AND USES THEREOF

TECHNICAL FIELD

The present invention relates to the field of dyes and pigments. More particularly, the invention relates to actinorhodin metals salts and processes of preparation thereof. It also relates to the use of such actinorhodin metals salts as colouring agents and/or pigments, and colouring compositions comprising the same

BACKGROUND OF THE INVENTION

Colouring substances are an integral part of our daily lives. Among other things, they are widely used for colouring textiles, decorative objects and home furnishings, inks and paper products, as well as food, cosmetic and pharmaceutical products. Because they are inexpensive to produce, the great majority of the colorants used to date are synthetic in nature. Increased awareness of environmental problems and of public health safety has led to an evaluation of the environmental toxicity and impact of these colorants. It thus emerged that many were significantly toxic and/or were sources of environmental pollution.

These disadvantages led to a growing interest in colorants of natural origin, especially from plants or microorganisms. At present, some of these pigments are commonly used in the food industry, for example riboflavin from Ashbya gossypi (yellow), Arpink Red™ from Penicillium oxalicum (red), ankaflavin (yellow), monascorubramine (red) and mbropunctatin (orange) derived from Monascus-type filamentous fungi, or b-carotene from Blakeslea trispora (orange-yellow), or in the textile industry, for example prodigiosin, a red pigment notably produced by many strains of Serratia marcescens, or violacein (violet), derived from strains of Chromobacterium, Janthinobacter or Iodobacter. Though many microorganisms are known to produce yellow, orange, red or violet pigments, the production of natural compounds that can provide blue colouring is rarer and, at present, the demand for such compounds of potential use in numerous fields remains strong and unsatisfied.

In this context, the use of actinorhodin and the derivatives thereof as a blue colouring agent has been already reported. More specifically, WO 2018/138089 discloses efficient properties of actinorhodin in numerous fields such as textile and cosmetic industries. However, actinorhodin exhibits specific physico-chemical properties that makes difficult and restrictive its use as a blue colouring or pigment agent. It has been observed that actinorhodin is stable only at basic pH and its instability at other pH (acid and neutral) is characterized by a loss of the blue color. More particularly, it has been observed that actinorhodin turned red below pH 8 and its strong blue colour was only available at highly alkaline pH (greater than 10).

Therefore, it remains a need to provide novel forms of actinorhodin having and keeping a blue colour suitable for use in colouring applications. More particularly, there is a need to find suitable insoluble forms of actinorhodin to stabilize the blue colour of actinorhodin.

SUMMARY OF THE INVENTION

In this context, the inventors have provided stable metal salts of actinorhodin having a blue color at different pH. More specifically, the inventors have demonstrated that the calcium salt of actinorhodin is stable at acidic, neutral, and basic pH and has a blue color similar to the blue colour of the micronized indigo and Brilliant Blue FCF (E133) used as reference in the dyes market.

The invention as defined herein thus concerns a metal salt of actinorhodin or one of its derivatives, their process of preparation, and their uses as a colouring agent or a pigment.

An object of the invention relates to a metal salt of actinorhodin or one of its derivatives, wherein the metal is selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, Zn, and mixtures thereof.

In a preferred embodiment, the metal is Ca. In a particular embodiment, the derivative of actinorhodin is g-actinorhodin, e-actinorhodin, and/or actinorhodinic acid.

Another object of the invention relates to a composition comprising such a metal salt of actinorhodin or one of its derivatives as defined herein, and a buffer. In a preferred embodiment, the buffer is aluminum potassium tartrate.

A further object of the invention is a process for preparing a metal salt of or one of its derivatives comprising the following steps of: (a) contacting actinorhodin or one of its derivatives with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than 11;

(b) heating the reaction mixture obtained at step (a) at a temperature comprised between 80 °C and 120 °C; and

(c) recovering the metal salt of actinorhodin or one of its derivatives.

In a preferred embodiment, said at least one basic metal salt is a metal hydroxide, preferably calcium hydroxide.

In a particular embodiment, the process of the invention further comprises, between the step b) and the step c), a step (b’) of contacting the reaction mixture with a buffer. In a preferred embodiment, the buffer is aluminum potassium tartrate.

In a further particular embodiment, the process of the invention further comprises a purification step of the metal salt of actinorhodin or one of its derivatives. Preferably, the purification step comprises at least one cycle including the steps of washing, filtrating, and drying.

In a preferred embodiment, actinorhodin or one of its derivatives implemented in the process of the invention is obtained from a Streptomyces coelicolor culture, preferably Streptomyces coelicolor Ml 45.

Another object of the invention is metal salt of actinorhodin or one of its derivatives obtained by the process as defined herein.

