Bioprospecting of Microorganism-Based Industrial Molecules. Группа авторов

been projected for the development of skin moisturizers and skin repair [61]. In a study carried out on 30 volunteers, BC masks have been checked for the treatment of dry skin and improving skin hydration, and its in vivo efficacy was checked after single applications [61].

      4.4.2.3 Astaxanthin and Equol

Astaxanthin is a terpene of carotenoids family and is obtained from many algal and bacterial species. Astaxanthin is known to have antioxidant properties. A recent study focused on the comparison of Astaxanthin and Equol was carried out by gene expression analysis to analyze the properties like antioxidants, extracellular matrix integrity, growth factors, and inflammatory biomarkers. These findings indicate that Equol’s efficiency is greater than that of Astaxanthin [62]. Equol is also added in topical and oral applications to increase skin health and decrease photoaging.

      Equol is a comparatively novel phytochemical used as a constituent for human skincare. Equol is an isoflavan, which has a polyphenolic structure produced in plant and food sources [63]. Equol [7‐hydroxy‐3‐(4′‐hydroxyphenyl)‐chroman] belongs to the group of compounds known as nonsteroidal phytoestrogens. The heterocyclic structure contains two reactive hydroxyls and one relatively inert and unreactive oxygen in the central furan ring. It has selective estrogen receptor modulator (SERM) property that gives an improved/constant delivery into the dermal layers of the skin [63, 64], thus inhibiting dermal aging and improves facial appeal [63, 65]. Equol has been studied extensively for more than two decades [66]. But it has gained interest in its new application in skincare, where several reports using topical applications of Equol have demonstrated improved human dermal parameters, such as in vitro, in ex vivo, and in vivo studies and applications in cosmetics [63–66]. In effect, Equol is a unique cosmetic ingredient for which in vitro gene expression biomarkers have been shown to relate to protein expression [65].

      Equol is produced in the human intestine metabolized from daidzein by bacterial flora in the intestines. Daidzein is a type of isoflavone present in soybeans and other plant sources. In recent years, many bacterial isolates have been found from human fecal samples, which can produce Equol. These bacteria can prove to be a unique and novel source of Equol production by fermentation for commercial cosmetic products.

      4.4.3 Fungi Compounds

      4.4.3.1 Tyrosinase Inhibition

      Melanin is the major pigment accountable for skin tone and color. Due to continuous exposure, there is a sequential change in the function and structure of the skin. Due to overexposure to UV radiation, the melanin in the skin is increased due to the augmented level of tyrosinase activity. Tyrosinase is a rate‐limiting enzyme converting tyrosine to dihydroxyphenylalanine (DOPA) [67]. Further dopaquinone is converted to dopachrome with final product eumelanin leading to skin hyperpigmentation. Additionally, factors like hormonal changes signal transduction pathways also play a major role in skin pigmentation. Studies reporting the antityrosinase inhibitory activity are described using the Pleurotus species. Fruiting bodies of P. citrinopileatus species were reported for its tyrosinase activity and melanin production inhibition. Kojic acid, a low‐molecular‐weight organic acid, is widely known for its application in cosmetic and nutraceutical industries. Kojic acid is reported to be found in many fungal species with different types of substrates [68]. Due to its tyrosinase inhibition activity, kojic acid is used as an antioxidant in the cosmetic industry substituent to hydroquinone as the skin whitening agent.

      4.4.3.2 Hyaluronidase Inhibition

Hyaluronic acid (HA) is a natural glucose‐based polymer, which holds an important role in skin revitalization and moisture‐holding capacity [69]. In the aging process, the level of hyaluronic acid decreases with age, leading to moisture loss in the skin. Tropical lotions and creams provide alternatives, but such lotions are facing challenges because of their inflammatory response [69]. Dudek‐Makuch and Studzińska‐Sroka [70] reported the anti‐hyaluronidase activity from Aesculus hippocastanum species, and their reports suggest that inhibition of HA will work as a protector to skin and compounds like saponins.

