(19) TZZ _T

(11) EP 2 849 768 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int Cl.: of the grant of the patent: A61K 36/18 (2006.01) 01.06.2016 Bulletin 2016/22 (86) International application number: (21) Application number: 13732254.1 PCT/IB2013/054054

(22) Date of filing: 17.05.2013 (87) International publication number: WO 2013/171720 (21.11.2013 Gazette 2013/47)

(54) EXTRACT OF RADLKOFERI AND USE THEREOF EXTRAKT AUS UND VERWENDUNG DAVON EXTRAIT DE GREYIA RADLKOFERI ET SON UTILISATION

(84) Designated Contracting States: • MOODLEY, Indres AL AT BE BG CH CY CZ DE DK EE ES FI FR GB 4001 Durban (ZA) GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (74) Representative: Bates, Philip Ian Reddie & Grose LLP (30) Priority: 18.05.2012 ZA 201203648 16 Theobalds Road London WC1X 8PL (GB) (43) Date of publication of application: 25.03.2015 Bulletin 2015/13 (56) References cited: WO-A1-2007/098873 (73) Proprietors: • University of Pretoria • MAPUNYA M B ET AL: "Tyrosinase activity of 0002 Pretoria (ZA) Greyia flanaganii (Bolus) constituents.", 15 • University Of Kwazulu-Natal August 2011 (2011-08-15), PHYTOMEDICINE : Durban (ZA) INTERNATIONAL JOURNAL OF PHYTOTHERAPYAND PHYTOPHARMACOLOGY (72) Inventors: 15 AUG 2011, VOL. 18, NR. 11, PAGE(S) 1006 - • DE CANHA, Marco, Nuno 1012, XP002712502, ISSN: 1618-095X abstract 0002 Pretoria (ZA) • BRUCEA BOHM AND JAMES CHAN: "Flavonoids • LALL, Namrita and Affinities of Greyiaceae with a Discussion of 0054 Pretoria (ZA) the Occurrence of B-Ring Deoxyflavonoids in • HUSSEIN, Ahmed Dicotyledonous Families", SYSTEMATIC Cairo 11421 (EG) BOTANY, AMERICAN SOCIETY OF • MOGAPI, Elizabeth TAXONOMISTS, KENT, OH, US, vol. 17, no. 2, 1 1682 Midrand (ZA) January 1992 (1992-01-01), pages 272-281, XP009172281, ISSN: 0363-6445

Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 2 849 768 B1

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Description potential; and a high frequency of contact sensitivity. Ko- jic acid has also been found to discolour to a brown colour INTRODUCTION AND BACKGROUND TO THE IN- upon exposure to sunlight and ambient air, which also VENTION leads to decreased efficiency. Kojic dipalmitate has been 5 suggested as an alternative to kojic acid to overcome the [0001] This invention relates to the isolation and use disadvantages associated with kojic acid, but tests have of a plant extract in the treatment of skin hyper-pigmen- revealed that kojic dipalmitate does not exhibit the same tation. More particularly, this invention relates to the iso- effectiveness as kojic acid. lation of a tyrosinase inhibitor from plant material of the [0006] A further known compound indicated in the Greyia radlkoferi (G. radlkoferi) plant. 10 treatment of skin hyper-pigmentation is arbutin, which is [0002] Skin hyper-pigmentation is a condition caused derived from various berry-, including mulberry, by the overproduction of melanin, a pigment present in cranberry and blueberry. It is indicated as having skin about 10% of melanocytes. The copper containing mono- lightening properties, but has been associated with skin oxygenase enzyme referred to as ’tyrosinase’ is a key irritation. enzyme in the synthesis of melanin, due to melanin bio- 15 [0007] Glabridin and isoliquiritigenin, both extracted synthesis being regulated by the tyrosinase enzyme from liquorice (Glycyrrhiza glabra) have also been found which is responsible for catalysing the rate limiting step to exhibit skin lightening properties, but do not penetrate in the biosynthetic pathway. Over-activity of tyrosinase the skin effectively, and are both unstable when used in leads to over production of melanin which ultimately formulations. leads to hyper-pigmentation of the skin. Hyper-pigmen- 20 tation of the skin can be attributed to excessive exposure OBJECT OF THE INVENTION to UV light, adverse reactions to drugs and also occurs during ageing. [0008] It is accordingly an object of the current inven- [0003] Inhibition of the tyrosinase enzyme is therefore tion to provide a tyrosinase inhibitor with which the above a well known target for the treatment of skin hyper-pig- 25 disadvantages experienced with known tyrosinase inhib- mentation. Many known products used for the treatment itors and other treatments of skin hyper-pigmentation of skin hyper-pigmentation have been associated with could at least partially be overcome, or to provide a rel- toxicity and other adverse effects. These known products atively more useful, environmentally friendly, organic al- include agents such as hydroquinone, kojic acid, arbutin, ternative to the known tyrosinase inhibitors in a cost ef- glabridin and isoliquiritigenin. Some cosmetic products 30 ficient manner. containing these agents have shown to be cytotoxic and mutagenic in humans. In addition to being cytotoxic and SUMMARY OF THE INVENTION mutagenic, known treatments for skin hyper-pigmenta- tion have also been known to cause specific and unwant- [0009] According to a first aspect of the invention there ed side effects, as explained in more detail below. 35 is provided a method for preparing a plant extract having [0004] Hydroquinone has been largely acknowledged tyrosinase inhibitor activity for the treatment of skin hy- in medical research and literature as the primary topical per-pigmentation, the method including the steps of: ingredient for inhibition of melanin production. It has been known to cause skin irritation, and fears exist about per- - drying leaves of Greyia radlkoferi (G. radlkoferi); ceived carcinogenic properties. It has accordingly been 40 - pulverising the dried leaves; banned from use as a skin lightening agent in the member - mixing the pulverised leaves with a solvent to allow states of the European Union, and is regulated by the phenolic compounds to leach into the solvent; and FDA in the United States of America insofar as over the - removing the pulverised leaves from the solvent, counter sales are concerned. such that the plant extract remains in the solvent. [0005] Kojic acid is a by-product obtained from fer-45 menting rice in the production of Japanese rice wine, or [0010] Further according to the invention, the solvent sake as it is also commonly known. It has been touted may be selected from the group consisting of water and as an effective inhibitor of melanin production, and is ethanol. widely accepted as one of the most effective pure prod- [0011] The step of mixing the pulverised leaves with ucts indicated in the treatment of skin hyper pigmenta- 50 solvent may include the further step of agitating the mix- tion. However, the use of kojic acid in the treatment of ture to improve leaching of phenolic compounds from the skin hyper-pigmentation has become more and more leaves into the solvent. controversial, due to certain studies suggesting that kojic [0012] The step of separating the pulverised leaves acid might be carcinogenic, and it has subsequently been from the solvent may include the step of passing the sol- banned from cosmetic use in Korea and Japan. Over and 55 vent through a vacuum filter system. above the suggested carcinogenic potential of kojic acid, [0013] Further according to the invention the method it has also been found to be a potential cause of irritant includes the step of adding a preservative to the plant contact dermatitis; is allergenic; has a high sensitising extract. Preferably, the preservative is in the form of 1 %

