Patent Application
20170151299
The invention relates to a novel extract of Santolina chamaecyparissus L., to a composition comprising it, and to cosmetic and dermatological methods using same, especially as preservative, bactericide, fungicide and/or antioxidant.
Topical cosmetic, toiletry and pharmaceutical products such as creams, lotions, pastes, liquids, aerosols, shampoos, gels, wipes, bats, sticks, powders and granules, are known in the art to be susceptible to microbial infestation. The raw materials, packaging, and manufacturing environment for these products are often not sufficiently sterile, such that small amounts of microbiological contaminants can enter into final products. Often, a cosmetic, toiletry or pharmaceutical product may be exposed to higher temperatures than recommended which can also accelerate the growth rate of microbes unless a suitably effective antimicrobial component and/or components are incorporated into the formulation. Once product packages are opened, they are subject to further contamination from repeated consumer use. Microbial growth can cause discoloration and/or unpleasant odor of the product, but can also degrade chemical and/or active compounds in the cosmetic, toiletry or pharmaceutical formulation, which can lead to instability of the product and/or emulsion. A product that has been contaminated by microbiological organisms can also lead to user infections once it is applied to the skin, scalp and/or mucous membranes of a human.
It is therefore important for manufacturers and marketers of such products to be able to offer products that resist microbial growth and provide a stable and safe product with a long shelf life.
Acne, as a family of skin disorders is one of the most prevalent dermatologic diseases in the world. It usually affects almost everybody during the life (Feldman et al., 2004). The pathogenesis of acne is complex but dependent on four key factors including androgen-mediated stimulation of sebaceous gland activity, follicular hyperkeratinization, colonization of the bacterium Propionibacterium acnes (an anaerobic bacterium as a normal constituent of the skin microbial flora), and inflammation (Cunliffe and Shuster, 1969).
The high levels of sebum elicited by androgen cause proliferation of P. acnes in the pilosebaceous ducts and this proliferation triggers the host inflammatory response with a discharge of the proinflammatory cytokines, interleukin-1b (IL-1 b), IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor α (TNF-α) and complement deposition (Gollnick et al., 2003).
More precisely, Acne vulgaris, the most common chronic skin condition seen by dermatologists, is a disorder of the pilosebaceous unit characterized by papules, comedones and pustules. The face, back and chest are the areas most commonly affected as they possess a large number of sebaceous glands, about nine times the concentration found elsewhere on the body. It affects more than seventeen million people in the US and it has been estimated that 85 percent of the adolescent population experiences this condition. Acne affects both genders with a peak incidence at 14-17 years for girls and 16-19 years for boys. It also affects 8 percent of 25-34 years-old and 3 percent of 35-44 years-old adults3). However, the number of patients over the age of 25 objected by acne vulgaris is increasing. Adult women, in particular, may be affected and may experience premenstrual flares. In any case, severe acne tends to be more common in adolescent males then in people of other age-groups.
Although the primary cause of acne is end-organ hyper-responsiveness to circulating androgens triggering sebum overproduction in the follicle, an important role is also played by secondary bacterial infection that is favoured by abnormal desquamation of follicular epithelium. The increased amount of sebum produced, combined with excessive numbers of desquamated epithelial cells from the walls of the sebaceous follicle, accumulates within and distends the follicle, resulting in the formation of a clinically unapparent precursor lesion of acne vulgaris called the microcomedone. There are several explanations for ductal hypercornification. These include the comedogenic effects of certain sebaceous lipids, an androgen-controlled defect, retinoid control, local cytokine modulation and the effects of ductal bacteria.
Propionibacterium acnes is a member of the resident bacterial flora and resides in sebaceous follicles. The anaerobic environment of the follicles that are plugged, indeed, particularly facilitate proliferation of P. acnes causing the release of chemotactic factors and pro-inflammatory mediators into the follicle and surrounding dermis leading to the inflammations.
The clinical manifestations of these pathophysiological events include non-inflammatory closed (blackhead) or open (whitehead) comedos, as well as inflammatory lesions, including papules, pustules, cysts and nodules.
Acne can be divided into mild, moderate and severe based on the number of lesions and the surface of skin involved. Mild acne is characterised by open and closed comedones sometimes accompanied by few superficial inflammatory lesions, moderate acne is characterized by increasing largely superficial inflammatory lesions with pustules that have the tendency to scar with time. Nodules and cysts with marked scarring characterise severe acne.
Propionibacterium acnes (P. acnes) is a species of relatively slow growing aerotolerant gram-positive anaerobic bacilli that is associated with acne. In the skin of individuals with acne, the overgrowth of P. acnes in blocked pores leads to the rupture of the pores to form lesions. Therefore, antibiotics have often been used to control this bacterial growth. Some antibiotics that are currently used by dermatologists to control acne include tetracycline, doxycycline, minocycline, erythromycin, clindamycin, vancomycin and sulfonamides. In addition, keratolytic agents, such as benzoyl peroxide and retinoids (e.g. tretinoin, adapalene, tazarotene) are often used to clear the skin of patients with acne. Severe cases of inflammatory acne can be treated with the retinoid isotretinoin. However, isotretinoin has the drawback of being a teratogen, causing severe birth defects. In some cases antiandrogen therapy is even used to control androgen excess in women, since androgen production stimulates and causes enlargement of sebaceous glands.
Various skin care products are presently sold on the market to control acne.
However, none of these acne products use extracts of Santolina for the control of the acne producing bacteria P. acnes.
The field of this invention relates to the new antibacterial properties of Santolina extract against the bacterium Propionibacterium acnes; and its applications in the fields of cosmetics and of dermatology for the treatment of acne and skin disorders associated with P. acnes. The extracts are useful in personal care or skin care products to aid in the control, reduction, or elimination of P. acnes in individuals showing signs of skin acne.
Preservatives help maintaining the integrity of cosmetic, toiletry or pharmaceutical formulations. A preservative corresponds to any substance or mixture of substances able to prevent chemical or microbiological degradation of a product. More specifically, antimicrobial preservatives prevent bacterial or fungal damage (microscopic fungi or yeast). A preservative also prevents oxidation of a product, which may be related to its composition or its environment. An optimum preservative thus includes both efficacious antimicrobial and antioxidant effects.
