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Cosmetics are widely used by people around the world to protect the skin from external stimuli. Consumer preference towards natural cosmetic products has increased as the synthetic cosmetic products caused adverse side effects and resulted in low absorption rate due to the chemicals’ larger molecular size. The cosmetic industry uses the term “cosmeceutical”, referring to a cosmetic product that is claimed to have medicinal or drug-like benefits. Marine algae have gained tremendous attention in cosmeceuticals. They are one of the richest marine resources considered safe and possessed negligible cytotoxicity effects on humans. Marine algae are rich in bioactive substances that have shown to exhibit strong benefits to the skin, particularly in overcoming rashes, pigmentation, aging, and cancer. The current review provides a detailed survey of the literature on cosmeceutical potentials and applications of algae as skin whitening, anti-aging, anticancer, antioxidant, anti-inflammation, and antimicrobial agents. The biological functions of algae and the underlying mechanisms of all these activities are included in this review. In addition, the challenges of using algae in cosmeceutical applications, such as the effectiveness of different extraction methods and processing, quality assurance, and regulations concerning extracts of algae in this sector were also discussed.

Background Hyperpigmentation is a common acquired disorder that can be a cosmetic concern for many individuals. To reduce and prevent hyperpigmentation, numerous skin lightening agents have been developed. Potassium 4‐methoxysalicylate (4MSK) is a skin lightening agent that was approved as an active skin lightening ingredient of quasi‐drugs by the Ministry of Health, Labour and Welfare of Japan in 2003. For over 20 years, 4MSK has been widely used in quasi‐drug and cosmetic products. However, the mechanism of action and efficacy of 4MSK on skin pigmentation and skin lightness have not been publicly reported. Aims This study aimed to assess the mechanism of action and the efficacy of 4MSK on facial pigmentation. Methods The mechanism of action of 4MSK on epidermal cells was investigated using human melanocytes, human keratinocytes, and human 3D epidermal equivalents. The efficacy of 4MSK on facial pigmentation was evaluated by a human clinical study, which is a double‐blind, split‐face, placebo‐controlled, paired‐design study. Results 4MSK significantly suppressed melanin content in cultured human melanocytes and a 3D epidermal equivalent. It also promoted gene expression of differentiation markers of human keratinocytes. In the clinical study, a 4MSK formulation significantly increased skin lightness values in both pigmented and non‐pigmented areas of cheek skin. In addition, it reduced the desquamation area ratio of the cheek. Conclusions 4MSK reduces skin pigmentation and contributes to brighter skin by acting on both melanocytes and keratinocytes.

3,6-Anhydro-l-galactose (AHG), a major monomeric constituent of red macroalgae (Rhodophyta), was recently reported to possess skin whitening activity. Moreover, AHG-containing oligosaccharides, such as agarooligosaccharides (AOSs) and neoagarooligosaccharides (NAOSs), have various physiological activities, including anti-inflammatory, antioxidant, and skin moisturizing effects. In this study, AHG and NAOSs were produced from agarose by enzymatic reactions catalyzed by an endo-type β-agarase, an exo-type β-agarase, and a neoagarobiose hydrolase. In a cell proliferation assay, AHG, AOSs, and NAOSs at 12.5, 25, and 50 μg/mL concentrations did not exhibit cytotoxicity toward murine B16 melanoma cells or human epidermal melanocytes. In an in vitro skin whitening activity assay of AHG, AOSs, and NAOSs at 50 μg/mL, AHG showed the highest skin whitening activity in both murine B16 melanoma cells and human epidermal melanocytes; this activity was mediated by the inhibition of melanogenesis. Neoagarotetraose and neoagarohexaose also exhibited in vitro skin whitening activity, whereas neoagarobiose and AOSs with degrees of polymerization of 3 (agarotriose), 5 (agaropentaose), and 7 (agaroheptaose) did not. Therefore, AHG is responsible for the skin whitening activity of agar-derived sugars, and the structural differences among the AHG-containing oligosaccharides may be responsible for their different skin whitening activities.

3,6-Anhydro- l -galactose (L-AHG) constitutes 50 % of agarose, which is the main component of red macroalgae. No information is currently available on the mass production, metabolic fate, or physiological effects of L-AHG. Here, agarose was converted to L-AHG in the following three steps: pre-hydrolysis of agarose into agaro-oligosaccharides by using acetic acid, hydrolysis of the agaro-oligosaccharides into neoagarobiose by an exo-agarase, and hydrolysis of neoagarobiose into L-AHG and galactose by a neoagarobiose hydrolase. After these three steps, L-AHG was purified by adsorption and gel permeation chromatographies. The final product obtained was 95.6 % pure L-AHG at a final yield of 4.0 % based on the initial agarose. In a cell proliferation assay, L-AHG at a concentration of 100 or 200 μg/ mL did not exhibit any significant cytotoxicity. In a skin whitening assay, 100 μg/ mL of L-AHG showed significantly lower melanin production compared to arbutin. L-AHG at 100 and 200 μg/ mL showed strong anti-inflammatory activity, indicating the significant suppression of nitrite production. This is the first report on the production of high-purity L-AHG and its physiological activities.

