PLANT RAW MATERIAL EXTRACTS AS COMPONENTS OF COSMETIC PRODUCTS AND FORMULATIONS FOR TOPICAL ADMINISTRATION: THE PRODUCT RANGE, THE PRODUCTION CHARACTERISTICS (REVIEW)

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Plant raw materials extracts are the traditional source of biologically active substances, used topically for prevention and treatment of various diseases in particular of the skin, and for cosmetic skin care. Nowadays in pharmaceutical practice extracts are used as cosmetic products, and semi product for making formulations for topical administration (ointments, gels, liniments) and cosmetics. The aim is an overview of the scientific and technical information concerning materials relating to the specifics of the range and the technology of extracts used in the external drug and cosmetic products. Methods. To describe the range of extracts proposed for external use the analysis of the proposals of Russian and foreign producers submitted their official websites and online trading platforms was used. The specificity of extraction of biologically active substances of plant extracting agents: water, ethyl alcohol, glycols, vegetable oils, carbon dioxide used to obtain extracts was described on the basis of available scientific literature (eLIBRARY, PubMed, Cyberleninca, Google Books). Results. An analysis of the range of online pharmacies assortment of medicinal and cosmetic products with plant raw materials extracts is notably diverse. Table 1 presents semisolid formulations for topical administration and cosmetics with extracts of plant raw materials [1, 2, 3, 4]. Table 1 shows, that external medicines for topical administration and cosmetics, containing extract from plant raw materials, are represented by venotonic (anti-oedematous, microcirculation improvers), anti-inflammatory, irritant, reparative, analgesic compositions. In table 2 the examples of cosmetics for daily care containing plant raw material from a pharmacies range are presented [3, 4, 5]. The data presented in the table 2 shows, that plant extracts are used in cosmetic products for the face (creams and masks for different skin types care, products for under-eye skin care) and body care, as well as in hair cosmetic products. Cosmetic extracts are also an independent group of products for skin care (table 3), comprising oil extracts or CO2-extracts oil solutions, represented in pharmacy assortment [3, 4]. The products represented in table 3, are suitable for skin care use in pure form or in mixture with other oils, as well as for enriching cosmetic products. The product range analysis of plant raw materials extracts most commonly used as intermediate for obtaining formulations for topical administration and cosmetic products, both Russian and foreign, was carried out (table 4) [6-17]. The table 4 data shows, that the extracts assortment includes dry extracts prepared using water and water-alcohol mixtures; soft extracts, liquid aqueous, glycolic extracts, oil extracts, CO2-extracts, CO2 supercritical extracts and the extracts obtained using the two-phase mixtures (capryl/caprat triglycerides/water). There are standardized (so-called “titrated”) extracts, which indicates the content of active ingredients, but for the most part - are extracts in which the content of active ingredients not specified. The biological activity of the plant raw material extract is determined by its chemical composition that is dependent on used extracting solvent. Thus, aqueous nettle (Urtica dioica L.) extracts contain, according to manufacturer data, organic acids, in particular vitamin C (table. 4), have, according to reported data, keratolytic and antioxidant effect. Aqueous alcoholic extract contains silicic acid (tab. 4) - a drying agent, and phytosterols possessing sebo-regulating action. In the nettle leaf extract obtained with 40% alcohol, were, according to experimental studies, discovered flavonoids (rutin, possessing antioxidant and anti-inflammatory activity), coumarins (umbelliferone) and other polyphenolic compounds, also chlorophylls. At the same time lipophilic nettle CO-extracts as active ingredients contain chlorophylls developing, as reported, reparative, antimicrobial activity, and carotenoids [18-20]. Certain advantages, expanding the range of biological activity of plant raw materials extract, have two-phase extracts, containing a complex of lipophilic and hydrophilic biologically active substances of the plant [21]. Polysaccharides, proteins, amino acids, low molecular weight organic acids, tannins, alkaloids in the salts form, saponins, water-soluble vitamins can be extracts from plant raw materials by water. But in aqueous extracts only trace amounts of essential oils are observed. Several authors noted the low transition of flavonoids to aqueous