The present invention relates to the field of treating inflammatory diseases and/or disorders resulting from an excess of nitric oxide (NO); more particularly the object of the invention are o-quinone compounds as agents neutralizing nitric oxide and their therapeutic or cosmetic use.
Nitric oxide (NO) is one of the smallest molecules produced by biological systems. Its actions are also diverse in bodies as the cells capable of producing it. Indeed, its status of a relatively unstable free radical gives it its electronic structure (its half-life is 5 seconds) which allows it to act on a large number of molecules which are more or less sensitive to its action within cellular and extra-cellular metabolic processes.
In the 80s it was shown that nitric oxide specifically acted as an intermediate of vascular dynamics by controlling the relaxation of vessels. Among other cells, during inflammatory processes, this molecule is produced by endothelial cells (1,2) and macrophages (3,4) by enzymes, nitric oxide synthases (NOs), catalyzing the transformation of arginine into citrulline. These enzymes exist constitutively or are induced during immune reactions, these are referred to as iNOs. Vasodilation is induced via the stimulation of the guanylate cyclase of the smooth muscle (5). Nitric oxide is also formed by endothelial cells in response to a variety of substances like bradykinin (2), histamine and 5-hydroxytryptamine (6). Nitric oxide may also be formed by the macrophages activated by lipopolysaccharides or cytokines (6).
Nitric oxide also plays a role in immunity by its strong chemical reactivity which allows it to participate in the lysis of germs absorbed by the macrophages. In the presence of the super-oxide radical, nitric oxide is transformed into peroxynitrite, itself a particularly aggressive agent as an oxidant.
The induction of the synthesis of nitric oxide was shown during the inflammatory response initiated by microbial products during infections or during self-immune reactions. Nitric oxide is therefore an intermediary of physiology which has a positive face by regulating vasodilation and by participating in the immune function, and a negative face when it is emitted in a too large amount.
Present in an excess, it may produce an inflammation, a destruction of cells and of tissues and may also cause vasodilation inducing pain and fatal hypotension during septic or anaphylactic shocks.
It was notably shown that nitric oxide had an influence on the proliferation of keratinocytes (7) and on very strong levels of plasma nitric oxide were observed in subjects having psoriasis (8), suggesting the influence of this intermediary on this disease.
Atopy is a predisposition to the amplified reaction of the immune response. Under its dermatological form, atopic dermatitis affects about 15% of the children of developed countries. It was shown that a high production of nitric oxide is involved in the inflammation, the vasodilation and the oxidative damages to the cells and to the tissues of skins of subjects having atopic dermatitis (9).
Nitric oxide is also involved in the sun's erythema (10).
Also, at the joint level, nitric oxide is involved in inflammatory signs of arthritis. It was also shown in animal models that the administration of NOs inhibitors significantly reduces the inflammation of the cartilage (22).
As regards the systemic inflammatory response to which refers septic shock, it produces a generalized vasorelaxation due to the massive production of nitric oxide, which is expressed by hypotension which may lead to death in the absence of a suitable treatment applied as an emergency (11). This mechanism is also the one which develops during an anaphylactic shock (12).
Accordingly, if it may be sometimes desirable to provide nitric oxide to an organ which is lacking thereof like in the case for example in chronic hypertension associated with sequels of myocardial infarction or for preventing it, in many other cases, it would be necessary to neutralize this same nitric oxide in order to reduce its noxious effects, either in an ambulatory way, like in atopic dermatitis, eczema, psoriasis, coughing, or arthrosis, or in a massive emergency way for treating collapses associated with septic or anaphylactic shock.
The production of nitric oxide may be reduced by inhibiting the nitric oxide synthases (NOs), enzymes which release it from L-arginine, or else by neutralizing nitric oxide chemically or by capturing it with suitable complexing agents.
NOs inhibitors are known, among them derivatives of arginine, like methylated, nitrated or propylated derivatives of this amino acid (13), but their use in systemic therapeutics includes serious drawbacks (14). Indeed, the inhibition of NOs is difficulty controllable and for avoiding an overdosage which may lead to pulmonary hypertension, it is often necessary to administer gaseous nitric oxide via a respiratory route at the same time as the inhibitor of NOs, while monitoring the cardiovascular parameters of the patient. This drawback may be due to the lack of specificity of the inhibitors used towards the different isoforms of NOs, but for the moment, no specific inhibitor has proven its efficiency and its reliability in clinical trials.