The preservatives widely used in the cosmetic industry include chemical compounds like parabens, imidazolidinyl urea, DMDM Hydantoin or phenoxyethanol. However environmental and health concerns prevail regarding the usage of such chemical preservatives. For example, parabens are becoming increasingly controversial, particularly because of their potential estrogen-mimicking aspect (Golden R, Gandy J, Vollmer G (2005). “A review of the endocrine activity of parabens and implications for potential risks to human health”. Critical Reviews in Toxicology 35 (5): 435-58, Darbre et al (2004) “Concentrations of parabens in human breast tumours”, J. Appl. Toxicol. 24, 5-13).
There is thus an impetus to develop natural alternatives to chemical preservatives. As natural ingredients appeal to consumers and as plants are known to possess biological activities, there is thus a need for a natural antimicrobial ingredient to replace synthetic ones.
Surprisingly, the inventors discovered and developed preservatives coming from vegetal source, which include ingredients that have both antimicrobial and antioxidant effects.
The present inventors have hence sought to develop a natural plant material based preservative that dually functions as a sustained antimicrobial and antioxidant system and thus would enhance the shelf life of cosmetic and personal care formulations.
According to a first aspect, the invention therefore relates to an extract of Santolina chamaecyparissus L. obtained by extraction of the aerial parts with a solvent chosen from methanol, dichloromethane, ethyl acetate, acetone, tetrahydrofuran, supercritical carbon dioxide and a mixture ethanol:water in a ratio of from 70:30% v/v to 99:1% v/v, and preferably in a ratio of 96:4% v/v
Specifically, the invention relates to a process for preparing an extract of Santolina chamaecyparissus L., comprising the following steps:
a) mixing aerial parts of Santolina chamaecyparissus L. with a solvent chosen from methanol, dichloromethane, ethyl acetate, acetone, tetrahydrofuran, supercritical carbon dioxide and a mixture ethanol:water in a ratio of from 70:30% v/v to 99:1% v/v, and preferably in a ratio of 96:4% v/v
b) macerating the mixture obtained in a) during at least 1 h, preferably at ambient temperature or at around 50° C., and in such a case, most preferably at 50° C.
c) filtering the mixture obtained in b), so as to obtain the filtrate and the retentate, the filtrate being the crude extract.
c1) optionally decolorization and/or deodorization of the crude extract via charcoal yielding in decolorized extract.
The invention also relates to an extract of Santolina chamaecyparissus L. obtainable by said process, and to compositions comprising it.
Such an extract may be a crude extract, or decolorized and/or deodorized extract. Thus obtained decolorized and/or deodorized extract is almost free from volatile compounds. Such extract does not impact organoleptic features of a composition to which it is added.
Surprisingly, decolorized and/or deodorized extract maintains its antimicrobial/antifungal activity, despite its composition difference as compared to a crude extract which did not undergo a decolorization step.
Said extract or composition may be used as preservative, antioxidant, bactericide and/or fungicide.
Finally, the invention also relates to the use of the compound of formula (I):
as preservative, antioxidant, bactericide and/or fungicide. Said compound is comprised in the extract according to the invention. Its chemical name is 1,6-dioxaspiro[4,4]nona-2,8-dien-4-ol,7-(2,4-hexadiyn-1-ylidene)-,4-acetate.
Particularly, in view of the above, and of the present description, said extract (crude or decolorized and/deodorized extract) according to the invention is not an essential oil. Indeed, it is not obtained by distillation, but by extraction; it has thus a different composition.
In the present invention, “preservative” means any substance or mixture of substances which prevents chemical and microbiological degradation of a product comprising it. Particularly, a preservative is a substance or mixture of substances which prevents degradation by bacteria, fungi and yeast, of a product comprising it. Typically, the preservative properties of a substance or mixture of substances are evaluated on different strains of bacteria, like gram-positive bacteria and gram-negative bacteria; on yeasts; and on fungi. Typical gram-positive bacteria are Pseudomonas aeruginosa; typical gam-negative bacteria are Staphylococcus aureus or Escherichia coli; typical yeasts are Candida albicans; and typical fungi are Aspergillus brasiliensis or Aspergillus niger.
Thus, a preservative is a bactericide, a fungicide and an antioxidant.
“Antimicrobial” means bactericide and/or fungicide.
“Bactericide” means any substance or mixture of substances which prevents degradation by bacteria of a product comprising it.
In the same way, “fungicide” means any substance or mixture of substances which prevents degradation by fungi of a product comprising it.
“Antioxidant” means any substance or mixture of substances which prevents oxidation of a product comprising it.
The extract of Santolina chamaecyparissus L. according to the invention is obtained by extraction of the aerial parts with a solvent chosen from methanol, dichloromethane, ethyl acetate, acetone, tetrahydrofuran, supercritical carbon dioxide and a mixture ethanol:water in a ratio of from 70:30% v/v to 99:1% v/v, and preferably in a ratio of 96:4% v:v. Preferably, the extract comprises the compound of formula (I) mentioned above.
Santolina chamaecyparissus is a plant belonging to the family Asteraceae. Their flowers are yellow. The aerial parts of the plant may be flowers, stems, seeds, fruits or leaves. Preferably, said aerial parts comprise at least leaves.
The solvent used for extraction is very important in the present invention: indeed, it ensures the good properties of the final extract used as preservative.
Said solvent is chosen from:
If methanol is used, it is pure in the present invention (i.e. the solvent is 100% methanol). As shown in example 5, methanol, dichloromethane, ethyl acetate, acetone or tetrahydrofuran ensure a high concentration of the compound of formula (I) in the extract, and said compound is in part responsible for the good preservative and antioxidant activities (see example 4).
