Myra O. Villareal

Hirseins inhibit melanogenesis by regulating the gene expressions of Mitf and melanogenesis enzymes

Please cite this paper as: Hirseins inhibit melanogenesis by regulating the gene expressions of Mitf and melanogenesis enzymes. Experimental Dermatology 2009; 19: 450–457.

Hirseins A and B, daphnane diterpenoids from Thymelaea hirsuta that inhibit melanogenesis in B16 melanoma cells.

Two new daphnane diterpenoids, hirseins A (1) and B (2), were isolated from the aerial parts of Thymelaea hirsuta, and their structures were elucidated on the basis of spectroscopic data interpretation. Hirsein B (2) is an unusual daphnane in possessing a coumaroyl moiety. NOESY correlations of 2 implied that isomerization of the coumaroyl group in 2 was caused by equilibrium between the E (2e) and Z (2z) forms. Compounds 1 and 2 were found to inhibit melanogenesis in B16 murine melanoma cells.

Arthrophytum scoparium inhibits melanogenesis through the down-regulation of tyrosinase and melanogenic gene expressions in B16 melanoma cells

Melanin performs a crucial role in protecting the skin against harmful ultraviolet light. However, hyperpigmentation may lead to aesthetic problems and disorders such as solar lentigines (SL), melasma, postinflammatory hyperpigmentation and even melanoma. Arthrophytum scoparium grows in the desert in the North African region, and given this type of environment, A. scoparium exhibits adaptations for storing water and produces useful bioactive factors. In this study, the effect of A. scoparium ethanol extract (ASEE) on melanogenesis regulation in B16 murine melanoma cells was investigated. Cells treated with 0.017% (w/v) ASEE showed a significant inhibition of melanin biosynthesis in a time‐dependent manner without cytotoxicity. To clarify the mechanism behind the ASEE‐treated melanogenesis regulation, the expressions of tyrosinase enzyme and melanogenesis‐related genes were determined. Results showed that the expression of tyrosinase enzyme was significantly decreased and Tyr, Trp‐1, Mitf and Mc1R mRNA expressions were significantly down‐regulated. LC‐ESI‐TOF‐MS analysis of the extract identified the presence of six phenolic compounds: coumaric acid, cinnamic acid, chrysoeriol, cyanidin, catechol and caffeoylquinic acid. The melanogenesis inhibitory effect of ASEE may therefore be attributed to its catechol and tetrahydroisoquinoline derivative content. We report here that ASEE can inhibit melanogenesis in a time‐dependent manner by decreasing the tyrosinase protein and Tyr, Trp‐1, Mitf and Mc1R mRNA expressions. This is the first report on the antimelanogenesis effect of A. scoparium and on its potential as a whitening agent.

Caffeoylquinic Acid-Rich Purple Sweet Potato Extract, with or without Anthocyanin, Imparts Neuroprotection and Contributes to the Improvement of Spatial Learning and Memory of SAMP8 Mouse

The effects of caffeoylquinic acid (CQA)-rich purple sweet potato (PSP) extract, with (PSPEa) or without (PSPEb) anthocyanin, on the improvement of spatial learning and memory of senescence-accelerated prone mouse strain (SAMP) 8 was determined. SAMP8 was treated with 20 mg/kg/day of PSPEa or PSPEb for 30 days. The effect on spatial learning and memory and the molecular mechanism of this effect were determined in vivo (SAMP8) and in vitro (SH-SY5Y cells). PSPEa or PSPEb reduced the escape latency time of SAMP8 by 17.0 ± 8.0 and 14.2 ± 5.8 s (P < 0.01), respectively. PSPEa administration induced an overexpression of antioxidant-, energy metabolism-, and neuronal plasticity-related proteins in the brain of SAMP8. Additionally, PSPEa and PSPEb increased the cell viability by 141.6 and 133% as compared to Aβ1-42-treated cells. These findings suggest that PSP rich in CQA derivatives with or without anthocyanidine had a neuroprotective effect on mouse brain and can improve the spatial learning and memory of SAMP8.

