Isolation,Structural Assignment of Isoselagintamarlin A from Selaginella tamariscina and Its Biomimetic Synthesis

Isoselagintamarlin A(1),a selaginellin analogue featured a rare benzofuran unit,was isolated from Selaginella tamariscina.Its complete structural assignment was established through a combination of high-feld NMR technique and biomimetic synthesis.Notably,isoselagintamarlin A(1)was successfully synthesized via sequential oxidations and intramolecular cyclization.

Biomimetic Synthesis of CdSe Quantum Dots through Emulsion Liquid Membrane System of Gas-Liquid Transport

The cadmium selenide quantum dots (QD) have been synthesized by template-control in an emulsion liquid membrane system. The system consisted of kerosene as solvent, L152 (dialkylene succinimide) as surfactant, N7301 (trialiphatic amine, Ra, R=C8-C10) as carrier, 0.1 mol/L CdCl2 solution as internal-aqueous phase and H2Se gas as external phase. Additive organic template agent in internal-aqueous phase was necessary to fom CdSe QD. The influence of the nature of template and its concentration on sizes of the formed CdSe QD has also been studied. Transmission electron microscopy showed that the sizes of the products could be controlled down to 3-4 nm. X-ray diffraction analysis revealed that the crystals had cubic structure. The formation process and the optical properties of CdSe QD have also been presented.

A Novel Method for Biomimetic Synthesis of Mannich Bases

Since the early studies of Mannich, Mannich reaction has become an important tool for the synthesis of new compounds. Mannich bases can be either directly employed or used as intermediates. In this work, the one-carbon unit transfer reaction of tetrahydrofolate coenzyme was initiated. 1,3-Dimethylimidazolidine as a new tetrahydrofolate coenzyme model at formaldehyde oxidation level was used to react with ketone having active hydrogen atoms and amine to give the corresponding Mannich base in good yield by a covert Mannich reaction. A novel method for biomimetic synthesis of various Mannich bases is provided.

Biomimetic synthesis of active stilbenolignan derivatives by oxidative coupling and acid-catalyzed polymerization

Two new stilbenolignans and one novel lactone stilbenolignan with a seven-membered ring were biomimetically synthesized by an oxidative coupling reaction and acid-catalyzed polymerization with either isorhapontigenin and ferulic acid or sinapinic acid,respectively,as the starting materials.The structures of the stilbenolignans were defined using spectral analysis and their mechanisms of formation are discussed.Anti-oxidant and anti-inflammatory activities of the novel stilbenolignans were tested,and the lactone stilbenolignan was observed to exhibit potent anti-oxidant activity.

(+)/(-)-Gerbeloid A,a pair of unprecedented coumarin-based polycyclic meroterpenoid enantiomers from Gerbera piloselloides:Structural elucidation,semi-synthesis,and lipid-lowering activity

A pair of coumarin-based polycyclic meroterpenoid enantiomers(+)/(-)-gerbeloid A[(+)-1a and(-)-1b]were isolated from the medicinal plant Gerbera piloselloides,which have a unique caged oxatricyclo[4.2.2.0^(3,8)]decene scaffold.Their planar and three-dimensional structures were exhaustively characterized by comprehensive spectroscopic data and X-ray diffraction analysis.Guided by the hypothetical biosynthetic pathway,the biomimetic synthesis of racemic 1 was achieved using 4-hydroxy-5-methylcoumarin and citral as the starting material via oxa-6πelectrocyclization and intramolecular[2+2]photocycloaddition.Subsequently,the results of the biological activity assay demonstrated that both(+)-1a and(-)-1b exhibited potent lipid-lowering effects in 3T3-L1 adipocytes and the high-fat diet zebrafish model.Notably,the lipid-lowering activity of(+)-1a is better than that of(-)-1b at the same concentration,and molecular mechanism study has shown that(+)-1a and(-)-1b impairs adipocyte differentiation and stimulate lipolysis by regulating C/EBPα/PPARγsignaling and Perilipin signaling in vitro and in vivo.Our findings provide a promising drug model molecule for the treatment of obesity.

Hollow Bio-derived Polymer Nanospheres with Ordered Mesopores for Sodium-Ion Battery

Bio-inspired hierarchical self-assembly provides elegant and powerful bottom-up strategies for the creation of complex materials.However,the current self-assembly approaches for natural bio-compounds often result in materials with limited diversity and complexity in architecture as well as microstructure.Here,we develop a novel coordination polymerization-driven hierarchical assembly of micelle strategy,using phytic acid-based natural compounds as an example,for the spatially controlled fabrication of metal coordination bio-derived polymers.The resultant ferric phytate polymer nanospheres feature hollow architecture,ordered meso-channels of^12 nm,high surface area of 401 m2 g−1,and large pore volume of 0.53 cm3 g−1.As an advanced anode material,this bio-derivative polymer delivers a remarkable reversible capacity of 540 mAh g−1 at 50 mA g−1,good rate capability,and cycling stability for sodium-ion batteries.This study holds great potential of the design of new complex bio-materials with supramolecular chemistry.