If a mixture ethanol:water is used, then ethanol and water have to be in a ratio of from 70:30% v/v to 99:1% v/v, and preferably in a ratio of 96:4% v:v. For example, if one would like to use a ratio 75:25% v/v, then 75 ml of ethanol have to be used in mixture with 25 ml of water so as to obtain 100 ml of solvent. As shown in examples 2 and 5, said ratio ensures a high concentration of the compound of formula (I) in the extract, and said compound is in part responsible for the good preservative and antioxidant activities (see example 4). Indeed, as shown in example 2, the antimicrobial activity with said mixture is as good as the one obtained with methylparaben.
The invention also relates to a process for preparing an extract of Santolina chamaecyparissus L., comprising the following steps:
a) mixing aerial parts of Santolina chamaecyparissus L. with a solvent chosen from methanol, dichloromethane, ethyl acetate, acetone, tetrahydrofuran, supercritical carbon dioxide and a mixture ethanol:water in a ratio of from 70:30% v/v to 99:1% v/v, and preferably in a ratio of 96:4% v:v.,
b) macerating the mixture obtained in a) during at least 1 h, preferably at ambient temperature or at around 50° C. and in such a case, most preferably at 50° C.,
c) filtering the mixture obtained in b), so as to obtain the filtrate and the retentate, the filtrate being the crude extract,
c1) optionally decolorization and/or deodorization of the crude extract using activated carbon.
Step a) of the process comprises mixing said aerial parts with a solvent chosen from methanol, dichloromethane, ethyl acetate, acetone, tetrahydrofuran, supercritical carbon dioxide and a mixture ethanol:water in a ratio of from 70:30% v/v to 99:1% v/v. Preferably, if a mixture ethanol:water is used, the ratio of said mixture ethanol:water is from 75:25% v/v to 99:1% v/v, more preferably it is either around 80:20% v/v or around 99:1% v/v, and most preferably it is 96:4% v:v. The aerial parts may first be dried and ground into powder, before mixing with the solvent. Typically, the aerial parts of the plant are mixed with the required solvent in a ratio of 1 for 10 (i.e. 100 g of aerial parts of the plant for 1 L of solvent).
Then, the process comprises a step b) of macerating the mixture obtained in step a) during at least 1 h. Preferably, step b) is performed at ambient temperature or at around 50° C., and in such a case, most preferably at 50° C. By “ambient temperature”, it is meant a temperature between 20 and 25° C., preferably around 25° C. Preferably, step b) lasts at least 2 h. Preferably, step h) is performed under mechanical stirring.
Thereafter, the mixture obtained in step b) is filtered in step c). The solution is indeed filtered in order to remove the insoluble substances. This filtration step is usual in the plant extract field, and those skilled in the art are able to adjust the reaction parameters thereof, on the basis of their general knowledge.
At the end of step c), a filtrate and a retentate are obtained. The filtrate corresponds to an extract of the invention.
Steps a) to c) of the process according to the invention correspond to an extraction.
The process according to the invention may also comprise a further (second) extraction. More specifically, said process may preferably comprise a further step d) comprising:
The features of step a) described above are also applicable to step d1).
The features of step b) described above are also applicable to step d2).
The features of step c) described above are also applicable to step d3).
Finally, the last step d4) comprises mixing both filtrates of each extraction, so as to obtain a final filtrate, corresponding to an extract according to the invention.
The process according to the invention may also comprise a further step e) of evaporation of the solvent of the extract. Said evaporation may occur according to classical methods known in the art, like vacuum-concentration.
Preferably, step e) comprises addition of a liquid cosmetic compound, and evaporation of the solvent (i.e. methanol or the mixture ethanol:water in the required ratio). Said step e) may be called a step of solvent substitution. Preferably, step e) comprises:
Step e1) is typically performed at ambient temperature. Step e2) is typically performed by heating at a temperature comprised between 50° C. and 70° C., typically at around 60° C. If the polyol, alkyl-glucosides and alkyl-polyglucosides or the monoglyceride which is used is solid at ambient temperature, then said polyol, alkyl-glucosides and alkyl-polyglucosides or monoglyceride is previously heated so as to become liquid or semi-liquid at ambient temperature, before step e1).
The cosmetic compound chosen from polyols, alkyl-glucosides and alkyl-polyglucosides and monoglycerides is cosmetically acceptable, and is liquid or semi-liquid. By “cosmetically acceptable”, it is meant a compound compatible with the skin and its appendages. By “liquid or semi-liquid”, it is meant liquid or pasty. Typically, a liquid or semi-liquid compound is easy to mix in a cosmetic preparation at 30° C.
The cosmetic compound or carrier could be used as a solubilizer, an emulsifier, a surfactant or an humectant in order to improve the formulation of the said extract.
The said carrier could be a compound that does or does not occur in nature.
The cosmetic composition may contain combinations comprising at least one carrier. The polyols are also called glycols: they correspond to organic compounds comprising at least two —OH groups. Preferably, without being limited to, the polyols are diols (ie they comprise 2-OH groups), like substituted or non-substituted 1,2-propanediols, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol; or they are triols (ie they comprise 3-OH groups), like 1,2-octanediol or glycerol.
The monoglycerides comprise glycerol monolaurate, glycerol monocaprate, glycerol monocaprylate, glycerol monooleate, glycerol monomyristate, glycerol monopalmitate and glycerol monostearate.
The alkyl-glucosides and alkyl-polyglucosides comprise and are not limited to, decyl glucoside, arachidyl glucoside, butyl glucoside, caprylyl/capryl glucoside, caprylyl glucoside, cetearyl glucoside, coco-glucoside, ethyl glucoside, isostearyl glucoside, heptyl glucoside, lauryl glucoside, myristyl glucoside, hexadecyl glucoside, octadecyl glucoside, octyldodecyl glucoside or undecyl glucoside.
Preferably, the cosmetic compound is chosen from diols, triols and monoglycerides. Among the substituted 1,2-propanediols, ethylhexylglycerin is preferred.
1,2-octanediol is also called caprylyl
More preferably, the cosmetic compound is chosen from ethylhexylglycerin, ethylene glycol, pentylene glycol, diethylene glycol, propylene glycol, 1,2-octanediol (or caprylyl glycol) and glycerol.