extracts [22-25]. The water use as extracting solvent re- quires the intensification of the extraction process. The most common technique is the extraction at elevated temperatures. When using water as the solvent the need for additional evaporation and drying operations occurs, because the aqueous extracts are characterized by microbiological instability. And to prevent caking and clumping during storage the dry extract may contain fillers (silica, dextrin, starch, etc.) [26-28]. Ethanol is most often used extracting solvent in the pharmaceutical practice (as a rule, the extraction is carried out by the ethanol different concentration aqueous solutions). Flavonoids, coumarins, cinnamic acids, etc. polyphenolic compounds, saponins, terpenoids, chlorophyll, etc. can be extracted from the plant raw material by alcohol-water mixture [18, 21, 28-33]. However, ethyl alcohol is a flammable liquid and its application in production is accompanied by higher fire safety requirements. In addition, ethanol has a skin tanning effect, dries it, and its removal requires additional technological operations of evaporation and drying as respectively as aqueous extract production [28]. Therefore, the use of cosmetics ingredients such as glycerin, propylene glycol, butylene glycol, caprylic/capric glycerides, silicones, oils as solvents to produce liquid extracts for cosmetic purposes is acceptable at present time. These substances play in cosmetics enhancers, solubilization, moisturizing functions and therefore do not require the removal after extraction [34-39]. Glycols (glycerine, propylene glycol, butylene glycol), and ethanol are the polar extracting solvents [39]. Glycerol (1,2,3 propantriol), a trihydric alcohol. Colorless viscous liquid, odorless, mixes well with water and ethanol. In small concentrations glycerol moisturizes the skin, in large (over 30%) has a drying and antiseptic effect. Glycerol is used as solvent for dry extracts, and to prevent the moisture evaporation from cosmetic products (gels, creams) [36, 38]. Propylene glycol (1,2 propylene glycol), dihydric alcohol. Colorless viscous hygroscopic liquid, odorless, mixes well with water and ethanol. Used as a solvent. It possesses the properties of the penetrator and moisturizing agent [37, 38]. Butylene glycol (1,3-butanediol), a dihydric alcohol. It is colorless viscous liquid. It mixes well with water, alcohols, acetone, poorly with non-polar solvents. It possesses antimicrobial activity, moisture-retaining properties. Butylene glycol is used in formulations of cosmetic products [38, 39]. The aqueous glycols solutions, having a lower viscosity than pure substances, are used as extracting solvents to increase the process efficiency [39-42]. It has also been reported that, the extraction ability of propylene glycol 1,2 to the flavonoids and coumarins from Melilotus officinalis depends on the water content in mixture, and the maximum extraction capacity has 40% aqueous glycol solution [43]. Selectivity extraction of lipophilic biologically active compounds increases with increasing of glycol concentration in aqueous solutions. The following consisted pattern of the Lavandula raw materials extraction is reported: tannins are extracted by 40% aqueous propylene glycol, essential oil - by 100% propylene glycol [44]. It has been reported the extraction efficiency of anthocyanins from the so-called dark-colored plants (red Rosa, Vitis vinifera, Aronia melanocarpa, Ribes rubrum) by acidified mixture water and glycerol 1:1. As it was found the extraction of anthocyanins, containing hydroxyls from adjacent carbon atoms, presumably increases with increasing of polyhydric alcohol content with the structure of α-glycol in extracting solvent. It’s due to in the formation of chelate complexes through hydrogen bonds between solvent molecules and anthocyanins [45]. Another advantage of glycol was observed: for example, Ribes nigrum extract, containing chemically labile anthocyanins, obtained by glycerin extraction, have a high stability upon prolonged storage (>2 months) compared to ethanol extracts [46]. The efficiency of glycols extraction depends on operation temperature: the glycol viscosity is reduced at temperature increase and the diffusion of substances molecules from the raw material to the solvent facilitates [41]. The effect of temperature on the glycols extraction efficiency is similar to other extracting solvents: water, ethyl alcohol and oil [28]. Some studies have reported the efficiency of glycols extraction at elevated temperatures [44, 46]. The plant material to solvent rate used for cosmetic extracts production, in particular glycols, is 1:5 or 1:10, which is more in line with pharmacopoeial tinctures concentrations. To obtain pharmaceutical products (for example, gels for external use) more concentrated extract - liquid extracts of 1:1 (table. 