The invention further relates to the use of a metal salt of actinorhodin or one of its derivatives as defined herein as a colouring agent or a pigment.

The present invention also relates to a colouring composition comprising a metal salt of actinorhodin or one of its derivatives as defined herein.

LEGENDS OF THE FIGURES

Figure 1: Infrared spectrum (Figure 1A: Actinorhodin; Figure IB: Calcium lake (Compound #1); Figure 1C: Calcium lake (Compound #2); Figure ID: Magnesium lake (Compound #4). Figure 2: UV spectrum (Figure 2A: Actinorhodin; Figure 2B: Calcium lake (Compound #1); Figure 2C: Calcium lake (Compound #2); Figure 2D: Magnesium lake (Compound #4). DETAILED DESCRIPTION OF THE INVENTION

Compounds

The present invention relates to a metal salt of actinorhodin or one of its derivatives, wherein the metal is selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, Zn, and mixtures thereof. In a preferred embodiment the metal is Ca. A preferred object of the invention is thus a calcium salt (Ca ²⁺ ) of actinorhodin or one of its derivatives. In a further preferred embodiment, the metal is a mixture of Ca and Al. A further preferred object of the invention is thus a calcium-aluminium dimeric salt of actinorhodin or one of its derivatives.

As used herein, “Be” corresponds to beryllium, “Mg” corresponds to magnesium, “Ca” corresponds to calcium, “Sr” corresponds to strontium, “Ba” corresponds to barium, “Cu” corresponds to copper, “Fe” corresponds to iron, “Al” corresponds to aluminium, “Cr” corresponds to chromium, “Mn” corresponds to Manganese, “Co” corresponds to cobalt, “Ni” corresponds to nickel, and “Zn” corresponds to zinc. The metals according to the invention are preferably divalent metals.

The present invention further includes the derivatives of actinorhodin.

Actinorhodin is an intracellular polyketide produced by strains of Streptomyces coelicolor, a Gram-positive bacterium. This compound is blue in colour at basic pH and red at acidic pH. Depending on the culture conditions, actinorhodin can be transformed into its dioxide form at the benzylic position, actinorhodinic acid, which in turn can be transformed into its hemi- lactone form, e-actinorhodin, or into its lactone form, g-actinorhodin. They are secreted into the culture medium and have physicochemical properties relatively similar to actinorhodin.

As used herein, the term “derivatives of actinorhodin” refers to any derivative of actinorhodin retaining the colouring properties thereof. The derivatives of actinorhodin include, for instance, g-actinorhodin, a-actinorhodin, b-actinorhodin, d-actinorhodin, l-actinorhodin, e- actinorhodin and actinorhodinic acid. In a preferred embodiment, the derivatives of actinorhodin are g-actinorhodin, e-actinorhodin and actinorhodinic acid. The structures of actinorhodin, g-actinorhodin, e-actinorhodin and actinorhodinic acid are presented in table 1 below. In a particular embodiment, actinorhodin is in a pure form. A pure form is, for instance, a crystal of actinorhodin having a 100% purity.

In a further particular embodiment, actinorhodin is comprised in an extract. Preferably, the extract contains 10 to 100% of actinorhodin by weight. In a more preferred embodiment, the extract contains 20 to 70% of actinorhodin by weight.

In a further particular embodiment, actinorhodin is in a form of a liquid suspension. In a preferred embodiment, such a liquid suspension comprises from 0.1 to 10 g/L, preferably from 1 to 6 g/L of actinorhodin. In a further preferred embodiment, the liquid suspension is a culture medium of Streptomyces coelicolor or of any other actinorhodin-producing microorganism. Preferably, the culture medium is treated by the down-stream methods known by the skilled person such as, for example, pH rectification, concentration, dilution or solids separation or mixing.

Table 1: Structures of actinorhodin, g-actinorhodin, e-actinorhodin and actinorhodinic acid

As used herein, a metal salt of actinorhodin or one of its derivatives according to the invention is also called “metal lake”. For instance, a calcium salt (Ca ²⁺ ) of actinorhodin or one of its derivatives is also called a calcium lake. A beryllium salt (Be ²⁺ ) of actinorhodin or one of its derivatives is also called a beryllium lake. A magnesium salt (Mg ²⁺ ) of actinorhodin or one of its derivatives is also called a magnesium lake. A strontium salt (Sr ²⁺ ) of actinorhodin or one of its derivatives is also called a strontium lake. A barium salt (Ba ²⁺ ) of actinorhodin or one of its derivatives is also called a barium lake. A copper salt (Cu ²⁺ ) of actinorhodin or one of its derivatives is also called a copper lake. An iron salt (Fe ²⁺ ) of actinorhodin or one of its derivatives is also called an iron lake. An aluminium salt (Al ³⁺ ) of actinorhodin or one of its derivatives is also called an aluminium lake. A chromium salt (Cr ³⁺ ) of actinorhodin or one of its derivatives is also called a chromium lake. A manganese salt (Mn ²⁺ ) of actinorhodin or one of its derivatives is also called a manganese lake. A cobalt salt (Co ²⁺ , Co ³⁺ ) of actinorhodin or one of its derivatives is also called a cobalt lake. A nickel salt (Ni ²⁺ ) of actinorhodin or one of its derivatives is also called a nickel lake. A zinc salt (Zn ²⁺ ) of actinorhodin or one of its derivatives is also called a zinc lake. A mixture of a calcium salt (Ca ²⁺ ) and an aluminum salt (Al ³⁺ ) of actinorhodin or one of its derivatives is also called a calcium-aluminium lake.