More preferably, the cosmetic compound is chosen from ethylhexylglycerin, caprylyl glycol and their mixtures. A preferred mixture is the mixture ethylhexylglycerin/caprylyl glycol sold under the name Sensiva SC10 by Schülke & Mayr.
In this case, the extract of Santolina chamaecyparissus L. which is obtained at the end of step e2) comprises the cosmetic compound, preferably ethylhexylglycerin or caprylyl glycol, as solvent.
The present invention also relates to an extract of Santolina chamaecyparissus L. obtainable by the process described above. Said extract preferably comprises at least the compound of formula (I):
The compound of formula (I) could also be of a synthetic origin.
The present invention also relates to a composition, particularly cosmetic or dermatological, comprising, in a physiologically acceptable medium, an extract of Santolina chamaecyparissus L. according to the invention. By “physiologically acceptable medium”, it is meant a medium compatible with the administration to a subject. Preferably, the composition comprises from 0.1% to 10% by weight of the extract of Santolina chamaecyparissus L. according to the invention, more preferably from 0.2% to 7%, more preferably from 0.3% to 5% by weight, more preferably from 0.3% to 1% by weight.
Said composition may be cosmetic, pharmaceutical (preferably dermatological), a food composition, or a chemical composition.
Said cosmetic or pharmaceutical (preferably dermatological) composition can in particular be suitable for topical application.
Advantageously, said cosmetic or pharmaceutical (preferably dermatological composition) can be in the form of a powder, an emulsion, a microemulsion, a nanoemulsion, a suspension, a solution, a lotion, a cream, a gel cream, an aqueous or aqueous-alcoholic gel, a foam, a serum, an aerosol solution or dispersion, or a dispersion of lipid vesicles.
In the case of an emulsion, it may be a water-in-oil or oil-in-water emulsion.
The cosmetic or pharmaceutical (preferably dermatological) composition according to the invention also comprises a solvent chosen according to the various ingredients and to the administration form.
By way of examples, mention may be made of water (preferably demineralized water) or an alcohol such as ethanol.
Said cosmetic or pharmaceutical composition can also comprise at least one additive that is usual in the field, such as, for example, at least one compound chosen from an emollient or humectant, a gelling agent and/or thickener, a surfactant, an oil, an active agent, a dye, an active agent, an organic or inorganic powder, pigments, a sunscreen and a fragrance.
In particular, said composition can comprise:
Other additives normally used in cosmetics or in pharmacy can also be present in the composition according to the invention, in particular fragrances well known in the technical field.
Those skilled in the art are capable of choosing, among all these possible additives, both the type and the amount of those which will be added to the composition, in such a way that the latter conserves all its properties.
The invention also relates to the use of an extract of Santolina chamaecyparissus L. according to the invention, or to the use of a composition comprising it, as preservative, antioxidant, bactericide and/or fungicide.
The invention also relates to the use of the compound of formula (I):
as preservative, antioxidant, bactericide and/or fungicide.
The invention also relates to the use of a composition comprising the compound of formula (I):
as preservative, antioxidant, bactericide and/or fungicide.
The invention is illustrated in a non limiting manner by the examples below.
Aerial parts of Santolina chamaecyparissus L. (also called “santolina” in the examples, unless indicated otherwise) were harvested, dried, ground into powder and extracted under mechanical stirring using a mixture of water and ethanol (75:25 v/v) (steps a) and b)). The extraction was repeated once (step d)), and both extractions were performed at 25° C. during 2 hours (step c)). The obtained extracts were filtered, stirred together and vacuum-concentrated (step e)).
Crude extracts were analyzed by HPLC using an Agilent 1200 system equipped with a DAD and an ELSD detectors. Separation was performed using a Luna C18 column (Phenomenex, 250×4.6 mm; 5 μm). HPLC grade acetonitrile, water and 2-propanol (Sigma-Aldrich), acidified with formic acid 0.1%, were used according to the following gradient (Table 1):
The characteristic analytical profile (HPLC-ELSD) of S. chamaecyparissus was obtained (data not shown).
The crude extracts mentioned in this example were obtained in example 1.
1) Antimicrobial Activity Assay
Background and Samples Preparation:
Antimicrobial activity of the crude extracts was determined using a 96-well microtiter plate assay based on growth inhibition. The assay was performed on four different microbial strains, chosen according to the European Pharmacopoeia (ATCC references): Staphylococcus aureus (gram-negative bacteria), Escherichia coli (gram-negative bacteria), Pseudomonas aeruginosa (gram-positive bacteria), Propionibacterium acnes (anaerobic gram-positive bacteria), Aspergillus niger (fungus) and Candida albicans (yeast).
Samples for antimicrobial assay were prepared as follows: crude extracts were diluted at 200 mg/mL in a mixture of appropriate solvents, e.g. ethanol and water (60:40 v/v) or pure dimethylsulfoxide. After solubilization, the solutions were filtrated on 0.45 μm syringe filters.
Assay Procedure:
The assay was performed for each strain according as follows: samples (at 200 mg/mL) were first diluted to 4% in water, then to 2% and 0.2% in wells. Final concentrations were also 0.4 and 0.04% of crude extracts in wells. Each concentration was assessed in replicate with one supplementary control well containing no microbial strain. For the assay at 2%, samples were mixed up in the wells with growth medium (95 μL) and microbial suspension (representing an absorbance of 0.6 for C. albicans, S. aureus and P. aeruginosa and 40 spores/μL for A. niger). For the assay at 0.2%, samples were first diluted to 0.2% with water in the wells. Negative controls constituted of the solvent mixture used to prepare the sample solutions, and positive controls with a synthetic preservative (methyl-paraben and/or phenoxyethanol, positive standard) were also prepared. Results were also compared with those obtained using a commercial natural preservative (commercial preservative). The 96-well plates were incubated at 25° C.
The absorbance was read for each plate at 620 nm 24, 48 and 72 hours after the beginning of the incubation to evaluate the growth of each microorganism in presence of crude extracts.
The results were expressed as a percentage of growth inhibition by the samples for each microorganism.
