(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 extracted, and abundant in the algal biomass, which can be used as a substitute against synthetically derived gelling agents, or silicone‐derived ingredients. These compounds provide moisturizing and have antioxidant properties; hence they are used as gelling agents and stabilizers in emulsions [85, 86] (Table 4.2).
Table 4.2 Algal biomolecules, sources, origins, and applications in cosmetics.
Source: Wang et al. [85] and Wang et al. [86].
| Group of compound | Active compound | Algal species | Cosmetic properties | References |
|---|---|---|---|---|
| Polysaccharides | Agar | Gelidium sp.Gracilaria sp. | Emulsion stabilizers, gelling agents, thickeners | [87–89] |
| Alginates | Laminaria sp.Lessonia sp.Macrocystis sp. | Emulsion stabilizers, chelating agents, gelling, moisturizing, photo‐protective | [8490–92] | |
| Fucoidan | Saccharina sculpera Fucus vesiculosus, Turbinariaconoides, Undaria pinnatifida | Antiaging, anti‐wrinkle, antioxidative properties, UV protectant, skin lightening, spot reduction, elastase, tyrosinase inhibitors, skin fibroblast stimulation | [93–97] | |
| Laminarans | Laminaria japonica, Ecklonia kurome, Eiseniabicyclis, Saccharina, Ascophyllum, Fucus, Sargassum, and Undaria | Antioxidant, anti‐cellulite agent | [81, 98, 99] | |
| Porphyran | Porphyra sp. | Antioxidant and antiaging | [78, 88, 93, 100] | |
| Carrageenan | Acanthophora muscoidesChondrus crispus | Gelling agents, protective colloids, thickeners | [101–103] | |
| Ulvan | Ulva armoricana, Ulva lactuca, Ulva rotundata, and Ulva rigida | Antioxidative, chelating, gelling, moisturizing, and protective agents | [88, 104, 105] | |
| Pigments | Astaxanthin | Haematococcus pluvialis | Antiaging | [106] |
| β‐carotene | Chlorella, Spirulina, Dunaliella salina | Antiaging, antioxidant, radical scavengers, anti‐photoaging agents, and colorants | [88107–111] | |
| Chlorophylls(a, b, c, d) | Chlorella, Nannochloropsis | Coloring agents, UV‐protectant, reduce inflammation, Reducing wrinkles, inhibiting matrix metalloproteinases (MMPs) | [88, 92,112–114] | |
| Fucoxanthin | Fucus, Dictyota, Saragassum, and Laminaria | Anti‐tyrosinase activity in guinea pig UVB irradiated, and melanogenesis in mice UVB irradiated | [88115–117] | |
| Phycobiliproteins(APC, PE, PC) | Cyanobacteria | Antioxidant, anti‐inflammatory, colorants, radical scavenging agents | [88, 97,118–121] | |
| Secondary metabolites | Phlorotannins | Ecklonia cava, Eiseniabicyclis | Tyrosinase and hyaluronidase inhibitors, antioxidants, antiaging, UV‐photoprotectant, chelating agents | [79, 88, 122] |
| Mycosporine‐like amino acids (MAAs) | Scytonemin, Asterina‐330, Shinorine, PalythinePorphyra‐334 | Scytonema, Lyngbya, Porphyra umbilicalis | Photo‐protectant, sunscreen against UV‐A | [79, 111,122–124] |
4.4.4.2 Fucoidan
Fucoidans are heteropolysaccharides containing L‐fucose sugar and sulfate ester groups [10]. They are mostly derived from the brown seaweed. In some seaweeds, along with fucose sugar, other sugars such as glucose, galactose, mannose, xylose, and glucuronic acid (GlcA) have also been reported [125]. The application of
