Anti-adipogenic diarylheptanoids from Alnus hirsuta f. sibirica on 3T3-L1 cells

A new diarylheptanoid, (5S)-hydroxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-hepta-1E-en-3-one (1), was isolated along with seventeen known diarylheptanoids (2–18) from the methanol extract of Alnus hirsuta f. sibirica leaves using bioactivity-guided fractionation. Among the isolated compounds, compounds 1 and 2 and 4–12 reduced lipid accumulation dose-dependently in 3T3-L1 preadipocytes. Of the compounds active in the present assay system, the most potent compound 7, platyphyllonol-5-O-β-d-xylopyranoside, significantly suppressed the induction of peroxisome proliferator activated receptor γ (PPARγ and CCAAT/enhancer binding protein α (C/EBPα) protein expression, and inhibited adipocyte differentiation induced by troglitazone, a PPARγ agonist. It was demonstrated that compound 7 has anti-adipogenic activity mediated by the regulation of PPARγ dependent pathways.     

Structure–activity relationship of lupane-triterpene glycosides from Acanthopanax koreanum on spleen lymphocyte IL-2 and IFN-γ

Phytochemical investigation resulted in the isolation of three new lupane-triterpene glycosides acankoreosides M–O (1, 2 and 8) together with eight known lupane-triterpene glycosides (3–7, 9–11) from the leaves of Acanthopanax koreanum (Araliaceae). Their chemical structures were elucidated by mass, 1D and 2D NMR spectroscopy. The effect of eleven lupane-triterpene glycosides on Con A-induced splenolytic production of IL-2 and IFN-γ were measured as markers of acquired immune responses. Compounds 4, 5, 7, and 11 (5, 25, and 100 μM) significantly increased IFN-γ and IL-2 release in spleen cells.     

Phenolics from Glycyrrhiza glabra roots and their PPAR-γ ligand-binding activity

Bioassay-guided fractionation of the EtOH extract of licorice (Glycyrrhiza glabra roots), using a GAL-4-PPAR-γ chimera assay method, resulted in the isolation of 39 phenolics, including 10 new compounds (1–10). The structures of the new compounds were determined by analysis of their spectroscopic data. Among the isolated compounds, 5′-formylglabridin (5), (2R,3R)-3,4′,7-trihydroxy-3′-prenylflavane (7), echinatin, (3R)-2′,3′,7-trihydroxy-4′-methoxyisoflavan, kanzonol X, kanzonol W, shinpterocarpin, licoflavanone A, glabrol, shinflavanone, gancaonin L, and glabrone all exhibited significant PPAR-γ ligand-binding activity. The activity of these compounds at a sample concentration of 10 μg/mL was three times more potent than that of 0.5 μM troglitazone.     

Characterization of new PPARγ agonists: Benzimidazole derivatives—importance of positions 5 and 6, and computational studies on the binding mode

In this and previous studies we investigated the importance of partial structures of Telmisartan on PPARγ activation. The biphenyl-4-ylmethyl moiety at N1 and residues at C2 of the central benzimidazole were identified to be essential for receptor activation and potency of receptor binding. Now we focused our attention on positions 5 and 6 of the central benzimidazole and introduced bromine (3b–5/6, 3c), phenylcarbonyl (3d–5/6), hydroxy(phenyl)methyl (3g–5/6), hydroxymethyl (3h–5/6) and formyl (3i) groups. The selection of these moieties was inspired by the structure of Losartan and its metabolite EXP3179. In order to increase the hydrophobicity of the central part of the molecule, the benzimidazole was exchanged by a naphtho[2,3-d]imidazole (5). The compounds 3a–3i and 5 were tested in a differentiation assay using 3T3-L1 preadipocytes and a luciferase assay using COS-7 cells, transiently transfected with pGal4-hPPARγDEF, pGal5-TK-pGL3 and pRL-CMV, as established models for the assessment of cellular PPARγ activation. An enhanced effect on PPARγ activation could be observed if lipophilic moieties are introduced in these positions. 4′-[(2-Propyl-1H-naphtho[2,3-d]imidazol-1-yl)methyl]biphenyl-2-carboxylic acid (5) was identified as the most potent compound with an EC₅₀ of 0.26 μM and the profile of a full agonist.Together with compounds of the former structure–activity relationship study (position 2-substituted benzimidazole derivatives 4a–4j), the binding mode of Telmisartan and its derivatives have been analyzed in 3D pharmacophore-driven docking experiments.     

