Acid-promoted intra- and intermolecular [2+2] cycloaddition of indoles to aryl alkynes to access cyclobutene-fused indolines.

Herein, we have reported the first example of both intra- and intermolecular [2+2] cycloaddition of the electron-rich indoles and unactivated aryl alkynes promoted by the combination of Fe(NO3)3 and HNO3, which highlights efficient and selective access to several different types of functionalized cyclobutene-fused indolines from readily available starting materials with cheap catalysts and simple operations.

Modular and scalable synthesis of nematode pheromone ascarosides: implications in eliciting plant defense response.

A highly efficient and modular synthesis of nematode pheromone ascarosides was developed, which highlights a 4-step scalable synthesis of the common intermediate 10 in 23% yield from commercially available l-rhamnose by using orthoesterification/benzylation/orthoester rearrangement as the key step. Six diverse ascarosides were synthesized accordingly. Notably, biological investigations revealed that ascr#1 and ascr#18 treatment resulted in enhanced callose accumulation in Arabidopsis leaves. And ascr#18 also increased the expression of defense-related genes such as PR1, PDF1.2, LOX2 and AOS, which might contribute to the enhanced plant defense responses. This study not only allows a facile access to 1-O, 2-O, and 4-O substituted ascarosides, but also provides valuable insights into their biological activities in inducing plant defense response, as well as their mode of action.

Identification of anti-nociceptive constituents from the pollen of Typha angustifolia L. using effect-directed fractionation.

The pollen of T. angustifolia, also known as Pu huang in Chinese, has been used for treatment of stranguria, hematuria, dysmenorrhea, metrorrhagia and injuries in China for a long time. Extensive efforts have been directed toward its phytochemical and biological aspects. However, little is known about its anti-nociceptive implication and material basis. This work presented the investigation of the anti-nociceptive effect of Typhae Pollen using an effect-directed fractionation strategy, thereby leading to identification of isorhamnetin-3-O-neohesperidin (1) and typhaneoside (2), together with other minor flavonoid glycoside congeners, as the main anti-nociceptive constituents. This work not only unveils the anti-nociceptive potential of Typhae Pollen, but also establishes a method to enrich and identify the anti-nociceptive constitutes of Typhae Pollen. Moreover, this work is a successful example of effect-directed fractionation strategy, which represents a powerful tool in TCM-based drug discovery and development.

Divergent Reactivity in CuII-Catalyzed Oxidative Coupling between Indole/Tryptamine Derivatives and ß-Arylacrylic Acids.

Condition-controlled divergent oxidative coupling reactions between indole/tryptamine derivatives and ß-arylacrylic acids with the catalysis of copper(II) have been developed. Specifically, a formal Michael addition/dehydration sequence between indoles and ß-arylacrylic acids occurred in the presence of catalytic CuBr2 in CH3CN under air, thus affording highly functionalized 2,3-dihydro-1H-pyrrolo[1,2-a]indoles. In contrast, upon changing the oxidant to tBuOOH and the solvent to DCM, the reaction course switched to the unprecedented oxidative coupling/cyclization cascade to give the tetracyclic pyrrolo[2,3-b]indolines selectively.

Dual-targeting Rutaecarpine-NO donor hybrids as novel anti-hypertensive agents by promoting release of CGRP.

CGRP, known as the most potent vasodilator substance, plays an important role in hypertension initiation and development. TRPV1 and TRPA1 are critical in promoting the synthesis and release of CGRP, thereby regulating the cardiovascular tone. Rutaecarpine exhibits potent vasodilator and hypertensive effects by stimulating CGRP synthesis and release via activation of TRPV1. And NO has been shown to react with H2S in vivo to form HNO, thereby activating HNO-TRPA1-CGRP pathway. Inspired by combination therapy, 11 rutaecarpine-furoxan hybrids were designed, synthesized and evaluated. The results demonstrated that most hybrids exerted comparable or improved vasodilator activities. Among which, 13a is the most potent both ex vivo (EC50 = 13.1 nM) and in vivo. Mechanistic studies revealed that the vasodilator and anti-hypertensive effects of the hybrids might involve the promotion of CGRP release via dual activation of TRPV1 and TRPA1. This work suggests that dual-targeted hybrids might be an effective and promising approach to discover and develop novel anti-hypertensive drugs.

Alpha-glucosidase inhibitor 1-Deoxynojirimycin promotes beige remodeling of 3T3-L1 preadipocytes via activating AMPK.