The metal salt of actinorhodin or one of its derivatives according to the invention can be in any form suited to its use and/or storage. In particular, it can be in solid or liquid form, particularly in the form of a powder, an aqueous solution, a solution in an organic solvent such as, for example, methanol or ethanol, a dispersion, an emulsion, or granules. In a preferred embodiment, the metal salt of actinorhodin or one of its derivatives is a powder.

Process

The present invention further concerns a process for preparing a metal salt of actinorhodin metal salt or one of its derivatives as defined herein. Therefore, an object of the invention is a process for preparing a metal salt of actinorhodin or one of its derivatives comprising the following steps of:

(a) contacting actinorhodin or one of its derivatives with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than 11;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C; and

(c) recovering the metal salt of actinorhodin or one of its derivatives.

The step (a) of the process comprises contacting actinorhodin or one of its derivatives with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent.

As used herein “a basic metal salt” is a product of the neutralization of a strong base and a weak acid. A basic salt includes an alkali salt. The difference between a basic salt and an alkali is that an alkali is the soluble hydroxide compound of an alkali metal or an alkaline earth metal. A basic salt is any salt that hydrolyzes to form a basic solution. In a particular embodiment, the at least one basic metal salt is an alkali metal salt or an alkaline earth metal salt. In a preferred embodiment, the at least one basic metal salt is a metal hydroxide. Such a metal hydroxide is, for instance, calcium hydroxide, beryllium hydroxide, magnesium hydroxide, strontium hydroxide, barium hydroxide, copper hydroxide, iron hydroxide, chromium hydroxide, manganese hydroxide, cobalt hydroxide, nickel hydroxide, and zinc hydroxide. In a more preferred embodiment, the at least one basic metal salt is calcium hydroxide.

As used herein a “solvent” includes any solvent currently used by a skilled person to form and provide a metal salt of a compound. Such solvents include, for instance and without limitation, water, ethyl acetate, dimethylformamide (DMF), tetrahydrofuran (THF), alcohols such as methanol and ethanol, esters, ethers, and aromatic solvents such as toluene, benzene, and xylene. In a preferred embodiment, the solvent is water, more preferably distilled water.

In a preferred embodiment, the step (a) of contacting actinorhodin or one of its derivatives with said at least one basic metal salt in a solvent, preferably water, is implemented at a basic pH, i.e. greater than 7, preferably equal to or higher than 11. The step (b) of the process comprises heating the reaction mixture obtained at step (a) at a temperature comprised between 80 °C and 120 °C. In a preferred embodiment, the reaction mixture obtained at step (a) is heated at a temperature comprised between 85 °C and 115 °C, preferably comprised between 90 °C and 110 °C, between 95 °C and 105 °C, more preferably at a temperature of 100 °C. In a preferred embodiment, the step (b) is implemented from 10 minutes to 2 hours, preferably from 10 minutes to one hour, more preferably for 30 minutes.

The step (c) of the process comprises recovering the metal salt of actinorhodin metal salt or one of its derivatives. This final step (c) may be implemented by simple filtration.

In a particular embodiment, the process according to the invention further comprises between the step b) and the step c), a step (b’) of contacting the reaction mixture with a buffer.

A particular object of the invention is thus a process for preparing a metal salt of actinorhodin or one of its derivatives comprising the following steps of:

(a) contacting actinorhodin or one of its derivatives with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than 11;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C;

(b’) contacting the reaction mixture with a buffer; and

(c) recovering the metal salt of actinorhodin or one of its derivatives.

In a preferred embodiment, this particular process further comprises a step of cooling down the reaction mixture at raw temperature between the step (b) and the step (b’).

The buffer allows to decrease the pH of the reaction mixture. Particularly, the buffer decreases the pH of the reaction mixture from pH 11-12 to pH 6-7. In a particular embodiment, the buffer is an aluminium-, ammonium-, potassium-, rubidium-, and cesium- based alum, preferably an aluminium-based alum. In a more preferred embodiment, the buffer is aluminium potassium tartrate.

