A Rare Natural Benzo[,]xanthene as a Turn-Off Fluorescent Sensor for Cu Ion.

Rapid and efficient analyses of copper ions are crucial to providing key information for Cu in living cells because of their biological importance. In this study, we reported one new turn-off fluorescent sensor for Cu with a benzo[,]xanthene core, which served as an efficient cation sensor for copper ion over a wide range of other cations (Na, K, Ag, Hg, Cd, Co, Ni, Zn, Mg, and Fe) owing to the catechol group in the aromatic core. The sensor showed selectivity for Cu over other ions; the log for Cu binding to compound had a value of 13.

Chemoenzymatic Synthesis and α-Glucosidase Inhibitory Activity of Dimeric Neolignans Inspired by Magnolol.

A chemoenzymatic synthesis of a small library of dimeric neolignans inspired by magnolol (1) is reported. The 2-iodoxybenzoic acid (IBX)-mediated regioselective ortho-hydroxylation of magnolol is described, affording the bisphenols 6 and 7. Further magnolol analogues (12, 13, 15-17, 19-23) were obtained from eugenol (3), tyrosol (4), and homovanillic alcohol (5), through horseradish peroxidase (HRP)-mediated oxidative coupling and regioselective ortho-hydroxylation or ortho-demethylation in the presence of IBX, followed by reductive treatment with NaSO.

α-Glucosidase inhibition and antioxidant activity of an oenological commercial tannin. Extraction, fractionation and analysis by HPLC/ESI-MS/MS and (1)H NMR.

Two batches of the oenological tannin Tan'Activ R, (toasted oak wood - Quercus robur), were extracted with ethanol. A fractionation on XAD-16 afforded four fractions for each extract. Extracts and fractions were evaluated for antioxidant activity (DPPH), polyphenol content (GAE) and yeast α-glucosidase inhibitory activity.

Dihydrobenzofuran Neolignanamides: Laccase-Mediated Biomimetic Synthesis and Antiproliferative Activity.

The biomimetic synthesis of a small library of dihydrobenzofuran neolignanamides (the natural trans-grossamide (4) and the related compounds 21-28) has been carried out through an eco-friendly oxidative coupling reaction mediated by Trametes versicolor laccase. These products, after complete spectroscopic characterization, were evaluated for their antiproliferative activity against Caco-2 (colon carcinoma), MCF-7 (mammary adenocarcinoma), and PC-3 (prostate cancer) human cells, using an MTT bioassay. The racemic neolignamides (±)-21 and (±)-27, in being the most lipophilic in the series, were potently active, with GI50 values comparable to or even lower than that of the positive control 5-FU.

2,3-Dihydrobenzofuran privileged structures as new bioinspired lead compounds for the design of mPGES-1 inhibitors.

2,3-Dihydrobenzofurans are proposed as privileged structures and used as chemical platform to design small compound libraries. By combining molecular docking calculations and experimental verification of biochemical interference, we selected some potential inhibitors of microsomal prostaglandin E2 synthase (mPGES)-1. Starting from low affinity natural product 1, by our combined approach we identified the compounds 19 and 20 with biological activity in the low micromolar range.

Resveratrol-Related Polymethoxystilbene Glycosides: Synthesis, Antiproliferative Activity, and Glycosidase Inhibition.

A small library of polymethoxystilbene glycosides (20-25) related to the natural polyphenol resveratrol have been synthesized and subjected, together with their aglycones 17-19, to an antiproliferative activity bioassay toward Caco-2 and SH-SY5Y cancer cells. Six of the compounds exhibit antiproliferative activity against at least one cell line. In particular, compounds 17 and 18 proved highly active on at least one of the two cell cultures.

Anti-tumor properties of cis-resveratrol methylated analogs in metastatic mouse melanoma cells.

Resveratrol (E-3,5,4'-trihydroxystilbene) is a polyphenol found in red wine that has been shown to have multiple anti-cancer properties. Although cis-(Z)- and trans-(E)-isomers of resveratrol occur in nature, the cis form is not biologically active. However, methylation at key positions of the cis form results in more potent anti-cancer properties.

Quantification of the resveratrol analogs trans-2,3-dimethoxy-stilbene and trans-3,4-dimethoxystilbene in rat plasma: application to pre-clinical pharmacokinetic studies.

trans-2,3-Dimethoxystilbene (2,3-DMS) and trans-3,4-dimethoxystilbene (3,4-DMS) are two synthetic resveratrol (trans-3,5,4'-trihydroxystilbene) analogs. In this study, a simple HPLC method was developed and validated to determine 2,3-DMS and 3,4-DMS in rat plasma. Chromatographic separation was obtained with a reversed-phase HPLC column through a 12.

Effects of a ferulate-derived dihydrobenzofuran neolignan on angiogenesis, steroidogenesis, and redox status in a swine cell model.