Obesity is a serious health challenge in the world, and searching effective drugs to cure obesity is of great importance. 1-Deoxynojirimycin (DNJ) is extracted from mulberry leaves and acts as an α-glucosidase inhibitor to lower blood glucose. Recent studies demonstrated that it also has anti-obesity effect, but the mechanisms remain unknown. In our present study, we mainly examined the effects of DNJ on beige remodeling of 3T3-L1 preadipocytes. We observed that DNJ didn't affect the mRNA levels of fatty acid binding protein 4 (aP2), peroxisome proliferator-activated receptor γ (PPARγ), preadipocyte factor-1 (Pref-1) as well as the mitochondrial uncoupling protein 1 (UCP1), PR domain containing protein 16 (PRDM16), transmembrane protein 26 (TMEM26) in undifferentiated preadipocytes. But after inducing 3T3-L1 preadipocytes to differentiation with white or beige adipogenic medium, DNJ significantly reduced aP2, PPARγ and Pref-1 expressions, while up-regulated the expressions of UCP1, PRDM16 and TMEM26, accompanying with decreased lipid deposition. The ratio of p-AMPK/AMPK was up-regulated by DNJ (10 µM) treatment for 10 days, and the effects of DNJ on p-AMPK/AMPK, UCP1 and PRDM16 could be blocked by AMPK inhibitor Compound C. These results demonstrated that hypoglycemic agent DNJ could suppress the adipogenesis during the differentiation of white preadipocytes, and promote the switch of white preadipocytes to beige adipocytes via activating AMPK, which provided new mechanisms for explaining the benefits of DNJ on obesity-related disorders.

Five macrocyclic glycosides from Schoenoplectus tabernaemontani.

Macrocyclic glycosides with unique 22-membered dimeric lactone skeleton, are rare occurring natural products. There are only ten compounds reported so far. Herein we reported the isolation and characterisation of five macrocyclic glycosides from Schoenoplectus tabernaemontani, including three new compounds (Schoenopolide A-C, 1-3) and two known ones, Berchemolide (4) and Clemoarmanoside B (5). Their structures were established on the basis of extensive analysis of spectroscopic data. In addition, the anti-oxidative activity of Berchemolide (4) against H2O2-induced of renal tubular epithelial (HK-2) cells was also evaluated.

Access to 3a-Benzoylmethyl Pyrrolidino[2,3- b]indolines via CuII-Catalyzed Radical Annulation/C3-Functionalization Sequence.

A CuII-catalyzed radical annulation/C3-functionalization cascade of tryptamine derivatives with aryl ethylene is reported. The mild catalytic system enables the facile construction of 3a-benzoylmethylpyrrolidino[2,3- b]indolines with excellent chemo- and regioselectivities. Remarkably, this novel method utilizes earth-abundant and inexpensive cupric salt as the catalyst and air as the co-oxidant, rendering the process highly environmentally friendly and atom economic. Presumably, the reaction proceeds through CuII-initiated formation of pyrrolidino[2,3- b]indolines radical intermediate I, which is successively trapped by aryl ethylene and O2 to form the product. An 18O2-labeling experiment and several control experiments were designed to support the mechanistic proposal.

Phytochemicals of Pogostemon Cablin (Blanco) Benth. aqueous extract: Their xanthine oxidase inhibitory activities.

Bioassay-guided fractionation of the aerial part of P. cablin revealed that fraction A3 of the water extract exhibited significant xanthine oxidase inhibitory activities (IC50=85.42±1.71µg/mL), which further led to the isolation of ten more bioactive compounds, including two new compounds (1 and 2). The structures of compounds 1 and 2 were elucidated by extensive spectral analysis. It is revealed that flavonoids and phenolic compounds were found to be responsible for the xanthine oxidase inhibitory activities of P. cablin. Especially, rosmarinic acid was found to be with potent XO inhibitory activity (IC50=8.53±0.91µg/mL).

Polyphenolic glycosides isolated from Pogostemon cablin (Blanco) Benth. as novel influenza neuraminidase inhibitors.