Cyanidin-3-glucoside derived from black soybeans ameliorate type 2 diabetes through the induction of differentiation of preadipocytes into smaller and insulin-sensitive adipocytes

Black soybean is a health food has been reported to have antidiabetes effect. The onset of diabetes is closely associated with adipocyte differentiation, and at present, the effect of black soybean on adipocyte differentiation is unknown. Here, we investigated the antidiabetes effect of black soybean, and its anthocyanin cyanidin-3-glucoside (Cy3G), on adipocyte differentiation. Orally administered black soybean seed coat extract (BSSCE) reduced the body and white adipose tissue (WAT) weight of db/db mice accompanied by a decrease in the size of adipocytes in WAT. Furthermore, 3T3-Ll cells treated with BSSCE and Cy3G were observed to differentiate into smaller adipocytes which correlated with increased PPARγ and C/EBPα gene expressions, increased adiponectin secretion, decreased tumor necrosis factor-α secretion, activation of insulin signalling and increased glucose uptake. C2C12 myotubes cultured with conditioned medium, obtained from 3T3-L1 adipocyte cultures treated with Cy3G, also showed significantly increased expression of PGC-1α, SIRT1 and UCP-3 genes. Here we report that BSSCE, as well as its active compound Cy3G, has antidiabetes effects on db/db mice by promoting adipocyte differentiation. This notion is supported by BSSCE and Cy3G inducing the differentiation of 3T3-L1 preadipocytes into smaller, insulin-sensitive adipocytes, and it induced the activation of skeletal muscle metabolism. This is the first report on the modulation effect of Cy3G on adipocyte differentiation.

Anti-inflammatory and anti-arthritic effects of pentacyclic triterpenoids maslinic acid through NF-κB inactivation

SCOPE Consumption of olives (Olea europaea L.), including table olives and oil, is associated with low incidence of inflammation-related diseases. In this study, the effects of maslinic acid (MA), the main constituent of olive pomace, on the expression of genes and proteins involved in inflammatory activity in RAW 264.7 cells were investigated. Furthermore, the effect of MA on carrageenan-induced paw edema and collagen antibody induced arthritis in mice was determined. METHODS AND RESULTS We confirmed the suppressive effects of MA on LPS-induced tumor necrosis factor α production and on the expression of inflammatory response associated genes in RAW 264.7 cells. We also clarified the suppressive effect of MA on LPS-induced nuclear factor-kappa B activation as well as the phosphorylation of IκB-α. Furthermore, MA (200 mg/kg in the edema model or 100 mg/kg in the arthritis model) exerted anti-inflammatory and antiarthritis effects as shown by the suppression of paw edema, arthritis score, inflammatory cells, and destruction of synovium in knee joints. CONCLUSION Olive products containing MA are useful as a new preventive and therapeutic food ingredient for inflammatory and arthritic diseases.

Olive leaf components apigenin 7-glucoside and luteolin 7-glucoside direct human hematopoietic stem cell differentiation towards erythroid lineage

The generation of blood cellular components from hematopoietic stem cells is important for the therapy of a broad spectrum of hematological disorders. In recent years, several lines of evidence suggested that certain nutrients, vitamins and flavonoids may have important roles in controlling the stem cell fate decision by maintaining their self-renewal or stimulating the lineage-specific differentiation. In this study, main olive leaf phytochemicals oleuropein (Olp), apigenin 7-glucoside (Api7G) and luteolin 7-glucoside (Lut7G) were investigated for their potential effects on hematopoietic stem cell differentiation using both phenotypic and molecular analysis. Oleuropein and the combination of the three compounds enhanced the differentiation of CD34+ cells into myelomonocytic cells and lymphocytes progenitors and inhibited the commitment to megakaryocytic and erythroid lineages. Treatment with Lut7G stimulated both the erythroid and the myeloid differentiation, while treatment with Api7G specifically induced the differentiation of CD34+ cells towards the erythroid lineage and inhibited the myeloid differentiation. Erythroid differentiation induced by Api7G and Lut7G treatments was confirmed by the increase in hemoglobin genes expressions (α-hemoglobin, β-hemoglobin and γ-hemoglobin) and erythroid transcription factor GATA1 expression. As revealed by microarray analysis, the mechanisms underlying the erythroid differentiation-inducing effect of Api7G on hematopoietic stem cells involves the activation of JAK/STAT signaling pathway. These findings prove the differentiation-inducing effects of olive leaf compounds on hematopoietic stem cells and highlight their potential use in the ex vivo generation of blood cells.