A further object of the invention is also a composition comprising a metal salt of actinorhodin or one of its derivatives as defined herein, and a buffer. Preferably, the buffer is such as above defined. More preferably, the buffer is aluminium potassium tartrate. In a preferred embodiment, the composition comprises a calcium salt of actinorhodin or one of its derivatives as defined herein, and aluminium potassium tartrate.

In a particular embodiment, the process according to the invention further comprises a purification step of the metal salt of actinorhodine or one of its derivatives. Such a purification step can be implemented after the steps b) or b’). This purification step can also be included in the step c). Preferably, the purification step comprises at least one cycle including the steps of washing, filtrating, and drying. In a particular embodiment, the purification step comprises 1, 2, 3, 4, 5 cycles of washing, filtrating, and drying, preferably 1, 2 or 3 cycles.

A further particular object of the invention is thus a process for preparing a metal salt of actinorhodin or one of its derivatives comprising the following steps of:

(a) contacting actinorhodin or one of its derivatives with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than 11;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C and optionally cooling down the reaction mixture at room temperature;

(b’) optionally contacting the reaction mixture with a buffer;

(b”) purifying the reaction mixture; and

(c) recovering the metal salt of actinorhodin or one of its derivatives.

In a further particular embodiment, actinorhodin or one of its derivatives is obtained from a Streptomyces coelicolor culture, preferably Streptomyces coelicolor M145. Streptomyces coelicolor M145 (ATCC BAA-471) is a prototrophic strain derived from Streptomyces coelicolor A3 (2) (Bentley et al., Nature, 2002, 417, 141-147).

Preferably, the processes or the methods to obtain actinorhodin or one of its derivatives are those disclosed in the international patent application WO 2018/138089.

More preferably, the process to obtain actinorhodin or one of its derivatives comprises the following steps: - culturing a microorganism which produces actinorhodin and/or one or more derivatives thereof, preferably a strain of Streptomyces coelicolor, and in particular of Streptomyces coelicolor M145; and

- extracting the colouring agent contained in the culture biomass and/or supernatant. Even more preferably, the process to obtain actinorhodin or one of its derivatives is the process used in the examples of WO 2018/138089.

A further particular object of the invention is thus a process for preparing a metal salt of actinorhodin or one of its derivatives comprising the following steps of:

(ao) obtaining actinorhodin or one of its derivatives from a Streptomyces coelicolor culture, preferably Streptomyces coelicolor M145:

(a) contacting actinorhodin or one of its derivatives obtained at step (ao) with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than l i;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C and optionally cooling down the reaction mixture at raw temperature;

(b’) optionally contacting the reaction mixture with a buffer; and

(c) recovering the metal salt of actinorhodin or one of its derivatives.

A preferred object of the invention is a process for preparing a metal salt of actinorhodin or one of its derivatives comprising the following steps of:

(ao) obtaining actinorhodin or one of its derivatives from a Streptomyces coelicolor culture, preferably Streptomyces coelicolor M145:

(a) contacting actinorhodin or one of its derivatives obtained at step (ao) with at least one basic metal salt comprising a metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Cu, Fe, Al, Cr, Mn, Co, Ni, and Zn in a solvent, preferably at a pH equal to or higher than l i;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C and optionally cooling down the reaction mixture at raw temperature;

(b’) optionally contacting the reaction mixture with a buffer;

(b”) purifying the reaction mixture; and (c) recovering the metal salt of actinorhodin or one of its derivatives.

A more preferred object of the invention is a process for preparing a calcium salt of actinorhodin or one of its derivatives comprising the following steps of:

(ao) obtaining actinorhodin or one of its derivatives from a Streptomyces coelicolor culture, preferably Streptomyces coelicolor M145:

(a) contacting actinorhodin or one of its derivatives obtained at step (ao) with at least one basic metal salt comprising a metal Ca in a solvent, preferably at a pH equal to or higher than 11;

(b) heating the reaction mixture obtained in step (a) at a temperature comprised between 80 °C and 120 °C and cooling down the reaction mixture at raw temperature;

(b’) contacting the reaction mixture with a buffer;

(b”) purifying the reaction mixture; and

(c) recovering the calcium salt of actinorhodin or one of its derivatives.

A further object of the invention is a metal salt of actinorhodin or one of its derivatives obtained by a process as defined herein.

Another aspect of the invention is a use of a metal salt of actinorhodin or one of its derivatives a colouring agent or a pigment.

Accordingly, a metal salt of actinorhodin or one of its derivatives as defined herein is a “colouring agent”. As used herein, the terms “metal salt of actinorhodin or one of its derivatives” and “colouring agent” are interchangeable and correspond to the same entity unless otherwise specified.

