Flavonoide esters and their use notably in cosmetics

Details Flavonoide esters and their use notably in cosmetics Flavonoide esters and their use notably in cosmetics

2001-04-10

2002-10-29

Page, Thurman K. (Department: 1615)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S059000, C514S456000, C514S844000, C514S886000, C514S887000, C514S969000, C549S283000, C549S285000

Reexamination Certificate

active

06471973

ABSTRACT:

The invention relates essentially to novel flavonoid esters, to their use in cosmetics, dermopharmacy, pharmacy, dietetics and agri-foodstuffs, and to cosmetic, dermopharmaceutical, pharmaceutical, dietetic and agri-foodstuff compositions in which said flavonoid esters are used.
Within the framework of the invention, it has been discovered, surprisingly and unexpectedly, that specific flavonoid esters can be stabilized while at the same time preserving their initial property, particularly of free radical inhibition and enzyme inhibition, and for applications associated with these properties:
venous tonics, agents for increasing the strength of the blood capillaries, inhibitors of blotchiness, inhibitors of chemical, physical or actinic erythema, agents for treating sensitive skin, decongestants, draining agents, slimming agents, anti-wrinkle agents, stimulators of the synthesis of the components of the extracellular matrix, toners for making the skin more elastic, and anti-ageing agents.
State of the art:
Flavonoids are pigments found almost universally in plants. They are responsible for the coloration of the flowers, the fruits and sometimes the leaves. This is the case of the yellow flavonoids (chalcones, aurones, certain flavonols) and red, blue or violet anthocyanosides. They can also contribute to coloration via their role as copigments: thus colorless flavones and flavonols copigment and protect anthocyanosides.
Flavonoids absorb in the UV and their universal presence in the foliar cuticle and the epidermal cells of leaves enables them to protect the plant tissues against the harmful effects of UV radiation.
The approximately 3000 flavonoids known have a common biosynthetic origin and hence possess the same basic structural element, namely the 2-phenylchroman linkage. They can be grouped in different classes according to the degree of oxidation of the central pyran ring: thus a distinction is drawn between anthocyans, 2-phenylchromones (flavones, flavonols and their dimers, flavanones and dihydroflavonols), 3-phenylchromans (isoflavones and isoflavanones, etc.), 2-phenylchromans (flavans, flavan-3-ols, flavan-3,4-diols), chalcones, dihydro-chalcones and aurones.
These flavonoids can be glycosylated, in which case they are called heterosides. The osidic moiety can be mono-, di- or tri-saccharidic. The monoosides are formed with D-glucose, but also with D-galactose or D-allose, with pentoses (D-apiose, L-arabinose, L-rhamnose, D-xylose) or with D-glucuronic and D-galacturonic acids. The structural variability increases for the heterosides whose osidic moiety is a disaccharide or trisaccharide, which can be linear or branched.
Two types of heterosides have been described, namely O-glycosides and C-glycosides. In the case of the O-glycosides, the bond between the genin and the ose can be formed via any one of the phenolic hydroxyls of the genin, but as a general rule it is particularly the hydroxyl in the 7-position of flavones and the hydroxyl in the 3-position of flavonols which are involved. In the case of the C-glycosides, the bond is formed between the anomeric carbon of the sugar and the carbon in the 6-position or 8-position of the genin.
The known biological properties of flavonoids
Being potentially active on the veins, flavonoids reduce the permeability of the blood capillaries and increase their strength. This “vitamin P” property is historically associated with the observation that certain manifestations of scurvy which are cured by the administration of lemon juice are not cured by the administration of vitamin C alone. It was therefore postulated that ascorbic acid could only act in association with a factor “P”, identified with flavonoids. Often anti-inflammatories (apigenol, chrysin, taxifolin, 8-glycosylhypolaetin, gossypin, etc.), flavonoids can be antiallergics, liver protectors (isobutrin, hispidulin, flavanolignans, etc.), antispasmodics (flavonoids from thyme, etc.), hypo-cholesterolemics, diuretics, antibacterials, antivirals and cytostatics.
They are active in the regeneration of ascorbic acid in vivo via glutathione. More generally, flavonoids are scavengers of free radicals formed under various circumstances:
anoxia, which blocks the electron flow upstream of the cytochrome oxidases and causes the production of the superoxide radical anion;
inflammation, which corresponds inter alia to the production of superoxide anions by the membrane NADPH oxidase of the leukocytes, but also to the production (by disproportionation in the presence of ferrous ions) of the hydroxyl radical and other reactive species normally involved in the phenomenon of phagocytosis;
lipidic auto-oxidation, which is generally initiated by a hydroxyl radical and produces lipophilic alkoxy radicals via hydroperoxides.
Numerous flavonoids react with free radicals, thereby preventing the degradations associated with their intense reactivity towards the membrane phospholipids.
Flavonoids: enzyme inhibitors
As a general rule, flavonoids are enzyme inhibitors in vitro:
inhibition of histidine decarboxylase;
inhibition of protein kinases;
inhibition of elastase;
inhibition of hyaluronidase, which would make it possible to preserve the integrity of the ground substance of the vascular sheaths;
non-specific inhibition of catechol O-methyltransferase, which would increase the amount of catecholamines available and would therefore cause an increase in the vascular strength;
inhibition of cAMP phosphodiesterase, which could explain, inter alia, their platelet aggregation inhibiting activity;
inhibition of aldose reductase;
several flavonoids, monomeric flavonols and biflavonoids are potent inhibitors of lipoxygenase and/or cyclooxygenase, which, for many authors—at least as far as the inhibition of cyclooxygenase is concerned—is directly related to their capacity to scavenge free radicals. These properties, demonstrated in vitro, could explain, in the majority of cases, the anti-inflammatory and antiallergic activities recognized by numerous authors in several drugs known to contain flavonoids.
However, a number of major problems do not allow flavonoids to be used in a large number of cosmetic, pharmaceutical, dietetic or agri-foodstuffs applications:
It is extremely difficult to dissolve flavonoids and heterosides; thus, for example, heterosides are preferentially water-soluble, but this solubility is very low (rutoside, hesperidoside, etc.). Genins are preferentially soluble in apolar organic solvents, but here again this solubility is generally very low. These solubility problems can sometimes be solved by using extremely sophisticated excipients, although these are not suitable for the widespread use of flavonoids.
These flavonoids may or may not be colored, but in all cases their antioxidizing character and their very high reactivity towards oxygen or light makes them particularly unstable, and preparations, solutions, gels or emulsions containing them undergo spectacular color changes with time (white emulsions which become brown with time).
The concentration of these molecules in plant extracts is generally low and the stated activities are not systematically found in plant extracts.
Various solutions have been proposed in attempts to stabilize flavonoids.
For example, the document WO95/21018 to CNRS describes the preparation of microcapsules having walls crosslinked with plant polyphenols in order to stabilize the polyphenols, the polyphenols stabilized by crosslinking preserving their initial activity.
Also, the document WO94/29404 describes compositions of polyphenol derivatives, consisting of flavan derivatives and especially flavan-3-ol, for the stabilization of said compositions. In practice, said document essentially proposes the use of flavanolic oligomers or procyanolidic oligomers, abbreviated to PCO, in the form of stabilized derivatives.
All these flavans or flavanols are unsubstituted in the 4-position of the flavonoid heterocycle.
Objects of the invention:
As already described in the above-cited documents of the prior art, i.e. WO95/21018 and WO94/29404, flavonoids are p

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