Buddlejasaponin IV induces apoptotic cell death by activating the mitochondrial­dependent apoptotic pathway and reducing α2ß1 integrin­mediated adhesion in HT­29 human colorectal cancer cells.

Colon cancer is one of the most frequent malignant neoplasms worldwide. Epidemiological studies suggested that the development of colon cancer can be prevented by plant­derived ingredients. In the present study, the chemopreventive activity of buddlejasaponin IV (BS­IV), isolated from the aerial part of Pleurospermum kamtschaticum, was investigated using cell viability, DNA fragmentation, caspase­3 activity, anoikis, cell adhesion, and flow cytometry assays and a murine lung metastasis model. Protein expression levels were detected by western blotting. Treatment with BS­IV significantly reduced cell viability and caused DNA fragmentation in HT­29 human colorectal cancer cells. BS­IV increased the ratio of Bax to Bcl­2 by significantly inhibiting Bcl­2 expression levels. BS­IV reduced expression levels of procaspase­9, procaspase­3, and full­length poly (ADP­ribose) polymerase (PARP) and increased cleaved PARP and nonsteroidal anti­inflammatory drug activated gene­1 expression levels and caspase­3 activity. In addition, BS­IV decreased the attachment of HT­29 cells to the extracellular matrix proteins collagen type I and IV and downregulated cell surface expression of α2ß1 integrin by inhibiting its glycosylation. BS­IV also reduced the expression and phosphorylation levels of focal adhesion kinase (FAK) and Akt, and the reduced FAK and Akt levels were rescued by treatment with a caspase­3 inhibitor Z­VAD­FMK. Furthermore, orally administered BS­IV inhibited the formation of tumor nodules in Balb/C mice intravenously injected with CT­26 murine colorectal cancer cells. Collectively, these findings indicated that BS­IV induces apoptosis via the mitochondrial­dependent pathway by increasing the ratio of Bax to Bcl­2 and activating caspases. BS­IV also induces anoikis by inhibiting α2ß1 integrin­mediated cell adhesion and signaling and inhibits the lung metastasis of colon cancer cells. Therefore, BS­IV may serve as a promising cancer chemopreventive agent.

Anti-Inflammatory Effects of Water Chestnut Extract on Cytokine Responses via Nuclear Factor-κB-signaling Pathway.

Water chestnut (Trapa japonica Flerov.) is an annual aquatic plant. In the present study, we showed that the treatment of water chestnut extracted with boiling water resulted in a significant increase 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and decrease the intracellular H2O2-induced accumulation of reactive oxygen species. In addition, water chestnut extract (WCE) inhibited lipopolysaccharide (LPS)-induced nitric oxide production and suppressed mRNA and protein expression of the inducible nitric oxide synthase gene. The cytokine array results showed that WCE inhibited inflammatory cytokine secretion. Also, WCE reduced tumor necrosis factor-α-and interleukin-6-induced nuclear factor-αB activity. Furthermore, during sodium lauryl sulfate (SLS)-induced irritation of human skin, WCE reduced SLS-induced skin erythema and improved barrier regeneration. These results indicate that WCE may be a promising topical anti-inflammatory agent.

Caffeic acid induces keratinocyte differentiation by activation of PPAR-α.

OBJECTIVES: Peroxisome proliferator-activated receptors (PPAR)-α plays an important role in epidermal differentiation and barrier recovery, and topical treatment with PPAR-α agonists restores epidermal homeostasis in essential fatty acid deficiency and permeability barrier in skin disruptions. Therefore, we performed structure-based pharmacophore screening to search for a novel PPAR-α agonist. Caffeic acid was ultimately selected and evaluated for its effects on keratinocyte differentiation and epidermal permeability barrier. METHODS: The transactivation activity of PPAR-responsive element (PPRE) and cornified envelope (CE) formation were assayed. Also, immunoblot analysis and anti-oxidant activity were investigated on caffeic acid. KEY FINDINGS: Caffeic acid increases the transactivation activity of PPRE and CE formation in keratinocytes. In addition, caffeic acid promotes the expression of genes and proteins related to CE formation such as involucrin and transglutaminase-1. Additionally, anti-oxidant activity were improved by caffeic acid. CONCLUSIONS: Caffeic acid can promote keratinocyte differentiation and restore skin barrier homeostasis and is suggested to be an appropriate skin therapeutic agent for improving epidermal permeability barrier function.