Increasing cAMP levels of preadipocytes by cyanidin-3-glucoside treatment induces the formation of beige phenotypes in 3T3-L1 adipocytes ☆

Obesity is a serious health problem and a major risk factor for the onset of several diseases such as heart disease, diabetes, stroke and cancer. The conversion of white adipocytes to brown-like adipocytes, also called beige or brite adipocytes, by pharmacological and dietary compounds has gained attention as an effective treatment for obesity. Cyanidin-3-glucoside (Cy3G), a polyphenolic compound contained in black soybean, blueberry and grape, has several antiobesity effects. However, there are no reports on the role of Cy3G in the induction of differentiation of preadipocytes to beige adipocytes and corresponding phenotypes. Here, the formation of beige adipocyte phenotypes following treatment with Cy3G was evaluated using 3T3-L1 adipocytes. Cy3G induced phenotypic changes to white adipocytes, such as increased multilocular lipid droplets and mitochondrial content. Additionally, the expression of mitochondrial genes (TFAM, SOD2, UCP-1 and UCP-2), UCP-1 protein and beige adipocyte markers (CITED1 and TBX1) in 3T3-L1 adipocytes was increased by Cy3G. Furthermore, Cy3G promoted preadipocyte differentiation by up-regulating of C/EBPβ through the elevation of the intracellular cAMP levels. These results indicated that Cy3G elevates the intracellular cAMP levels, which induces beige adipocyte phenotypes. This is the first report on the effect of Cy3G on induction of differentiation of preadipocytes into beige adipocyte phenotypes.

Acteoside inhibits type Ι allergy through the down-regulation of Ca/NFAT and JNK MAPK signaling pathways in basophilic cells

We have previously reported that acteoside inhibits the release of β-hexosaminidase from immunoglobulin E (IgE)-sensitized and bovine serum albumin-stimulated rat basophilic leukemia cells as well as the intracellular calcium level, release of histamine from, and production of tumor necrosis factor-alpha and interleukin-4 in human basophilic (KU812) cells. However, the molecular mechanism underlying the anti-allergic effects of acteoside has not yet been elucidated. Here, we used microarray analysis to determine the global gene expression profile of KU812 cells treated with acteoside and calcium ionophore A23187 plus phorbol-12-myristate 13-acetate (A23187+PMA), and the results were validated by real-time polymerase chain reaction (PCR) and Western blotting. Microarray analysis results showed that of the 201 genes in the microarray, 149 genes were up-regulated, while 52 genes were down-regulated. The significantly down-regulated genes have functions as chemokine and IgE receptors, as well as for immune response. Results of the validation of the microarray results using real-time PCR showed a significant decrease in the expressions of Fc fragment of IgE, high affinity I, receptor for; alpha polypeptide (FCER1A) and nuclear factor of activated T cell, cytoplasmic, calcineurin-dependent 1 (NFATC1) genes. Furthermore, Western blotting showed a decrease in the phosphorylation of mitogen-activated protein kinase (MAPK) Jun N terminal kinase (JNK), revealing the role of JNK MAPK in acteoside-mediated allergy inhibition. We determined that the anti-allergy effects of acteoside were due to the down-regulation of the expressions of the chemokine ligand 1 (CCL1), CCL2, CCL3, CCL4,FCER1A and NFATC1 genes and the inhibition of the MAPK pathway through decreased JNK phosphorylation.

Activation of MITF by Argan Oil Leads to the Inhibition of the Tyrosinase and Dopachrome Tautomerase Expressions in B16 Murine Melanoma Cells

Argan (Argania spinosa L.) oil has been used for centuries in Morocco as cosmetic oil to maintain a fair complexion and to cure skin pimples and chicken pox pustules scars. Although it is popular, the scientific basis for its effect on the skin has not yet been established. Here, the melanogenesis regulatory effect of argan oil was evaluated using B16 murine melanoma cells. Results of melanin assay using B16 cells treated with different concentrations of argan oil showed a dose-dependent decrease in melanin content. Western blot results showed that the expression levels of tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT) proteins were decreased. In addition, there was an increase in the activation of MITF and ERK1/2. Real-time PCR results revealed a downregulation of Tyr, Trp1, Dct, and Mitf mRNA expressions. Argan oil treatment causes MITF phosphorylation which subsequently inhibited the transcription of melanogenic enzymes, TYR and DCT. The inhibitory effect of argan oil on melanin biosynthesis may be attributed to tocopherols as well as the synergistic effect of its components. The results of this study provide the scientific basis for the traditionally established benefits of argan oil and present its therapeutic potential against hyperpigmentation disorders.