In a particular embodiment, the colouring agent comprises, or consists essentially of a metal salt of actinorhodin as defined herein or one or several derivatives thereof selected from the group consisting of g-actinorhodin, a-actinorhodin, b-actinorhodin, d-actinorhodin, l- actinorhodin, e-actinorhodin, and actinorhodinic acid. Preferably, the colouring agent comprises, or consists essentially of a metal salt as defined herein of actinorhodin, g- actinorhodin, e-actinorhodin and actinorhodinic acid. More preferably, the colouring agent comprises, or consists essentially of a metal salt of actinorhodin as defined herein. As used herein, the expression “consists essentially of’ means that the colouring agent does not comprise other compounds which can have a colouring activity, and more particularly which can have a blue colouring activity.

The colouring agent according to the invention can be used in combination with one or more additional colouring agents and, optionally, one or more additives, in particular additives which facilitate the action of the colouring agent. As used herein, an additional colouring agent is not a colouring agent of the invention, i.e. a metal salt of actinorhodin or one of its derivatives. These additional colorants and additives can be easily selected by those skilled in the art according to the applications envisaged. In particular, the colouring agent according to the invention can be used in combination with one or more detergents, dispersants, lubricants, binders, reducing agents, oxidising agents, acidifying agents, basifying agents, inorganic salts, mordants such as alum, cream of tartar, stannous chloride, cupric sulphate, ferrous sulphate, or potassium bichromate, a buffer system, sweeteners, flavourings, anti-caking agents, disintegrants, wetting agents, and/or preservatives.

A further aspect of the invention is the use of a metal salt of actinorhodin or one of its derivatives according to the invention for preparing a colouring composition. It also concerns the use of a metal salt of actinorhodin or one of its derivatives according to the invention in a colouring composition. It further concerns a colouring composition comprising metal salt of actinorhodin or one of its derivatives according to the invention.

As used herein, the term “colouring composition” refers to a composition for colouring a composition or a material, on the surface or in the mass, and comprising for that purpose one or more colouring agents, including the metal salt of actinorhodin or one of its derivatives according to the invention and, optionally, one or more additives.

The colouring agent according to the invention can be used for preparing a colouring composition in the form of a pigment or a dye. As used herein, the term “dye” refers to a substance which is soluble in water. The term “pigment” refers to a chemically inert substance which is insoluble in water, which can colour a support or surface when mixed with a binder. The colouring composition according to the invention can be in any form suited to the colouring of the composition or material envisaged. In particular, it can be in solid or liquid form, and in particular in the form of a powder, a preferably aqueous solution, a dispersion, an emulsion, or granules.

The amount of colouring agent present in the colouring composition according to the invention can vary according to the application envisaged and the colouring intensity sought. Typically, the colouring composition according to the invention can comprise from 0.01 to 50 wt% colouring agent, preferably from 0.1 to 10 wt% colouring agent, and particularly preferably from 0.1 to 5 wt% colouring.

The colouring composition according to the invention can further comprise one or more additional colouring agents and/or one or more additives which facilitate the colouring of the composition or material to be dyed and/or improve the stability of the colouring composition.

As used herein, an additional colouring agent is not a colouring agent of the invention, i.e. a metal salt of actinorhodin or one of its derivatives. The additional colouring agents can be easily selected by those skilled in the art according to the applications envisaged. In particular, the colouring composition according to the invention can further comprise one or more detergents, dispersants, lubricants, binders, reducing agents, oxidising agents, acidifying agents, basifying agents, inorganic salts, mordants such as alum, cream of tartar, stannous chloride, cupric sulphate, ferrous sulphate, or potassium bichromate, a buffer system, sweeteners, flavourings, anti-caking agents, disintegrants, wetting agents, and/or preservatives.

The colouring composition according to the invention can be used for colouring a very large variety of substrates. It can in particular be a dyestuff for colouring textiles or skins, an ink, a food, paints and coatings, cosmetic or pharmaceutical colouring, or a colouring composition for mass colouring of plastics, waxes, cellulosic materials or silicones.

The present invention also concerns the use of a colouring composition according to the invention for preparing a dyestuff for colouring textiles or skins, an ink, a food, paints and coatings, cosmetic or pharmaceutical colouring, or a colouring composition for mass colouring of plastics, waxes, cellulosic materials or silicones. It further concerns the use of a colouring composition according to the invention for colouring textiles, skins, inks, food, paints and coatings, cosmetic or pharmaceutical compositions, plastics, waxes, cellulosic materials or silicones.

According to one aspect, the colouring composition according to the invention is a dyestuff for colouring textiles or skins.