      4.4.3.3 Collagenase and Elastase Inhibition

      The epidermis of the skin is attached firmly by connective tissue beneath dermis. The fibroblast (dermis) produces two proteins: collagen and elastin, which serves as a protective role in the skin [71]. Elastin is an important protein providing elasticity to the connective tissues, viz., cartilage, lungs, and skin. In aging phenomena, degradation of elastin is occurring due to the elevated level of elastase enzyme. Collagen is an important part of skin responsible for maintaining elasticity and flexibility of the skin. During the aging process, a significant decrease in the level of collagen, elastin, and HA results in loss of flexibility, moisture, and strength of skin, resulting in wrinkle formation. [72]. Additionally, MMPs are endopeptidases that degrade the extracellular matrix associated with pathological and physiological conditions like inflammatory response and also carcinogenesis [73]. Kim et al. [71] has reported the mycelial extracts of Tricholoma and Grifola sp. possess the anti‐collagenase and anti‐elastase activity. Further two‐hybrid compounds, ascorbyl‐3‐pcoumarate and the ascorbyl‐2‐p‐coumarate mixture of ascorbic acid and p‐coumaric acid serve as necessary cosmeceutical agents for increasing the collagen synthesis from dermal fibroblast and also decreasing the MMP protein expression [74].

      4.4.4 Algae Compounds

      Due to increasing awareness of natural compounds, attention has been shifted toward the use of novel bioactive compounds from microbial sources. Among these microbial communities, the importance of algae is a prominent one due to the presence of numerous biologically active compounds [75]. Algae are eukaryotic organisms with a primary photosynthetic pigment. Most of them have an autotrophic mode of nutrition and are related to various polyphyletic groups [76]. Algae can be broadly classified based on the chlorophyll pigments and type of reserve food materials. According to the pigments, a few major types of class are Chlorophyceae (green algae), Phaeophyceae (brown algae), Xanthophyceae (yellow green), Rhodophyceae (red algae), Chrysophyceae (golden algae), Bacillariophyceae (diatoms), and Dinoflagellates [77]. Based upon the cell size and morphology, they can be further grouped as microalgae and macroalgae (seaweeds). Furthermore, depending upon salinity, algae can occur in freshwater, marine, or brackish water habitats [78].

Algae are known to produce abundant bioactive molecules associated with antiaging and skin lightening products, which have potential applications in the cosmetic industry [79]. Algal products widely used in the cosmetic industry include bioactive compounds such as antioxidants, sunscreens lotions, UV protectants, anti‐photoaging compounds, skin smoothing, thickening, gelling, moisturizing, skin lightening, and de‐pigmenting agents to enrich the competence of skin against abrasions, tanning, sunburn, aging, and increase the overall radiance of skin [80–82]. These products comprise complex and simple compounds such as carbohydrates, proteins (enzymes, peptides, and amino acids), lipids (PUFA, MUFA, omega‐3‐fatty acids, sterols), pigments, and vitamins, antioxidants, and secondary metabolites [83]. These wide arrays of compounds can be extracted, solubilized, isolated, and purified by several different methods based on their physicochemical properties, molecular size, and solubility for utilization in cosmetic products. To use these potential bioactive molecules in the cosmetic application, the downstream recovery, purification of these ingredients of the whole process must be streamlined as per GRAS (Generally Recognized as Safe) practice, under the sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act.

      4.4.4.1 Carbohydrates from Algae

Algae are very well known to produce a wide array of polysaccharides. These polysaccharides play a crucial role in imparting the structure of cell walls and act as energy storage units during unfavorable stressful conditions. Some of the major types of biologically active polysaccharides in algal tissues are fucoidan, lamnarian, alginates, agar, carrageenan, galactan, porphyran, glucan, and ulvan, which demonstrate typical structural and functional characteristics [84]. These polysaccharides are nontoxic, cost‐effective, easily