2 3 EP 2 849 768 B1 4 of a mixture of phenoxyethanol and ethylhexylglycerin leaves is preferably 70% ethanol. Deionised distilled wa- added to the plant extract on a weight per weight basis. ter could be used as an alternative solvent to ethanol to [0014] Further according to the invention, the method provide an organic extract. includes the further step of preparing the plant extract in [0022] The plant extract is preserved by adding a pre- a topical dosage form selected from the group consisting 5 servative in the form of 1% of a mixture of phenoxyethanol of creams; lotions; aqueous solutions; balms; sun- and ethylhexylglycerin added to the plant extract on a screens; skin-oils and ointments. weight per weight basis, after which it is stored in a cold [0015] According to a second aspect of the invention room at 4° Celsius. The preservative challenge test indi- there is provided a plant extract for the treatment of skin cated that the preservative that was added to the extract hyper-pigmentation by inhibiting tyrosinase activity pre- 10 was successful at inhibiting the growth of certain micro- pared in accordance with a method of the first aspect of organisms, including Eschericia coli, Staphylococcus au- the invention, characterised in that the extract includes reus, Pseudomonas aureginosa, Candida albicans and 5,7-dihidroxyflavone[(2S)-pinocembrin]; 2’,6’-dihydroxy- Aspergillus. 4’-methoxydihydrochalcone; 2’,4’,6’-trihydroxyhydroch- [0023] To determine the constituent compounds of the alcone; 3,5,7-trihydroxyflavone and 4’,5’7-trihydroxyiso- 15 plant extract, the plant extract is subjected to bioassay flavone. guided fractionation. In doing so, approximately 59.5 g [0016] Further according the invention, the plant ex- of the plant extract is dissolved in a minimal amount of tract displays tyrosinase inhibitory activity by exhibiting acetone solvent and mixed with silica gel. The mixture is a 50% inhibitory concentration (IC 50) ranging from 17,96 then left to dry until formation of a fine powder. This fine mg/ml to 32.62 mg/ml when using L-tyrosine and dihy- 20 powder is then chromatographed on a silica gel column droxyphenylalanine (DOPA) as substrates. using hexane (Hex):ethylacetate (EtOAc) mixtures of in- [0017] According to a third aspect of the invention there creasing polarity (100:0 Hex to 0:100 EtOAc). A total of is provided for use of the plant extract according to the 40 preliminary fractions of approximately 500 ml each first and second aspects of the invention in the prepara- are collected. The column is then washed with 2 litres of tion of a topical dosage form for use in a method of treat- 25 100% methanol (MeOH). The preliminary fractions are ing a patient suffering from skin hyper-pigmentation. then concentrated using a rotor vapour and spotted on [0018] According to a fourth aspect of the invention a thin layer chromatography (TLC) plate which is then