NOs inhibitors have been proposed for treating esthetic disorders of the skin (15, 16) but their use is limited by the detrimental secondary effects, such as arterial hypertension, which they may cause and the fact that these inhibitors are all synthetic products while consumers today prefer turning themselves towards substances of natural origin.
There also exist molecules capable of neutralizing nitric oxide such as haemoglobin which is considered as the reference molecule in this field, and diverse synthetic molecules like carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) (17) and ruthenium derivatives (18). The use of all these molecules include drawbacks in particular for therapeutic and cosmetic applications; as an example, the derivatives of ruthenium are considered as potentially toxic and carcinogenic.
Apart from these three groups of molecules, a very large number of other components of plant origin have been proposed as possible agents for neutralization of nitric oxide, like flavanoids and more particularly polyphenols. But the evaluation of their neutralizing effect by the Griess method which measures the NO2− ion, do not allow evaluation of the actual effect of the tested molecule. Indeed, any antioxidant capable of reducing the concentration of oxygenated radicals in the medium is an inhibitor of the reaction which leads from NO to the ion NO2−, and therefore the Griess method provides a wrong indication of the actual effect of the molecule on its power of neutralizing nitric oxide, since it is impossible to distinguish between the antioxidant power and the neutralizing power towards nitric oxide.
With the purpose of having a real appreciation of the neutralizing effect of compound towards nitric oxide, the Inventors have developed a specific method in vitro which directly evaluates the concentration of nitric oxide in the medium and which measures the neutralization thereof in real time in the presence of the tested molecules; example I describes this method.
For this, the nitric oxide is prepared in a separated container by achieving reduction of sodium nitrite with ferrous sulfate and carry away with a nitrogen gas stream into another container containing the product to be tested in solution in a buffer. In this solution, is placed an amperometric probe which measures in real time the current produced by the presence of nitric oxide in solution.
Once provided with this specific method for evaluating the neutralization of nitric oxide, the Inventors were able to confirm the neutralizing effect of certain molecules known as such, like hemoglobin, but also to discover surprisingly that certain molecules, described as good neutralizers of nitric oxide were in reality not so, once passed to the screening of this specific method, notably flavanoids like quercetin, catechin and luteolin.
They also identified molecules which prove to be very good neutralizers of nitric oxide and which have never been described as such.
Thus, the present invention targets the identification of compounds neutralizing efficiently nitric oxide, which may easily be used in therapeutics or in cosmetics and do not have the drawbacks of those described earlier.
The invention relates to a compound of formula (I):
wherein R1 is selected from the group comprising:
with R2 which may represent:
With:
for its use for preventing and/or treating diseases and/or disorders resulting from an excess of NO.
By physiologically acceptable, is meant compatible with administration to a subject, preferably a mammal, through any administration route.
The excess of NO may be determined by measuring the level of nitrates in the blood serum (9). It is then considered that a human individual has an excess of NO when its concentration in nitrates in the blood serum is greater than or equal to 14 mmol/L, in particular 30 mmol/L or further 50 mmol/L.
According to an alternative of the invention, the compound of formula (I) is such that R1 is selected from among the group comprising:
with R2 which may represent:
With:
According to another alternative of the invention, the latter relates to a compound of formula (Ia) such as:
with R2 being able to represent:
According to further other alternatives of the invention, the latter relates to a compound of formula (I) such as:
According to a preferred alternative of the invention, the latter relates to the compounds mentioned below or to their physiologically acceptable salts for their use for preventing and/or treating diseases and/or disorders resulting from an excess of NO:
By linear, optionally substituted C1-C3 alkyl chain, is meant a hydrocarbon chain with 1 to 3 carbon atoms, saturated, linear, optionally substituted such as methyl, ethyl or propyl.
By hydroxyl function is meant the group —OH.
By carboxylic function is meant the group —COOH.
By benzene ring, is meant the aromatic functional group of raw formula C6H6:
By diphenol, is meant an aromatic compound consisting of a benzene ring and of two hydroxyl functions, of raw formula C6H6O2.
By caffeoyl radical, is meant the radical derived from caffeic acid, of formula: —O—CO—CH═CH-(3,4)diphenol.
By pyranose ring, is meant a saturated C6 ring, consisting of 5 carbon atoms and one oxygen atom.
As an example, reference may be made of glucose which has a pyranose ring substituted with a —CH2—OH and 4 OH hydroxyls.
By rhamnose, is meant the ose in its D or L conformation, in its α or β form, of formula:
The compounds of formula (I) may be synthesized chemically or else extracted from plants.