In a second step for the optimized extract of S. chamaecyparissus, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were also measured including E. coli and P. acnes. The MIC is defined as the lowest concentration of an antimicrobial that will inhibit the visible growth of a microorganism after incubation from 24 h to 72 h according to the microbial strains. The MBC is the lowest concentration of antibacterial agent required to kill a particular bacterium, that is to say to reduce the viability of the initial bacterial inoculum by >99.9%. The dilutions were run in triplicate for the MIC and MBC test. At the end of the incubation, the tubes were read for the growth inhibition and then the MBC was determined by sampling all the macroscopically clear tubes and the first turbid tube in the series.
The results were expressed in mg/mL of extract.
2) Results for S. chamaecyparissus Crude Extracts
S. chamaecyparissus crude extracts exhibited antimicrobial activity as shown in Table 2 (the results presented correspond to one reference crude extract, which is representative of most of extracts that have been evaluated):
Aspergillus niger
102
101
Candida albicans
100
100
Pseudomonas aeruginosa
Staphylococcus aureus
97
Aspergillus niger
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
Aspergillus niger
100
100
Candida albicans
99
100
Pseudomonas aeruginosa
Staphylococcus aureus
80
Positive Standard: Methylparaben
=> As antimicrobial activity was considered to be interesting above 60% of growth inhibition, Santolina chamaecyparissus crude extracts showed a very interesting activity on 3 of the 4 microbial strains, e.g. S. aureus, A. niger and C. albicans. It was interesting to notice that a commercial extract sold for its preservative properties did not show any activity, in contrast to the positive standard (methylparaben).
3) Description of the Antioxidant Assays
Sample solutions for antioxidant assays were prepared in methanol, sonicated and filtered on 0.45 μm syringe filters.
Total Phenolic Content (Folin-Ciocalteu Assay)
Total phenolic content of santolina crude extracts was determined using the Folin-Ciocalteu method based on oxidation of a phenolate ion from an antioxidant sample and reduction of the phosphotungstic-phosphomolybdate reagent (Folin-Ciocalteu reagent) under alkaline conditions. As a result of this reduction, the chromophore moiety turns into from a yellow complex to a blue phosphotungstic-phosphomolybdic, representative of the presence of phenols (antioxidant biological species) in the sample. The concentration of these biological species is proportional to the light absorption at a wavelength of 750 nm, where other biological species do not absorb. The absorbance values of the samples were compared to a standard, which is commonly gallic acid. Total phenolic content is thus expressed as gallic acid equivalent (GAE) in milligrams per gram of plant extract.
Antiradical Power: DPPH Assay
The antiradical power of the sample was measured by the DPPH (2,2-diphenyl-1-picryl-hydrazyl) electron-transfer assay. DPPH is a free radical, which is purple in solution and reduced and getting yellow to colorless in presence of an antioxidant sample. The antiradical power of a sample is thus measured by the capacity to neutralize free radicals responsible for oxidation. DPPH reduction is observed by a spectrophotometric measurement of absorbance value at 520 nm (the lower the absorbance, the stronger the antioxidant activity). The IC50 (inhibiting concentration 50%) is the parameter determined with this assay. It corresponds to the concentration of antioxidant sample that reduces 50% of the initial DPPH concentration, expressed in micrograms of sample per milliliters of methanol.
4) Antioxidant Activity of Crude Extracts
Different S. chamaecyparissus crude extracts were evaluated (different origins and harvesting periods) and showed a total phenolic content (GAE) varying between 33 and 70 mg/g. As standards, natural rosemary extracts commercialized for their high antioxidant properties were evaluated and expressed a total phenolic content of about 85 mg/g. Another commercial antioxidant extract made of wasabi was evaluated and expressed only about 27 mg/g GAE.
Concerning the DPPH assay, the lowest IC50 of S. chamaecyparissus extracts was 118 μg/mL. As a comparison, an extract of rosemary, known for its antioxidant potential, presented a very similar IC50, namely 103 μg/mL.
=> As a conclusion, the S. chamaecyparissus crude extracts according to the invention seem to present an interesting antioxidant potential.
1) Fractionation of the Crude Extract
As the reference S. chamaecyparissus extract (ethanol:water 75:25 v/v) exhibited a strong antimicrobial activity, bioguided fractionation was performed to identify the fraction(s) containing active metabolites. Open column chromatographic fractionation of the crude extract was performed.
Fractionation was performed on a silica gel (normal phase) open column and yielded five fractions: cyclohexane fraction (F1), cyclohexane:ethyl acetate fraction (F2), ethyl acetate fraction (F3), ethyl acetate:methanol fraction (F4) and methanol fraction (F5).
All obtained fractions were analyzed by HPLC-ELSD in the same conditions as the crude extracts to have a qualitative idea of the different metabolites constituting each fraction.
2) Antimicrobial Activity of santolina Fractions
Fractions obtained from S. chamaecyparissus crude extract were submitted to antimicrobial activity assays (as explained in example 2) if sufficient quantity was present. Sample solutions were prepared at 100 mg/mL in DMSO and assessed the same way as crude extracts.
The results were as following in Table 3 (only fractions with an activity, even weak, are shown):
Aspergillus niger
100
100
Candida albicans
99
98
Pseudomonas aeruginosa
94
Staphylococcus aureus
105
113
Aspergillus niger
90
103
Candida albicans
96
Pseudomonas aeruginosa
Staphylococcus aureus
Aspergillus niger
68
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
=> F2 cyclohexane:ethyl acetate fraction showed an increased activity. The presence of one major metabolite in this fraction that is not present in the other normal-phase fractions, is noticed, and this metabolite could be responsible for the antimicrobial activity (or part of) of santolina crude extracts.
Semi-preparative HPLC was performed on the active cyclohexane:ethyl acetate santolina fraction in order to purify the major metabolite supposed to be responsible for the antimicrobial activity. It was carried out on a Luna C18 column (Phenomenex, 250×10 mm; 5 μm). Elution profile was optimized and the single component of interest was successfully isolated using a gradient of non-acidified HPLC grade water and acetonitrile. The single component was vacuum-concentrated and submitted to structure elucidation techniques.
