cell cultures of iris, initiated as described, e.g. in EP 0 353 683
or mixtures thereof.
The extraction of the final product is conveniently carried out by conventional methods as used nowadays for the isolation of volatiles from plants, e.g. for the production of fragrances and flavours raw materials, i.e., hydrodistillation (steam distillation), extraction using any suitable volatile organic solvent, i.e alcohols, hexane, and mixtures thereof. By the preferred method, i. e. hydrodistillation, the resulting iris butter contains, e.g. 15-30% of irones depending on the quality of the rhizomes.
It has surprisingly been found that among a collection of different clones of Iris, e.g. of
Iris pallida
and
Iris germanica
, of various origins, an important variability was observed as far as the content of irone precursors is concerned (Jehan et al., C.R. Acad. Sci. Paris, Sciences de la vie/Life science, 1994; 317: 424-429). Thus applying the above described maturation process on 56 different plants (
I. pallida
), the irone content after treatment has been shown to be within the range of ca.1100-ca.1800 mg irones/kg dry rhizomes. Several clones have been found which exceed the irone content of an average population of commercial
I. pallida
rhizomes by a factor of over 50% to 65%. Thus the present invention rel
Courtois Didier
Ehret Charles
Firmin Laurence Marthe Marie
Cave LLP Bryan
Haracz Stephen M.
Saucier Sandra
Waddell Mark E.
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