Ultraviolet light-emitting diode-assisted highly sensitive room temperature NO2 gas sensors based on low-temperature solution-processed ZnO/TiO2 nanorods decorated with plasmonic Au nanoparticles.

Nanostructured semiconducting metal oxides such as SnO2, ZnO, TiO2, and CuO have been widely used to fabricate high performance gas sensors. To improve the sensitivity and stability of gas sensors, we developed NO2 gas sensors composed of ZnO/TiO2 core-shell nanorods (NRs) decorated with Au nanoparticles (NPs) synthesized via a simple low-temperature aqueous solution process, operated under ultraviolet irradiation to realize room temperature operation. The fabricated gas sensor with a 10 nm-thick TiO2 shell layer shows 9 times higher gas sensitivity and faster response and recovery times than ZnO NR-based gas sensors. This high performance of the fabricated gas sensor can be ascribed to band bending between the ZnO and TiO2 core-shell layers and the localized surface plasmon resonance effect of Au NPs with a sufficient Debye length of the TiO2 shell layer.

Ultraviolet Photoactivated Room Temperature NO2 Gas Sensor of ZnO Hemitubes and Nanotubes Covered with TiO2 Nanoparticles.

Prolonged exposure to NO2 can cause lung tissue inflammation, bronchiolitis fibrosa obliterans, and silo filler's disease. In recent years, nanostructured semiconducting metal oxides have been widely used to fabricate gas sensors because of their unique structure and surface-to-volume ratio compared to layered materials. In particular, the different morphologies of ZnO-based nanostructures significantly affect the detection property of NO2 gas sensors. However, because of the large interaction energy of chemisorption (1-10 eV), metal oxide-based gas sensors are typically operated above 100 °C, overcoming the energy limits to attain high sensitivity and fast reaction. High operating temperature negatively affects the reliability and durability of semiconductor-based sensors; at high temperature, the diffusion and sintering effects at the metal oxide grain boundaries are major factors causing undesirable long-term drift problems and preventing stability improvements. Therefore, we demonstrate NO2 gas sensors consisting of ZnO hemitubes (HTs) and nanotubes (NTs) covered with TiO2 nanoparticles (NPs). To operate the gas sensor at room temperature (RT), we measured the gas-sensing properties with ultraviolet illumination onto the active region of the gas sensor for photoactivation instead of conventional thermal activation by heating. The performance of these gas sensors was enhanced by the change of barrier potential at the ZnO/TiO2 interfaces, and their depletion layer was expanded by the NPs formation. The gas sensor based on ZnO HTs showed 1.2 times higher detection property than those consisting of ZnO NTs at the 25 ppm NO2 gas.

Bioactive compounds from the roots of Asiasarum heterotropoides.

A new tetrahydrofuran lignan, (7S,8R,7'S,8'S)-3-methoxy-3',4'-methylenedioxy-7,9'-epoxylignane-4,7',9-triol (1), and 21 known compounds 2-22 were isolated from the roots of Asiasarum heterotropoides by chromatographic separation methods. The structures of all compounds 1-22 were elucidated by spectroscopic analysis including 1D- and 2D-NMR. Fourteen of these compounds (1-3, 7, 10, 12-17, 19, 21, and 22) were isolated from this species in this study for the first time. All of the isolates were evaluated for their anticancer activities using in vitro assays. Among the 22 tested compounds, two (compounds 5 and 7) induced the downregulation of NO production, FOXP3 expression, and HIF-1α transcriptional activity.

Cytotoxic and anti-inflammatory constituents from the seeds of Descurainia sophia.

A new sinapoyl glycoside, 1,3-di-O-sinapoyl-ß-D-glucopyranose (1) along with 13 known compounds, including, sinapoyl glycosides (2 and 3), cardenolide glycoside (4), flavonoids (5-10), lignan (11), phenolic acids (12 and 13), and phytosterol (14), were isolated from the seeds of Descurainia sophia by chromatographic separation methods. The structures of 1-14 were determined by the interpretation of spectroscopic data as well as by comparison of that data with previously reported values. Compounds 2, 3, 5, 6, and 11 were identified in and isolated from this plant for the first time in this study. All isolates were evaluated for in vitro cytotoxic activities against seven human cancer cell lines and for in vitro anti-inflammatory potential using LPS-stimulated RAW264.7 murine macrophages. Compound 4 showed potent cytotoxicity (IC50 values ranging from 0.034 to 0.596 µM) against all human cancer cell lines tested and was identified as the main active cytotoxic constituent of this plant. Compound 8 (ED50 = 5.45 µM) and 11 (ED50 = 10.02 µM) exerted dose-dependent inhibitory effects on NO production in LPS-stimulated RAW264.7 cells.

Anticancer potential of an ethanol extract of Asiasari radix against HCT-116 human colon cancer cells in vitro.