1) are used at the same time [1, 28, 39]. The use of low cosmetic extracts concentrations is justified by that, in general, the concentrations used in cosmetic products are lower than for pharmaceuticals. And, as a rule, the extracts contain the complex of substances that possess a synergistic skin effect [19, 47]. For example, using the aqueous-alcoholic Urtica dioica extracts in cosmetics for skin with acne is justified by the fact that they contained phytosterols possessing sebo-regulating action, silicic acid - drying effect, flavonoids - anti-inflammatory and capillary protecting effects, chlorophylls - a regenerative, antiseptic [19]. In addition, high plant extracts concentrations may change cosmetic products color and its sensory characteristics that affect cosmetics favorable perception. High extract concentrations will be able to cause the changes of the rheological properties of gel bases (gels of carbomer) [48, 49]. Aqueous glycols solutions do not possess antimicrobial activity in contrast to aqueous ethanol solutions, so to prevent microbial spoilage and to extend shelf life the preservatives (phenoxyethanol, methylisothiazolinone, potassium sorbate, sodium benzoate etc.) are added to glycolic extract [15, 39, 50]. As one can see from table 4 data, carbon dioxide is also quite widely used extracting solvent for cosmetic industry needs [51, 52]. Efficiency of CO -extracts application in cosmetic products is provided by lipophilic character of biologically active compounds extracted with liquefied carbon dioxide from plant raw materials. They have the affinity to skin structural components. Lipophilic character allows extracted for plant raw materials biologically active substances to penetrate easy into skin deeper layers and provide not only surface effect. The other advantage of liquid carbon dioxide as a component of cosmetics is its inability to maintain microorganisms and fungi growth that allows pure extracts producing, unlike hydrophilic extracting solvents [30, 51]. Features as the extracting solvent of carbon dioxide is determined by its good diffusion properties, low distillation temperature enabling the extracting solvent removing at small temperature and saving the extracted substances in the native state; the dielectric constant, which is close to the characteristic non-polar solvents, and this indicates the possibility of extraction non-polar or weakly polar substances. These include essential and fatty oils; carbonyl compounds; lipid-soluble vitamins (К, E); steroids; alkaloids in bases form; furocoumarins; furanochromons, etc. There is data showing the possibility of extraction of the Schisandra fruit lignans schizandrin and of γ-schizandrin with CO2. Reported that Rhodiola rosea CO2-extract contains as dominant component cinnamic alcohol, and some other low-polar or lipophilic substances such as tyrosol, rosarita, β-sitosterol, etc. [22, 31, 51-54]. Supercritical CO -extracts are used currently along with subcritical extracts. The possibility of production of essential oil extracts from plant raw materials with a given composition by this method in various studies have been reported. Supercritical СО2 have proven effectiveness for extracting essential oils for foods, cosmetics and pharmaceutical industries use. This method is considered as an intensified. [51, 55]. One of the technique extraction from plant raw materials using supercritical carbon dioxide for pure form individual thermo labile compounds separation is suitable: at various process parameters the serial fractions output from the lightest to heaviest is carried out. Reported the results of studies on selecting the optimum extraction of desired biologically active Salvia officinalis extract producing; rose flavonoids with standard composition and a specific range of volatile aromatic sub- stances obtaining. There is also data about technology development of supercritical CO2-extract of Tagetes with high lutein content [56-58]. The most practical application has the method of supercritical СО2-extracts producing by sequential treatment of plant raw materials sample with one solvent in several technological regimes allowing obtaining the sum extract lipophilic substances fractions of plant materials [6, 51]. Supercritical СО2-extracts are more potent antioxidants as compared with extracts produced by classical methods. The effectiveness of the supercritical СО2-extracts of rosemary and sage use in cosmetics as antioxidants to prevent oxidation of the fatty oils was currently proven [59]. Vegetable oil along with water is the extracting solvent, having a long history of use in pharmaceutical practice. Oil extracts (macerata) available in wide range of European manufacturers