Design and synthesis of a series of α-benzyl phenylpropanoic acid-type peroxisome proliferator-activated receptor (PPAR) gamma partial agonists with improved aqueous solubility

In the continuing study directed toward the development of peroxisome proliferator-activated receptor gamma (hPPARγ) agonist, we attempted to improve the water solubility of our previously developed hPPARγ-selective agonist 3, which is insufficiently soluble for practical use, by employing two strategies: introducing substituents to reduce its molecular planarity and decreasing its hydrophobicity via replacement of the adamantyl group with a heteroaromatic ring. The first approach proved ineffective, but the second was productive. Here, we report the design and synthesis of a series of α-benzyl phenylpropanoic acid-type hPPARγ partial agonists with improved aqueous solubility. Among them, we selected (R)-7j, which activates hPPARγ to the extent of about 65% of the maximum observed with a full agonist, for further evaluation. The ligand-binding mode and the reason for the partial-agonistic activity are discussed based on X-ray-determined structure of the complex of hPPARγ ligand-binding domain (LBD) and (R)-7j with previously reported ligand-LDB structures. Preliminal apoptotic effect of (R)-7j against human scirrhous gastric cancer cell line OCUM-2MD3 is also described.     

Thiazolidine-2,4-diones derivatives as PPAR-γ agonists: Synthesis,molecular docking,in vitro and in vivo antidiabetic activity with hepatotoxicity risk evaluation and effect on PPAR-γ gene expression

A library of conjugates of chromones and 2,4-thiazolidinedione has been synthesized by Knoevenagel condensation followed by reduction using hydrogen gas and Pd/C as a catalyst. Compounds 5c and 5e were most effective in lowering the blood glucose level comparable to standard drug pioglitazone. Compound 5e exhibited potent PPAR-γ transactivation of 48.72% in comparison to pioglitazone (62.48%). All the molecules showed good glide score against the PPAR-γ target in molecular docking study. PPAR-γ gene expression was significantly increased by compound 5e (2.56-fold) in comparison to standard drug pioglitazone. Compounds 5e and 5c did not cause any damage to the liver and may be considered as promising candidates for the development of new antidiabetic agents.     

Phenylethanoid and secoiridoid glycosides from the leaves of Ligustrum purpurascens

A new phenylethanoid glycoside (2) and a new secoiridoid glycoside (16) were isolated from the leaves of Ligustrum purpurascens together with fourteen known compounds (1 and 3–15). The structures of the new compounds were determined by spectroscopic analyses (UV, IR, HR-ESI-MS, 1D, and 2D NMR). The absolute configuration of 16 was further determined by CD analysis. All phenylethanoid glycosides were prepared and their up-regulation of IFN-γ production in mouse splenic lymphocytes was evaluated. Compounds 1, 5, 6, 10, 11, 13 and 15 exhibited potent stimulatory effect on IFN-γ secretion.     

Lobaric acid and pseudodepsidones inhibit NF-κB signaling pathway by activation of PPAR-γ

Herein we report the anti-inflammatory activity of lobaric acid and pseudodepsidones isolated from the nordic lichen Stereocaulon paschale. Lobaric acid (1) and three compounds (2, 7 and 9) were found to inhibit the NF-κB activation and the secretion of pro-inflammatory cytokines (IL-1β and TNF-α) in LPS-stimulated macrophages. Inhibition and docking simulation experiments provided evidence that lobaric acid and pseudodepsidones bind to PPAR-γ between helix H3 and the beta sheet, similarly to partial PPAR-γ agonists. These findings suggest that lobaric acid and pseudodepsidones reduce the expression of pro-inflammatory cytokines by blocking the NF-κB pathway via the activation of PPAR-γ.     

Design and synthesis of a potent,highly selective,orally bioavailable,retinoic acid receptor alpha agonist

A ligand-based virtual screening exercise examining likely bioactive conformations of AM 580 (2) and AGN 193836 (3) was used to identify the novel, less lipophilic RARα agonist 4-(3,5-dichloro-4-ethoxybenzamido)benzoic acid 5, which has good selectivity over the RARβ, and RARγ receptors. Analysis of the medicinal chemistry parameters of the 3,5-substituents of derivatives of template 5 enabled us to design a class of drug-like molecules with lower intrinsic clearance and higher oral bioavailability which led to the novel RARα agonist 4-(3-chloro-4-ethoxy-5-isopropoxybenzamido)-2-methylbenzoic acid 56 that has high RARα potency and excellent selectivity versus RARβ (2 orders of magnitude) and RARγ (4 orders of magnitude) at both the human and mouse RAR receptors with improved drug-like properties. This RARα specific agonist 56 has high oral bioavailability (>80%) in both mice and dogs with a good PK profile and was shown to be inactive in cytotoxicity and genotoxicity screens.     