Radix of Asiasarum heterotropoides var. mandshuricum F. Maekawa (A. radix) has been prescribed for treating pain, allergies and inflammatory disorders in traditional oriental medicine. However, only limited information on the anticancer effects of A. radix is currently available. The aim of this study was to determine the anticancer effect of the ethanol extract of A. radix (EEAR) on HCT-116 human colon cancer cells and to investigate its underlying mechanisms of action. EEAR significantly induced G2/M cell cycle arrest and apoptosis in HCT-116 cells. EEAR-induced apoptosis was observed in parallel with activation of caspases and an increased ratio of Bax (pro-apoptotic)/Bcl2 (anti-apoptotic). Western blot analyses revealed that EEAR elevated the expression of p53 and p21(Waf/Cip1) and decreased the expression of the regulator proteins of G2/M phase progression, such as cdc2 and cyclin B. The upregulation of p53 by EEAR was due to the increased levels of p53 mRNA without a similar increase in proteasome-mediated p53 degradation. EEAR-induced apoptosis in HCT-116 cells was dependent on p53 expression, as determined by siRNA-mediated p53 knockdown. Taken together, these results suggest that EEAR inhibits the growth of the HCT-116 cells through induction of G2/M cell cycle arrest and apoptosis, which are mediated by p53 expression.

Ethanol extract of Gleditsia sinensis thorn suppresses angiogenesis in vitro and in vivo.

BACKGROUND: Gleditsia sinensis thorns have been widely used in traditional Korean medicine for the treatment of several diseases, including obesity, thrombosis, and tumor-related diseases. The aim of the study is to determine the antiangiogenic effect of Gleditsia sinensis thorns in vitro and in vivo in a bid to evaluate its potential as an anticancer drug. METHODS: Ethanol extract of Gleditsia sinensis thorns (EEGS) were prepared and used for in vitro and in vivo assays. In vitro antiangiogenic effect of EEGS was determined in HUVEC primary cells by cell migration and tube formation assays. In vivo antiangiogenic effect of EEGS was determined by measuring vessel formation and vascular endothelial cells migrating into the implanted matrigels in nude mice. The angiogenesis-related proteins of which expression levels were altered by EEGS were identified by proteomic analysis. RESULTS: EEGS exerted a dose-dependent antiproliferative effect on HUVEC cells without significant cytotoxicity. Angiogenic properties, such as cell migration and tube formation, were significantly inhibited by EEGS in a dose-dependent manner. New vessel formation was also suppressed by EEGS, as determined by the directed in vivo angiogenesis assays in nude mice. EEGS reduced the expression of proangiogenic proteins, endothelin 1 and matrix metallopeptidase 2, in HUVEC cells. CONCLUSIONS: Our findings suggest that EEGS can inhibit angiogenesis by down-regulating proangiogenic proteins, and therefore it should be considered as a potential anticancer drug targeting tumor-derived angiogenesis.

Anti-proliferative neolignans from Saururus chinensis against human cancer cell lines.

Activity-guided fractionation of an 80% EtOH extract from the aerial parts of Saururus chinensis led to isolation of three anti-proliferative neolignans (1-3) along with four flavonoids (4-7) and four aristolactams (8-11). Their chemical structures were identified by analysis of spectroscopic data. All compounds 1-11 were evaluated for their activities against 28 human cancer cell lines using an in vitro cell proliferation assay. Compounds 1-3 showed potent anti-proliferative activities against cervical (C33a, IC50=0.01 µM for 1; 0.28 µM for 2; 2.80 µM for 3) and lung (NCI-H460, IC50=0.05 µM for 1; 1.37 µM for 2; 6.46 µM for 3) cancer cells without any remarkable cytotoxic effects on human normal lung cells as a control. Taken together, these data demonstrated the identification of anti-proliferative neolignans which are active components of S. chinensis.

Soluble components of Hericium erinaceum induce NK cell activation via production of interleukin-12 in mice splenocytes.

AIM: To investigate the immunoregulatory functions of water extracts of Hericium erinaceum (WEHE) focusing on natural killer (NK) cell-based anticancer activities. METHODS: Mouse splenocytes or purely isolated NK cells were stimulated with 1-100 mg/L WEHE for 24 h followed by co-culture with (51)Cr-labeled Yac-1 cells for 4 h, then NK cell-derived cytolytic activity was measured using a radio-release assay. Neutralizing antibodies against mouse interleukin-12 (IL-12) were added into the WEHE-stimulated splenocytes, thereafter, cytotoxicity was measured to examine the involvement of IL-12. RT-PCR and ELISA analyses were performed to confirm the induction of transcription and the translation of IL-12 and interferon-gamma (IFN-gamma) in the WEHE-treated splenocytes. RESULTS: WEHE enhanced the cytolytic activity of total splenocytes towards Yac-1 cells in a dose-dependent manner. However, this activation was not observed when the NK cells isolated from the splenocytes were treated with WEHE. Furthermore, the treatment with antibodies against IL-12 abolished the effect of WEHE on splenocyte-derived cytolytic activity. RT-PCR and ELISA analyses showed the induction of IL-12 and IFN-gamma in the WEHE-treated splenocytes. CONCLUSION: WEHE indirectly activates the cytolytic ability of NK cells via the induction of IL-12 in total splenocytes, and possibly via other immuno-mediators or cellular components.