Background Cordyceps is a valuable Chinese herbal medicine known for its various components with antioxidant properties, which may theoretically improve melasma. This study aimed to evaluate the efficacy of a new skin‐lightening cosmetic containing Cordyceps extract (referred to as Cordyceps essence) in treating female patients with melasma. Methods Sixty‐two women with melasma were enrolled and randomly assigned to two groups for 12 weeks of treatment. Group A received oral tranexamic acid (TXA) combined with topical hydroquinone cream, while Group B received oral TXA combined with topical Cordyceps essence. Changes in the Melasma Area and Severity Index (MASI), melanin index (MI), and erythema index (EI) were monitored and assessed before and after treatment. Patient‐reported satisfaction and adverse events were also recorded. Additionally, a metabolomic analysis was conducted on 15 randomly selected patients from Group B. Results After 12 weeks of treatment, intra‐group comparisons revealed that MASI scores, MI, and EI significantly decreased in both Group A and B compared to baseline (p < 0.05). However, inter‐group comparisons showed no statistical differences in MASI scores, MI, or EI between the two groups after treatment (p > 0.05). Adverse reactions occurred in 4 people (13.8%) in Group A and 1 person (3.3%) in Group B. Patient satisfaction with treatment was similar in both groups. The metabolomic analysis identified significant differences in 29 metabolites and 15 metabolic pathways after treatment (p < 0.05). Conclusions Our study demonstrated that both oral TXA combined with hydroquinone cream and oral TXA combined with Cordyceps essence significantly improved melasma in women. However, the incidence of adverse reactions was lower with topical Cordyceps essence than that with hydroquinone cream. Cordyceps essence appeared to be a promising alternative for patients intolerant to hydroquinone cream. Metabolomic analysis revealed that modulation of melanogenesis‐related metabolites, enhanced antioxidant activity, and improved skin barrier function collectively contributed to the clinical improvement in melasma severity. The improvement of melasma with oral TXA and topical Cordyceps essence may be closely linked to changes in endogenous differential metabolites in the skin and the regulation of amino acid metabolic pathways.

Objective Charcoal based oral care products have gained popularity in the last few years. The aim of this in vitro study was to compare the effects of different charcoal based whitening toothpastes on color, surface roughness and microhardness of human enamel. Materials and methods Forty-eight specimens obtained from human permanent upper incisor teeth were randomly divided into 4 groups(n=12):Group-1:Colgate Total 12(CT); Group-2:Body Kingdom(BK); Group-3:Black is White(BW), Group-4:Colgate optic white(COW). Following 4 days cycle of darkening(2-min chlorhexidine and 60-min black tea per day), a 12- week brushing(twice daily for 1 min)was performed. Color of specimens was measured using a spectrophotometer. A contact type profilometer was used to measure surface roughness (Ra) and Vicker's hardness tester was used for the changes in microhardness(VHN). A representative sample from each group was visualized by SEM. Data were analyzed by One-way ANOVA, Welch, Fisher's, Kruskall-Wallis, Wilcoxon Sign Rank and Paired t-tests(p<0.05). Results After 12- week brushing, no differences were found among the groups in terms of color change(p=0.989). All toothpastes tested showed no clinically acceptable whitening performances. A substantial increase in surface roughness was found in all groups, except BW(p<0.05). An increase was found in microhardness with CT(p=0.013), while no changes were found with BK, BW and COW(p>0.05).Only few scratches were observed on the enamel surfaces by SEM evaluations. Conclusion Twelve week brushing with charcoal based whitening toothpastes and a regular fluoridated toothpaste presented similar effects in color of enamel. Surface roughness was increased(except BW) while microhardness was not affected(except CT) with charcoal based whitening toothpastes. Clinical relevance Charcoal based whitening toothpastes do not promise to whiten the human permanent teeth and their effects on enamel abrasion should not be disregarded.