Study on the Reaction of Benzimidazolium Salt with Amine Compounds

The addition-hydrolysis reaction of benzimidazolium salt with some mono- and bifunctional amine nucleophiles is reported, and a novel method of biomimetic synthesis for formamides and heterocycle compounds is provided.

Roles of glutathione and L-cysteine in the biomimetic green synthesis of CdSe quantum dots

Biological synthesis of quantum dots （QDs） as an environmental-friendly and facile preparation method has attracted increasing interests. However, it is difficult to distinguish the roles ofbio-thiols in QDs synthesis process because of the complex nature in organisms. In this work, the CdSe QDs synthesis conditions in organisms were reconstructed by using a simplified in vitro approach to uncover the roles of two small bio-thiols in the QDs formation. CdSe QDs were synthesized with glutathione （GSH） and L-cysteine （Cys） respectively. Compared with Cys at the same molar concentration, the CdSe QDs synthesized by GSH had a larger and broader particle size distribution with improved optical properties and crystal structure. Furthermore, quantum chemical calculations indicate that the stronger Cd^2＋ binding capacity ofGSH contributed a lot to the CdSe QDs formation despite ofthe greater capability Cys for selenite reduction. This work clearly demonstrates the different roles of small thiols in the Cd2^＋- stabilization in the environment and biomimetic QDs synthesis process.

An Efficient Cationic Cyclization Approach for the Construction of Labdane Diterpenoid Decalin Ring Skeleton

An effective approach for the construction of the decalin ring skeleton of labdane diterpenoids was developed based on a key biomimetic cationic polyene cyclization of an epoxy allylsilane precursor. The synthetic approach demonstrated here would be useful in the enantioselective and diastereoselective total synthesis of natural labdane diterpenoids in general.

Discovery of unusual phloroglucinol-triterpenoid adducts from Leptospermum scoparium and Xanthostemon chrysanthus by building blocks-based molecular networking

The first phloroglucinol-triterpenoid hybrids,myrtphlotritins A-E(1-5),were rapidly recognized and isolated from two species of Myrtaceae by employing the building blocks-based molecular network(BBMN)strategy.Compounds 1-5 featured new carbon skeletons in which phloroglucinol derivatives were coupled with lupane-and dammarane-type triterpenoids through different linkage patterns.Their structures and absolute configurations were elucidated by comprehensive analysis of spectroscopic data and quantum chemical calculations.Biosynthetic pathways for compounds 1-5 were proposed on the basis of the coexisting precursors.Guided by the biogenetic pathways,the biomimetic synthesis of compound 1 was also achieved.Additionally,compounds 2,3,and 5 exhibited potent antiviral activities against herpes simplex virus type-1(HSV-1)infection,and compounds 2 and 5 displayed significant anti-inflammatory activities on RAW264.7 cells.

Biomimetic Cationic Cyclization toward ent-Kaurene-type Diterpenoids

Terpenoids comprise the largest family of natural products and include various structurally different genus which play important roles in living organisms. Biosynthetically, diterpenoids are derived from （E,E,E）-geranylgeranyl diphosphate （GGPP）. From GGPP, diterpene cyclase catalyzes a sequence of carbocation- mediated cyclizations, rearrangements, and further oxidations, leading to a class of structurally unique ent-kaurenes, such as cafestol, gibberellin A3 and oridonin. According to the biosynthesis pathway of ent-kaurene, we designed a chiral acetal-enabled and SnCln-promoted biomimetic polyene cationic cyclization. With a following Birch reduc- tiort/alkylation cascade, a core skeleton of representative ent-kaurenes diterpenoids was completed.

Psiguamers A-C, three cytotoxic meroterpenoids bearing a methylated benzoylphloroglucinol framework from Psidium guajava and total synthesis of 1 and 2

Three sesquiterpene-based meroterpenoids psiguamers A-C(1-3)with new skeletons were isolated from Psidium guajava leaves.Compounds(±)-1 and(±)-2 were two pairs of humulene-de「ived meroterpenoids bearing a rare methylated benzoylphloroglucinol unit,while 3 was an unprecedented adduct of bicyclogermacrene and methylated benzoylphloroglucinol.Their structures were determined based on comprehensive analyses of spectroscopic data,calculated electronic circular dichroism(ECD)spectra,total synthesis,and X-ray crystallographic data.The biomimetic synthesis of(±)-1 and(±)-2 was achieved.Compound(+)-1 exhibited cytotoxic activities against five human tumor cell lines(HCT-116,HepG2,BGC-823,A549,and U251),with IC_(50) values of 2.94,9.01,6.45,5.42,and 5.33 μmol/L,respectively.