The colouring agent according to the invention can be present in the dyestuff in the form of a pigment or a dye and the dyestuff can be a solution in which the colouring agent according to the invention is dissolved or dispersed, or an emulsion. Generally, the dyestuff comprises from 0.1 to 10 wt% colouring agent.

According to one embodiment, the dyestuff comprises a solvent, preferably water, and one or more colouring agents including that according to the invention and, optionally, one or more additives which facilitate the colouring of the textile or skin.

The additive(s) is/are preferably selected from the group consisting of antifoaming agents, anticreasing agents, wetting agents, dispersants, lubricants, detergents, inorganic salts, reducing agents, oxidising agents, carriers which cause polyester fibres to swell during dyeing and thus allow the colorants to penetrate, and antioxidants.

The dyestuff according to the invention can also comprise an acid or a base, or an acidic or basic pH buffer. According to a preferred embodiment, the dyestuff has a pH above 8, preferably above 8.5, and particularly preferably above 9 or 9.5.

The present invention also concerns the use of a dyestuff according to the invention for colouring textiles or skins. The present invention more particularly concerns a process for dyeing a textile or skin comprising contacting the textile or skin to be dyed with a dyestuff according to the invention and described above, and rinsing the dyed textile or skin.

Generally, the dyeing is carried out at a temperature from about 20°C to about 100°C, preferably from about 40°C to about 90°C, and particularly preferably of about 80°C. In the present document, the term “about” refers to a range of values of ± 10% of the stated value. By way of example, “about 50” comprises the values of 50 ± 10%, i.e., the values of the range 45 to 55. Preferably, the term “about” refers to a range of values of ± 5% of the stated value.

Generally, the dye bath comprises from about 0.1% to about 20% (by weight of material to be dyed) colouring agent, preferably about 2%. The technique used to contact the textile or skin with the dyestuff according to the invention depends on the nature of said textile or skin and will be easily selected by those skilled in the art. By way of example, flock dyeing is suitable for fibres, package or hank dyeing for yarns, rope jet dyeing for fabrics, drum dyeing for garments, and spray dyeing for nylon stockings. The process can further comprise a step of pre-treating the textile or skin in order to promote the colouring thereof. These pre-treatments can vary according to the nature of said textile or skin and will be easily selected by those skilled in the art. Examples of pre-treatment include, but are not limited to, steps of washing, degreasing, drying, scouring, desizing, bleaching, mercerizing, carbonizing, fulling or felting. The process according to the invention can further comprise a preliminary mordanting step. The mordanting is carried out in the presence of metal salts such as alum, cream of tartar, stannous chloride, cupric sulphate, ferrous sulphate, aluminium lactate, iron lactate or potassium bichromate, and optionally in the presence of one or more additives such as citric acid, vinegar or oxalic acid. According to a particular embodiment, the process comprises a step of mordanting in the presence of alum and optionally of cream of tartar. According to an alternative embodiment, the process comprises a step of mordanting in the presence of a metal salt, preferably aluminium lactate, at acidic pH. The process according to the invention can also further comprise a post-treatment step. These post-treatments can vary according to the nature of said textile or skin and will be easily selected by those skilled in the art. In particular, these treatments can comprise adding a fixative.

The terms “skin” and “leather” are used interchangeably herein and refer to the skin of an animal, preferably a non-human mammal such as cattle or swine, having undergone a tanning process.

As used herein, the term “textile” refers to textile fibres in any form, for example in the form of yarns, pieces of fabric, or garments. The textiles can comprise natural, plant or animal fibres, or synthetic fibres, or a mixture of both. The natural plant fibres can be cotton, flax or hemp, for example. The natural animal fibres can be silk or wool, for example. The synthetic fibres can be modal, viscose, polyamide, polyester or elastane, for example. According to a preferred embodiment, the textile to be dyed comprises natural plant or animal fibres, preferably flax, silk, wool or cotton fibres. Particularly preferably, the textile to be dyed comprises at least 70, 75, 80, 85, 90 or 95% natural plant or animal fibres.

The present invention also concerns a textile or skin dyed by using the colouring agent, the dyestuff or the process according to the invention. It also concerns the products comprising said textiles or skins, in particular clothing, decorative, or home furnishing products.

According to another aspect, the colouring composition according to the invention is an ink.

In particular, the ink according to the invention can be a pen ink, for example for a ballpoint pen or a fountain pen, a printing ink, or a screen-printing ink.

The ink according to the invention comprises the colouring agent according to the invention and, optionally, one or more additional colouring agents, in a suitable formulation. The formulation can be easily selected by those skilled in the art in order to provide a suitable viscosity and stability.