BACKGROUND: Influenza is historically an ancient disease that causes annual epidemics and, at irregular intervals, pandemics. At present, the first-line drugs (oseltamivir and zanamivir) don't seem to be optimistic due to the spontaneously arising and spreading of oseltamivir resistance among influenza virus. Pogostemon cablin (Blanco) Benth. (P. cablin) is an important traditional Chinese medicine herb that has been widely used for treatment on common cold, nausea and fever. In our previous study, we have identified an extract derived from P. cablin as a novel selective neuraminidase (NA) inhibitor. RESULTS: A series of polyphenolic compounds were isolated from P. cablin for their potential ability to inhibit neuraminidase of influenza A virus. Two new octaketides (1, 2), together with other twenty compounds were isolated from P. cablin. These compounds showed better inhibitory activity against NA. The significant potent compounds of this series were compounds 2 (IC50 = 3.87 ± 0.19 µ mol/ml), 11, 12, 14, 15, 19 and 20 (IC50 was in 2.12 to 3.87 µ mol/ml), which were about fourfold to doubled less potent than zanamivir and could be used to design novel influenza NA inhibitors, especially compound 2, that exhibit increased activity based on these compounds. With the help of molecular docking, we had a preliminary understanding of the mechanism of the two new compounds (1-2)' NA inhibitory activity. CONCLUSIONS: Fractions 6 and polyphenolic compounds isolated from fractions 6 showed higher NA inhibition than that of the initial plant exacts. The findings of this study indicate that polyphenolic compounds and fractions 6 derived from P. cablin are potential NA inhibitors. This work is one of the evidence that P. cablin has better inhibitory activity against influenza, which not only enriches the compound library of P. cablin, but also facilitates further development and promises its therapeutic potential for the rising challenge of influenza diseases.

Design, synthesis, and biological evaluation of crenatoside analogues as novel influenza neuraminidase inhibitors.

Natural products, especially derived from TCMH, have been found to exert antiviral effects against influenza virus. Crenatoside, a phenylethanoid glycoside from Pogostemon cablin Benth, which has been shown as a novel effective NA inhibitor previously, is considered as the leading compound for our further SARs studies. This work presented design, synthesis of novel crenatoside analogues from readily available d-Glucose and l-rhamnose in a convergent manner. Furthermore, their biological activities and SARs were also investigated. Especially, compound 2 h showed impressive IC50 = 27.77 µg/mL against NAs, which is 3 folds more potent than the leading compound crenatoside (IC50 = 89.81 µg/mL). These results would promise their therapeutic potential for influenza disease.

Chemical constituents of Morus alba L. and their inhibitory effect on 3T3-L1 preadipocyte proliferation and differentiation.

Mulberry leaf, an important traditional Chinese medicine, possesses many biological activities, including effects of anti-obesity. However, which constituents of mulberry leaf are responsible for its anti-adipogenic action is unclear. This study primarily investigated the chemical constituents from mulberry leaf and their bioactivity on the proliferation and differentiation of 3T3-L1 preadipocytes. A new flavane derivative, (2S)-4'-hydroxy-7-methoxy-8-prenylflavan (1), together with twelve known compounds including three flavanes (2-4), three chalcones (5-7), two flavones (8-9), two benzofurans (10-11) and two coumarin (12-13) was isolated from mulberry leaf. The structure of the new compound was elucidated by various spectroscopic methods including UV, HR-ESI-MS, (1)H and (13)C NMR and CD. The results of activity screening showed that compound 2, 6 and 7 inhibited the proliferation and differentiation of 3T3-L1 preadipocytes.

Purified vitexin compound 1 inhibits growth and angiogenesis through activation of FOXO3a by inactivation of Akt in hepatocellular carcinoma.

Vitexins, isolated from the seeds of the Chinese herb Vitex negundo, is known to exert antitumor activity in cancer xenograft models and cell lines. The aim of the current study was to examine whether the Akt/forkhead box protein O3a (FOXO3a) pathway mediates the biological effects of purified vitexin compound 1 (VB-1) in hepatocellular carcinoma (HCC) cells. The effect of VB-1 on the viability of the HCC cell lines HepG2, Hep3B, Huh-7 and the human embryonic liver cells L-02 was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Growth inhibition was assessed by clonogenic assay, and cell cycle arrest was investigated using flow cytometry. Inhibition of angiogenesis was evaluated using a matrigel in vitro HUVEC tube formation assay. The effects on the Akt/FOXO3a pathway were detected by western blotting. VB-1 suppressed the proliferation of HepG2, Hep3B, Huh-7 cells, but had little effect on L-02 cells. VB-1 inhibited anchorage-dependent and -independent HepG2 cell growth in a concentration-dependent manner by induction of cell cycle arrest at G1/G0. VB-1 also reduced the secretion of vascular endothelial growth factor (VEGF), resulting in the inhibition of endothelial tube formation. Phosphorylated Akt and its downstream effector FOXO3a were downregulated in VB-1-treated HepG2 cells. Knockdown of Akt1 by small interfering RNA (siRNA) enhanced growth inhibition, and silencing FOXO3a by siRNA attenuated this action. VB-1 inhibited growth and induced cell cycle arrest at G1/G0 by regulating the Akt/FOXO3a pathway. The findings suggested that VB-1 is a potentially promising candidate for the treatment of HCC.