Diverse strategic approaches en route to Taxol total synthesis

Taxol is one of the most famous diterpenoid natural products used in clinical cancer therapy.Taxol and its analogues are popular synthetic targets and have attracted worldwide attention over the past decades.Tremendous research efforts have already been made and ten groups have achieved the total synthesis of Taxol since 1994.This mini-review summarized the recent highlights of divergent strategic approaches towards the chemical synthesis of Taxol's carbocyclic framework bearing a bridged eight-membered ring.

Experimental Investigation on Saline Water Purification Using Reverse Osmosis by a Novus Biomimetic Membrane

A substantial amount of Earth’s water is inadequate for human consumption while local demand is outstripping traditional supplies in many world regions;thereby,brackish and seawater treatment has become a prerequisite.This investigation suggested a complete design of an RO-based desalination filter with a multilayer biomimetic membrane.The study demonstrated a comprehensive method for experimentally fabricating a proprietary biomaterial-based multilayer nano-porous membrane.This analysis revealed that Silk Nano-Fibril(SNF)and Hydroxyapatite(HAP)extracted from Bombyx Mori silkworm cocoons may be utilized to manufacture highly methodical multilayer membranes by incorporating protein-self-assembly and in-situ-bio-mineralization.Membrane’s aquaporin layer containing lipid-bilayers has rapid water permeability and high efficacy at eliminating salt ions and contaminants.The 4µm thick SNF/HAP membrane showed a considerable decrease in salinity,with a salt rejection of 93.33%.The proposed membrane had a saline water permeability of 6.58 LMH/bar,almost 61.09%higher than conventional TFC membranes.Hydrophobic barrier and spiral-wrapped filter architecture of the membrane enable low fouling and self-cleaning properties.The schematic filter design and biomimetic fabrication of the SNF/HAP membrane have formulated a conceptual framework that might direct to the broad-scale,low-cost RO water purification filters,increasing the efficiency of water desalination and boosting the effectiveness of water treatment technologies to reduce potable water scarcity.

Ultra-low Friction and High Load-Bearing Hydrogel with Tubular Structure Based on Controllable Light-Induced Dissociation

With high water content,excellent biocompatibility and lubricating properties,and a microstructure similar to that of the extracellular matrix,hydrogel is becoming one of the most promising materials as a substitute for articular cartilage.However,it is a challenge for hydrogel materials to simultaneously satisfy high loading and low friction.Most hydrogels are brittle,with fracture energies of around 10 J·m^(-2),as compared with∼1000 J·m^(-2) for cartilage.A great deal of effort has been devoted to the synthesis of hydrogels with improved mechanical properties,such as increasing the compactness of the polymer network,introducing dynamic non-covalent bonds,and increasing the hydrophobicity of the polymer,all at the expense of the lubricating properties of the hydrogel.Herein,we develop a hydrogel material with anisotropic tubular structures where the compactness gradually decreases and eventually disappears from the surface to the subsurface,achieving a balance between lubrication and load-bearing.The porous layer with hydrophilic carboxyl groups on the surface exhibits extremely low friction(coefficient of friction(COF)∼0.003,1 N;COF∼0.08,20 N)against the hard steel ball,while the bottom layer acts as an excellent load-bearing function.What is more,the gradual transition of the tubular structures between the surface and the subsurface ensures the uniform distribution of friction stress between a lubricating and bearing layers,which endows the material with long-lasting and smooth friction properties.The extraordinary lubricious performance of the hydrogels with anisotropic tubular structure has potential applications in tissue engineering and medical devices.

Mussel-Inspired Adhesive Hydrogels: Chemistry and Biomedical Applications

Adhesive hydrogels are an emerging class of hydrogels that combine three-dimensional hydrated networks with adhesive properties.These properties facilitate intimate tissue-material contact in diverse biomedical applications,enhancing tissue joining,drug transport,and signal transmission.Inspired by the universal adhesiveness of mussel foot proteins,3,4-dihydroxyphenyl-L-alanine (DOPA) and its analogs have been extensively exploited for the fabrication of adhesive hydrogels,within which the DOPA moieties can not only serve as cross-linking mediators but also participate in various intermolecular and surface interactions to mediate wet adhesion.This mini-review highlights recent achievements in the development of mussel-inspired adhesive hydrogels,focusing on: (1) elucidating DOPA-mediated adhesion mechanisms through nanomechanical characterizations,(2) designing injectable adhesive hydrogels toward applications in drug delivery,hemostasis,and wound closure,which includes in situ gelling liquids and shear-thinning preformed hydrogels,and (3) fabricating tough adhesive hydrogels with enhanced mechanical properties for use in tissue regeneration,biosensing,and bioimaging,with typical examples of nanocomposite and double-network hydrogels.The challenges and prospects in this rapidly developing field are also discussed.