1) Structure Elucidation
1D- and 2D NMR
NMR experiments were performed using a BRUKER Avance spectrometer (1H 500, 13 MHz). All 1D (1H, 13C) and 2D (COSY, HSQC, HMBC, NOESY) spectra were acquired in chloroform (CDCl3). The following structure of formula (I) was identified:
This molecule has following molecular formula: C15H12O4 and following molecular weight: 256,2534 g/mol. It is already known as 1,6-dioxaspiro[4,4]nona-2,8-dien-4-ol,7-(2,4-hexadiyn-1-ylidene)-,4-acetate and belongs to the secondary metabolites polyacetylenes family.
UPLC-HRMS
The isolated metabolite was analyzed by UPLC-ESI-HRMS using a Waters Acquity system. The inventors used UPLC-HRMS to identify the active metabolite in santolina crude extract. With the developed method, the mass-to-charge ratio (m/z) of its ion in positive mode was [M+H]+=257.0816 g/mol (data not shown).
This information confirmed the hypothesis of the proposed molecule, since the molecular weight of the known compound was established as M=256.2534 g/mol.
2) Validation of the Activity of the Pure Compound (Formula (I))
The pure compound appeared to be unstable once isolated, and particularly in aqueous and acid conditions. Since antimicrobial assays were performed in water, its antimicrobial activity could not be evaluated as for crude extracts or plant fractions. Thus, the inventors tried to establish a relationship between antimicrobial activity and active substance content in crude extracts.
Relationship between Antimicrobial Activity and Active Substance Content
A quantitation of the active substance was performed by HPLC-UV. The same solvent gradient as for HPLC-ELSD analysis was applied but stopped at 43 min. A calibration curve was determined using a trans-cinnamic acid standard (that has a retention time relatively close to the active substance retention time) prepared at different concentrations (from 0.0078 to 1 mg/mL) in methanol. Different santolina crude extracts (E1 to E2) were diluted to 20 mg/mL in methanol and analyzed by HPLC-UV at 310 nm, which is the absorption maximum of the active substance (and which allows comparison between the different extracts). The linear regression equation generated by the calibration curve permitted to calculate the value of active substance by corresponding integration and area peak measurement.
Antimicrobial activity assays (as explained in example 2) were also performed on said crude extracts, and the following results were obtained (table 4):
A.
C.
P.
S.
niger
albicans
aeruginosa
aureus
=> The results show that a relationship between active substance concentration in crude extracts and their antimicrobial activity can be observed, especially on A. niger and C. albicans.
However, the activity on S. aureus seems to be independent of the presence of the active substance (formula (I)).
To confirm this hypothesis, the inventors wondered if other plants of the genus Santolina also containing the active substance would present the same results.
Antimicrobial Activity of other Santolina Species Containing the Active Substance
Two other Santolina species (Santolina rosmarinifolia L. and Santolina pinnata L.) were investigated. Crude extracts were prepared and analyzed by HPLC-ELSD to confirm the presence of the active substance. They were then submitted to the same HPLC-UV quantitation as described in the previous paragraph, and to antimicrobial activity assays, and the following results were obtained (table 5):
A.
C.
P.
S.
niger
albicans
aeruginosa
aureus
S.
rosmarinifolia
S. pinnata
=> The results show differences of activity between these extracts and S. chamaecyparissus extracts. It can be explained by differences of chemical composition of the species.
=> The presence of the active substance (formula (I)) and the antimicrobial activity can although be correlated.
I) Optimization of the Extraction Process
Optimization of Solvent Extraction
As the inventors demonstrated that antimicrobial activity is in relation with active metabolite (compound of formula (I)) concentration, optimization of the extraction process was performed with modification of solvents.
Ethanol/Water Gradient
The initial solvent of extraction was a mix of ethanol/water 75:25 v:v. First step was also to change this gradient from 100% of ethanol to 100% of water. Seven new solvents were evaluated as described in Table 6:
These crude extracts were then analyzed using UV-HPLC at 310 nm and the active metabolite was quantified following the method described in example 4. Higher concentration was found for EtOH/Water 80:20 v:v gradient. No active was observed in water extract, neither for weak percentage of water in extraction solvent. Higher active substance concentration was found for 80% and 96% of ethanol and decreased then for higher purity of ethanol.
=> Optimal gradient was thus between 60 and 96% v/v of ethanol.
Other Solvents
The second step was to compare other solvents to extract the plant and then quantify the metabolite concentration. Tested solvents were tetrahydrofuran, acetone, dichloromethane, methanol, absolute ethanol, ethanol 96°, ethyl acetate and methyltetrahydrofuran.
As shown in Table 7, methanol was the extraction solvent giving the higher concentration of metabolite before dichloromethane, acetone and ethyl acetate which gave very good data too.
All these 4 solvents gave higher active concentrations than ethanol/water 80:20 v/v. Methanol was also selected for the rest of the optimization of the extraction process to produce a cosmetic ingredient.
2) Optimization of a Cosmetic Preservative
Solvent extract of Santolina chamaecyparissus was not an easy to use ingredient for cosmetic as it was thick and doughy. To remove this drawback, a liquid and specific cosmetic raw material was added. In order to do this, extraction process was modified as follows:
After the two methanolic extractions processing of aerial parts of Santolina chamaecyparissus L. (see example 1), the obtained extracts were filtered and stirred together. Then, one selected liquid cosmetic raw material was added to the extract under stirring. Finally, methanol was eliminated under vacuum.
Several cosmetic raw materials were selected. They were polyols (like glycols, such as glycerol) and monoglyceride esters.
After concentration of the extract, the inventors obtained a product easier to use in cosmetic formulations.
Extract Solubility in Liquid Cosmetic Raw Material
The list of cosmetic raw materials added during the extraction process is described in Table 8.
Santolina chamaecyparissus was extracted (methanol extraction) according to the above protocol, and each of the cosmetic raw materials was added. Then, a classification was done in function of crude extract solubility therein as follows:
Santolina
chamaecyparissus
Ethylhexylglycerin was the raw material in which the crude extract of Santolina chamaecyparissus presented the best solubility. Three of the best raw materials for the plant extract were also selected for antimicrobial activity evaluation:
These 3 ingredients were liquid and easy to use for cosmetic formulations.