Molecular dynamics study-guided identification of cyclic amine structures as novel hydrophobic tail components of hPPARγ agonists

We previously reported that a α-benzylphenylpropanoic acid-type hPPARγ-selective agonist with a piperidine ring as the hydrophobic tail part (3) exhibited sub-micromolar-order hPPARγ agonistic activity. In order to enhance the activity, we planned to carry out structural development based on information obtained from the X-ray crystal structure of hPPARγ ligand binding domain (LBD) complexed with 3. However, the shape and/or nature of the binding pocket surrounding the piperidine ring of 3 could not be precisely delineated because the structure of the omega loop of the LBD was poorly defined. Therefore, we constructed and inserted a plausible omega loop by means of molecular dynamics simulation. We then used the reconstructed LBD structure to design new mono-, bi- and tricyclic amine-bearing compounds that might be expected to show greater binding affinity for the LBD. Here, we describe synthesis and evaluation of α-benzylphenylpropanoic acid derivatives 8. As expected, most of the newly synthesized compounds exhibited more potent hPPARγ agonistic activity and greater hPPARγ binding affinity than 3. Some of these compounds also showed comparable aqueous solubility to 3.     

Design,synthesis, and evaluation of imidazo[4,5-c]pyridin-4-one derivatives with dual activity at angiotensin II type 1 receptor and peroxisome proliferator-activated receptor-γ

Identification of a series of imidazo[4,5-c]pyridin-4-one derivatives that act as dual angiotensin II type 1 (AT1) receptor antagonists and peroxisome proliferator-activated receptor-γ (PPARγ) partial agonists is described. Starting from a known AT1 antagonist template, conformational restriction was introduced by incorporation of an indane ring that when combined with appropriate substitution at the imidazo[4,5-c]pyridin-4-one provided novel series 5 possessing the desired dual activity. The mode of interaction of this series with PPARγ was corroborated through the X-ray crystal structure of 12b bound to the human PPARγ ligand binding domain. Modulation of activity at both receptors through substitution at the pyridone nitrogen led to the identification of potent dual AT1 antagonists/PPARγ partial agonists. Among them, 21b was identified possessing potent dual pharmacology (AT1 IC₅₀ = 7 nM; PPARγ EC₅₀ = 295 nM, 27% max) and good ADME properties.     

Design and synthesis of 1,4-substituted 1H-1,2,3-triazolo-quinazolin-4(3H)-ones by Huisgen 1,3-dipolar cycloaddition with PI3Kγ isoform selective activity

A strategy for construction of medicinally important 1,4-substituted 1H-1,2,3-triazolo-quinazolin-4(3H)-ones has been devised and presented here. The compounds have been synthesized using one-pot multicomponent strategy under microwave assisted conditions. Triazolyl-quinazolinone based D-ring modified analogs are designed based on IC87114 scaffold, which is first known isoform selective inhibitor of PI3Kδ. Herein, we identified two triazolyl-quinazolinone compounds (5a and 5l) based on same scaffold with PI3Kγ specific inhibitory potential, the selectivity towards this isoform is well supported by in silico results, wherein, these compounds show better interaction and affinity and inhibitory activity for PI3Kγ rather than PI3Kδ. This repositioning of scaffold from PI3Kδ to PI3Kγ isoform can be very useful from medicinal chemistry and drug discovery perspective to unravel molecular interactions of this new scaffold in different cellular pathways.     

Estrogen and progesterone affect responses to malaria infection in female C57BL/6 mice