As an example, mention may be made of the orthoquinone of caffeic acid which may be obtained in crystallized form, by oxidation of the caffeic acid with o-chloranil, according to a method described in the prior art (20, 21).
Alternatively, the orthoquinone of caffeic acid may be extracted from plants such as Salvia officinalis, Mentha spicata, Cinnamomum verum, Thymus vulgaris.
One skilled in the art knows the methods for extracting chemical compounds from plants. From among these methods, mention may be made of the extraction by means of chemical solvents, with a supercritical fluid such as CO2, nanofiltration.
The quinone of verbascoside may be extracted from plants from the family of Lamiaceae (Phlomis, Scrophulariaceae, Verbascum phlomoides, Verbascum mallophorum) or from the family of Buddlejaceae (Buddleja globosa, Buddleja cordata) or from the family of Bignoniaceae (Pithecoctenium sp, Tynanthus panurensis) or from the family of Orobanchaceae (Cistanche sp, Orobanche rapumgenistae), from the family of Plantaginaceae (Plantago lanceolata, Verbenaceae, Verbena officinalis, Aloysia citrodora) from the family of Oleaceae (Olea europaea) from the family of Lentibulariaceae (Pinguicula lusitanica) and from the family of Byblidaceae (Byblis liniflora).
Further, the inventors have surprisingly shown and unlike what was assumed in the prior art (19), that an extract of a plant known for its anti-inflammatory effect, plantain (Plantago lanceolata) does not owe its anti-inflammatory effect to phenylhydantoic glycoside, verbascoside which it contains, but to the quinone derived from this polyphenol.
Thus, in another alternative of the invention, the latter relates to an extract of Plantago lanceolata selectively enriched with quinone of verbascoside; such an extract of Plantago lanceolata enriched with verbascoside quinone is preferably obtained from areal parts of the plant by alcoholic maceration; such an extract may be obtained according to the method described in example 5. This particular extract produces a significant effect of neutralization of NO.
The invention relates more particularly to the use of a compound or an extract of Plantago lanceolata according to the invention for preventing and/or treating diseases and/or inflammatory disorders.
In particular, the compounds or the extract of Plantago lanceolata according to the invention are useful for preventing and/or treating skin inflammatory diseases and/or disorders such as psoriasis, atopic dermatitis, contact dermatitis, skin irritation, contact hypersensitivity reaction, skin allergic expressions, excessive vasodilation, rosacea, sun erythema, acne.
The compounds of the extract of Plantago lanceolata according to the invention are further useful for preventing and/or treating joint inflammatory diseases and/or disorders such as arthritis, comprising rheumatoid arthritis, infectious arthritis and osteoarthritis, arthrosis, rheumatoid polyarthritis, ankylosing spondylitis, lupus erythematosus, chondritis.
The compounds or the extract of Plantago lanceolate according to the invention may be used for preventing or treating coughing, whether it is associated with a disease of the respiratory tracts such as bronchial obstruction of the newly born, bronchitis, influenza, whooping cough, tuberculosis, a bronchial cancer or associated with a particular state and/or environment as this is the case of the smoker coughing or caused by passive smoking, allergic coughing, coughing associated with asthma or further with gastro-esophageal reflux.
The compounds or the extract of Plantago lanceolate according to the invention may further be used for preventing or treating cardiovascular collapses associated with a hypovolemic shock, or a cardiogenic shock or to an anaphylactic shock or to a septic shock. Cardiovascular collapse corresponds to a collapse in the blood pressure; the systolic arterial pressure then becomes less than 80 mmHg.
The use of the compounds or of the extract of Plantago lanceolate according to the invention may also have a cosmetic purpose, in order to combat intrinsic or extrinsic ageing of the skin, more particularly for combating signs of cutaneous ageing, such as photo-ageing, wrinkles, fine lines, dried or cracked skins.
From among the other uses of these compounds or of the extract of Plantago lanceolate according to the invention is cosmetics, mention may be made of:
The present invention also relates to a pharmaceutical or cosmetic composition containing at least one compound of formula (I) or an extract of Plantago lanceolate according to the invention as well as a physiologically acceptable vehicle.
One skilled in the art will know how to adapt the formulation of the compositions according to the invention according to their physico-chemical properties and to their administration route.
The compositions according to the invention may be administered via any administration route which notably includes the topical route, in particular on the skin or on the hair, but also orally.
Preferably, when the compositions according to the invention are used for treating skin or joint inflammatory diseases and/or disorders, or else when they are used for a cosmetic purpose, they are administered via the topical route and may be selected from among a cream, a gel, an oil, a lotion, a milk.
