Unveiling the Potential of Ultrasonic-Assisted Ethanol Extract from Sargassum horneri in Inhibiting Tyrosinase Activity and Melanin Production in B16F10 Murine Melanocytes.

BACKGROUNDS: Melanogenesis, regulated by genetic, hormonal, and environmental factors, occurs in melanocytes in the basal layer of the epidermis. Dysregulation of this process can lead to various skin disorders, such as hyperpigmentation and hypopigmentation. Therefore, the present study investigated the effect of ultrasonic-assisted ethanol extract (SHUE) from Sargassum horneri (S. horneri), brown seaweed against melanogenesis in α-melanocyte-stimulating hormone (MSH)-stimulated B16F10 murine melanocytes. METHODS: Firstly, yield and proximate compositional analysis of the samples were conducted. The effect of SHUE on cell viability has been evaluated by using 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. After that, the melanin content and cellular tyrosinase activity in α-MSH-stimulated B16F10 murine melanocytes were examined. Western blot analysis was carried out to investigate the protein expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2). In addition, the effect of extracellular signal-regulated kinase (ERK) on the melanogenesis process was assessed via Western blotting. RESULTS: As per the analysis, SHUE contained the highest average yield on a dry basis at 28.70 ± 3.21%. The findings showed that SHUE reduced the melanin content and cellular tyrosinase activity in α-MSH-stimulated B16F10 murine melanocytes. Additionally, the expression levels of MITF, TRP1, and TRP2 protein were significantly downregulated by SHUE treatment in α-MSH-stimulated B16F10 murine melanocytes. Moreover, SHUE upregulated the phosphorylation of ERK and AKT in α-MSH-stimulated B16F10 murine melanocytes. In addition, experiments conducted using the ERK inhibitor (PD98059) revealed that the activity of SHUE depends on the ERK signaling cascade. CONCLUSION: These results suggest that SHUE has an anti-melanogenic effect and can be used as a material in the formulation of cosmetics related to whitening and lightening.

Protective effects of phlorotannins against ultraviolet B radiation in zebrafish (Danio rerio).

Exposure to ultraviolet B (UV-B) radiation has been associated with a variety of adverse effects in all forms of life, including micro-organisms, plants, animals and humans. Ultraviolet B induces cell damage at the molecular level and consequently organisms must employ strategies to protect themselves from sunlight and to repair UV-B-induced cellular damage. In this study, the UV-B protective effects of four different phlorotannins isolated from a brown alga (Ecklonia cava) were determined using zebrafish (Danio rerio) as an in vivo model. Zebrafish embryos were pretreated with phlorotannins and exposed to UV-B (50 mJ/cm(2)). The heart rate, generation of reactive oxygen species and nitric oxide, cell death and hyperpigmentation were assessed in order to evaluate UV-B-induced photo-damage. Treatment of the embryos with the algal phorotannins reduced UV-B-induced reactive oxygen species and nitric oxide levels, protected against UV-B-induced cell death and significantly reduced hyperpigmentation. We therefore suggest that phlorotannins isolated from E. cava can protect against UV-B radiation. Editor Note. Readers of the journal may be unfamiliar with the use of zebrafish embryos in research studies. There is no indication in this article of an ethical review of the study. This is because the use of fish embryos in research, at least in the UK, is not subject to a licensing procedure if they are less than 5 days post fertilization (dpf). In this study the embryos were 2 dpf.

Apoptotic and antiproliferative effects of Stigmast-5-en-3-ol from Dendronephthya gigantea on human leukemia HL-60 and human breast cancer MCF-7 cells.

The genus Dendronephthya encompasses marine soft corals that produce a wide spectrum of biofunctional terpenoids. Anticancer properties of these metabolites are widely exploited as potential chemotherapeutic agents. The present study reports the purification and isolation of a potential antiproliferative constituent, stigmast-5-en-3-ol from the 70% ethanol extract of the soft coral Dendronephthya gigantea. Among several other 3ß-hydroxy-Δ5-steroidal congeners, stigmast-5-en-3-ol indicated prominent antiproliferative effects on HL-60 (leukemia) and MCF-7 (breast cancer) cell lines with IC50 values of 37.82 and 45.17 µg/ml respectively. Stigmast-5-en-3-ol increased apoptotic body formation, accumulation of sub G1 apoptotic cells, and DNA damage in HL-60 and MCF-7 cells. It increased the expression of Bax, caspases, and PARP cleavage while decreasing Bcl-xL levels in both cancer cell lines indicating that the effects are arbitrated via the mitochondria-mediated apoptotic pathway. Steroidal derivatives were identified by GC MS/MS and the identity of stigmast-5-en-3-ol was confirmed by NMR spectra. The present study suggests that stigmast-5-en-3-ol could be a promising candidate for anticancer drug research.