Background: Previous data from our laboratory suggest that gonadally intact C57BL/6 male mice are more likely than their female counterparts to die from Plasmodium chabaudi infection, to recover more slowly from weight loss and hematocrit loss, and to have reduced interferon-γ (IFN-γ) and interleukin-10 (IL-10) responses. Removal of the ovaries, and hence, the primary production of sex steroids in females, reverses these differences.Objective: We hypothesized that sex differences in response to P chabaudi may be mediated by differential synthesis of IFN-γ and IL-10 that is influenced by estrogen, progesterone, or both.Methods: C57BL/6 female mice (n = 200; n = 10/time point/treatment/experiment) were ovariectomized and implanted with a 21-day controlled-release pellet containing either 0.1 mg of 17β-estradiol (E₂), 10 mg of progesterone (P₄), 0.1 mg of E₂ plus 10 mg of P₄, or cholesterol (placebo). Females were inoculated with 10⁶P chabaudi-infected erythrocytes. Body mass, body temperature, hematocrit, parasitemia, cytokine production, and antibody responses were monitored 0, 3, 5, 7, 10, 14, and 21 days postinoculation.Results: Administration of E₂, either alone or in combination with P₄, mitigated infection-induced weight loss, hematocrit loss, and hypothermia, compared with females receiving placebo pellets (P < 0.05 in each case). Hormone treatment did not affect levels of parasitemia. Females administered E₂ alone or in combination with P₄ produced 4 to 7 times higher IFN-γ and IL-10 during peak parasitemia than did females implanted with pellets containing either P₄ alone or placebo (P < 0.05 in each case). Exposure to E₂, either alone or in combination with P₄, increased anti-P chabaudi immunoglobulin G (IgG1) responses and the ratio of IgG1 to IgG2c (P < 0.05 in each case).Conclusion: This animal study suggests that physiological levels of estrogen, rather than progesterone, enhance immunity and, possibly, protect females from disease symptoms during malaria infection.     

Exploring the PI3Kα and γ binding sites with 2,6-disubstituted isonicotinic derivatives

A homology model of the p110α catalytic subunit of PI3Kα was generated from the p110γ crystal structure. Using this model, an isonicotinic scaffold was designed for chemically exploring the PI3Kα and γ binding sites. A focused library of derivatives was synthesized and tested. The morpholine acids 5a and 5b proved to be the most potent analogs.     

Synthesis of benzopyran derivatives as PPARα and/or PPARγ activators

We describe the synthesis of 26 compounds, small polycerasoidol analogs, that are Lipinski’s rule-of-five compliant. In order to confirm key structural features to activate PPARα and/or PPARγ, we have adopted structural modifications in the following parts: (i) the benzopyran core (hydrophobic nucleus) by benzopyran-4-one, dihydrobenzopyran or benzopyran-4-ol; (ii) the side chain at 2-position by shortening to C3, C4 and C5-carbons versus C-9-carbons of polycerasoidol; (iii) the carboxylic group (polar head) by oxygenated groups (hydroxyl, acetoxy, epoxide, ester, aldehyde) or non-oxygenated motifs (allyl and alkyl). Benzopyran-4-ones 6, 12, 13 and 17 as well as dihydrobenzopyrans 22, 24 and 25 were able to activate hPPARα, whereas benzopyran-4-one (7) with C5-carbons in the side chain exhibited hPPARγ agonism. According to our previous docking studies, SAR confirm that the hydrophobic nucleus (benzopyran-4-one or dihydrobenzopyran) is essential to activate PPARα and/or PPARγ, and the flexible linker (side alkyl chain) should containg at least C5-carbon atoms to activate PPARγ. By contrast, the polar head (“carboxylic group”) tolerated several oxygenated groups but also non-oxygenated motifs. Taking into account these key structural features, small polycerasoidol analogs might provide potential active molecules useful in the treatment of dyslipidemia and/or type 2 diabetes.     

Identification of pirinixic acid derivatives bearing a 2-aminothiazole moiety combines dual PPARα/γ activation and dual 5-LO/mPGES-1 inhibition

The concept of dual PPARα/γ activation was originally proposed as a new approach for the treatment of the metabolic syndrome. However, recent results indicated that PPARα as well as PPARγ activation might also be beneficial in the treatment of inflammatory diseases and cancer. We have recently identified aminothiazole-featured pirinixic acids as dual 5-lipoxygenase (5-LO) and microsomal prostaglandin E₂ synthase-1 (mPGES-1) inhibitors. Here we present the structure–activity relationship of these aminothiazole-featured pirinixic acids as dual PPARα/γ agonists and discuss their advantages with their potential as dual 5-LO/mPGES-1 inhibitors in inflammatory and cancer diseases. Various pirinixic acid derivatives had already been identified as dual PPARα/γ agonists. However, within this series of aminothiazole-featured pirinixic acids we were able to identify the most potent selective PPARγ agonistic pirinixic acid derivative (compound 13, (2-[(4-chloro-6-{[4-(naphthalen-2-yl)-1,3-thiazol-2-yl]amino}pyrimidin-2-yl)sulfanyl]octanoic acid)). Therefore, docking of 13 on PPARγ was performed to determine the potential binding mode.     