When the compositions according to the invention are used for treating coughing, preferably they will be administered orally. The selected galenic form will be a syrup, a lozenge to be sucked, a gelatin capsule, a tablet.
Nitric oxide is prepared extemporaneously in a container A, obturated with a flexible polymeric plug through which pass an entering tubing and an exiting tubing, with an inner diameter comprised between 50 μm and 300 μm, but particularly of 100 μm (cf.
The container B in which is measured the nitric oxide is a container opaque to light, with a double jacket allowing circulation of water maintaining the temperature at 25° C., obturated with a plug through which pass the tubing stemming from the container A and an exhaust tubing (cf.
Once they are mixed, the solutions are stirred for the whole period of the measurement with a magnetic stirrer, in container A and in container B.
Nitrogen gas is admitted at a flow rate comprised between 20 ml/min and 120 ml/min, preferably 80 ml/min in the bottom of the container A. The nitrogen thereby carries away the nitric oxide through the exiting tubing of container A as far as into container B where it is measured with a device provided for this purpose equipped with an amperometric probe provided with a specific membrane (apparatus of ref. TBR 1025 from World Precision Instruments, probe ISO-NOP). The probe thereby delivers a variable current between 10 and 1,000 nA proportional to the concentration of nitric oxide in the tested solution, of the order of magnitude of μM. The electric current produced by the probe under the influence of nitric oxide is recorded with a suitable device.
Before any measurement, the probe is calibrated by measuring the current produced by releasing known increasing amounts of nitric oxide. It is thus checked that there exists a linear relationship between the electric current produced by the probe and the molar concentration of nitric oxide and the correspondence between this electric current and the molar concentration of nitric oxide is determined. For this, 20 ml of the following aqueous solution is placed in the container B disconnected from the container A during the calibration period:
50 μl, 100 μl, 150 μl and 200 μl of a solution of sodium nitrite (NaNO2, ref. Sigma-Aldrich 237213) are then successively added to a concentration of 360 μM.
The curve giving the correspondence between the nitric oxide concentration in the reaction medium and the electric intensity produced by the probe expressed in nA is plotted for each addition of the nitric oxide solution.
During a typical measurement, 20 ml of the ferrous sulfate solution are placed in the container A and 20 ml of phosphate buffer at pH 7.4 are placed in the container B. In the container A, nitrogen gas is admitted for 10 mins, which passes in transit towards the container B, in order to remove the dissolved oxygen present in the solutions of the containers A and B. After these 10 mins, the recording of the measurement of nitric oxide is launched.
At time T0, the sodium nitrite solution is injected into the container A through the flexible polymeric plug by means of a syringe equipped with a needle. The recording of the nitric oxide shows a positive evolution which will stabilize shortly after about 3 mins, before slowly decreasing in order to return to the baseline in about 20 mins. At time T1=T0+4 mins, 400 μl of a hydro-ethanol solution with an alcoholic titer comprised between 0% and 100% according to the solubility of the product to be tested, are injected, containing an amount P of product from 4 to 8 mg, according to the efficiency of the product to be tested, through the flexible plug of the container B by means of a syringe equipped with a needle.
A control is produced with 400 μl of solvent in which is dissolved the product to be tested.
The value E of the neutralization effect of nitric oxide by the product to be tested, expressed in μM of nitric oxide neutralized per second and per mg of product to be tested is obtained by the following expression:
With: ΔHtest=difference in concentration in nitric oxide test, expressed in pM of nitric acid between T1 and T2=T1+30 s, obtained with the solution of product to be tested. ΔHtem=difference in concentration of control nitric oxide, expressed in pM of nitric oxide between T1 and T2=T, +30 s, obtained with the solvent of the product to be tested.
P=amount of product to be tested in mg.
The test described in example 1 was applied for testing the following molecules:
Rosmarinic acid (Aldrich 536954)
p-coumaric acid (Sigma C9008)
(+) catechin hydrate (Sigma C1251)
Caffeic acid (Sigma-Aldrich C0625)
Chlorogenic acid (Sigma-Aldrich C3878)
Quercetin dihydrate (Sigma Q0125)
Porcine hemoglobin (Sigma H4131)
After having calibrated the probe for measurement of the concentration of nitric oxide of the apparatus described in example 1, in the container A, as described in example 1 and illustrated in
In the container B, as described above and in
Nitrogen gas is admitted into the apparatus at a flow rate of 80 ml/min for 10 mins, and then the recording of the value of the intensity of the electric current produced by the probe for detection of nitric oxide is launched and (at time T0) it is injected into the container A, a 0.5 ml of an aqueous solution of sodium nitrite (NaNO2, ref. Sigma-Aldrich 237213) at a concentration of 0.70%.