of plant material cosmetic assets. Peach, almond, sunflower, olive oils are most commonly used as the solvent. The vegetable oils extract from plant raw materials a lipophilic biologically active substances: carotenoids, chlorophyll, essential oils, en-in-ciclodiethers, coumarins (ex. herniarin), lignans (ex. schizandrine). Oil extracts (Chamomilla, Calendula, Hipericum, Chelidonium) are used as cosmetic products for everyday skin care. To prevent oxidation of saturated acids and improve the shelf life oil vitamin E can be added to extracts [16, 21, 28, 60, 61]. Currently there is the interest in lipophilic components of cosmetic products (silicones, synthetic glycerides) as plant raw materials solvents as more resistant to oxidation during storage than natural oils. Thus, the research of silicones in particular of cyclopentasiloxane using as well as vegetable oils, for lipophilic carotenoid containing extracts production on the example of pumpkin pulp was presented [62]. The extractive capacity in relation to chlorophyll increases in the number of soybean oil - capryl/capric triglycerides - isopropyl myristate. On the example of Urtica dioica leaves was proved. This fact is associated with the synthetic oils low viscosity, their lower molecular mass and high affinity to lipophilic biologically active compounds [35]. To the extracts production, along with the classic methods, maceration and percolation, the benefits of which include the extraction at low temperatures, that allows you to save thermo labile biologically active substances in the native form, are currently used intensified methods [27, 63- 65]. Thus, a multi-stage countercurrent extraction of plant raw materials in the original extractors circulation type with further concentration of the extracts in a vacuum-evaporating installations and subsequent spray drying is used to obtain extracts (production of “ArtLife techno”) [7]. The original technology of circulating vacuum extraction of the plant materials was tested on the basis of Scientific research Institute of vacuum technologies in Altai state technical University. The ability to produce the extraction of raw water at low temperatures (40-50 °C), thus avoiding the degradation of thermo labile substances is mentioned as its advantage [10]. On the base of LLC “Korolevpharma” the technology of production of extracts - electro-plasma-dynamic extraction was developed and implemented. The method consists in creating a pulse of electrical discharge voltage about 30 to 40 kV between the electrodes inside the chamber pulsed with the mixture of plant raw material and extracting solvent. Intensification of extraction is done by solvent leaching of biologically active substances of from the destroyed cells, and by increasing the speed of circulation of the extracting sol- vent. According to the manufactures data, this method allows you to extract 30-40% more active ingredients than using classical methods of extraction and stable substances, as the process goes without fever. There is also significant reduction in the time to 10-15 min. In addition, under the action of high voltage electric current the additional effect of disinfection of raw materials is achieved. Using as solvents water, oil, and water-glycerol or water-propylene glycole mixtures manufacturer produces extracts using this technology [50, 66]. Conclusion. Thus, the plant raw materials extracts are used in formulations for topical administration, means of medical cosmetics and cosmetic products as active ingredients with different activity. The investigated range of extracts from plant material for use in external drug and cosmetic shows that at the present time the extracts assortment is very diverse and represented by the dry extracts obtained using as extracting solvents water and water-alcohol mixtures; soft extracts; liquid glycolic extracts, oil extracts, CO2-extracts, CO2 supercritical extracts and the extracts obtained using the two-phase mixtures (capryl/caprat triglycerides/water). The extracts used in medicines, distinguished by a higher concentration of active components. A general trend of practical use as extracting solvents that are components of cosmetics is reflected in respective studies. Modern manufacturers also actively provide CO2-extracts of plant materials. Industrial manufacturers along with traditional methods of extraction use variations of the intense extraction.

About the authors

S. B Evseeva

«Bivitex»

Email: sbevseeva@yandex.ru
Nalchik, Russian Federation

B. B Sysuev

The Volgograd State Medical University of Public Health Ministry of the Russian Federation; State Budgetary Institution «Volgograd medical research center»

Volgograd, Russian Federation

References

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