Unravelling the Structural Development of Peptide-Coordinated Iron-Sulfur Clusters:Prebiotic Evolution and Biosynthetic Strategies

Iron-sulfur(Fe-S)proteins are among the most common type of natural metalloproteins that participate in a large range of key metabolic processes.To date,enormous research works on the exploration of protein structures and catalytic mechanisms have revealed that the active sites are generally composed of a Fe-S cluster and a highly conserved coordination environment.Accordingly,people are enlightened by the prebiotic evolution of an-cient clusters and are dedicated to the development of biosynthetic methods for modern clusters.This review aims to systemically summarize the structural development of peptide-coordinated iron-sulfur clusters from two perspectives:"bottom-up"approaches involving evolution of prebiotic chemical synthesis for natural proteins and"top-down"analyses of biosynthesis in modern biological systems for artificial metalloproteins.Moreover,current challenges and the direction of future development are also presented to provide new perspectives of developing enzyme mimics and further mechanistic studies.

Colloidal Virus Particles with Hierarchical Nanomorphology and Facile Biosurface Modification

Aiming to the enormous requirement for the epidemic defense researches,we designed and constructed a spherical colloidal virus particle(CVP)to mimic nature virus in morphology,physical,chemical and biological characteristics,via coating spiky protein on col-loidal nanoparticles(CNPs)core with bulge hierarchical nanomorphology.The novel virus-like surface nanoparticles can easily be synthesized.The physical,chemical nature and the formation mechanism of the prepared CVPs were characterized and discussed.The synthesized CVPs are similar in size and envelope thickness to common natural viruses.It was demonstrated that the diameter of CVPs is about 238±12 nm,including an 8 nm thickness protein crown with bulges of 33 nm in average width.The CVPs with an isoelectric point of 4.5,meets the native virus property of negative charge under neutral condition.The protein crown enhances the roughness remarkably from 10 nm(CNPs)to 22 nm(CVPs)determined by atomic force microscopy.Thanks to the biomimetic rough morphology,the CVPs show greatly superior cellular uptake performance compared to CNPs,ovalbumin(OVA)and smoothed col-loidal particles(SCPs).The formation mechanism of protein crown with specific thickness can be attributed to the electrostatic in-teraction,protein's flexible structure and specific wettability.These results indicate that the as-prepared artificial virions mimic na-ture viruses in multi-dimension,in terms of size,surface rough morphology,surface negative charge and glycoprotein envelope composition.The synthetic colloidal virus particles pave a facile way toward engineering virus particles substitute for virus-related diseases prevention,diagnostics and cellular delivery vectors.

Yeast-Controlled Double-Shelled CacO_(3)/CaF_(2)Hollow Nanospheres with Hierarchically Porous for Sustained pH-Sensitive Drug Release

Hierarchically porous materials(HP materials)are believed one of the most hopeful matrix materials because of their distinctive multimodal pore structures and tremendous application potentials in the field of biomedicine.However,green and facile synthesis of hierarchically porous nanomaterials with beneficial water dispersibility and biocompatibility is still a great challenge.Herein,a novel biomimetic strategy is proposed to prepare the cell-tailored double-shelled HPCaCO_(3)/CaF_(2) hollow nanospheres under the mediation of yeast cells.The biomolecules derived from the secretion of yeast cells are used as conditioning and stabilizing agents to control the biosynthesis of the HPCaCO_(3)/CaF_(2) materials,which exhibit excellent water dispersibility and favorable biocompatibility.The double-shelled CaCO_(3)/CaF_(2) nanospheres hold hierarchically porous structure and have abundant pore channel and large specific surface area,showing high drug-loading and a prolonged drug sustainable release profile by the pore-by-pore diffusion pattern of the hierarchical pores.Otherwise,the HPCaCO_(3) with pH-sensitivity could controllably release drug doxorubicin hydrochloride(DOX)at the acidic tumor microenvironment.Both in vitro and in vivo results demonstrate that HPCaCO_(3)/CaF_(2) has the sustainable pH-sensitive drug release property,showing an enhanced therapeutic effect.Summarily,this study provides a biomimetic strategy to synthesize the hierarchically porous double-shelled hollow nanomaterials for applying in sustainable drug delivery system.