By way of example, the inks generally comprise, in addition to the colouring agent(s), a binder, for example an epoxy, polyamide or acrylic resin, a solvent such as, for example, xylene, toluene, a mineral oil, an alcohol, an ester, a ketone or water. The inks can also contain various additives such as waxes, plasticisers, antifoaming agents, optical brighteners or drying agents.

The present invention also concerns a pen cartridge comprising an ink according to the invention, as well as a pen, in particular of the ballpoint or fountain type, comprising such a cartridge.

Because of its safety, the colouring agent according to the invention is particularly advantageous for uses in the food-processing, cosmetic and pharmaceutical fields. Thus, according to yet another aspect, the colouring composition according to the invention is a food or cosmetic and/or pharmaceutically acceptable colouring. The food colouring according to the invention comprises the colouring agent according to the invention and, optionally, one or more additional colouring agents.

It can be used for colouring any kind of food compositions. In particular, the colouring according to the invention can be used in liquid compositions such as plain or sparkling water, fruit juices, flavoured beverages or alcoholic beverages, dairy products such as milk-based beverages, yogurts, cheeses or ice creams, confectionery products such as sweets, chewing gum, food additives, food supplements, prepared meat products, and ready-made dishes.

The present invention also concerns a food composition comprising the colouring agent or a colouring composition according to the invention.

The colouring composition according to the invention can also be a cosmetic dye. In particular, said dye can be used in the preparation of skin care products, make-up products or hair dyes (dyes for keratin fibres).

The cosmetic composition, as defined in the invention, can thus be a hygiene product (for example toothpaste, deodorant, shower gel, soap, shampoo), a cosmetic skin care product (for example anti-wrinkle cream, day cream, night cream, moisturizing cream, flower water, exfoliator, milk, beauty mask, lip balm, tonic), a hair product (for example conditioner, relaxer, gel, oil, hair spray, mask, dye), a fragrance (for example cologne, toilet water, perfume), a make-up product (for example concealers, self-tanner, eyeliner, blusher, foundation, kohl, mascara, powder, skin-lightening product, lipstick and/or nail polish) and/or a sun product (for example sun and after-sun creams, oils or lotions).

In particular, the cosmetic composition can be an aqueous phase or an oil phase. The aqueous phase can in particular be an aqueous gel such as a shower gel or a shampoo, or an aqueous emulsion (oil-in-water type) such as a skin cream or milk. The oil phase can in particular be an oil emulsion (water-in-oil type) such as a skin or make-up cream, or an anhydrous oil phase such as a lipstick.

According to a preferred embodiment, the cosmetic composition is an emulsion of the water- in-oil type or an anhydrous oil phase, preferably an anhydrous oil phase, and particularly preferably a lipstick. Preferably, during the colouring of this type of composition, the colouring agent is used in the form of pigment powder. The cosmetic composition according to the invention can in particular be packaged in cream, gel, emulsion, powder, foam, spray, lotion, oil, solid stick or pencil form.

According to a particular embodiment, the colouring composition is a hair dye comprising the colouring agent or a colouring composition according to the invention. In addition to the colouring agent or a colouring composition according to the invention, the hair dye can comprise compounds conventionally used in this type of preparation, such as oxidising agents, thickeners, buffers, chelating agents and/or other colouring agents.

The present invention also concerns a cosmetic composition comprising the colouring agent or a colouring composition according to the invention, in particular a cosmetic composition as defined above.

The present invention also concerns a pharmaceutical composition comprising the colouring agent or a colouring composition according to the invention. The pharmaceutical composition according to the invention can be in the form of tablets, hard capsules, soft capsules, granules, powder, suspensions, emulsions, solutions, polymers, nanoparticles, microspheres, suppositories, rectal capsules, enemas, gels, pastes, ointments, creams, plasters, potions, injections, implants, sprays or aerosols.

The amount of colouring agent(s) comprised in the food, cosmetic or pharmaceutical composition according to the invention can vary widely according to the applications and colour intensities sought. Typically, the food, cosmetic or pharmaceutical composition according to the invention can comprise from 0.01 to 10 wt% colouring agent according to the invention, preferably from 0.1 to 10 wt% colouring agent according to the invention, and particularly preferably from 1 to 10 or from 1 to 5 wt% colouring agent according to the invention. The colouring agent according to the invention can be used alone or in combination with other colouring agents.

According to yet another aspect, the colouring composition according to the invention is for colouring paints and coatings, and more particularly aqueous-based paints, acrylic paints or other solvent-based paints and coatings. The colouring composition according to the invention can be applied to these formulations directly during the paint formulation as a solid or as a liquid dispersion of the pigment in water, solvent and with the necessary additives known by the skilled person.

