Hui-Min Wang

Ellagic acid protects human keratinocyte (HaCaT) cells against UVA-induced oxidative stress and apoptosis through the upregulation of the HO-1 and Nrf-2 antioxidant genes.

UV radiation from the sun is a potent environmental risk factor in the pathogenesis of skin damage. Much of the skin damage caused by ultraviolet A (UVA) irradiation from the sun is associated with oxidative stress. The aim of this study was to investigate the protective role of ellagic acid (25-75 μM), a natural antioxidant, against UVA (5-20 J/cm(2))-induced oxidative stress and apoptosis in human keratinocyte (HaCaT) cells and to reveal the possible mechanisms underlying this protective efficacy. Ellagic acid pre-treatment markedly increased HaCaT cell viability and suppressed UVA-induced ROS generation and MDA formation. Moreover, ellagic acid pre-treatment prevented UVA-induced DNA damage as evaluated by the comet assay. Ellagic acid treatment also significantly inhibited the UVA-induced apoptosis of HaCaT cells, as measured by a reduction of DNA fragmentation, mitochondria dysfunction, ER stress, caspase-3 activation, and Bcl-2/Bax deregulation. Notably, the antioxidant potential of ellagic acid was directly correlated with the increased expression of HO-1 and SOD, which was followed by the downregulation of Keap1 and the augmented nuclear translocation and transcriptional activation of Nrf2 with or without UVA irradiation. Nrf2 knockdown diminished the protective effects of ellagic acid. Therefore, ellagic acid may be useful for the treatment of UVA-induced skin damage.

Novel Biodegradable Porous Scaffold Applied to Skin Regeneration

Skin wound healing is an important lifesaving issue for massive lesions. A novel porous scaffold with collagen, hyaluronic acid and gelatin was developed for skin wound repair. The swelling ratio of this developed scaffold was assayed by water absorption capacity and showed a value of over 20 g water/g dried scaffold. The scaffold was then degraded in time- and dose-dependent manners by three enzymes: lysozyme, hyaluronidase and collagenase I. The average pore diameter of the scaffold was 132.5±8.4 µm measured from SEM images. With human skin cells growing for 7 days, the SEM images showed surface fractures on the scaffold due to enzymatic digestion, indicating the biodegradable properties of this scaffold. To simulate skin distribution, the human epidermal keratinocytes, melanocytes and dermal fibroblasts were seeded on the porous scaffold and the cross-section immunofluorescent staining demonstrated normal human skin layer distributions. The collagen amount was also quantified after skin cells seeding and presented an amount 50% higher than those seeded on culture wells. The in vivo histological results showed that the scaffold ameliorated wound healing, including decreasing neutrophil infiltrates and thickening newly generated skin compared to the group without treatments.

Identifying melanogenesis inhibitors from Cinnamomum subavenium with in vitro and in vivo screening systems by targeting the human tyrosinase

Abstract:u2002 Tyrosinase is known to be the first two and rate‐limiting enzyme in the synthesis of melanin pigments responsible for colouring skin, hair and eyes. Tyrosinase inhibition is one major strategy used to treat hyperpigmentation. In human skin melanocytes, the cellular tyrosinase inhibition was examined by the conversion of l‐tyrosine and oxidation of l‐DOPA to dopaquinone. We evaluated the skin pigmentation inhibitor effects with both in vitro and in vivo systems to find skin‐whitening agents without cytotoxic concerns. First, linderanolide B and subamolide A were isolated from the stems of Cinnamomum subavenium and exhibited mushroom tyrosinase inhibition. Then, these two herbal compounds were proved to have good pigmentation inhibitory abilities at low doses and demonstrated free cytotoxicities to normal human skin cells and zebrafish system. With molecular docking, in a virtual model of human tyrosinase, linderanolide B and subamolide A displayed metal‐coordinating interactions with Cu2+ ions. The results obtained from biological assays showed that linderanolide B and subamolide A possessed anti‐tyrosinase properties, which exhibited potential for application in medical cosmetology.

(-)-N-Formylanonaine from Michelia alba as a human tyrosinase inhibitor and antioxidant

Tyrosinase is the first and rate limiting enzyme in the synthesis of melanin pigments for coloring hair, skin, and eyes. As reported in this study, a natural product, (-)-N-formylanonaine isolated from the leaves of Michelia alba D.C. (Magnolianceae), was found to inhibit mushroom tyrosinase with an IC50 of 74.3 microM and to have tyrosinase and melanin reducing activities in human epidermal melanocytes without apparent cytotoxicity to human cells, superior to the known tyrosinase inhibitors, such as kojic acid and 1-phenyl-2-thiourea (PTU). Based on homology modeling, the compound binds the active site by coordinating with two Cu2+ ions. In addition, the compound had antioxidation activities in tests for scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), reducing power, and chelating metal ions. To our knowledge, this is the first study to reveal the bioactivities of (-)-N-formylanonaine from this plant species.