there is provided a topical dosage form selected from developed with dichoromethane (DCM:MeOH) 95:5, any one of the group consisting of a cream; lotion; aque- viewed under UV light and immersed in a vanillin solution ous solution; balm; sunscreen; skin-oil; and an ointment, 30 (7.5 g vanillin, 250 ml EtOH and 5 ml concentrated 98% for the treatment of skin hyper-pigmentation comprising sulphuric acid (H 2SO4)) and heated to detect compounds a plant extract according to the second aspect of the in- not absorbing under UV light. Fractions which contained vention, in a suitable dermatologically acceptable carrier. a similar profile of compounds on the TLC plate are com- bined and concentrated using a rotor vapour. These frac- DESCRIPTION OF A PREFERRED EMBODIMENT OF 35 tions are then further chromatographed for isolation and THE INVENTION identification of bioactive compounds. Following this step, certain fractions are then subjected to a series of [0019] A preferred embodiment of the invention will sephadex columns LH-20 eluted with 100% EtOH and now be described in more detail with reference to a non- then washed with 100% MeOH to yield Compound C1. limiting example. 40 Other fractions are firstly subjected to series of sephadex [0020] In accordance with a preferred embodiment of columns using 100% MeOH as a solvent to yield certain the invention, a method for preparing a plant extract hav- fractions, one of which is also subjected to a sephadex ing tyrosinase inhibitor activity for the treatment of skin column using 100% MeOH to obtain sub-fractions. One hyper-pigmentation includes the steps of: of these sub-fractions is subjected to a preparative TLC 45 eluted with DCM:MeOH (9:1) to isolate Compound C2. - air drying leaves of G. radlkoferi away from exposure Afurther fraction is subjectedto asephadex column using to the sun at room temperature; 100% MeOH, from this Compound C3 is isolated. Com- - pulverising the dried leaves; pounds C4 and C5 are isolated using similar methods. - mixing 25 g of the pulverised leaves with 200 ml sol- [0024] The end products of the bioassay guided frac- vent to form a mixture; 50 tination are the isolation of five known phenolic com- - subjecting the mixture to shaking for 48 hours to al- pounds, namely 5,7-dihidroxyflavone[(2S)-pinocembrin] low phenolic compounds to leach into the solvent; (C1); 2’,6’-dihydroxy-4’-methoxydihydrochalcone (C2); and 2’,4’,6’-trihydroxyhydrochalcone (C3); 3,5,7-trihydroxy- - separating the pulverised leaves from the solvent flavone (C4) and 4’,5’7-trihydroxyisoflavone (C5), all of through vacuum filtration by using a Buchner funnel 55 which have been shown to exhibit individual tyrosinase to form the plant extract. inhibitory capabilities, as well as a synergistic action in the inhibition of tyrosinase activity. [0021] The solvent used to mix with the pulverised [0025] These compounds have previously been ex-