Melanogenesis is a process to synthesize melanin, which is a primary responsible for the pigmentation of human skin, eye and hair. Although numerous enzymatic catalyzed and chemical reactions are involved in melanogenesis process, the enzymes such as tyrosinase and tyrosinase-related protein-1 (TRP-1) and TRP-2 played a major role in melanin synthesis. Specifically, tyrosinase is a key enzyme, which catalyzes a rate-limiting step of the melanin synthesis, and the downregulation of tyrosinase is the most prominent approach for the development of melanogenesis inhibitors. Therefore, numerous inhibitors that target tyrosinase have been developed in recent years. The review focuses on the recent discovery of tyrosinase inhibitors that are directly involved in the inhibition of tyrosinase catalytic activity and functionality from all sources, including laboratory synthetic methods, natural products, virtual screening and structure-based molecular docking studies.

Background: Tooth discoloration has become a common esthetic problem in recent years. Removal of stains by bleaching is well-documented. Low concentration home bleaching products are available in market in different forms and concentrations. Aim: The aim of this study is to evaluate and compare the efficacy of low concentration commercially available home bleaching products (whitening strip, gel, and mouthwash) in removing stains and whitening the tooth using clinical and digital methods. Materials and Methods: Sixty permanent enamel samples mounted in an acrylic block were artificially stained and randomly divided into four groups. Negative control, 15 % Carbamide peroxide gel group, 2% Hydrogen 16 peroxide mouthwash group and 6% Hydrogen peroxide strip group respectively. The samples were bleached with respective agents according to the manufacturer's instructions. The efficacy on 7th and 14th day was evaluated clinically (SGU change), photographically (ΔE), and using quantitative light-induced fluorescence (ΔF). The data were analyzed using paired t-test and analysis of variance. Results: Postbleaching, 6% hydrogen peroxide strips and 15% carbamide peroxide gel showed maximum improvement (ΔΔF - 15.73 and 11.89, ΔE - 19.8 and 18.9, respectively) when compared to 2% hydrogen peroxide mouthwash and negative control group (ΔΔF - 9.68 and 6.59, ΔE - 15.04 and 9.44, respectively). The difference was statistically significant (P = 0.001). Conclusion: 6% hydrogen peroxide strips and 15% carbamide peroxide gel showed maximum improvement in stain removal and tooth whitening however, the strips showed better efficacy than the gel. Strips have the added advantage of lesser contact period, less salivary dilution, and no gingival contact. Therefore, strips can be a better alternative for gels and mouthwashes.

(1) This study investigated the whitening effect, cytotoxicity and enamel surface alterations induced by different over-the-counter (OTC) bleaching agents in comparison to hydrogen peroxide. (2) Human teeth (n = 60) were randomly assigned into 6 groups (n = 10), stained with coffee solution for 7 d, followed by a whitening period of 7 d with either placebo, bromelain, sodium bicarbonate, sodium chlorite, PAP or hydrogen peroxide. Color measurements were performed with a spectrophotometer. Scanning electron micrographs (SEM) were taken to assess the enamel structure. Cytotoxicity of the tested substances was assessed based on the cell viability of primary human fibroblasts. (3) The application of all whitening gels resulted in a greater color difference of the enamel (ΔE) in comparison to the negative control. Hydrogen peroxide caused the greatest color difference. Bromelain and PAP treatment showed no enamel surface changes, in contrast to hydrogen peroxide treatment, which showed very mild interprismatic dissolution. Bromelain was the only non-cytotoxic agent. (4) The maximum effect achieved by all OTC bleaching agents was the removal of stains, whereas hydrogen peroxide was capable of further whitening the teeth. Bromelain treatment was neither cytotoxic, nor resulted in enamel surface alterations, and its whitening effect was less, yet still effective, compared to hydrogen peroxide.

To increase the stability of selenium in nano state and further improve its antioxidant and skin whitening ability, Bombyx batryticatus polypeptide (BBPP) was prepared. The optimum synthesis conditions of Bombyx batryticatus polypeptide nano-selenium (BBPP-SeNPs) were determined by a double-peak method. BBPP-SeNPs were characterized by transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), and particle size analysis (PSS). The 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS), superoxide anion free radical scavenging rate, and total antioxidant capacity of BBPP, vitamin C (VC), and BBPP-SeNPs were measured for comparison. The inhibitory ability of BBPP and BBPP-SeNPs on tyrosinase was measured. Using mouse modeling, the skin whitening ability of VC and BBPP-SeNPs was measured. The results showed that the optimal conditions were obtained when the concentration of BBPP was 0.16 mg/mL, sodium selenite was 0.01 mol/L, ultrasound was carried out for 30 min, ascorbic acid was added in 0.04 mol/L, and stirring temperature was 20 °C for 4 h. The antioxidant capacity of BBPP-SeNPs has significantly improved. It can be observed that BBPP-SeNPs has obvious scavenging ability on skin-reactive oxygen species through a Reactive Oxygen Species (ROS) staining section. Through Hematoxylin–Eosin (H&E) staining, it can be proven that BBPP-SeNPs has a high security threshold.