In the ongoing search for new therapeutic compounds, lignans and neolignans, which are widely distributed in plants, deserve special attention because of their interactions with several biological targets. Searching for potential antiangiogenic agents related to natural lignans/neolignans, we were attracted by a previously studied synthetic dihydrobenzofuran neolignan. We synthesized the compound by means of an eco-friendly, enzyme-mediated biomimetic coupling of the methyl ester of ferulic acid, and the present study was aimed to deeply investigate its effect in angiogenesis bioassays validated in our laboratory.

Bio-inspired benzo[k,l]xanthene lignans: synthesis, DNA-interaction and antiproliferative properties.

In this work twelve benzo[k,l]xanthene lignans were synthesized by biomimetic, Mn-mediated oxidative coupling of caffeic esters and amides. These compounds, bearing different flexible pendants at position C1/C2 of the aromatic core, interact with DNA in a dual mode, as confirmed by DF-STD NMR analysis and molecular docking: the planar core acts as a base pair intercalant, whereas the flexible pendants act as minor groove binders. Their antiproliferative activity was evaluated on a panel of six tumor cell lines: HT-29, Caco-2, HCT-116 (human colon carcinoma), H226, A549 (human lung carcinoma), and SH-SY5Y (human neuroblastoma).

Inhibition of CYP17A1 activity by resveratrol, piceatannol, and synthetic resveratrol analogs.

Background: Resveratrol (RSV) and resveratrol analogs have a potential use in prostate cancer chemoprevention due to effects on for example, cell growth, apoptosis, angiogenesis, and metastasis. However, inhibition of CYP17A1, a key enzyme in the androgen biosynthesis and a target for prostate cancer therapy, has not been explored as a possible mechanism behind the effects on prostate cancer.

Methods: Human adrenocortical carcinoma cells, H295R, were treated with RSV, piceatannol (PIC), 3,5,4'-triacetylresveratrol (RSVTA), 3,5-diacetylresveratrol (RSVDA), and 3,5,4'-trimethylresveratrol (RSVTM) for 24 hr at concentrations of 1, 5, 10, 25, and 50 µM.

Phenethyl caffeate benzoxanthene lignan is a derivative of caffeic acid phenethyl ester that induces bystander autophagy in WiDr cells.

We recently reported that Phenethyl caffeate benzoxanthene lignan (PCBL), a semisynthetic compound derived from Caffeic Acid Phenethyl Ester (CAPE), induces DNA damage and apoptosis in tumor cells. In this study, we further investigated whether PCBL induces autophagy in WiDr cells. We also analyzed the pathways regulating autophagy and the role of autophagy in PCBL-induced cell death.

Effect of resveratrol-related stilbenoids on biomembrane models.

The interactions of the two resveratrol analogues 2-hydroxy-3,5,3',5'-tetramethoxystilbene (4) and 2-hydroxy-3,5,3',4'-tetramethoxystilbene (5) with model biomembranes were studied. The aim of this investigation was to highlight possible differences in the interactions with such biomembranes related to the minimal structural differences between these isomeric stilbenoids. In particular, different experiments on stilbenoid/biomembrane model systems using both differential scanning calorimetry (DSC) and Langmuir-Blodgett techniques were carried out to evaluate stilbenoid/multilamellar vesicle and stilbenoid/phospholipid monolayer interactions, respectively.

Reaction of benzoxanthene lignans with peroxyl radicals in polar and non-polar media: cooperative behaviour of OH groups.

Benzo[kl]xanthene lignans, promising bioactive polyphenols obtained by biomimetic oxidative coupling of caffeic acid derivatives, react efficiently with peroxyl radicals in both polar and non-polar solvents, thanks to the simultaneous presence of guaiacol-like and catechol-like OH-groups.

Phenethyl caffeate benzo[kl]xanthene lignan with DNA interacting properties induces DNA damage and apoptosis in colon cancer cells.

Aims: Phenethyl caffeate benzoxanthene lignan (PCBL) is a synthetic compound with DNA interacting, antiangiogenic, antiproliferative and tumor cell death inducing abilities. Though PCBL exhibits the qualities of a prospective antitumor agent, the basic mechanism of PCBL induced cell death remains unknown. This study aims to analyze the molecular mechanisms of PCBL induced cell death in tumor cells to further substantiate its antitumor abilities.

Natural-derived polyphenols as potential anticancer agents.

In this short review we report selected examples from recent literature to show the potential of natural-derived, low molecular weight polyphenols as antitumor agents. The two major groups of polyphenol analogues have been reviewed here, namely flavonoids and stilbenoids. Notwithstanding these limitations, we listed 75 compounds, many of them representing only the most potent member in a library.

Methoxy stilbenes as potent, specific, untransported, and noncytotoxic inhibitors of breast cancer resistance protein.

