Toll-like receptors (TLRs) play a central role in innate immunity as pathogen sensors. During the last decade, structural analyses of TLRs have revealed the mechanisms of ligand recognition and signal transduction. Each TLR recognizes its cognate ligand in a different manner, whereas signal transduction is achieved by a common mechanism. In this review, the mechanisms of ligand recognition and signal transduction by TLRs are summarized based on recent structural information.

This study aims to develop a gastroretentive sustained-release drug delivery system of paeonol using floating properties and to investigate its therapeutic effects in rat models. The gastric retention tablets of paeonol (GRT-Ps) were prepared by a direct compression method, and the Box–Behnken design was used to optimize its formulation. The optimized formulation containing 15% NaHCO₃ and a 2 : 1 ratio of paeonol and HPMC-K4M floated within 1 min and remained afloat for more than 8 h in the simulated gastric fluid (200 mL, pH=1.2) and simultaneously showed the desired sustained drug release. Moreover, small tablets (3 mm) were prepared according to the same formulation and the process technology of big tablets (8 mm). A similar drug release behavior was observed between two kinds of tablets (f₂=52), and then the evaluations of efficacy and retention capacity in vivo were conducted with small tablets. In vivo retention studies showed that the T_max (2 h) of GRT-P in rat stomachs was significantly extended compared with the T_max (0.5 h) of normal reference preparation. Compared with the model group, low and high doses of GRT-P could significantly inhibit the increase of malondialdehyde (MDA) in serum. Studies showed that the higher MDA content in inflammation tissue increases the inflammatory response. The ulcer inhibition rates of GRT-P in the high-dose group were 59.0 and 64.1% in the ranitidine group. Results indicated that GRT-Ps had the potential for a sustained drug release and an enhanced gastric residence time with relatively high drug concentrations in the tissue distribution.

Indoleamine 2,3-dioxygenase 1 (IDO1) plays an important role in the immune escape of tumors and has emerged as a promising target for cancer immunotherapy. Despite its potential in immuno-oncology, very few chemotypes have been reported to date. Here, we disigned a novel high throughput virtual screening (HTVS) cascade protocol, combining both pharmacophore modeling and molecular docking and it was employed to query commercially available compounds to identify novel inhibitors. Among the 23 compounds selected for the in vitro IDO1 inhibitory activity assay, five compounds exhibit greater than 20% inhibition at a test concentration of 10 µM, with two compounds having an IC₅₀ value of 23.8 and 8.8 µM, respectively. The novel scaffold together with a ligand efficiency of 0.28 kcal/mol per heavy atom makes both compounds as suitable starting points for future chemistry elaboration. Our HTVS protocol was validated and could be employed in discovery of IDO1 inhibitors.

Reduction-sensitive nanogel was developed by including dithiodipropionic acid (DTPA) in tripolyphosphoric acid (TPPA) cross-linked poly(ethylenimine) (PEI) nanogel. According to the light scattering measurement, DTPA (a disulfide compound) seemed to cross-link PEI chains in a cooperative manner with TPPA (a multi-valent anion). Nanogels composed of TPPA, PEI, and DTPA exhibited negative zeta potential and the absolute value increased with the amount of TPPA and DTPA. TPPA and DTPA were found to be contained in the nanogel, evidenced by Fourier transform (FT)-IR spectroscopy and Raman spectroscopy, respectively. ¹H-NMR spectroscopy also revealed DTPA was contained in the nanogel. The DTPA content in the nanogel was determined colorimetrically to be 7.14 and 9.4%, depending on the DTPA content in the raw mixture for the preparation of nanogel. On the transmission electron microscopy (TEM) micrographs of the negatively stained nanogel, the diameter was about 20–30 nm. The specific loading of carboxylic fluorescein (CF) in the nanogel was around 1.8%, determined by fluorometric analysis, and it was not affected by the DTPA content. The maximum release degree of CF loaded in nanogel containing no DTPA was less than 10% and it was almost the same regardless of dithiothreitol (DTT) concentration. Whereas, the release of the dye loaded in nanogel containing DTPA was markedly promoted by DTT, possibly because the disulfide bond can be broken by DTT and the diffusivity of the dye through the nanogel matrix can increase.

We have focused on melt adsorption as manufacture method of wax matrices to control particles size of granules more easily than melt granulation. The purpose of present study was to investigate the possibility of identifying a hydrophobic material with a low melting point, currently used as a meltable binder of melt granulation, to apply as a novel carrier in melt adsorption. Glyceryl monostearate (GM) and stearic acid (SA) were selected as candidate hydrophobic materials with low melting points. Neusilin US2 (US2), with a particle diameter of around 100 µm was selected as a surface adsorbent, while dibasic calcium phosphate dihydrate (DCPD), was used as a non-adsorbent control to prepare melting granules as a standard for comparison. We prepared granules containing ibuprofen (IBU) by melt adsorption or melt granulation and evaluated the particle size, physical properties and crystallinity of granules. Compared with melt granulation using DCPD, melt adsorption can be performed over a wide range of 14 to 70% for the ratio of molten components. Moreover, the particle size; d50 of obtained granules was 100–200 µm, and these physical properties showed good flowability and roundness. The process of melt adsorption did not affect the crystalline form of IBU. Therefore, the present study has demonstrated for the first time that melt adsorption using a hydrophobic material, GM or SA, has the potential capability to control the particle size of granules and offers the possibility of application as a novel controlled release technique.