3 5 EP 2 849 768 B1 6 tracted from other plants and their tyrosinase inhibitory tage of decreased skin penetration shown by other qualities have been documented before. G. radlkoferi is known compounds like glabridin and isoliquiritigenin however the first plant wherein all five of these com- which can be extracted from the liquorice plant. pounds (C1 to C5) have been found in one single plant, [0035] Serious disadvantages, including cytotoxicity, which is also indigenous to . 5 mutagenicity and carcinogenicity, that are associated [0026] These individual phenolic compounds exhibit with hydroquinone and kojic acid, both known treatments differing levels of tyrosinase inhibition when used in iso- of skin hyper-pigmentation, are also overcome by the lation. C3 (2’, 4’, 6’-trihydroxydihydrochalcone) exhibits plant extract according to the invention. an 50% inhibitory concentration (IC50) value of 17.86 [0036] It will be appreciated that variations in details mg/ml, C4 (3,5,7-trihydroxyflavone, also known as ga- 10 are possible with a plant extract and method of extracting langin) exhibits an IC50 value of 2.23 mg/ml with more the same, for use in the treatment of skin hyper-pigmen- than 50% of melanin being inhibited at concentrations as tation according to the invention, without departing from low as 3.1 mg/ml. C2 (2’,6’-dihydroxy-4’-methoxydihydro- the scope of the appended claims. chalcone, also known as genistein) exhibits an IC 50 value of 21.42 mg/ml and 20% melanin reduction is observed 15 at 3.125 mg/ml. Claims [0027] The plant extract from G. radlkoferi shows sig- nificant inhibitory activity by exhibiting a IC50 value of 1. A method for preparing a plant extract having tyro- 17.96 mg/ml when L-tyrosine and DOPA are used as sub- sinase inhibitor activity and being suitable for the 20 strates, which IC50 compares favourably against known treatment of skin hyper-pigmentation, the method in- compounds like kojic acid (3.78 mg/ml), isoliquirtigenin cluding the steps of: (896.88 mg/ml), arbutin (149 mg/ml) and an extract from Greya flanaganii (32.62 mg/ml). - drying leaves of Greyia radlkoferi (G. radlkof- [0028] The plant extract also exhibits increased skin eri); even tone at 3% in a clinical study known as the spot 25 - pulverising the dried leaves; reduction and skin even tone test, whereas G. flanaganii - mixing the pulverised leaves with a solvent to does not show the same effectiveness at 3%. allow phenolic compounds to leach into the sol- [0029] The inhibition of hyper-pigmentation is not re- vent; and stricted to inhibition at the enzyme level but melanin in- - removing the pulverised leaves from the sol- hibition can also be achieved in vitro by the inhibition of 30 vent, such that the plant extract remains in the melanin release by melanocyte cells. In conducting this solvent. test, the plant extract was compared with an arbutin pos- itive control, and 50% melanin reduction in melanocytes 2. A method according to claim 1, wherein the solvent was observed with cells being viable at concentrations is selected from the group consisting of water and up to 50 mg/ml. 35 ethanol. [0030] The plant extract is non-mutagenic even when tested at a relatively high concentration of 5.0 mg/ml. 3. A method according to claim 1 or claim 2, wherein [0031] Microbial and heavy metal analysis investiga- the step of mixing the pulverised leaves with solvent tion of the cosmeceutical actives of G. radlkoferi shows includes the further step of agitating the mixture to absence of any microbial contamination and heavy met- 40 improve leaching of phenolic compounds from the als such as lead, arsenic and mercury. leaves into the solvent. [0032] The plant extract according to the invention is to be included in a topical dosage form for the treatment 4. A method according to any one of the preceding of skin hyper-pigmentation, formulated to provide the ap- claims, wherein the step of removing the pulverised plication of approximately 5 ml plant extract per 20 cm2 45 leaves from the solvent includes the step of passing of skin affected by skin hyper-pigmentation. This topical the solvent through a vacuum filter system. dosage form is prepared as a cream; lotion; aqueous solution; balm; sunscreen; skin-oil; and/or an ointment in 5. A method according to any one of the preceding a suitable dermatologically acceptable carrier such as claims, including the further step of adding a pre- aqueous cream. 50 servative to the plant extract. [0033] One of the disadvantages that has been record- ed with known compounds for the treatment for skin hy- 6. A method according to claim 5 wherein the preserv- per-pigmentation, like arbutin, is skin irritation. This dis- ative is in the form of 1% of a mixture of phenoxyeth- advantage is accordingly overcome by the plant extract anol and ethylhexylglycerin added to the plant ex- and method for extracting same according to the inven- 55 tract on a weight per weight basis. tion. [0034] The plant extract also shows increased skin 7. A method according to any one of the preceding penetration, and accordingly overcomes the disadvan- claims, including the further step of preparing the