Hesperidin Suppresses Melanosome Transport by Blocking the Interaction of Rab27A-Melanophilin.

We investigated the inhibitory effects of hesperidin on melanogenesis. To find melanosome transport inhibitor from natural products, we collected the structural information of natural products from Korea Food and Drug Administration (KFDA) and performed pharmacophore-based in silico screening for Rab27A and melanophilin (MLPH). Hesperidin did not inhibit melanin production in B16F10 murine melanoma cells stimulated with α-melanocyte stimulating hormone (α-MSH), and also did not affect the catalytic activity of tyrosinase. But, hesperidin inhibited melanosome transport in melanocyte and showed skin lightening effect in pigmented reconstructed epidermis model. Therefore, we suggest that hesperidin is a useful inhibitor of melanosome transport and it might be applied to whitening agent.

N-Nicotinoyl dopamine, a novel niacinamide derivative, retains high antioxidant activity and inhibits skin pigmentation.

We synthesized a novel derivative of a well-known skin-lightening compound niacinamide, N-nicotinoyl dopamine (NND). NND did not show inhibitory effects of tyrosinase and melanin synthesis in B16F10 mouse melanoma cells. However, NND retains high antioxidant activity without affecting viability of cells. In a reconstructed skin model, topical applications of 0.05% and 0.1% NND induced skin lightening and decreased melanin production without affecting the viability and morphology of melanocytes and overall tissue histology. Moreover, no evidence for skin irritation or sensitization was observed when 0.1% NND emulsion was applied onto the skin of 52 volunteers. The effect of NND on skin lightening was further revealed by pigmented spot analyses of human clinical trial. Overall, NND treatment may be a useful trial for skin lightening and treating pigmentary disorders.

Retinyl retinoate induces hyaluronan production and less irritation than other retinoids.

Hyaluronan, a non-sulfated glycosaminoglycan, retains water, maintains the extracellular spaces and facilitates the transport of ion solutes and nutrients. Hyaluronan is closely involved in keratinocyte proliferation, migration and differentiation. The synthesis of hyaluronan in vitro can be stimulated by several growth factors, including retinoids, dibutyryl cyclic adenosine monophosphate and peroxisome proliferator-activated receptor-alpha agonist. In this study, we examined retinyl retinoate (a novel retinol derivative) on hyaluronan expression in primary human keratinocytes and in hairless mouse epidermal skin. Histochemistry using hyaluronan-binding protein revealed that topical retinyl retinoate increased the intensity of hyaluronan staining in murine skin. Moreover, topical retinyl retinoate increased CD44 (hyaluronan receptor) expression. Using reverse transcription polymerase chain reaction, we assessed the expression level of the hyaluronan synthase 2 (HAS2) gene in primary human keratinocytes and in hairless mouse epidermal skin. We found that retinyl retinoate upregulated mouse HAS2 and human HAS2 mRNA. Application of retinyl retinoate induced increasing transepidermal water loss less than retinol, retinoic acid and retinaldehyde. Taken together, we suggest that retinyl retinoate is more effective on hyaluronan production and less of an irritant than other retinoids.

Pleurospermum kamtschaticum extract induces apoptosis via mitochondrial pathway and NAG-1 expression in colon cancer cells.

To evaluate the anticarcinogenic activity of methanol extract of Pleurospermum kamtschaticum (PKE), we assessed its apoptosis-inducing capability in HT-29 colon carcinoma cells. PKE treatment for 2 h reduced cell viability in a dose-related manner, and induced apoptotic morphological changes. Flow cytometric analysis indicated that PKE treatment at 0.05 mg/ml induced early apoptosis in 66.2% of HT-29 cells. Additionally, Bcl-2 expression was substantially reduced in PKE-treated HT-29 cells, increasing the Bax/Bcl-2 ratio. The protein levels of procaspase-9 and procaspase-3 were decreased markedly, reflecting caspase-9 and caspase-3 activation, and resulting PARP cleavage was noted in the PKE-treated HT-29 cells. Furthermore, we detected increased NAG-1 expression in the PKE-treated HT-29 cells. In an in vivo study, intraperitoneal PKE administration suppressed the formation of tumor nodules in the lungs of mice. These results indicate that PKE can serve as a beneficial supplement in the treatment and the prevention of colon cancer.