Efficient routes to various kinds of heterocycles incorporating the p-halophenyl moiety have been synthesized. Different pyrrole derivatives have been synthesized, as well, by Thorpe–Ziegler cyclization. Therefore, we synthesized different analogues of tacrine by Friedländer reaction of o-amino nitriles (pyrazolo, furano and pyrrolo) with different cycloalkanones. The use of microwave irradiation leads to shorter production times and high product conversion. These synthesized compounds were biologically evaluated by Ellman’s test on acetylcholinesterase inhibition.

From the chloroform extract of the fresh fruits of Diospyros maritima BLUME (Ebenaceae), five new naphthoquinone derivatives, 2,7′-dimethyl-2′,3-bijuglone (27), 2,7′-dimethyl-3,3′-bijuglone (28), 2,7′-dimethyl-6,8′-bijuglone (29), 7,7′-dimethyl-3,3′-ethylidenebijuglone (30), and 2′,7-dimethyl-3,6′-ethylidenebijuglone (31), were isolated, in addition to twenty-one known naphthoquinone derivatives: plumbagin (4), droserone (5), 2,3-epoxyplumbagin (8), 3,3′-biplumbagin (9), chitranone (10), 3,8′-biplumbagin (11), elliptinone (12), maritinone (13), isozeylanone (14), methylene-3,3′-biplumbagin (15), ethylidene-3,3′-biplumbagin (16), ethylidene-3,6′-biplumbagin (17), ethylidene-6,6′-biplumbagin (18), 7-methyl-β-dihydrojuglone (19), 7-methyljuglone (20), 2,3-epoxy-7-methyljuglone (21), neodiospyrin (22), mamegakinone (23), ehretione (24), isoxylospyrin (25) and β-dihydroplumbagin (26). The structures of the new compounds were established by spectral analysis. The quinones obtained from the chloroform extract of the fruits were compared with previously reported quinones obtained from ethanol extracts. The quinones in the fruits were categorized in three groups: quinones from ethanol extract only, quinones from chloroform extract only, and quinones from both extracts. The six naphthoquinones, 19–21, 25, 26, and 29, were examined for their ichthyotoxic activity and germination inhibitory activity. Quinones 19–21, 26, and 29 showed ichthyotoxic activity against Japanese killifish (Oryzias latipes var.) at 10 ppm; quinones 19 to 21 and 26 showed germination inhibitory activity toward lettuce seeds (Lactuca sativa L. var. Great Lakes) at 100 ppm.

Malaria is the most devastating parasitic disease worldwide. Artemisinin is the only drug that can cure malaria that is resistant to quinine-derived drugs. After the commercial extraction of artemisinin from Artemisia annua, the recovery of dihydroartemisinic acid (DHAA) from artemisinin extraction by-product has the potential to increase artemisinin commercial yield. Here we describe the development and optimization of an ultrasound-assisted alkaline procedure for the extraction of DHAA from artemisinin production waste using response surface methodology. Our results using this methodology established that NaOH at 0.36%, extraction time of 67.96 min, liquid–solid ratio of 5.89, and ultrasonic power of 83.9 W were the optimal conditions to extract DHAA from artemisinin production waste. Under these optimal conditions, we achieved a DHAA yield of 2.7%. Finally, we conducted a validation experiment, and the results confirmed the prediction generated by the regression model developed in this study. This work provides a novel way to increase the production of artemisinin per cultivated area and to reduce artemisinin production costs by recycling its commercial waste to obtain DHAA, an immediate precursor of artemisinin. The use of this technology may reduce the costs of artemisinin-based antimalarial medicines.

From the leaves of Zanthoxylum ailanthoides, 4′-O-p-E-coumaric acid esters of 2-propanol β-D-glucopyranoside, megastigmane and megastigmane glucosides were isolated. Their structures were elucidated by spectroscopic evidence. The absolute configurations of the megastigmane and aglycone of megastigmane glucosides were determined by the octant rule and modified Mosher’s method after protection of carboxylic acids by p-bromophenacyl esters and primary alcohols by pivaloyl esters.

