Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Compositions comprising a mixture of bioflavonols
This is a divisional application of Canadian Patent Application
No. 2,348,395 filed on October 16, 1999. It should be understood that
the expression "present invention" or the like encompasses the subject
matters of both this and the parent applications.
The present invention relates to novel compositions containing a mixture
of two or three bioflavonols like isoquercetin, quercetin-4'-glycoside, ru-
tin and quercetin, which show differences in their pharmacokinetics.
These compositions are useful as food supplements possessing preven-
tive properties against damage to human tissues due to their antioxidant
properties. Furthermore, these compositions secure a continuum of the
presence of bioflavonols in human plasma.
Structures of body tissues are susceptible to damage caused by the oxi-
dative stress, e.g., by the accumulation of reactive oxygen species dur-
ing ageing, chronic environmental stress, inflammations or general
metabolic dysfunctions. The role of reactive oxygen species in aetiology
of human diseases (e.g. cancer, atherosclerosis, rheumatoid arthritis,
inflammatory bowel diseases, immune system dysfunctions, brain func-
tion decline, connective tissue dysfunctions) is well established. Chronic
exposure to reactive oxygen species leads to chronic intracellular dam-
age, to oxidative stress and premature ageing. Cells of the human body
possess metabolic antioxidant defences which are supported by dietary
antioxidants. The early observations of the antioxidant defence meta-
bolic processes involved flavonoids.
Quercetin, an aglycone, isoquercetin, a quercetin glycoside, and rutin, a
quercetin rutinoside, are flavonois that are being recently extensively
studied due to their antioxidant properties. Gycosylation of an aglycone
makes the molecule less reactive towards free radicals and more water-
soluble. Kind and the position of the glycosylation are the sources of the
pharmacokinetic differences among flavonols that have the same agly-
cone.
Common glycosylation positions are: the 7-hydroxyl in flavones, isofla-
vones and dihydroflavones; the 3- and 7-hydroxyl in flavonols and dihy-
droflavonols, and the 3- and 5-hydroxyl in anthocyanidins. The sugar
most usually involved in the glycoside formation is glucose, although
galactose, rhamnose, xylose and arabinose also occur, as well as sev-
eral disaccharides. For example, onions contain mostly isoquercetin,
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apples contain various quercetin glycosides, galactosides, arabinosides,
rhamnosides, xylosides and glucosides. Many plants contain the quer-
cetin disaccharide, rutin.
Flavonols are metabolized by animal cells, especially those of the liver.
No residuals of flavonols are accumulated in the body (see Havsteen B.
(1983), Flavonoids, a class of natural products of high pharrnacofogical
potency, Biochemical Pharmacology 32(7), 1141-1148).
Also absorption kinetics of flavonols is highly dependent on their chemi-
cal structure. The bioavailabilities of isoquercetin, rutin and quercetin
differ. The bioavaifability of rutin is only 30 % of the bioavaiiability of
iso-
quercetin. Hollman (see Holiman, P.C.H., et al. (1997) Bioavailability of
the dietary antioxidant flavonol quercetin in man, Cancer Lett. 114: 139-
140) explains the superior absorption of isoquercetin by the fact that
isoquercetin is actively absorbed using sodium-glucose absorption
mechanism. Quercetin is absorbed as an aglycone and is present in the
human plasma in its free form (see Noteborn, H.P.J.M. et al. (1997) Oral
absorption and metabolism of quercetin and sugar-conjugated deriva-
tives in specific transport systems, Cancer Lett. 114:175-177; Conquer,
J.A., et al. (1998) Supplementation with Quercetin Markedly increases
Plasma Quercetin Concentration without Effect on Selected Risk Factors
for Heart Disease in Healthy Subjects, J. Nutr. Mar 1; 128(3): 593-597)
and in the giycosylated forms when absorbed as a glycoside. It has been
shown that quercetin is preferentially absorbed as its monoglucosides
(see Papanga, G. Rice-Evans, C.A. (1997) The identification of flavo-
noids as giycosides in human plasma, FEBS Lett. 401(1): 78-82; and
Hollman, P.C.H. et al. (1997) Relative bioavailability of the antioxidant
flavonoid quercetin from various foods in man, FEBS Lett., Nov. 24;
418(1-2): 152-156).
As expected all of these compounds, quercetin, isoquercetin, quercetin-
4'-glycoside and rutin differ in their pharmacokinetics.
For orally administered isoquercetin the time to reach peak is about 0.70
h (see Holiman, P.C.H., (1997) Determinants of the absorption of the
dietary flavonoid quercetin in man; Proefschrift). For the free quercetin
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the time to peak could be evaluated at about 3 h(seL Da Silva, E.L., et
al. (1998) Inhibition of mammafian 15-iipoxygenase-dependent lipid per-
oxidation in low-density lipoprotein by quercetin and quercetim mnoglu-
cosides, Archives of Biochemistry and Biophysics 349, (2) Jan. 15,
~ 313-320). For rutin the time was about 7 to 9 h (see Holiman, P.C.H., (1997)
Determinants of the absorption of the dietary flavonoid quercetin in man;
Proefschrift).
After having reached the peak (after different periods of time), the con-
centration of the flavonols quickly decreases by metabolization.
Therefore, it is not possible so far to obtain a continuum presence of
bioflavonols in the human plasma for an extended time span.
