Latest ArticlesTwo unprecedented polycyclic spirooliganones C and D (1 and 2) with a novel spiro[bicyclo[2.2.2]octane-2, 2′-bicyclo[3.1.0]hexane] carbon skeleton, one known dimeric prenylated C6C3 compound (3), and a pair of new enantiomeric prenylated C6C3 compounds (+)-5 and (−)-5 together with their direct precursors (+)-4 and (−)-4 were isolated from the roots of Illicium oligandrum. Their structures and absolute configurations were elucidated by spectroscopic analysis, single crystal X-ray diffraction data, and electronic circular dichroism calculations. A possible biosynthetic pathway for compounds 1 and 2 involving the Diels-Alder reaction between (−)-sabinene and cyclic prenylated tetrahydropyrano-type C6C3 compounds was proposed. The characteristic prenylated C6C3 compounds (+)-4 and (−)-4 were separated on a chiral stationary phase and their absolute configurations were determined by calculated ECD for the first time. In the antiviral bioassays, compounds 1 and (+)-5 exhibited significant inhibitory activity against CVB3 with IC50 values of 11.11 µmol/L and 1.11 µmol/L, respectively. Compounds 1 and 2 also showed moderate inhibition against influenza A (H1N1) virus.
Well-developed mitochondria-targeted nanocarriers for function regulation are highly desirable. Numerous studies have been conducted on the treatment of mitochondria-related diseases; however, further improvements are required to develop more effective drug delivery methods. Herein, we comprehensively introduce recent developments progress in rational design of mitochondria-targeted nanocarriers, and discuss the different strategies of available nanocarriers for targeting mitochondria. We also highlight the advantages and disadvantages of various carrier systems that are currently in use. Finally, perspective on new generation for mitochondria-targeted delivery systems in the emerging area of drug-based therapeutics is also discussed.
A new, stable and scalable reagent for deuteriodifluoromethylthiolation (deuterated N-difluoromethylthiophthalimide, PhthSCF2D) has been developed. This reagent can be applied for the photocatalytic radical deuteriodifluoromethylthiolation of various olefins and aldehydes (30 examples). Meanwhile, it can achieve the electrophilic deuteriodifluoromethylthiolation of a series of electrophilic substrates including electron-rich arenes, aryl/vinylboronicacids, alkynes, amines, thiols and β-ketoesters (22 examples). Some complex molecules can also be applied in both radical and electrophilic deuteriodifluoromethylthiolation using PhthSCF2D as the reagent.
Although targeted therapy and immunotherapy are now shining in the treatment of some cancers, chemotherapy is still the cornerstone of drug treatment for many cancer patients. The emergence of chemotherapy prodrugs can improve the drug activity and reduce the side effects of chemotherapy. When used, the tumor microenvironment has characteristics different from normal tissues, and the existence of the microenvironment provided a more convenient way to design responsive nanodrugs. Herein, we designed a glutathione (GSH)-responsive prodrug nanogels for enhancing tumor chemotherapy. In the nanogels of HHNP, 10-hydroxycamptothecin (HCPT) played an essential role in killing cancer cells. HCPT was jointed with a cross-linker agent with disulfide bond and was further coated with polyethylene glycol, which not only prolonged the half-life of the drug, but also made HCPT accurate transport to the tumor fractions and achieved precise and controllable release. The proposal of HHNP effectively retained the biological activity of the drug, and introduced functions such as targeting, selective release and biodegradation, which greatly improved the medical efficiency of the drug and effectively reduced the toxic and side effects. This chemotherapeutic prodrug nanogel offers a new window for constructing efficient drug delivery platform.
Since antigen and adjuvant are rapid clearance in vivo, insufficient delivery to induce dendritic cells (DCs) maturation and cross-presentation, as well as limited migration efficiency of DCs to secondary lymph organs, greatly hinders the development of DCs-based immunotherapy. Herein, PCL-PEG-PCL polymersomes (PCEP-PS) as antigen and adjuvants delivery nanoplatforms (IMO-PS) were well-designed, which can electrostatically adsorb OVA antigen on the surface via DOTAP lipid and effectively encapsulate OVA antigen into the inner hydrophilic cavity to achieve both initial antigen exposure as well as slow and sustained antigen release, incorporate MPLA within the lipid layer to ligate with extracellular TLR4 of DCs as well as encapsulate IMQ in the hydrophobic membrane to ligate with intracellular TLR7/8 of DCs for activating synergistic immune responses via different signaling pathways. The IMO-PS significantly improved antigen uptake, promoted DCs maturation and cytokines production. DCs treated with IMO-PS could enhance migration into draining lymphoid nodes, and eventually induced antigen-specific CD8+ and CD4+ T cell responses and OVA-specific cytotoxic T lymphocyte (CTL) responses. Prophylactic vaccination of EG7-OVA tumor-bearing mice by IMO-PS + DCs significantly extended tumor-free time, effectively suppressed tumor growth, and greatly extended median survival time. The strategy may provide an effective nanoplatform for co-delivery antigen and dual-adjuvants in a spatio-temporally programmed manner for DC-based cancer immunotherapy.