At time T1=T0+4 mins, 400 μl of a hydro-ethanol solution with an alcoholic titre comprised between 0% and 100% depending on the solubility of the product to be tested, containing an amount P of product to be tested expressed in mg, adjusted according to the efficiency of the tested product.
The values of the concentrations of nitric oxide are noted at time T0, T1=T0+4 mins and T2=T1+30 s. The values of E calculated according to formula (1) appears in the table 1 below.
The ortho-quinone of caffeic acid:
may be obtained crystallized, by oxidation of caffeic acid by the o-chloranil in solution in a mixture of ether and of tetrahydrofurane (4/1) at −70° C., according to a method described in the prior art (20, 21).
According to the method for measuring the neutralization effect of nitric oxide as described in example 1, the caffeoyl-quinone produces an effect E of 24.36 μM·s−1·mg−1.
A high value of E is therefore observed for this molecule comparatively with the effects produced by molecules already known as capable of neutralizing nitric oxide.
In order to determine the method for treating the plant and the extraction method leading to better neutralization efficiency of nitric oxide, it was proceeded with the extraction of a dry plant and of a fresh plant with hydro-alcoholic solutions with titers varying from 10 to 10 ranging from 0% to 100% of ethanol, either by maceration at room temperature for 48 h, in solvent volumes corresponding to 10 times the weight of the plant (v/w), or by extraction upon boiling at reflux for 30 mins with solvent volumes also corresponding to 10 times the weight of the plant (v/w). Subsequently to these preliminary tests, the following method was selected, since it produces the most active extract:
Aerial parts of Plantago lanceolate are harvested and rapidly frozen at −18° C. in order to ensure their preservation. 1 kg of this batch is coarsely milled and put to ripen in 10 liters of aqueous ethanol at 60% for 48 h. This alcoholic titer is defined by taking into account the water content of the plant, determined beforehand by drying on a representative sample. At the end of the maceration, the plant is removed by sifting, and then the extracted solution is filtered on a filter with 0.45 μM of porosity for removing the major portion of the germs present. The solution is then concentrated under reduced pressure so as to obtain a total volume of 1 l, totally without any ethanol.
This solution is then dried by freeze-drying in order to obtain a final weight of 43 g.
The efficiency E of neutralization of nitric oxide is 0.16 μM·s−1·mg−1.
Aerial parts of Plantago lanceolate are harvested and rapidly frozen to −18° C. in order to ensure their preservation. 1 kg of this batch is coarsely milled and set to ripen in 10 liters of aqueous ethanol at 60% for 48 h. This alcoholic titer is defined by taking into account the water content of the plant, determined beforehand by drying on a representative sample. At the end of the maceration, the plant is removed by sifting, and then the extracted solution is filtered on a filter with 0.45 μM of porosity for removing the major portion of the germs present. The solution is then concentrated under reduced pressure so as to obtain a total volume of 1 l, totally without any ethanol.
This concentrated solution is then extracted with a counter current with 5 times 200 ml of ethyl acetate. The organic solutions are collected, dried on anhydrous sodium sulfate, filtered and then dry evaporated under reduced pressure. 1.12 g of dry extract is thereby obtained which is taken up with 25 ml of pure ethanol.
This ethanol solution is subject to flash chromatography (apparatus Grace Reveleris X2) on a silica gel column of 40 g (Grace Reveleris Silica Cartridge 40 g) with a dichloromethane-methanol gradient like in table 2 below:
The fractions of 2 ml which are subject to the neutralization test of nitric oxide are collected. The most active fractions are retained which correspond to the elution volumes of 568 ml to 576 ml, which provide the whole 17.7 mg of dry material after evaporation of the solvent under reduced pressure, and which has a neutralization efficiency E of nitric oxide of 0.96 μM·s−1·mg−1.
The presence of the o-quinone of the verbascoside is then checked in high resolution mass spectrometry in tandem, with electrospray ionization in a negative mode, by the presence of a doubly charged ion at m/z 311, corresponding to the relevant quinone and having the characteristic fragmentation of phenylhydantoic heterosides, in this case related to that of the verbascoside.
A cream is prepared having the following weight formula, according to a method and with standard materials as known from the prior art:
For a gelatin capsule no. 0 (Capsugel):
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/FR2015/050064 | 1/12/2015 | WO | 00 |