Metabolite Concentration in Optimized Extract
Before biological test, HPTLC analysis were done on these three optimized extracts and compared with the crude extract without any cosmetic raw material.
HPTLC Analysis
Metabolite relative quantification was done using a Camag HPTLC system (Muttenz, Switzerland) equipped with an automatic TLC sampler (ATS4), an automatic developing chamber (ADC 2), a visualizer and a TLC scanner 4 controlled with WinCATS software. Sample solutions were applied on silica gel 60 F254 plates (20×10 cm×0.20 mm) purchased from Merck. All plates were developed until 70 mm from the lower edge, with humidity control from 33 to 38% and 20 min of saturation. Mobile phase for plates development was toluene/ethyl acetate/formic acid 96:4:1 v/v. Plates were scanned at 315 nm in reflectance mode, with D2 and W lamp, slit dimension of 8.00 mm×0.40 mm, scanning speed of 20 mm/s and data resolution of 100 μm/step.
Calibration curve was performed with stock solutions of Santolina chamaecyparissus (crude methanolic extract) at 1 mg/mL in methanol. Several amount of the stock solution (1, 2, 6, 8 and 12 μL) were applied on plates which were then developed and scanned. The calibration plots of peak areas versus concentration were polynomial equation (second degree). R2 coefficient was acceptable above 0.99. The metabolites eluted with a Rf of 0.42.
Identification of the metabolite through TLC development was performed using isolated compounds.
HPTLC Dosage
Active compound concentration was compared in each sample as described in Table after pilot extraction. A very high metabolite concentration in all products (between 31.3 and 38.9 mg of active/g of extract) was observed. Also, the addition of cosmetic raw material during the extraction process did not affect the active compound.
chamaecyparissus
Santolina chamaecyparissus + RM1
Santolina chamaecyparissus + RM2
Santolina chamaecyparissus + RM3
For the rest of the study, the three evaluated products are named as follows:
Antimicrobial Activity of Santolina chamaecyparissus Extract with Selected Cosmetic Raw Materials
Antimicrobial activity of the methanolic crude extract and the three ingredients containing the crude extract and selected cosmetic raw materials was evaluated against five microorganisms at 0.4 and 0.04% during 48 to 72 h:
Details of results are described in Tables 10 to 13 below.
Santolina chamaecyparissus at 0.4 and 0.04% at 24, 48 and 72 h.
Santolina chamaecyparissus
Aspergillus niger
Escherichia coli
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
Santolina chamaecyparissus
Aspergillus niger
Escherichia coli
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
Santolina chamaecyparissus
Aspergillus niger
Escherichia coli
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
Santolina chamaecyparissus
Aspergillus niger
Escherichia coli
Candida albicans
Pseudomonas aeruginosa
Staphylococcus aureus
Crude extract was active against A. niger, C. albicans and S. aureus at 0.4%.
Ingredient 1 was active against A. niger and E. coli at 0.4 and 0.04% and against C. albicans and S. aureus at 0.4% of Santolina chamaecyparissus extract. Finally, it was moderately active against P. aeruginosa.
Ingredient 2 was active against the five microorganisms at 0.4% of Santolina chamaecyparissus extract and additionally it was active against A. niger at 0.04% during 48 h.
Ingredient 3 was active against the five microorganisms at 0.4% of Santolina chamaecyparissus extract.
=> Finally, a better inhibition of all ingredients was observed in comparison to the crude extract alone. These ingredients were also optimized for antimicrobial activity and cosmetic use.
3) Evaluation of the Antimicrobial Activity for Cosmetic Preparations
Challenge Test (Description of the Test)
The challenge test is designed to provide the level of biological activity possessed by the preservative system of cosmetic products. Briefly, a controlled amount of specific microorganisms is inoculated in products. Mixtures are stocked in controlled conditions and microorganisms are counted at known times for 28 days.
Antimicrobial preservative effectiveness of the formulations was performed following the method recommended by the European Pharmacopeia (7th edition—2011).
Microorganisms
Tested Microorganisms were:
Bacteria
Fungi & Mold
These one are potential pathogenic germs and could contaminate products as they are issued from biotypes such as water, skin, intestinal or environmental.
Culture Media
Tested strains were prepared as described in Table 14:
P. aeruginosa
S. aureus
E. coli
C. albicans
A. brasiliensis
Procedure
The test organisms specified were to be tested separately in cosmetic products.
The product to be tested is distributed in single-use sterile flasks (20 g of product/flask) and every flask is inoculated with the suspension of one strain to be tested. Final concentration is about 105 to 106 microorganisms/g.
Inoculated products were to be held at 22.5° C.±2.5° C. in darkness during the test.
Neutralization
Neutralization of preservative system was validated and performed on the 5 strains with LT 100 Broth at 1/10th and 1/100th dilution.
Interpretation
Sampling and analysis are done after 2-day, 7-day, 14-day and 28-day period. Each sample was neutralized and enumeration method was applied (results in CFU/g). The microbial densities obtained during the follow-up for each of the tested strains are counted and compared with the thresholds of the logarithmic reduction imposed by the reference table (table 15).
Cosmetic Formulations
Challenge tests were realized with oil-in-water (O/W) emulsions comprising or not Santolina chamaecyparissus extract. The O/W emulsion formulations are described in Table 16.
Simmondsia chinensis (Jojoba) seed oil
Triticum vulgare (weat) germ oil
Butyrospermum parkii butter
Santolina chamaecyparissus Extract
In the experiments, Formula 1 comprised 4% of glycerin and Formula 2 comprised 10% of glycerin.
Challenge tests were systematically performed:
Antimicrobial Activity
Antimicrobial Activity in Formulation I
Santolina chamaecyparissus extract was first tested at 0.5% and 2% in formulation 1 with Ingredient 2 or 3. As ingredients 1 to 3 contained 50% of plant extract, they were introduced at 1 and 4% respectively.
The results are in Table 17.