The ABCG2 multidrug transporter is known to confer cancer cell multidrug resistance by causing the efflux of anticancer drugs; therefore, selective inhibitors have the potential to improve chemotherapeutic treatments. Here, various methoxy derivatives of resveratrol are shown to be potent inhibitors of mitoxantrone efflux by ABCG2: among a series of 11 derivatives, compound 9 (3,5,3',4'-tetramethoxy trans-stilbene) had an IC(50) of 0.16 μM and showed a maximal inhibition of 75%, as measured by flow cytometry.

Determination of trans-2,4,3',4',5'-pentamethoxystilbene in rat plasma and its application to a pharmacokinetic study.

trans-2,4,3',4',5'-Pentamethoxystilbene (2,4,3',4',5'-PMS) is a resveratrol derivative that displayed promising pre-clinical anti-cancer activities. In this study, a simple HPLC method was developed and validated to determine 2,4,3',4',5'-PMS in rat plasma. The lower limit of quantification was 9ng/ml.

Quantification of trans-3,4,5,4'-Tetramethoxystilbene in rat plasma by HPLC: application to pharmacokinetic study.

A simple HPLC method was established to quantify trans-3,4,5,4'-tetramethoxystilbene (MR-4 or DMU-212) in rat plasma. Chromatographic separation was obtained with a reversed-phase HPLC column through an 11 min gradient delivery of a mixture of acetonitrile and water at a flow rate of 1.5 mL/min at 50 °C.

Structural basis for the potential antitumour activity of DNA-interacting benzo[kl]xanthene lignans.

The biological properties and possible pharmacological applications of benzo[kl]xanthene lignans, rare among natural products and synthetic compounds, are almost unexplored. In the present contribution, the possible interaction of six synthetic benzo[kl]xanthene lignans and the natural metabolite rufescidride with DNA has been investigated through a combined STD-NMR and molecular docking approach, paralleled by in vitro biological assays on their antiproliferative activity towards two different cancer cell lines: SW 480 and HepG2. Our data suggest that the benzo[kl]xanthene lignans are suitable lead compounds for the design of DNA selective ligands with potential antitumour properties.

Antiangiogenic properties of an unusual benzo[k,l]xanthene lignan derived from CAPE (caffeic acid phenethyl ester).

Angiogenesis is normally a highly regulated process that occurs during development, reproduction, and wound repair. However, angiogenesis can also become a fundamental pathogenic process in cancer and several other diseases. To date, the synthesis of angiogenesis inhibitors has been researched in several ways also starting from bioactive plant compounds.

Structural determinants of resveratrol for cell proliferation inhibition potency: experimental and docking studies of new analogs.

Resveratrol is the subject of intense research because of the abundance of this compound in the human diet and as one of the most valuable natural chemopreventive agents. Further advances require new resveratrol analogs be used to identify the structural determinants of resveratrol for the inhibition potency of cell proliferation by comparing experimental and docking studies. Therefore, we synthesized new trans/(E)- and cis/(Z)-resveratrol - analogs not reported to date - by modifying the hydroxylation pattern of resveratrol and a double bond geometry.

Biological effects on granulosa cells of hydroxylated and methylated resveratrol analogues.

Several resveratrol analogues have been designed to improve bioactivity: among these polymethoxystilbenes appear to be particularly promising. The present study was set up to investigate the biological functions of polymethoxystilbenes 2 and 3, recently found in our lab as antiangiogenic agents, on a well-defined swine granulosa cell model. Proliferative activity and effects on steroidogenesis were evaluated, as well as the effect on granulosa cell vascular endothelial growth factor (VEGF) production, since these cells in basic conditions synthesize the main proangiogenic peptide.

beta-Cyclodextrins influence on E-3,5,4'-trimethoxystilbene absorption across biological membrane model: a differential scanning calorimetry evidence.

E-3,5,4'-trimethoxystilbene (TMS) is a naturally occurring analog of resveratrol. The anti-neoplastic, antiallergic and anti-angiogenic activities of TMS have been recently reported. From the viewpoint of metabolism, TMS may be more favourable than resveratrol because all of its hydroxyl groups, which are subjected to extensive glucuronide or sulphate conjugation in the metabolic pathways of resveratrol, are protected by methylation.

New lipophilic piceatannol derivatives exhibiting antioxidant activity prepared by aromatic hydroxylation with 2-iodoxybenzoic acid (IBX).

Piceatannol (E-3,5,3',4'-tetrahydroxystilbene) is a phytoalexin synthesized in grapes in response to stress conditions. It exhibits strong antioxidant and antileukaemic activities due to the presence of the catechol moiety. To modify some physical properties like solubility, and miscibility in non-aqueous media some new previously unreported piceatannol derivatives having lipophilic chains on the A-ring were prepared in good yields by a simple and efficient procedure.