Model systems for the detection of DNA-binding compounds and chemopreventive agents.

Model systems for the detection of DNA-binding compounds and chemopreventive agents

Effects of natural products on the inhibition of 5α-reductase type 2 for the development of chemopreventive agents in LNCaP cells

The enzyme steroid 5α-reductase is responsible for the conversion of testosterone into the most potent androgen dihydrotestosterone (DHT). In man, this steroid acts on a variety of androgen-responsive target tissues to mediate such diverse endocrine processes as male sexual differentiation in the fetus and prostatic growth in men. Androgen levels in the prostate may influence carcinogenesis in this organ. The use of a 5α-reductase inhibitor, finasteride, in the chemoprevention of prostate cancer is being evaluated in a clinical trial and have been used successfully for treatment of benign prostatic hyperplasia. Therefore, for the discovery of 5α-reductase type 2 inhibitors, we have evaluated the inhibitory effects of solvent fractionated extracts of natural products on 5α-reductase type 2 activity. We have tested approximately 80 kinds of natural products after partition into n-hexane, ethyl acetate and aqueous layer from 100% methanol extracts of plants. The ethyl acetate fractions of Perilla sikokiana (seed, IC50 : 6.2 ug/ml), Sophora flavescens (root, IC50 : 8.9 ug/ml), and Angelica tenuissima (root, IC50 : 11.7 ug/ml) revealed inhibitory effects on 5α-reductase 2 activity in LNCaP cells. The effective ethyl acetate fractions of Perilla sikokiana, Sophora flavescens, Hydnocarpus anthelmintica, and Angelica tenuissima were subfractionated by column chromatography and tested. The subfractions F4 (IC50 : 1.1. ug/ml), F5 (IC50 : 2.0 ug/ml), and F6 (IC50 : 5.8 ug/ml) of the ethyl acetate fraction of Perilla skikokiana and the subfraction F8 (IC50 : 5.3 ug/ml) of the ethyl acetate fraction of Sophora flavescens displayed greater inhibition of 5α-reductase type 2 than did finasteride in LNCaP cells. These active fractions are under the process of further sequential fractionation to find the effective pure compounds against 5α- reductase 2 activity

TERT mRNA expression is up-regulated in MCF-7 cells and a mouse mammary organ culture (MMOC) system by endosulfan treatment

Endosulfan is one of the organochlorine pesticides, which are well-known endocrine disruptors (EDs), and it acts as an estrogen agonist. Estrogen is a group of-hormones that play an important role in mammary gland function and are implicated in mammary carcinogenesis. In the present study, we studied the effects of endosulfan on nodule like alveolar lesion (NLAL) formation in mouse mammary gland development using a mouse mammary gland organ culture (MMOC) system. Although endosulfan-treated mammary glands did not form NLALs, more alveolar buds were formed in this group than in the negative control (vehicle-treated) group. In addition, telomerase reverse transcriptase (TERT) mRNA expression levels were increased in enclosulfan-treated mammary glands in a dose-dependent manner. Telomerase can be activated by estrogen, therefore, we examined the effects of endosulfan on telomerase activity, and found that the telomerase activity in estrogen receptor-positive MCF-7 cells was up-regulated by endosulfan treatment. Moreover, this activation was accompanied by the up-regulation of the TERT mRNA expression. Also, transient expression assays using CAT reporter plasmids containing various fragments of the TERT promoter showed that this imperfect palindromic estrogen-responsive element is almost certainly responsible for the transcriptional activation by endosulfan. These results may help elucidate the endocrine disrupting mechanism of endosulfan

Effects of Cudrania tricuspidata Fruit Extract and Its Active Compound, 5,7,3′,4′-Tetrahydroxy-6,8-diprenylisoflavone, on the High-Affinity IgE Receptor-Mediated Activation of Syk in Mast Cells

Cudrania tricuspidata fruit extract contains a rich source of prenylated flavonoids with potential antiatherosclerotic, hepatoprotective, and anti-inflammatory properties. However, the effect of <i>C. tricuspidata</i> fruit extracts and its active compounds on the high-affinity IgE receptor (FcεRI)-mediated signaling remains unknown. In the present study, the effect of methanol extract from the fruits of <i>C. tricuspidata</i> (MFC) and its active compound, 5,7,3′,4′-tetrahydroxy-6,8-diprenylisoflavone (THDPI), on FcεRI-mediated signaling in mast cells was investigated. MFC and THDPI suppressed mast cell degranulation and Ca²⁺ influx. MFC also interfered with IgE–FcεRI interaction and decreased FcεRIβ mRNA expression in mast cells. Furthermore, MFC and THDPI inhibited the phosphorylation of Syk, LAT, and PLCγ and F-actin redistribution. These results indicate that MFC and its active compound, THDPI, inhibit mast cell activation through the inhibition of FcεRI-mediated Syk activation, suggesting a therapeutic potential for controlling mast cell activation in inflammatory and/or allergic processes