However, it would be desirable to have orally applicable formulation of
these specific antioxidants leading to an increased and continued pres-
ent concentration of bioflavonols having the same aglycone in the hu-
man plasma over a prolonged period of time.
Accordingly, there was a need for a composition useful for the en-
hancement of antioxidant activity in human plasma during an extended
time span in order to prevent damage to human tissues.
Now it has been found that the mixture of two or three flavonols, when
administered jointly to humans, will secure the very similar concentra-
?5 tions of flavonols in plasma assuring similar pharmacological and nu-
traceutical activity for an extended time period.
One aspect of the present invention is therefore an orally applicable compo-
sition comprising a niixture of the biotlavonois isoquercetin (quercetin-3-
0 glucoside) or quercetin-4'-glucoside and rutin, optionally together with
quercetin.
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According to another aspect of the present
invention, there is provided a composition suitable for oral
administration comprising isoquercetin and rutin, wherein
the isoquercetin to rutin molar ratio is about 1:4.
According to still another aspect of the present
invention, there is provided a commercial package comprising
a composition of the invention, together with a written
matter describing instructions for the use thereof in the
treatment of a disease or condition described herein.
It has been found that a mixture of isoquercetin
or quercetin-4'-glucoside, quercetin and rutin in the molar
ratio of 1:1.5:3 or similar ratios will secure
pharmacological and nutraceutical activity for an extended
period of time up to 48 hours.
The composition of these antioxidants according to
the present invention is highly suitable for treatments like
cardiovascular disease or the prevention of neoplastic
growth.
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Besides, the antiviral properties of quercetin are also effective in these
compositions.
In a preferred embodiment of the present invention the composition
comprises isoquercetin and rutin in a molar ration of about 1 : 4. When
administered to humans, this composition will secure up to 24 hours a
continued high concentration of flavonols in plasma assuring similar
pharmacological activity during the 24-hour time period.
It has been found that these combinations are most effective in preven-
tion of and in defence against stress dysfunctions, especially against
oxidative damage of living tissues. Furthermore, the combinations ac-
cording to this invention will secure pharmacological and nutraceutical
effectiveness for an extended period time for specially designed treat-
ments with these specific antioxidants, e.g. treatment of cardiovascular
disease, or the prevention of neoplastic growth. The effect of the conti-
nuity of their concentrations is obtained by the summation of their spe-
cific concentration kinetics in the human body.
The daily dose of the mixture of the flavonols that have the same agly-
cone is about 100 mg of quercetin glycoside and 400 mg of rutin. It is
possible that the dose may be increased to an expected maximum of
about 400 mg of quercetin glycoside and 1600 mg of rutin, maintaining
the proportion of flavonols of 1:4 as discussed above. For the mixture of
isoquercetin or quercetin-4'-glucoside, quercetin and rutin in the molar
ratio of 1: 1,5 : 3 a similar daily dose is suggested like about 100 mg
quercetin glycoside, 150 mg of quercetin and 300 mg of rutin up to a
maximum dose of about 400 mg of quercetin glycoside, 600 mg of quer-
cetin and 1200 mg of rutin, always maintaining the proportion.
)0 The compositions according to the present invention may be used in
form of tablets, capsules or syrups with usable excipients.
The compositions of the present invention preferably are useful as food
>> supplements, but they may also be administered in a pharmaceutical
treatment.
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The present invention makes available:
- a method of maintaining a continued presence of high con-
centrations of bioflavonols in human plasma for an extended
period of time,
- a method of protection against oxidative damage to human
organs, tissues and ceils,
- a method of supporting a pharmacological treatment of a dis-
ease or dysfunction caused by oxidative damage,
- a method of prevention of cardiovascular diseases, and other
damage to vascular tissues, of bacterial and viral infections,
of metabolic dysfunctions involving oxidative damages or of
neopiastic growth,
by oral administration of a composition described above.
The decision which further ingredients should be components of a com-
position useful in one of the above-mentioned methods depends on the
special indication. Usually, if the composition is administered as a way of
protection or prevention, useful further ingredients may be vitamins,
salts of Mg, Ca, K, Fe and trace elements in known amounts as used in
food supplements. Compositions useful in a method of supporting phar-
macological treatments may differ from them.
Therefore, a highly efficient dietary antioxidant composition is prepared
using among other ingredients the mixtures of isoquercetin or quercetin-
4'-glycoside and rutin, optionally together with quercetin. The advanta-
geous properties of these compositions are induced by the effect of
building a kind of bioflavanoid complex with delayed release of the bio-
flavonols.
A subject of this invention is that in humans the oral administration of a
mixture of isoquercetin or quercetin-4'-glycoside and rutin, optionally to-
gether with quercetin, with a suitable molar ratio described above, con-
veys veys sufficient protection against oxidative damages, due to a continued
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presence of bioflavonols assuring similar pharmacological and nutraceu-
tical activity during a prolonged period of time.
From the foregoing description, one skilled in the art can easily ascertain
the essential characteristics of this invention and, without departing from
the spirit and scope thereof, can make various changes and modifica-
tions of the invention to adapt it to various applications and conditions.
Example 1
A composition according to this invention is prepared by mixing 400 mg
rutin with 100 mg isoquercetin. The results of this formula are shown in
diagram 1 .