According to yet another aspect, the colouring composition according to the invention is for colouring plastics, and more particularly polyolefins such as polyethylene or polypropylene; waxes, preferably natural waxes, cellulosic materials such as paper, or silicones.

The colouring composition according to the invention can be applied to these materials or can be included in these materials during the manufacturing processes thereof (mass colouring), in particular during a step when the viscosity is sufficiently low to allow uniform distribution of the colorant.

According to a preferred embodiment, the colouring composition is used for colouring paper.

The present invention also concerns the plastics, waxes, cellulosic materials and silicones comprising the colouring agent or a colouring composition according to the invention.

All references cited in this application, including journal articles or abstracts, published patent applications, granted patents or any other reference, are fully incorporated herein by reference, which includes all results, tables, figures and texts presented in said references.

Other features and advantages of the invention will appear more clearly on reading the following examples given by way of non-limiting illustration.

EXAMPLES

Example 1: Preparations of the lakes of the invention

Calcium lake: Compound #1 (process of the invention without buffer)

1 gram of actinorhodin was dispersed in 200 mL of distilled water. 25 mL of a 10% wt Ca(OH)2 aqueous solution (plus rinsing the Becher with approx. 25 mL) were then added and the mixture was heated to the boil (100 °C) during 30’. Upon addition, the solution turned light blue and milky. The resulting suspension was filtered hot and a blue solid was recovered on th efritte. The solid was rinsed with 200 mL of distilled cold water and the filtrate was slightly blue coloured and had a 11.8 pH. After a night drying under the bench, the solid was weighted and 2.54 grams of a light blue solid was isolated. Infrared and UV spectrums are presented in figures IB and 2B.

To a stirred solution of 2 grams of actinorhodine in 10 mL of distilled water were added portion wise 30 mL of a 10 wt% suspension of Ca(OH)2 in water. The resulting milky blue solution was then heated to 100 °C for 30 minutes and cooled down with a cold-water bath. The Erlenmeyer was rinsed with approximately 10 mL of distilled water and the pH was observed to be at 12.5. Dropwise addition of a saturated solution of Aluminium potassium tartrate (approximately 10%) allowed to drop the pH to a value below 7 (final pH = 5.8 with approximately 100 mL of the latter solution). The suspension was then filtered on frit glass and the press cake was rinsed twice with distilled water. The filter cake was dried in a 60 °C oven during one night, weighted, and 7.24 grams of a light blue solid was isolated. Infrared and UV spectrums are presented in figures 1C and 2C.

3.2 g of actinorhodin, 0.5 g of Mg(OH)2 and 15 mL of distilled water are added in a 50 mL round bottom flask. The reaction mixture is heated at 90 °C for 3 hours. Aluminium potassium tartrate (1.5 g) is then added by portion until the pH drops below 7 (6.4). The mixture is filtered on paper with a vacuum pump, then the cake is rinsed two time with 20 mL of distilled water.

The blue product is dried at 90 °C to afford 2.9 g of a dark blue solid.

Example 2: Preparations of the comparative lakes

Talc lake: Compound #3

100 mg of actinorhodin was dispersed in 250 mL of distilled water. 3 g of talc (Mg Si ₄ Oio(OH)2) and 30 mL of distilled water were then added and the mixture was heated to the boil (100 °C) during 30’. The resulting suspension was filtered hot and a red-purple solid was recovered on th efritte. The solid was rinsed with 200 mL of distilled water, filtered and dried at 50 °C for one night. 2.58 grams of a purple solid was isolated. Example 3: Stability tests and coloring observations

The material (Compound #2) was suspended in three bechers with different pHs: Suspension 1: 3.4; Suspension 2: 6.4; and Suspension 3: 9.1 (respectively, distilled water with a drop of AcOH, distilled water, and distilled water with a drop of 1M aqueous NaOH) to study its behaviour. The three suspensions were performed with 100 mg of the lake in 100 mL of water (0.1%). The suspensions were left still during 24 hours and the pH was measured: Suspension 1: 4; Suspension 2: 5.6; and Suspension 3: 8.5. No visual modification of the suspensions 1, 2, and 3 were observed, neither solubilization nor colouring of the water. Such results show that calcium lake is insoluble and stable (blue color) in water whatever the pH value.

The same protocol has been performed with Compound #1, and reference dyes, namely micronized Indigo and Brilliant Blue FCF (E133).

The results are presented in the following table 1.

Table 1: In conclusion, the inventors have demonstrated that the metal salts of actinorhodin, particularly calcium and magnesium salts of actinorhodin, are insoluble and stable whatever the pH value. On the contrary, micronized Indigo is unstable at acid PH and loses its blue color, and Brilliant Blue FCF (E133) is soluble at acid and basic pH and quite unstable at basic pH.