4 7 EP 2 849 768 B1 8

plant extract in a topical dosage form selected from der Schritt des Mischens der pulverisierten Blätter the group consisting of creams; lotions; aqueous so- mit Lösungsmittel den weiteren Schritt des Rührens lutions; balms; sunscreens; skin-oils and ointments. des Gemischs beinhaltet, um das Auslaugen von Phenolverbindungen aus den Blättern in das Lö- 8. A plant extract for inhibiting tyrosinase activity pre- 5 sungsmittel zu verbessern. pared in accordance with a method of any one of the preceding claims, characterised in that the extract 4. Verfahren nach einem der vorherigen Ansprüche, includes 5,7-dihidroxyflavone[(2S)-pinocembrin]; wobei der Schritt des Entfernens der pulverisierten 2’,6’-dihydroxy-4’-methoxydihydrochalcone; Blätter aus dem Lösungsmittel den Schritt des Lei- 2’,4’,6’-trihydroxyhydrochalcone; 3,5,7-trihydroxy- 10 tens des Lösungsmittels durch ein Vakuumfiltersys- flavone and 4’,5’7-trihydroxyisoflavone. tem beinhaltet.

9. A plant extract according to claim 8 displaying tyro- 5. Verfahren nach einem der vorherigen Ansprüche, sinase inhibitory activity by exhibiting a 50% inhibi- das ferner den Schritt des Zugebens eines Konser- 15 tory concentration (IC50) ranging from 17,96 mg/ml vierungsmittels zum Pflanzenextrakt beinhaltet. to 32.62 mg/ml when using L-tyrosine and dihydrox- yphenylalanine (DOPA) as substrates. 6. Verfahren nach Anspruch 5, wobei das Konservie- rungsmittel in Form von 1% eines Gemischs aus 10. A plant extract according to claim 8 or claim 9 for Phenoxyethanol und Ethylhexylglycerin vorliegt, das use in the treatment of skin hyper-pigmentation. 20 dem Pflanzenextrakt auf Gewichtsbasis zugegeben wird. 11. A plant extract for use according to claim 10, wherein the plant extract is in topical dosage form. 7. Verfahren nach einem der vorherigen Ansprüche, das den weiteren Schritt des Bereitstellens des 12. A plant extract according to claim 8 or claim 9 for 25 Pflanzenextrakts in einer topischen Dosierungsform use in the treatment of skin hyper-pigmentation, beinhaltet, die aus der Gruppe bestehend aus wherein the plant extract is in topical dosage form. Cremes, Lotionen, wässrigen Lösungen, Balsamen, Sonnenschutzmitteln, Hautölen und Salben ausge- 13. A topical dosage form selected from any one of the wählt ist. group consisting of a cream; lotion; aqueous solu- 30 tion; balm; sunscreen; skin-oil; and an ointment, for 8. Pflanzenextrakt zum Inhibieren der Tyrosinaseakti- the treatment of skin hyper-pigmentation comprising vität, der mit einem Verfahren nach einem der vor- a plant extract according to any one of claims 8 and herigen Ansprüche hergestellt wird,dadurch ge- 9, in a suitable dermatologically acceptable carrier. kennzeichnet, dass der Extrakt 5,7-Dihidroxyfla- 35 von[(2S)-pinocembrin]; 2’,6’-Dihydroxy-4’-methoxy- dihydrochalcon; 2’,4’,6’-Trihydroxyhydrochalcon; Patentansprüche 3,5,7-Trihydroxyflavon und 4’,5’,7-Trihydroxyisofla- von enthält. 1. Verfahren zur Herstellung eines Pflanzenextrakts mitTyrosinase-Inhibitoraktivität, der zur Behandlung 40 9. Pflanzenextrakt nach Anspruch 8, der Tyrosinase- einer Überpigmentierung der Haut geeignet ist, wo- Inhibitionsaktivität hat, indem er eine 50 % inhibito-

bei das Verfahren die folgenden Schritte beinhaltet: rische Konzentration (IC50) von 17,96 mg/ml bis 32,62 mg/ml bei der Verwendung von L-Tyrosin und - Trocknen von Blättern vonGreyia radlkoferi Dihydroxyphenylalanin (DOPA) als Substrate auf- (G. radlkoferi); 45 weist. - Pulverisieren der getrockneten Blätter; - Mischen der pulverisierten Blätter mit einem 10. Pflanzenextrakt nach Anspruch 8 oder Anspruch 9 Lösungsmittel, damit Phenolverbindungen in zur Verwendung bei der Behandlung einer Überpig- das Lösungsmittel auslaugen können; und mentierung der Haut. - Entfernen der pulverisierten Blätter aus dem 50 Lösungsmittel, so dass der Pflanzenextrakt in 11. Pflanzenextrakt zur Verwendung nach Anspruch 10, dem Lösungsmittel bleibt. wobei der Pflanzenextrakt in topischer Dosierungs- form vorliegt. 2. Verfahren nach Anspruch 1, wobei das Lösungsmit- tel aus der Gruppe bestehend aus Wasser und Etha- 55 12. Pflanzenextrakt nach Anspruch 8 oder Anspruch 9 nol ausgewählt ist. zur Verwendung bei der Behandlung einer Überpig- mentierung der Haut, wobei der Pflanzenextrakt in 3. Verfahren nach Anspruch 1 oder Anspruch 2, wobei topischer Dosierungsform vorliegt.

