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The ligand-activated farnesoid X receptor is an emerging therapeutic target for the development of drugs against metabolic syndrome-related diseases. In this context, selective bile acid receptor modulators represent a novel concept for drug development. Selective bile acid receptor modulators act in a target gene- or tissue-specific way and are therefore considered less likely to elicit unwanted side effects. Based on leoligin, a lignan-type secondary plant metabolite from the alpine plant Leontopodium nivale ssp. alpinum , 168 synthesized structural analogs were screened in a farnesoid X receptor in silico pharmacophore-model. Fifty-six virtual hits were generated. These hits were tested in a cell-based farnesoid X receptor transactivation assay and yielded 7 farnesoid X receptor-activating compounds. The most active one being LT-141A, with an EC50 of 6 µM and an Emax of 4.1-fold. This analog did not activate the G protein-coupled bile acid receptor, TGR5, and the metabolic nuclear receptors retinoid X receptor α , liver X receptors α / β , and peroxisome proliferator-activated receptors β / γ. Investigation of different farnesoid X receptor target genes characterized LT-141A as selective bile acid receptor modulators. Functional studies revealed that LT-141A increased cholesterol efflux from THP-1-derived macrophages via enhanced ATP-binding cassette transporter 1 expression. Moreover, cholesterol uptake in differentiated Caco-2 cells was significantly decreased upon LT-141A treatment. In conclusion, the leoligin analog LT-141A selectively activates the nuclear receptor farnesoid X receptor and has an influence on cholesterol transport in 2 model systems. [ABSTRACT FROM AUTHOR]

The roots of Bupleurum chinense have a long history in traditional medicine to treat infectious diseases and inflammatory disorders. Two major compounds, saikosaponins A and D, were reported to exert potent anti-inflammatory activity by inhibiting NF-κB. In the present study, we isolated new saikosaponin analogues fromthe roots of B. chinese interfering with NF-κB activity in vitro. Themethanol-soluble fraction of the dichloromethane extract of Radix Bupleuri was subjected to activity-guided isolation yielding 18 compounds, including triterpenoids and polyacetylenes. Their structures were determined by spectroscopic methods as saikogenin D (1), prosaikogenin D (2), saikosaponins B2 (3), W (4), B1 (5), Y (6), D (7), A(8), E (9), B4 (10), B3 (11), and T (12), saikodiyne A (13), D (14), E (15)andF(16), falcarindiol (17), and 1-linoleoyl-sn-glycero-3-phosphorylcholine (18). Among them, 4, 15, and 16 are new compounds, whereas 6, previously described as a semi-synthetic compound, is isolated from a natural source for the first time, and 13-17 are the first reports of polyacetylenes from this plant. Nine saponins/triterpenoids were tested for inhibition of NF-κB signaling in a cell-based NF-κB-dependent luciferase reporter gene model in vitro. Five of them (1, 2, 4, 6,and 8) showed strong (> 50%, at 30 µM) NF-κB inhibition, but also varying degrees of cytotoxicity, with compounds 1 and 4 (showing no significant cytotoxicity) presenting IC50 values of 14.0 µM and 14.1 µM in the cell-based assay, respectively. [ABSTRACT FROM AUTHOR]

Bulbus of Fritillaria pallidiflora, the dried bulb of F. pallidiflora, is widely used in Chinese folk medicine due to its powerful biological activities. The aim of this study was to investigate in vitro and in vivo antitumor activity of different fractions and isosteroidal alkaloids from bulbus of F. pallidiflora and clarify its putative mechanism of antitumor activity. Firstly, we assayed in vitro antitumor effects of different fractions from bulbus of F. pallidiflora and found that chloroform extracts and purified total alkaloids of bulbus of F. pallidiflora showed higher cytotoxic activity than other tested extracts. We further isolated four main alkaloids, chuanbeinone, imperialine-β-N-oxide, isoverticine and isoverticine-β-N-oxide, from the total alkaloids of bulbus of F. pallidiflora and found that they display significant cytotoxicity, whereby chuanbeinone showed the highest activity against Lewis lung carcinoma cells. Moreover, we found that chuanbeinone induced S phase arrest and further increased apoptosis of Lewis lung carcinoma cells. The results of Western blotting experiments showed that the expression of the antiapoptotic Bcl-2 was reduced by chuanbeinone treatment, while the proapoptotic protein Bax and caspase-3 were increased. Moreover, we investigated the in vivo antitumor activity of chuanbeinone and characterized its putative antitumor mechanism of action by the TUNEL assay and by histological and immunohistochemical analyses. Our results showed that chuanbeinone exhibited significant antitumor activity in vivo, while notably inhibiting tumor angiogenesis and inducing apoptosis characterized by an increased expression of caspase-3. Our findings show that chuanbeinone exhibits significant antitumor activity in vitro and in vivo, and points to possible therapeutic potential for this compound as well as for its natural source, bulbus of F. pallidiflora. [ABSTRACT FROM AUTHOR]