P. aeruginosa
S. aureus
E. coli
E. coli
C albicans
A. brasiliensis
The results show that 0.5% of Santolina chamaecyparissus extract was sufficient to be in accordance with criteria A of European pharmacopeia against P. aeruginosa, E. coil and C. albicans and in accordance with criteria B against S. aureus.
At 2% of crude extract in Ingredient 2 (=4% of ingredient 2), challenge test on formula 1 was in accordance with criteria A against all bacteria and yeast, and with criteria B against mold. It was noted that after 28 days of incubation, formula 1 was in keeping with criteria A against all microorganisms. The antifungal activity against A. brasiliensis was only slower than expected in the method.
With 2% of Santolina chamaecyparissus in ingredient 3 (=4% of ingredient 3), challenge test on formula 1 was in accordance with criteria A against all microorganisms.
Antimicrobial Activity in Formulation 2
Ingredient 1 was tested at 2% in formulation 2 (=1% of crude extract). As shown in Table 17, 1% of Santolina chamaecyparissus extract was sufficient to be in accordance with criteria A of European pharmacopeia against P. aeruginosa, S. aureus, E. coli and C. albicans and with criteria B against A. brasiliensis.
Optimization of Solvent Extraction
As the inventors demonstrated that antimicrobial activity is in relation with active metabolite (compound of formula (I)) concentration, optimization of the extraction process was performed with modification of solvents, temperature of extraction and the time of extraction.
Ethanol/Water Gradient
The initial solvent of extraction was a mix of ethanol/water 75:25 v:v. A different plant batch, more abundant incompound (I) was used, to which the extraction gradient ranging from 60% to 100% of ethanol was assessed, as described in Table 18. Two successive extraction steps were performed prior to extract concentration and analysis.
These crude extracts were then analyzed using UV-HPLC at 310 nm and the active metabolite was quantified following the method described in example 4. Higher concentration was found for EtOH/Water 99:1 v:v gradient. Higher active substance concentration was found for 80% and 98% of ethanol and decreased then for higher purity of ethanol.
=> Optimal gradient was thus confirmed between 75 and 98% v/v of ethanol.
Temperature of Extraction
The second step involved an evaluation of the impact of different temperatures of extraction on extraction yield and compound (1) concentration. Only one extraction step was performed during the optimization of the temperature of extraction.
As shown in Table 19, a higher concentration in the active substance (I) was reached at 50° C. rather than when lower temperatures were used.
Extraction Time
The plant extraction was performed at 50° C., as previously optimized.
As mentioned in Table 20, only 3 hours and no more are required to reach the highest concentration in active substance (I) contained within the said Santolina chamaecyparissus L. extract.
The optimized extract was then assessed for its antimicrobial activity and more particularly in order to determine the minimum bactericidal concentration for the following microbial strains: Staphylococcus aureus (gram-negative bacteria), Escherichia coli (gram-negative bacteria), Pseudomonas aeruginosa (gram-positive bacteria), Aspergillus niger (fungus) and Candida albicans (yeast).
Due to a higher active substance (I) content, it convinces to evaluate the impact on its antimicrobial activity.
A.
C.
P.
S.
niger
albicans
aeruginosa
aureus
E. coli
S. chamaecyparissus
The optimized extract was then assessed for its antimicrobial activity and more particularly in order to determine the minimum inhibitory concentration for Propionibacterium acnes (gram-positive bacteria). Methyl paraben and phenoxyethanol, as universal antimicrobial agents, were used as positive control. Due to the a higher active substance (I) content, the impact on the antimicrobial activity and more particularly on an anaerobic bacteria was evaluated.
P. acnes
S. chamaecyparissus
Surprisingly, the said extract is able to strongly inhibit the growth of this anaerobic bacteria acting only at 1.27 mg/mL.
In order to decrease its color and odor impact in a cosmetic formulation, the Santolina extract was (crude extract) deodorized and decolored using activated carbon. This step was performed at ambient temperature or at 50° C. and the treatment time lasted at least 30 min using from 1% w/w extract to 20% w/w extract of activated carbon. Preferably, 5-15% w/w extract of activated carbon was used. After this step, a decrease on the active substance (I) content was observed. The optimized extract was then assessed for its antimicrobial activity and more particularly in order to determine the minimum bactericidal concentration for the following microbial strains: Staphylococcus aureus (gram-negative bacteria), Escherichia coli (gram-negative bacteria), Pseudomonas aeruginosa (gram-positive bacteria), Aspergillus niger (fungus) and Candida albicans (yeast). The following conditions of decoloration/deodorization were assessed with activated carbon:
As mentioned below in the Table 24, the decolorized/deodorized extract used is representative to the above conditions of decoloration/deodorization. Despite the decrease of the active substance (I) content, the level of active substance (I) remained sufficient to maintain a protection against large antimicrobial spectrum.
A.
C.
P.
S.
E.
niger
albicans
aeruginosa
aureus
coli
The optimized extract was then assessed for its antimicrobial activity and more particularly in order to determine the minimum inhibitory concentration for Propionibacterium acnes (gram-positive bacteria). Methyl paraben and phenoxyethanol, as universal antimicrobial agents, were used as positive control. Due to the a higher active substance (I) content, it convinces to evaluate the impact on its antimicrobial activity and more particularly on an anaerobic bacteria.
As mentioned below in the Table 25, despite the decrease of the active substance (I) content, the level of active substance (I) remained sufficient to inhibit the microbial growth of P. acnes.
P. acnes
Cunliffe, W. J., Shuster, S., 1969. Pathogenesis of acne. The Lancet 293, 685-687.
Feldman, S., Careccia, R. E., Barham, K. L., Hancox, J., 2004. Diagnosis and treatment of acne. American Family Physician 69, 2123-2138.
Gollnick, H., Cunliffe, W., Berson, D., Dreno, B., Finlay, A., Leyden, J. J., Shalita, A. R., Thiboutot, D., 2003. Management of acne: a report from a Global Alliance to Improve Outcomes in Acne. Journal of the American Academy of Dermatology 49, S1-S37.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14305401.3 | Mar 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/055910 | 3/20/2015 | WO | 00 |