High expression of heme oxygenase-1 is associated with tumor invasiveness and poor clinical outcome in non-small cell lung cancer patients

BackgroundHeme oxygenase-1 (HO-1), a rate-limiting enzyme in heme catabolism, is known to play a role in the protection of cells against oxidative stress, inflammation, anomalous proliferation and apoptosis. As yet, the role of HO-1 expression in non-small cell lung cancer (NSCLC) development and metastasis remains unclear and insufficient data are available regarding its impact on the prognosis of NSCLC patients.MethodsSeventy NSCLC patients who underwent surgical resection were included in this HO-1 expression study and, concomitantly, clinical parameters were collected. Two lung adenocarcinoma cell lines (A549 and H441) were used to assess both invasive and migratory parameters in vitro.ResultsNSCLC patients with a high HO-1 expression ratio (tumor tissue/normal tissue) (> 1) exhibited a significantly poorer prognosis and a higher metastatic rate compared to those with a low HO-1 expression ratio (pu2009<u20090.05). The invasive and migratory abilities of A549 and H441 cells significantly increased after exogenous HO-1 over-expression and significantly decreased after siRNA-mediated HO-1 expression silencing. HO-1 up- and down-regulation also positively correlated with the expression of metastasis-associated proteins EGFR, CD147 and MMP-9. In addition, we found that HO-1 expression can be inhibited by PI3K and AKT inhibitors, but not by MAPK inhibitors.ConclusionsHO-1 is a poor prognostic NSCLC predictor and its over-expression may increase the metastatic potential of NSCLC. Based on our findings and those of others, HO-1 may be considered as a novel NSCLC therapeutic target.

Anonaine Induces DNA Damage and Inhibits Growth and Migration of Human Lung Carcinoma H1299 Cells

The anticancer effects of (-)-anonaine were investigated in this current study. (-)-Anonaine at concentration ranges of 50-200 μM exhibited significant inhibition to cell growth and migration activities on human lung cancer H1299 cells at 24 h, albeit cell cycle analyses showed that (-)-anonaine at the above concentration ranges did not cause any significant changes in cell-cycle distributions. Significant nuclear damages of H1299 cells were observed with 10-200 μM (-)-anonaine treatment in a comet assay, whereas higher concentrations (6 and 30 mM) of (-)-anonaine concentrations were required to cause DNA damages in an in vitro plasmid cleavage assay. In summary, our results demonstrated that (-)-anonaine exhibited dose-dependent antiproliferatory, antimigratory, and DNA-damaging effects on H1299 cells. We inferred that (-)-anonaine can cause cell-cycle arrest and DNA damage to hamper the physiological behavior of cancer cells at 72 h, and therefore, it can be useful as one of the potential herbal supplements for chemoprevention of human lung cancer.

Obtusilactone A and ())-sesamin induce apoptosis in human lung cancer cells by inhibiting mitochondrial Lon protease and activating DNA damage checkpoints

Several compounds from Cinnamomum kotoense show anticancer activities. However, the detailed mechanisms of most compounds from C. kotoense remain unknown. In this study, we investigated the anticancer activity of obtusilactone A (OA) and (−)‐sesamin in lung cancer. Our results show that human Lon is upregulated in non‐small‐cell lung cancer (NSCLC) cell lines, and downregulation of Lon triggers caspase‐3 mediated apoptosis. Through enzyme‐based screening, we identified two small‐molecule compounds, obtusilactone A (OA) and (−)‐sesamin from C. kotoense, as potent Lon protease inhibitors. Obtusilactone A and (−)‐sesamin interact with Ser855 and Lys898 residues in the active site of the Lon protease according to molecular docking analysis. Thus, we suggest that cancer cytotoxicity of the compounds is partly due to the inhibitory effects on Lon protease. In addition, the compounds are able to cause DNA double‐strand breaks and activate checkpoints. Treatment with OA and (−)‐sesamin induced p53‐independent DNA damage responses in NSCLC cells, including G1/S checkpoint activation and apoptosis, as evidenced by phosphorylation of checkpoint proteins (H2AX, Nbs1, and Chk2), caspase‐3 cleavage, and sub‐G1 accumulation. In conclusion, OA and (−)‐sesamin act as both inhibitors of human mitochondrial Lon protease and DNA damage agents to activate the DNA damage checkpoints as well induce apoptosis in NSCLC cells. These dual functions open a bright avenue to develop more selective chemotherapy agents to overcome chemoresistance and sensitize cancer cells to other chemotherapeutics. (Cancer Sci 2010; 101: 2612–2620)

Baicalein, an active component of Scutellaria baicalensis, protects against lipopolysaccharide-induced acute lung injury in rats.