Purified vitexin compound 1 induces apoptosis through activation of FOXO3a in hepatocellular carcinoma.

We previously reported that purified vitexin compound 1 (VB1, a neolignan from the seed of Chinese herb Vitex negundo) exhibited antitumor activity in cancer cell lines and xenograft models. In the present study, we examined the molecular mechanisms by which activation of the FOXO3a transcription factor mediated VB1-induced apoptosis in hepatocellular carcinoma (HCC) cells. The effects of VB1 on the proliferation of HCC cell lines HepG2, Hep3B, Huh-7 and human embryo liver L-02 cells were investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptotic death in HepG2 cells was examined using an enzyme-linked immunosorbent assay (ELISA) detection kit, flow cytometry after propidium iodide (PI) staining, and by DNA agarose gel electrophoresis. Caspase activity was measured using ELISA. The AKT/FOXO3a and ERK/FOXO3a pathways were analyzed using western blotting. VB1 inhibited human HCC cell proliferation in a concentration-dependent manner and increased the percentage of sub-G1 population HepG2 cells. Histone/DNA fragmentation and active caspase-3, -8 and -9 levels increased in a concentration-dependent manner and a DNA ladder was formed. The phosphorylation of AKT and ERK1/2 were inhibited and FOXO3a transcription factor was activated, resulting in apoptotic death. Knockdown of AKT1 by small interfering RNA (siRNA) and the MEK1/2 inhibitor, PD98059, enhanced VB1-induced apoptosis and FOXO3a transcriptional activity. Suppression of FOXO3a expression by siRNA inhibited VB1-induced apoptosis. VB1 induced expression of Bim, TRAIL, DR4 and DR5. Activation of the FOXO3a transcription factor appears to mediate pro-apoptotic effects of VB1 by inhibiting the AKT and ERK pathways.

Lipophilic components from Fructus Viticis Negundo and their anti-tumor activities.

Two new triterpenoids, (24R/S)-24-hydroxy-3α 10α-epoxy-9-eip-cucurbita-25-ene (1a, b), as well as six known compounds (3-8), were isolated from the extraction of Fructus Viticis Negundo. Their structures were established on the basis of spectral analysis. In addition, all the compounds were tested for inhibitory effect against K-562 and A-549 cell lines.

Purified vitexin compound 1 suppresses tumor growth and induces cell apoptosis in a mouse model of human choriocarcinoma.

OBJECTIVE: In our previous study, we had isolated a series of lignan compounds, termed vitexins, from the seed of Chinese herb Vitex negundo and found broad antitumor activities of these compounds in many cancer xenograft models and cell lines. This study was aimed to determine the antitumor effect of purified vitexin compound 1 (VB1) on choriocarcinoma in vitro and in vivo. MATERIALS AND METHODS: The severe combined immunodeficiency mouse model of choriocarcinoma was established to investigate the in vivo effect of VB1. Its effect on proliferation and apoptosis in JEG-3 cell line was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay and flow cytometry, respectively. The expression of caspase-3, Bcl-2, and some molecules involved in the mammalian target of rapamycin (mTOR) signaling was detected by Western blot. RESULTS: Vitexin compound 1 significantly inhibited the growth of choriocarcinoma in severe combined immunodeficient mice and reduced the serum ß-human chorionic gonadotropin level. Vitexin compound 1 inhibited cell proliferation, induced apoptosis, and inhibited the mTOR signaling in JEG-3 cell line. CONCLUSION: Vitexin compound 1 could inhibit choriocarcinoma via inducing cell apoptosis and suppressing the mTOR pathway.

Two acylated flavonoid glycosides from the leaves of Quercus dentata.

Two new acylated flavonoid glycosides have been isolated from the leaves of Quercus dentata Thunb. On the basis of chemical and spectral data, the structures of the compounds have been elucidated as kaempferol 3-O-(2", 4"-diacetyl-3"-cis-p-coumaroyl-6"-trans-p-coumaroyl)-beta-D-glucopyranoside (1), and kaempferol 3-O-(2"-trans-p-coumaroyl-3", 4"-diacetyl-6"-cisp-coumaroyl)-beta-D-glucopyranoside (2).