Using tissue engineering technique to repair cartilage damage caused by osteoarthritis is a promising strategy. However, the regenerated tissue usually is fibrous cartilage, which has poor mechanical characteristics compared to hyaline cartilage. Chondrocyte hypertrophy plays an important role in this process. Thus, it is very important to find out a suitable way to maintain the phenotype of chondrocytes and inhibit chondrocyte hypertrophy. Curcumin deriving from turmeric was reported with anti-inflammatory and anti-tumor pharmacological effects. However, the role of curcumin in metabolism of chondrocytes, especially in the chondrocyte hypertrophy remains unclear. Mesenchymal stem cells (MSCs) are widely used in cartilage tissue engineering as seed cells. So we investigated the effect of curcumin on chondrogenesis and chondrocyte hypertrophy in MSCs through examination of cell viability, glycosaminoglycan synthesis and specific gene expression. We found curcumin had no effect on expression of chondrogenic markers including Sox9 and Col2a1 while hypertrophic markers including Runx2 and Col10a1 were down-regulated. Further exploration showed that curcumin inhibited chondrocyte hypertrophy through Indian hedgehog homolog (IHH) and Notch signalings. Our results indicated curcumin was a potential agent in modulating cartilage homeostasis and maintaining chondrocyte phenotype.

Antimetabolite drugs, including the adenosine deaminase inhibitor cladribine, have been shown to induce apoptosis in a variety of cancer cells, and have been widely used in clinical trials of various cancers in conjunction with tyrosine kinase inhibitors (TKIs). Combination treatment with cladribine and gefitinib or dasatinib is expected to have a synergistic inhibitory effect on breast cancer cell growth. Our results demonstrated that the combination treatment had synergistic activity against human breast cancer (MCF-7) cells, enhanced G₂/M cell arrest and reactive oxygen species (ROS) generation, and increased the loss of mitochondrial membrane potential and cell apoptosis. In addition, the combination treatment decreased Bcl-2 expression. Our results demonstrated that cladribine in combination with gefitinib or dasatinib exerted synergistic anticancer effects on MCF-7 cells by inducing cell cycle arrest, ROS production and apoptosis through the mitochondria-mediated intrinsic pathway.

The evaluation of effective skin chemical penetration enhancers (CPEs) is a crucial process in the development of transdermal and dermal formulations with the capacity to overcome the stratum corneum barrier. In the present study, we aimed to investigate the potential of stratum corneum lipid liposomes (SCLLs) as an alternative tool for the screening of various types and concentrations of CPEs. SCLLs were prepared using a thin-film hydration technique, and two types of fluorescent probes (sodium fluorescein [FL] or 1,6-diphenyl-1,3,5-hexatriene [DPH] were entrapped separately into SCLLs (FL-SCLL and DPH-SCLL, respectively). FL leakage from SCLLs as well as the fluidity of DPH-SCLLs were determined after incubating with various types of CPEs as a function of their concentrations. The obtained results showed a concentration-dependent relationship for most CPEs both for FL leakage and the fluidity of SCLLs. When observing these data in detail, however, the concentration profiles could be classified into five main categories depending on the mode of action of the CPEs. These results strongly suggest the usefulness of SCLLs for high-throughput screening of effective CPEs as well as the understanding of their possible mode of action, especially in the early stage of skin formulation development.

The hedgehog (Hh) signaling pathway performs important roles in embryonic development and cellular proliferation and differentiation. However, in many cancer cells Hh signaling is aberrantly activated, which has provided a strong impetus for the development of Hh pathway inhibitors. To address this, we synthesized a series of heterocyclic flavonoids and evaluated their Hh signaling inhibitory activity on cancer cell lines using our cell-based assay system. Of the synthetic flavonoids, compounds 4a and g showed good inhibitory activity (IC₅₀ was 16.8 and 21.8 µM, respectively), and were cytotoxic toward human pancreatic (PANC1) and prostate (DU145) cancer cells in which Hh signaling was activated. Compounds 4a and g had moderate selectivity against PANC1 cells. Western blotting analyses revealed that PTCH and GLI1 expression was reduced after treatment with these compounds. Overall, these synthetic flavonoids represent promising new additions to our expanding panel of Hh pathway inhibitors, and with further development these molecules may ultimately be considered for clinical use.

A 7-hydroxy derivative of 3-methyleneisoindolin-1-one 1 was synthesized and its properties as a new fluorophore undergoing excited-state intramolecular proton transfer (ESIPT) were investigated. In alcohols and dimethylsulfoxide, 1 exhibited dual emission at ca. 380 and 525−540 nm when excited at ca. 336 nm, which agreed well with the density functional theory (DFT) and time-dependent (TD)-DFT-calculated emission predictions of 1 and its ESIPT tautomer. In aqueous solutions at near neutral pH, 1 exhibited a broad emission band at ca. 497 nm, presumably caused by the overlap of emissions from 1 and the excited state phenolate species of 1. In binary mixtures of H₂O and EtOH, the wavelength and intensity of fluorescence maxima were dependent on the dielectric constant of the solvent, suggesting that 1 could be applied as a fluorescent probe to monitor aqueous environments.

The efficient oxidation of benzylic alcohols to carbonyl compounds was performed using chloramine-T and a catalytic amount of indium(III) triflate. The primary benzylic alcohols were converted to the corresponding aldehydes in a good yield, and the secondary benzylic alcohols were oxidized to ketones in a high yield. The optimized reaction conditions required 0.3 eq of indium(III) triflate and the use of acetonitrile as a solvent.