Alkylsulfonamide-containing quinazoline derivatives as potent and orally bioavailable PI3Ks inhibitors

Phosphoinositide 3-kinases (PI3Ks) are regarded as promising targets for treatment of various cancers due to their roles in regulating cell proliferation, differentiation, migration, and survival. Here we report our efforts to develop potent and orally bioavailable PI3K inhibitors for the treatment of cancers. The alkylsulfonamide-containing quinazoline derivatives A1–A18 significantly inhibited PI3Kα, and cell proliferation among HCT-116, MCF-7 and SU-DHL-6 cell lines. The optimal compound A1 displayed potent inhibitory activity against PI3Kα (IC₅₀ = 4.5 nM), PI3Kβ (IC₅₀ = 4.5 nM), PI3Kγ (IC₅₀ = 4.5 nM), PI3Kδ (IC₅₀ = 4.5 nM) and significantly inhibited the growth of HCT-116, MCF-7 and SU-DHL-6 cell lines with IC₅₀ values of 0.82 µM, 0.99 µM and 0.19 µM, respectively. Western blot analysis demonstrated A1 significantly suppressed the phosphorylation of AKT^S473 in a dose-dependent manner. Furthermore, A1 could markedly inhibit cancer growth at the dose of 25 mg/kg in nude mouse HCT-116 xenograft model in vivo without causing significant weight loss or toxicity.     

New steroid and other compounds from non-polar extracts of Clusia burle-marxii and their chemotaxonomic significance

Phytochemical investigation of the non-polar extract of Clusia burle-marxii led to the identification of a new steroid (1), along with friedelinol (2), β-sitosterol (3), friedelin (4), stigmast-5-en-3β,7β-diol (5), stigmast-5-en-3β,7α-diol (6), stigmasterol (7), sitostenone (8), betulinic acid (9), butyrospermol (10), euphol (11), betulin aldehyde (12), 2,2-dimethyl-5-hydroxy-7-phenyl-chromane (13), 6-deoxyisojacareubin (14), padiaxanthone (15) and betulonic acid (16). This is the first report of the identification of compounds 5, 6 and 10 in the family, the first report of compounds 14 and 15 in the genus, and the first report of compounds 2, 3, 7, 8, 12, 16 in the species. Chemotaxonomic significance of these compounds is described herein.     

Design,synthesis, molecular docking and biological activity evaluation of some novel indole derivatives as potent anticancer active agents and apoptosis inducers

Reaction of 5-morphilinosulfonylisatin (1) with acetophenones (2a–e) afforded 3-hydroxy-3-substituted-2-oxoindoles 3a-e, when treated with acetic acid the expected 3-phenacylidene-2-oxoindoles 4a-d and 4-hydroxy-5′-(morpholinosulfonyl) spiro [chromene-2, 3′-indolin]-2′-one 6 were obtained. Isatin derivative (1) was stirred with cyano derivatives to produce the arylidines (7a-c), while under reflux condition, it gave pyrrolo[2,3–b]indoles (8, 9). Moreover, istain (1) reacted with pyrazolo-5-one or 3-substituted phenol in presence of malononitrile to afford spiroxindole derivatives (10a,b) and (11a,b). Also, compounds (10a,b) and (11a,b) were obtained through cyclization of (7a) with pyrazolo-5-one or 3-substituted phenol. The obtained compounds were identified by IR, ¹H NMR, ¹³C NMR and elemental analysis. Anticancer activity against three cancer cell lines (HepG-2, HCT-116 and MCF-7) were evaluated using sulforhodamine B assay method. Compounds 4b, 4c, 7a, 7c and 9 showed broad spectrum anticancer activity on the three tested cell lines with IC₅₀ values less than 10 µM. Cell cycle analysis was performed for the most promising derivatives, compounds 4b and 7c arrested HepG-2 cells at G2-M phase, while compounds 7a and 9 accumulated cells at G0-G1 phase, all of them induced apoptosis at priG1 phase in the range of (11.32–19.17%). Additionally compounds 4b, 7a and 9 showed more potent activity against EGFR than Lapatinib, their IC₅₀ values are from 0.019 to 0.026 µM while IC₅₀ of Lapatinib is 0.028 µM. Molecular docking studies were conducted to investigate the binding mode, amino acid interactions and free binding energy of these potent derivatives.