ETHNOPHARMACOLOGICAL RELEVANCEnBaicalein (BE), a phenolic flavonoid extracted mainly from the root of Scutellaria baicalensis Georgi, a Chinese herb, is traditionally used in oriental medicine. Several studies have demonstrated that BE exerts many beneficial effects including anti-inflammatory and antioxidant activities. However, its effect on acute lung injury (ALI) and the molecular mechanisms involved remain unclear and warrant further investigation. The aim of the study is to investigate whether BE improves lipopolysaccharide (LPS, intratracheally, i.t.)-induced ALI in rats, and further study the underlying mechanisms of its activity.nnnMATERIAL AND METHODSnRats were administrated with LPS (5mg/kg/body weight, i.t.) through a 24-gauge catheter to establish the ALI model. The effects of BE on the levels of pro-inflammatory cytokines, nitrite/nitrate in bronchoalveolar lavage fluid, and the expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and nuclear factor-kappa B (NF-κB) activation as well as the histopathological changes were evaluated.nnnRESULTSnResults showed that BE (20mg/kg, i.p.) treatment markedly attenuated LPS-induced lung edema, elevation of the levels of IL-1β, TNF-α, IL-6, CINC-3, and nitrite/nitrate in bronchoalveolar lavage fluid accompanied by a remarkable improvement of lung histopathological symptoms. The LPS-enhanced inflammatory cell infiltration and myeloperoxidase activity, O2(-) formation and the expression of inducible nitric oxide synthase and nitrotyrosin in lungs were all attenuated by BE. Notably, BE could augment Nrf2/HO-1 cascade, but inhibited NF-κB activation in LPS-instilled lungs that was strongly reversed by blocking HO-1 activity.nnnCONCLUSIONnThis study is the first to demonstrate that BE protects against LPS-induced ALI in rats. The underlying mechanisms may include inhibition of NF-κB-mediated inflammatory responses and upregulation of Nrf2/HO-1 pathway, which ultimately alleviates the pathological symptoms of ALI.

Subamolide E from Cinnamomum subavenium Induces Sub-G1 Cell-Cycle Arrest and Caspase-Dependent Apoptosis and Reduces the Migration Ability of Human Melanoma Cells

The aim of this work was to investigate the anticancer cytotoxic effects of natural compound subamolide E on the human skin cancer melanoma A375.S2 cells. Subamolide E was isolated from Cinnamomum subavenium and demonstrated cytotoxicities in the cell-growth assay at concentration ranges from 0 to 100 μM at 24 h. Propidium iodide staining and flow cytometry analyses were used to evaluate cell-cycle distribution and found that subamolide E caused DNA damage in the sub-G1 phase with a dose-dependent manner after 24 h of treatment. According to the western blot result, subamolide-E-treated cells with the increase of caspase-dependent apoptotic proteins induced related pathway mechanisms. Subamolide E also showed antimigratory activities of A375.S2 cells on the wound-healing assay. Finally, subamolide E demonstrated minor cytotoxicities to normal human skin cells (keratinocytes, melanocytes, and fibroblasts); therefore, it is a potential chemotherapeutic agent against skin melanoma.

Extraction of astaxanthin from Haematococcus pluvialis by supercritical carbon dioxide fluid with ethanol modifier

Conventional solvent extraction methods cannot attain high‐quality antioxidant extracts from microalgae and also require solvent recovery and posttreatment. In this study, we utilized environmental friendly supercritical carbon dioxide fluid extraction (SFE‐CO2) techniques to obtain pigment (i.e. astaxanthin) from Haematococcus pluvialis. The effects of key operating parameters on the extraction efficiency of astaxanthin were investigated, giving an optimal condition of H. pluvialis weight, 6.5 g; CO2‐flow rate, 6.0 NL/min; extraction time, 20 min; extraction pressure, 4500 psi; volume of ethanol modifier added, 9.23 mL/g; extraction temperature, 50°C; modifier composition, 99.5%. Under these optimum conditions, the astaxanthin yield was 73.9% (10.92 mg/g dry H. pluvialis powder) after eight cycle of extraction cycles. The saponification index (CS/C0, representing the ratio of astaxanthin concentration after and before the saponification procedures) of the extract could be increased from 1 to 12.78 by saponification with 3.5 M NaOH.