73 NATURAL ACTIVE INGREDIENTS AND SKIN HYDRATION Therefore, they are widely used in cosmetic applications to maintain skin homeostasis and to restore disrupted skin layers (56). Seong-Beom Han et al. studied Asterina pectinifera, a marine species of starfish found mainly in Korea, eastern Russia, Japan, and China. Collagen peptides were isolated from A pectinifera starfish with a lower molecular weight. These were then encapsulated into elastic liposomes with high efficiency to overcome the low absorption rate of collagen peptides into the skin. In conclusion, they demonstrated this combination to be superior as a cosmetic ingredient by measuring the reduction of matrix metalloproteinase expression in photoaged cells (57). Collagens are found in cosmetic applications acting as moisturizers and natural humectants with anti-aging properties (58). Most marine organisms contain active ingredients such as polysaccharides, fatty acids, and collagens that possess excellent moisturizing properties for the skin (59). In a study by Li et al. (60), collagen extracted from sea cucumber contained a significant composition of moisture content. Sea cucumber collagen shows strong moisture absorption and high moisture retention ability, which determined the moisturizing properties for the skin. The author compared this collagen with those from the skins of tilapia and pigs. The three collagens that were extracted exhibited better moisture- retention and moisture-absorption capacity than glycerol. This showed that the collagen molecules were rich in hydrophilic groups, which have potential applications in cosmetic formulations. Another study suggested that the moisture absorption and retention potential of collagen in sea cucumber extract was excellent compared with glycerol. Therefore, the extracted collagen could be utilized as a moisturizer in the cosmetic industry (15). Studies by Wang et al. (3) concluded that extracts from algae or other marine organisms can be used for skin moisturization, as they are promising substances that can boost collagen synthesis, helping to promoting skin tissue, which eventually helps in reducing wrinkles. Another study by Brunt and Burgess (61) found that collagen extracted from jellyfish had a notable moisturizing effect on skin. Swatschek et al. (62) reported the successful extraction of collagen from the marine sponge Chondrosia reniformis. A total of a 30% yield of freeze- dried collagen was obtained, and two cosmetic formulae were trialed on human skin. They found no significant difference in skin hydration between the sponge collagen treatments and the existing collagen product control however, there was a significant increase in skin lipid content of 140–180 lg cm−2 1 hour after treatment. A review by Uppala (63) stated that hydras can be used as a moisturizer, as it contains vitamin C, which helps to increase collagen production in the dermis, and vitamin E, which helps in enhancing the skin’s barrier properties. Hydras are also rich in olive oil, which has emollient properties. Shark fish liver oil is highly rich in fatty acids and squalene, which have moisturizing properties. The application of seaweed as a cosmetic ingredient was also found to be effective as a moisturizing agent. This was supported by a study from Wang et al. (3), which showed that polysaccharides extracted from brown algae absorbed and retained more moisture than those from four other species of algae. The abundance of polysaccharides in red algae species also have hydrating, therapeutic, and moisturizing effects (15). An extract from green algae was also found to be efficient in regulating water distribution in the skin, thus protecting the skin from becoming dry, particularly in arid environments (15). In addition to producing HA, exopolysaccharides (EPS) are also produced by microalgae and can be considered significant moisturizing products. EPS involve several significant high molecular weight biopolymers. Microalgae produce these biopolymers and secrete them to a medium size during their cultivation (64,65). Glucuronic acid is one of the

74 JOURNAL OF COSMETIC SCIENCE biopolymers that can be utilized to protect the skin from dry environmental conditions and can help regulate the water content in the skin (64,66). EPS produced by microalgae show variability as a result of changes in the biosynthesis mechanism according to nutrients, culture conditions, and strains. C pyrenoidosa FACHB-9, Chlorococcum sp., Porphyridium cruentum, Spirulina platensis, and Scenedesmus sp. are known as EPS producers. Their cell- free cultivation mediums might be evaluated as cosmetics because of their glucuronic acid content (64,67). It has also been shown that cell-free cultivation mediums of P cruentum and S platensis might be good candidates for cosmetic ingredients because of their glucuronic acid content. Research on the bioactivity of fish collagen Type II (C-II) is in its beginning stages. The information that exists is limited almost entirely to shark C-II and is separated into three categories. First, because of its terrestrial sources, C-II from the blue shark (Prionace glauca) and the whale shark (Rhincodon typus) cartilage has anti-inflammatory activity (6,69). Chen et al. (70) showed that oral administration of C-II from the blue shark suppresses rheumatoid arthritis in experimentally induced rheumatoid arthritis model rats. Second, whale shark C-II stimulates osteogenesis and suppresses osteoclastogenesis when used as cellular scaffolds (71), and blue shark C-II scaffold promotes osteoblast cell formation (72). Third, whale shark C-II has antioxidant activity (73). Three peptides isolated from shark (Mustelus griseus) cartilage hydrolysate scavenge radicals were shown to inhibit lipid peroxidation and provide protection to H 2 O 2 -stressed HepG2 cells (74). Antioxidant peptides that help to improve the skin barrier from two skate species, Raja porosa and Rostanga pulchra cartilage, have also been reported (75,76). Other studies have reported antioxidant activities from salmon cartilage chondroitin sulphate (77,78). Puścion-Jakubik et al. (79) studied the consumption of certain ingredients (vitamins A, C, D, and E, and Cu, Mn, and Zn) on 172 young women. The study was assessed using the Diet 6.0 program, body composition was assessed using electrical bioimpedance, and skin hydration and lubrication were assessed using the corneometric and sebumetric methods, respectively. The results indicated that one-third of students showed insufficient consumption of vitamin C, vitamin E, and Zn, while approximately 99% showed insufficient vitamin D levels. The highest degree of hydration was observed in the areas of the eyelids, neckline, and chin. The greatest amount of sebum was found in the area of the nose and forehead. Low positive correlations were observed between hydration or lubrication and Cu, vitamin A, and vitamin E. The author concluded that in order to properly moisturize and lubricate the skin, young women should eat products that are rich in ingredients with antioxidant properties, particularly fat-soluble vitamins A and E and copper (79). Vitamin A and its derivatives contribute to the proper exfoliation of the SC, which improves its protective function and reduces TEWL (80). By penetrating deep into the lipid barrier of skin cells, vitamin E seals and strengthens the cell membrane, which results in water retention (81). CONCLUSION To date, the use of natural resources has been beneficial to consumers for healthier skin conditions and eventually a healthier lifestyle. In our review, natural sources from plants or marine sources were shown to provide hydration properties that warrant their use as cosmetic ingredients. The natural cosmetics sectors show encouraging development worldwide and are likely to keep growing and expanding alongside the increasing interest and demand among consumers.