Relying on the electron energy loss spectrum (EELS) of metallic elements to obtain microstructure analysis is an investigation method of the reaction mechanisms of transition metal oxides (TMOs) in catalysis, energy storage and conversion. However, the low signal from K shell owing to insufficient electron beam energy, and the complicated electronic structure in L shell of the metal element restrict the analysis of the coordination environment of the TMOs. Herein, density functional theory (DFT) calculation, Fourier transform (FT) and wavelet transform (WT) were employed to probe the relationship between the four individual peaks in O K-edge spectra of iron oxides and the microstructure information (chemical bonds and atomic coordination). The findings show that the peak amplitude ration is in a linear correlation with the valence state of Fe element, and that the coordination number obtained by radial distribution function (RDF) is favorably linearly correlative with that from the standard coordination structure model. As a result, the quantitative analysis on the change of valence state and atomic coordination in microstructure can be realized by EELS O K-edge spectra. This study establishes EELS O K-edge spectrum as a promising pathway to quantitatively analyze the valence state and atomic coordination information of TMOs, and offers an effective method to conduct microstructure analysis via the EELS spectra of the non-metal element.
Guided by MS/MS molecular networks strategy, chlospicenes A and B (1 and 2), the first example of cyclopropane moiety cracked lindenane sesquiterpene Michael addition dimers, along with their biogenetic analogues (3 and 4), were targetedly discovered from the roots of Chloranthus henryi. Their structures including absolute configurations were characterized by NMR, ECD and X-ray diffraction analysis. The plausible biogenic pathway speculation indicated that cyclopropylcarbinyl rearrangement may dominate the key crack of cyclopropane moiety. In addition, compounds 1 and 2 showed significant anti-nonalcoholic steatohepatitis (NASH) activity in free fatty acid (FFA)-induced HepG2 cells by decreasing intracellular lipid accumulation.
Sulfur dioxide and its derivative sulfite widely existed in air, water as the environment pollutant. Sulfite is also commonly used as preservative and additive in fresh fruits, vegetables, wines and pharmaceutical materials. Due to sulfite is closely related with human diseases, it is very urgent for the sensitive and rapid quantification of sulfite in various samples. In our study, a turn-on near infrared (NIR) fluorescent probe (MDQ) was developed for sulfite detection based on a Michael addition reaction, with high sensitivity (LOD 4.16 nmol/L), selectivity and fast response time (400 s). Using MDQ, a quantify method for sulfite in traditional Chinese medicines (TCMs) was developed with the advantages of high precision, accuracy and convenient operation. Furthermore, according to the photophysical property of MDQ, a portable fluorescence detector is designed to quantify sulfite for TCMs and surface water in Dalian city of China. Therefore, the developed fluorescent probe MDQ and portable fluorescent detector as a rapid inspection instrument were successfully used to real-time monitor the sulfite in various complex samples.
Photo-assisted electrochemical technique provides a promising approach towards carcinogen chromium(Ⅵ) detection, which requires reasonable catalyst design. Herein, an unusual hexa-nuclear cadmium cluster functionalized reductive phosphomolybdate hybrid as photo-electrochemical sensor was designed and synthesized with formula of {[Cd(H2O)2]2[Cd(btmbp)]2}{Cd(P4Mo6O31H7)2}·20H2O (1) (btmbp= 4,4′-bis((1H-1,2,4-triazol-1-yl)methyl)biphenyl), in which the photoactive hexa-nuclear {Cd6} clusters cooperated with reductive phosphomolybdate [P4Mo6O31]12− endow the material with wide light absorption and remarkable redox activity, thus achieving efficient photo-assisted electrochemical Cr(Ⅵ) detection performance. Under visible-light assistance, the detection limit (LOD) and sensitivity of Cr(Ⅵ) is 4.17 nmol/L (0.225 ppb) and 226.32 µA L/µmol, which is apparently superior to the performance without photo-assistance (6.25 nmol/L and 106.95 µA L/µmol) and far satisfies the demands of world health organization (WHO) for potable water (50 ppb). Moreover, compound 1 showed prominent Cr(Ⅵ) detection performance in practical water samples together with remarkable anti-interference capacity and good electrochemical durability. This work provides an important guidance for designing efficient polyoxometalate-based crystalline sensors for Cr(Ⅵ) detection.
Corneal wound closure for surgical eye surgeries or accidents is typically performed to prevent pathogens from the sterile intraocular environment and avoid potential postoperative complications. Tissue adhesives are increasingly employed for corneal wound closure with superior treatment efficiency and less adverse effects. In this study, we successfully develop a novel corneal adhesive based on functionally coupled PEG-lysozyme (PEG-LZ) hydrogels for wound closure after surgical eye surgeries. PEG-LZ hydrogels have plenty of micropores and gradually decreased pore size with increasing concentration from 10%, 15% to 20% (w/v), in which PEG-LZ (15%) represents the suitable pH value, gelation time and elastic modulus. PEG-LZ hydrogels have no in vitro cytotoxicity and excellent ex vivo wound closure effectiveness in porcine eyes. The in vivo wound sealant in rabbit eyes by PEG-LZ hydrogels presents a superior therapeutic effect compared with the conventional methods of stromal hydration and suture, in terms of the wound closure percent, mean corneal thickness, percent of wound gaping, and the Descemet membrane detachment. PEG-LZ hydrogels do not induce obvious histological pathology changes. The PEG-LZ corneal adhesive is considered as a tissue adhesive alternative for wound closure after surgical eye surgeries.
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