Successful vascular healing after percutaneous coronary interventions is related to the inhibition of abnormal vascular smooth muscle cell proliferation and efficient re-endothelialization. In the search for vascular smooth muscle cell anti-pro-liferative agents from natural sources we identified piperine (1), the main pungent constituent of the fruits from Piper nigrum (black pepper). Piperine inhibited vascular smooth muscle cell proliferation with an IC50 of 21.6 µM, as quantified by a resazurin conversion assay. Investigations of ten piperamides isolated from black pepper fruits and 15 synthesized piperine derivatives resulted in the identification of three potent vascular smooth muscle cell proliferation inhibitors: the natural alkaloid pipertipine (4), and the two synthetic derivatives (2E,4E)-N,N-dibutyl-5-(3,5-dimethoxy-phenyl)penta-2,4-dienamide (14) and (E)-N,N-di-butyl-3-(naphtho[2,3-d][1,3]dioxol-5-yl)acryl-amide (20). They showed IC50 values of 3.38, 6.00, and 7.85 uM, respectively. Furthermore, the synthetic compound (2E,4E)-5-(4-fluorophenyl)-1-(piperidin-1-yl)penta-2,4-dien-1-one (12) was found to be cell type selective, by inhibiting vascular smooth muscle cell proliferation with an IC50 of 11.8 µM without influencing the growth of human endothelial cells. [ABSTRACT FROM AUTHOR]

Vascular smooth muscle cell (VSMC) proliferation contributes to the development of atherosclerosis. Red wine consumption due to the polyphenol content has been reported to counteract atherosclerosis progression possibly through inhibition of VSMC proliferation, among other mechanisms. In this study we investigate the antiproliferative activity of four wine polyphenols: resveratrol, quercetin, ethyl gallate, and (+)-catechin in rat aortic VSMC. All four polyphenols inhibited serum-induced VSMC proliferation when applied as a single treatment. To further address a potential synergistic action of the investigated polyphenols, the antiproliferative effect of different combinations in equimolar, as well as equipotent ratios were quantified. The IC50 values of single polyphenols regarding the inhibition of VSMC proliferation ranged from 49.58 μM to 86.06 μM. However, apparent inhibitory efficacy of each compound increased by a factor of 10.4 in the quadruple equipotent mixture, as calculated from the dose-reduction index. Thus, the effective IC50 values of each of the four mixture constituents ranged from 4.76 μM to 8.27 μM. The calculated combination index (CI, where CI <, =, or > 1 indicate synergy, additivity, or antagonism, respectively) values of equimolar combinations of the polyphenols indeed indicated mainly synergy (CI ranging from 0.24 ± 0.01 to 1.51 ± 0.13). Optimized equipotent mixture showed enhanced synergy (CI ranging from 0.18 ± 0.04 to 1.36 ± 0.26). In conclusion, we show for the first time that four major polyphenols from wine synergistically inhibit VSMC proliferation. [ABSTRACT FROM AUTHOR]

The therapy of type-2 diabetes mellitus is one of the major challenges of our age. A possible strategy to prevent the progression of this disease is the inhibition of protein tyrosine phosphatase 1B (PTP1B), a major negative regulator in the insulin and leptin signalling pathway. Phellodendri amurensis cortex is a well-known Asian herbal drug traditionally used as antiphlogistic, antibacterial, and anti-inflammatory agent, and its efficacy against diabetes-related symptoms is reported as well. However, information regarding active principle(s) or the molecular mode of action was scarce. By bioguided isolation using an in vitro enzyme assay with human recombinant PTP1B, (9Z)-octadec-9-enoic acid (oleic acid) could be identified as a major PTP1B inhibitor in the bark of Phellodendron amurense Rupr. (Rutaceae); it showed an IC50 value of 6.2 μM. Consistent with this inhibition of PTP1B, oleic acid was capable of enhancing insulin signalling in wildtype, but not PTP1B knockout fibroblasts. By testing a series of other fatty acids of different chain length and degree of saturation, their general PTP1B-inhibitory potential in the micromolar range was observed. More pronounced effects were associated with a longer carbon backbone and saturation of the double bonds. Therefore, our work provides first scientific evidences for the antidiabetic properties of P. amurense via a new target, effects which seem to be explainable by oleic acid. The discovery of a PTP1B inhibition by many fatty acids also adds a novel facet to the pharmacological properties of a class of compounds that is found in many food items in considerable amount and triggers speculation over their possible involvement in the feedback regulation of cellular fatty acid synthesis. [ABSTRACT FROM AUTHOR]

The ligand-activated farnesoid X receptor is an emerging therapeutic target for the development of drugs against metabolic syndrome-related diseases. In this context, selective bile acid receptor modulators represent a novel concept for drug development. Selective bile acid receptor modulators act in a target gene- or tissue-specific way and are therefore considered less likely to elicit unwanted side effects. Based on leoligin, a lignan-type secondary plant metabolite from the alpine plant Leontopodium nivale ssp. alpinum , 168 synthesized structural analogs were screened in a farnesoid X receptor in silico pharmacophore-model. Fifty-six virtual hits were generated. These hits were tested in a cell-based farnesoid X receptor transactivation assay and yielded 7 farnesoid X receptor-activating compounds. The most active one being LT-141A, with an EC50 of 6 µM and an Emax of 4.1-fold. This analog did not activate the G protein-coupled bile acid receptor, TGR5, and the metabolic nuclear receptors retinoid X receptor α , liver X receptors α / β , and peroxisome proliferator-activated receptors β / γ. Investigation of different farnesoid X receptor target genes characterized LT-141A as selective bile acid receptor modulators. Functional studies revealed that LT-141A increased cholesterol efflux from THP-1-derived macrophages via enhanced ATP-binding cassette transporter 1 expression. Moreover, cholesterol uptake in differentiated Caco-2 cells was significantly decreased upon LT-141A treatment. In conclusion, the leoligin analog LT-141A selectively activates the nuclear receptor farnesoid X receptor and has an influence on cholesterol transport in 2 model systems. [ABSTRACT FROM AUTHOR]