Vitexins, nature-derived lignan compounds, induce apoptosis and suppress tumor growth.

PURPOSE: Lignans such as secoisolariciresinol diglucoside in flaxseed, are metabolizes to bioactive mammalian lignans of END and ENL. Because mammalian lignans have chemical structural similarity to the natural estrogen, they are thought to behave like selective estrogen receptor modulators and therefore have anticancer effect against hormone-related cancers. We isolated a series of lignan compounds, named as Vitexins, from the seed of Chinese herb Vitex Negundo. EXPERIMENTAL DESIGN: We purified several Vitexin lignan compounds. Cytotoxic and antitumor effects were analyzed in cancer cells and in tumor xenograft models. In vivo metabolism of Vitexins was determined in rat. RESULTS: Contrasts to the classic lignans, Vitexins were not metabolized to END and ENL. A mixture of Vitexins EVn-50 and purified Vitexin compound 6-hydroxy-4-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-7-methoxy-3, 4-dihydro-2-naphthaldehyde have cytotoxic effect on breast, prostate, and ovarian cancer cells and induces apoptosis with cleavage in poly ADP ribose polymerase protein, up-regulation of Bax, and down-regulation of Bcl-2. This induction of apoptosis seems to be mediated by activation of caspases because inhibition of caspases activity significantly reduced induced apoptosis. We showed a broad antitumor activity of EVn-50 on seven tumor xenograft models including breast, prostate, liver, and cervical cancers. Consistent with in vitro data, EVn-50 treatment induced apoptosis, down-regulated of Bcl-2, and up-regulated Bax in tumor xenografts. CONCLUSION: Vitexin is a class of nature lignan compounds, whose action and anticancer effect is mediated by the mechanisms different from the classic lignans. Vitexin-induced antitumor effect and cytotoxic activity is exerted through proapoptotic process, which is mediated by a decreased Bcl-2/Bax ratio and activation of caspases.

[Studies on flavonoid glycosides of Sarcandra glabra].

OBJECTIVE: To in vestigate the chemical constituents of Sarcandra glabra and obtain a more comprehensive understanding on its effective components. METHOD: The constituents were isolated by various column chromatographic method and their structures were elucidated by physico-chemical properties and spectroscopic analysis. RESULT: Five flavonoid glycosides were isolated and identified as kaempferol-3-O-beta-D-glucuronide (1), quercetin-3-O-alpha-D-glucuronide (2), quercetin-3-O-beta-D-glucuronopyranoside methyl ester (3), 5, 7, 4'-trihydroxy-8-C-beta-D-glucopyranosyl flavanone (4), neoastilbin (5), 5-O-caffeoylquinic acid methyl ester (6), 3, 4-dihydroxybenzoic acid (7), isofraxidin (8). CONCLUSION: Compounds 1-6 were isolated from the genus Sarcandra for the first time. The glucuroide compounds compounds 1-3, were first isolated from the genus Sarcandra.

[Studies on constituents of Oldenlandia diffusa].

OBJECTIVE: To investigate the chemical constituents of Oldenlandia diffusa. METHOD: The column chromatography with polyamide Sephadex LH -20, silica gel as packing materials and HPLC, were used to separate and purify the chemical components. The structures were elucidated on the basis of physicochemical properties and spectral data. RESULT: Nine compounds were isolated and identified as 2, 6-dihydroxy-1-methoxy-3-methylanthraquinone (1), 2-hydroxy-1-methoxy-3-methylanthraquinone (2), 2-hydroxy-3-methylanthraquinone (3), quercetin-3-O-[2-O-(6-O-E-sinapoyl)-beta-D-glucopyranosyl]-beta-glucopyranoside (4), quercetin-3-O-[2-O-(6-O-E-feruloyl)-beta-D-glucopyranosyl]-beta-glucopyranoside (5), kaempferol-3-O-[2-O-(6-O-E-feruloyl)-beta-D-glucopyranosyl]-beta-galactopyranoside (6), quercetin-3-O-(2-O-beta-D-glucop-yranosyl)-beta-D-glucopyranoside (7), rutin (8) and quercertin (9). CONCLUSION: Compounds 1 and 8 were obtained from this plant for the first time, and compound 1 was a new compound.