Effects of natural products on the inhibition of lipopolysaccharide- inducible nitric oxide synthase activity in RAW264.7 cell culture system

Nitric oxide (NO) is a free radical synthesized from L-arginine by nitric oxide synthase (NOS). It is believed that NO is an important mediator in numerous physiological and inflammatory responses. Particularly, a large amount of NO released from the inducible nitric oxide synthase (iNOS) is mostly associated with inflammatory processes. Overproduction of NO in these processes including sepsis and autoimmune diseases can have deleterious consequences and pathophysiologic relevance. Therefore, for the discovery of new inhibitory agents against iNOS activity, we have evaluated about 100 kinds of natural products after partition into three layers (n-hexane, ethyl acetate and aqueous) from 100% methanol extracts to study inhibitory effects on iNOS activity induced by lipopolysaccharide (LPS) in RAW264.7 cells culture system. As a positive control, curcumin, which is known as an anti- tumor promotor, anti-inflammatory agent as an iNOS inhibitor, was used and showed the dose-dependent inhibitory effect (IC50. 2.5 μm/ml). Among tested fractions, the n-hexane fraction of Cimicifuga heracleifolia (IC50: 9.65 μg/ml), Forsythiae fructus (IC50: 6.36 μg/ml), Saposhnikovia divaricata (IC50: 5.92 mg/ml), and the ethyl acetate fraction of Chrysanthemum sibiricum (IC50: 2.56 μg/ml), Gastrodia elata (IC50: 3.46 μg/ml), and the aqueous fraction of Dianthus chinensis (IC50: 6.73 μg/ml), Euonymus alatus (IC50: 6.78 μg/ml), Mechania urticifoloria (IC50: 8.01 μg/ml) showed strong inhibitory activity against LPS- stimulated iNOS. Especially, the ethyl acetate fraction of Chrysanthemum sibiricum (IC50: 2.56 μg/ml), which exhibited the strongest inhibition against iNOS, was fractionated with silica-gel column chromatography. These subfractions exhibited dose-dependent inhibition against iNOS activity in the range of 2.59-5.6 μg/ml except for fraction No. 3, 4, 5, 6, 8, 9, and 16. Our study shows that Chrysanthemum sibiricum has the strongest inhibitory effect against iNOS activity and has similar effect to curcumin. Therefore, further studies for the identification of active principles from Chrysanthemum sibiricum and investigation for the mechanism of the inhibition of iNOS by active principles will be performed

Determination of S-(-)-lansoprazole in dexlansoprazole preparation by capillary zone electrophoresis

Capillary zone electrophoresis was successfully applied to the enantiomeric purity determination of dexlansoprazole using sulfobutyl ether-β-cyclodextrin and methyl-β-cyclodextrin as chiral selectors. Separations were carried out in a 50 μm, 64/56 cm fused-silica capillary. The optimized conditions included 90 mM phosphate buffer, pH 6.0, containing 30 mM sulfobutyl ether-β-cyclodextrin, 20 mM methyl-β-cyclodextrin as background electrolyte, an applied voltage of 25 kV and a temperature of 16 °C, detection was at 280 nm. The assay was validated for the S-(−)-lansoprazole in the range of 0.2–1.0%. The limit of detection was 0.07%, the limit of quantitation was 0.20%, relative to a total concentration of 4.0 mg mL−1. Intra-day precision varied between 1.72 and 2.07%. Relative standard deviations of inter-day precision ranged between 1.62 and 1.96% for peak area ratio. The assay was applied for the determination of the chiral purity of dexlansoprazole capsules. Recovery in capsules was ranged between 101.7 and 103.1%.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors thank the Institute of New Drug Development Research and the Central Laboratory of Kangwon National University for the use of analytical instrument.OAIID:RECH_ACHV_DSTSH_NO:T201713897RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A001568CITE_RATE:2.242FILENAME:Arch Pharm Res (2017) 40 (8) 962-971.pdfDEPT_NM:제약학과EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/9f246ee8-e3da-4b78-b64f-136dc6d6f697/linkCONFIRM:

Neuroprotective Xanthones from the Root Bark of <i>Cudrania tricuspidata</i>

Seventeen new prenylated xanthones (<b>1</b>–<b>17</b>) were isolated from an ethyl acetate-soluble extract of root bark of <i>Cudrania tricuspidata</i> together with 17 previously identified xanthones. The structures of the new compounds were elucidated by spectroscopic methods. Six new compounds (<b>3</b>, <b>7</b>, <b>8</b>, <b>9</b>, <b>15</b>, and <b>16</b>) and six known compounds (<b>18</b>–<b>23</b>) showed neuroprotective effects against 6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y cells, with EC₅₀ values of 0.7–16.6 μM