3ß-Hydroxy-Δ5-steroidal congeners from a column fraction of Dendronephthya puetteri attenuate LPS-induced inflammatory responses in RAW 264.7 macrophages and zebrafish embryo model.

Bioactive compounds from marine organisms and their action mechanisms have provided new insights into medicinal and natural product research. Here, we report the identification of 3ß-hydroxy-Δ5-steroidal congeners from a purified column fraction (DPCMH24) of the soft coral Dendronephthya puetteri harvested from Jeju, South Korea. DPCMH24 exerted strong anti-inflammatory effects through a dose-dependent decrease in the levels of nitric oxide (NO) in LPS-induced RAW 264.7 macrophages (IC50 value = 6.54 ± 0.38 µg mL-1). Further, DPCMH24 attenuated the levels of PGE2 and the pro-inflammatory cytokines, TNF-α, IL-1ß, and IL-6. The above effects were mediated via the inhibition of nuclear factor κB activation and mitogen-activated protein kinase pathways. In vivo evaluation indicated that DPCMH24 reduced NO, iNOS, COX-2, ROS production and cell death in LPS-induced zebrafish embryos, confirming its anti-inflammatory potential. The constituent compounds were identified by GC-MS/MS analysis. These findings suggest that the steroidal congeners from D. puetteri may offer ample therapeutic potential against LPS-induced inflammation.

Protective effect of fucoidan against AAPH-induced oxidative stress in zebrafish model.

Fucoidan, extracted from Ecklonia cava, has been extensively studied because of its wide biological activities. However, antioxidative activities have not been yet examined. Therefore we evaluated in vitro and in vivo studies on antioxidative activities of E. cava fucoidan (ECF). ECF exhibited more prominent effects in peroxyl radical scavenging activity, compared to the other scavenging activities. Thus, ECF was further evaluated for its protective ability against 2,2'-azobis dihydrochloride induced oxidative stress in Vero cells and ECF strongly reduced the AAPH-induced oxidative damage through scavenging intracellular reactive oxygen species. Furthermore, we evaluated protective effect of ECF against AAPH-induced oxidative stress in zebrafish model. ECF significantly reduced ROS generation, lipid peroxidation and cell death in zebrafish model. These findings indicate that ECF has antioxidant activities in vitro Vero cells and in vivo zebrafish model, even though ECF is not a polyphenol or flavonoid compound and does not contain benzene rings or conjugated structures.

Anti-inflammatory effect of fucoidan extracted from Ecklonia cava in zebrafish model.

Fucoidan extracted from Ecklonia cava had strong anti-inflammatory activities. However, the direct effects of fucoidan of E. cava on anti-inflammatory activities in vivo model remained to be determined. Therefore, the present study was designed to assess in vivo anti-inflammatory effect of fucoidan extracted from E. cava (ECF) using tail-cutting-induced and lipopolysaccharide (LPS)-stimulated zebrafish model. Treating zebrafish model with tail-cutting and LPS-treatment significantly increased the ROS and NO level. However, ECF inhibited this tail-cutting-induced and LPS-stimulated ROS and NO generation. These results show that ECF alleviated inflammation by inhibiting the ROS and NO generation induced by tail-cutting and LPS-treatment. In addition, ECF has a protective effect against the toxicity induced by LPS exposure in zebrafish embryos. This outcome could explain the potential anti-inflammatory activity of ECF, which might have a beneficial effect during the treatment of inflammatory diseases.

Molecular characteristics and anti-inflammatory activity of the fucoidan extracted from Ecklonia cava.

Enzymatic extraction has been successfully used for extracting numerous biologically active compounds from a wide variety of seaweeds. In this study, we found that enzymatic extraction of the fucoidan from Ecklonia cava may be more advantageous than water extraction. Therefore, we studied the E. cava fucoidans extracted by the enzymatic extraction technique and used ion-exchange chromatography to determine their molecular characteristics and anti-inflammatory activities. The crude and fractionated fucoidans (F1, F2, and F3) consisted mostly of carbohydrates (47.1-57.1%), uronic acids (9.0-15.8%), and sulfates (16.5-39.1%), as well as varying levels of proteins (1.3-8.7%). The monosaccharide levels significantly differed, and the composition included fucose (53.1-77.9%) and galactose (10.1-32.8%), with a small amount of rhamnose (2.3-4.5%), xylose (4.0-8.2%), and glucose (0.8-2.2%). These fucoidans contained one or two subfractions with an average molecular weight (Mw) ranging from 18 to 359×10(3)g/mol. These fucoidans significantly inhibited NO production in lipopolysaccharide (LPS)-induced Raw 264.7 macrophage cells by down-regulating the expression of iNOS, COX-2, and pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1ß. Thus, the present results suggest that E. cava fucoidan may be a potentially useful therapeutic approach for various inflammatory diseases.