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13. Topische Dosierungsform, die aus beliebigen der pe consistant en crèmes ; lotions ; solutions Gruppe bestehend aus einer Creme, Lotion, wäss- aqueuses ; baumes ; écrans solaires ; huiles pour la rigen Lösung, einem Balsam, Sonnenschutzmittel, peau et pommades. Hautöl und einer Salbe ausgewählt ist, zur Behand- lung einer Überpigmentierung der Haut, die ein5 8. Extrait de plante pour inhiber l’activité de la tyroki- Pflanzenextrakt nach einem der Ansprüche 8 und 9 nase préparé conformément à un procédé selon in einem geeigneten dermatologisch akzeptablen l’une quelconque des revendications précédentes, Träger beinhaltet. caractérisé en ce que l’extrait comprend de la 5,7- dihydroxyflavone[(2S)-pinocembrine] ; 2’,6’-dihy- 10 droxy-4’-méthoxydihydrochalcone ; 2’,4’,6’- Revendications trihydroxyhydrochalcone ; 3,5,7-trihydroxyflavone et 4’,5’,7’-trihydroxyisoflavone. 1. Procédé de préparation d’un extrait de plante ayant une activité d’inhibiteur de tyrokinase et convenant 9. Extrait de plante selon la revendication 8, faisant au traitement de l’hyperpigmentation de la peau, le 15 preuve d’une activité d’inhibiteur de tyrokinase en procédé comprenant les étapes consistant à : présentant une concentration inhibitrice 50 % (CI 50) allant de 17,96 mg/ml à 32,62 mg/ml en utilisant de - sécher des feuilles deGreyia radlkoferi (G. la L-tyrosine et de la dihydroxyphénylalanine (DO- radlkoferi) ; PA) en tant que substrats. - pulvériser les feuilles séchées ; 20 - mélanger les feuilles pulvérisées avec un sol- 10. Extrait de plante selon la revendication 8 ou la re- vant pour permettre la lixiviation des composés vendication 9, à utiliser dans le traitement de l’hy- phénoliques dans le solvant ; et perpigmentation de la peau. - retirer les feuilles pulvérisées du solvant, de telle sorte que l’extrait de plante demeure dans 25 11. Extrait de plante à utiliser selon la revendication 10, le solvant. où l’extrait de plante est sous forme de présentation topique. 2. Procédé selon la revendication 1, dans lequel le sol- vant est sélectionné parmi le groupe consistant en 12. Extrait de plante selon la revendication 8 ou la re- eau et éthanol. 30 vendication 9, à utiliser dans le traitement de l’hy- perpigmentation de la peau, où l’extrait de plante est 3. Procédé selon la revendication 1 ou la revendication sous forme de présentation topique. 2, dans lequel l’étape consistant à mélanger les feuilles pulvérisées avec un solvant comprend l’éta- 13. Forme de présentation topique sélectionnée parmi pe supplémentaire consistant à agiter le mélange 35 l’unquelconque du groupe consistanten une crème ; afin d’améliorer la lixiviation des composés phéno- une lotion ; une solution aqueuse ; un baume ; un liques des feuilles dans le solvant. écran solaire ; une huile pour la peau ; et une pom- made, pour le traitement de l’hyperpigmentation de 4. Procédé selon l’une quelconque des revendications la peau comprenant un extrait de plante selon l’une précédentes, dans lequel l’étape consistant à retirer 40 quelconque des revendications 8 et 9, dans un vé- les feuilles pulvérisées du solvant comprend l’étape hicule dermatologiquement acceptable. consistant à passer le solvant à travers un système de filtration sous vide.

5. Procédé selon l’une quelconque des revendications 45 précédentes, comprenant l’étape supplémentaire consistant à ajouter un conservateur à l’extrait de plante.

6. Procédé selon la revendication 5, dans lequel le con- 50 servateur est sous forme de 1 % d’un mélange de phénoxyéthanol et d’éthylhexylglycérine ajouté à l’extrait de plante sur une base de poids par poids.

7. Procédé selon l’une quelconque des revendications 55 précédentes, comprenant l’étape supplémentaire consistant à préparer l’extrait de plante en une forme de présentation topique sélectionnée parmi le grou-

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