The parallel biosynthesis routes of hyperoside from naringenin in Hypericum monogynum

Hyperoside is a bioactive flavonoid galactoside in both medicinal and edible plants.It plays an important physiological role in the growth of flower buds.However,the hyperoside biosynthesis pathway has not been systematically elucidated in plants,including its original source,Hypericaceae.Our group found abundant hyperoside in the flower buds of Hypericum monogynum,and we sequenced its transcriptome to study the biosynthetic mechanism of hyperoside.After gene screening and functional verification,four kinds of key enzymes were identified.Specifically,HmF3Hs(flavanone 3-hydroxylases)and HmFLSs(flavonol synthases)could catalyze flavanones into dihydroflavonols,as well as catalyzing dihydroflavonols into flavonols.HmFLSs could also convert flavanones into flavonols and flavones with varying efficiencies.HmF3′H(flavonoid 3′-hydroxylase)was found to act broadly on 4′-hydroxyl flavonoids to produce 3′,4′-diydroxylated flavanones,dihydroflavonols,flavonols,and flavones.HmGAT(flavonoid 3-O-galactosyltransferase)would transform flavonols into the corresponding 3-O-galactosides,including hyperoside.The parallel hyperoside biosynthesis routes were thus depicted,one of which was successfully reconstructed in Escherichia coli BL21(DE3)by feeding naringenin,resulting in a hyperoside yield of 25 mg/l.Overall,this research not only helped us understand the interior catalytic mechanism of hyperoside in H.monogynum concerning flower development and bioactivity,but also provided valuable insights into these enzyme families.

Two types of coumarins-specific enzymes complete the last missing steps in pyran- and furanocoumarins biosynthesis

Pyran-and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans,respectively,exhibiting diverse physiological and medical bioactivities.However,the biosynthetic mechanisms for their core structures remain poorly understood.Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants.These included three distinct P.praeruptorum prenyltransferases(PpPT1e3)responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors,and two novel CYP450 cyclases(PpDC and PpOC)crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds.Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring.The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis.We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process.This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.

Endless exploration for natural products: dedicated to the 80th birthday of Prof. SUN Han-Dong

Natural Products always exhibit more intellectual bioactivities and atom economy,and it’s also an important source of innovative drugs.Prof.SUN Han-Dong,Academician of Chinese Academy of Sciences from Kunming Institute of Botany,has made outstanding contributions to natural product chemistry,andsetagoodexamplefor ouryounggeneration.Onthe occasion ofProfSun’s 80th birthday,I’d like to express my deep respect to him,and wish Prof.SUN a happy birthday and good health.

Pharmacokinetic and NMR metabolomics approach to evaluate therapeutic effect of berberine and Coptidis Rhizoma for sepsis

Objective: Sepsis, a systemic response to infection, often leads to end-organ dysfunction. Despite its high rates of mortality and morbidity, its pathophysiology is still poorly understood. Coptidis Rhizoma and its main active alkaloid compound, berberine, have been as anti-bacterial and anti-inflammatory drugs used in clinic. The objective of this study was to gain more insights towards understanding the sepsis associated with drug absorption and disposition and treatments of berberine and Coptidis Rhizoma dynamically.Methods: Pharmacokinetic and metabolomic studies of Coptidis Rhizoma and its main active component berberine have been performed.Results: Cecal ligation and puncture(CLP) induced sepsis showed marked changes of metabolites concerning energy metabolism and amino acids metabolisms, which could be reversed towards the normal state by Coptidis Rhizoma and berberine.Conclusion: Berberine exhibited an equivalent and even better therapeutic effect than Coptidis Rhizoma.

Identification of a novel PHGDH covalent inhibitor by chemical proteomics and phenotypic profiling

The first rate-limiting enzyme of the serine synthesis pathway(SSP), phosphoglycerate dehydrogenase(PHGDH), is hyperactive in multiple tumors, which leads to the activation of SSP and promotes tumorigenesis. However, only a few inhibitors of PHGDH have been discovered to date, especially the covalent inhibitors of PHGDH. Here, we identified withangulatin A(WA), a natural small molecule,as a novel covalent inhibitor of PHGDH. Affinity-based protein profiling identified that WA could directly bind to PHGDH and inactivate the enzyme activity of PHGDH. Biolayer interferometry and LC-MS/MS analysis further demonstrated the selective covalent binding of WA to the cysteine 295 residue(Cys295)of PHGDH. With the covalent modification of Cys295, WA blocked the substrate-binding domain(SBD)of PHGDH and exerted an allosteric effect to induce PHGDH inactivation. Further studies revealed that with the inhibition of PHGDH mediated by WA, the glutathione synthesis was decreased and intracellular levels of reactive oxygen species(ROS) were elevated, leading to the inhibition of tumor proliferation.This study indicates WA as a novel PHGDH covalent inhibitor, which identifies Cys295 as a novel allosteric regulatory site of PHGDH and holds great potential in developing anti-tumor agents for targeting PHGDH.

Recent advances on the structural modification of parthenolide and its derivatives as anticancer agents

Parthenolide(PTL)is a sesquiterpene lactone derived from medicinal plant feverfew(Tanacetum parthenium).Recent studies have demonstrated that it has multiple pharmacological activities,especially in the treatment of various hematological and solid cancers.The superior anticancer activity of PTL suggests that it has the potential to be a first-line drug.However,due to the limited physical and chemical properties,as well as bioavailability,structural modification strategies are strongly recommended to improve the anticancer activity.This review describes representative PTL derivatives obtained by different modification strategies,which are reported to exert antiproliferative activities superior to the parent compound PTL.Furthermore,we also summarize their basic mechanisms on cancer-related signaling pathways,so as to explain the potential and characteristics of PTL and its derivatives in cancer therapy.

Sesquiterpenoids from the leaves of Sarcandra glabra

Sarglanoids A-F,six new sesquiterpenoids belonging to eudesmane(1-5)and eremophilane(6)types,were isolated from the leaves of Sarcandra glabra,a famous traditional Chinese medicine(TCM).Their structures including absolute configurations were elucidated through extensive spectroscopic analysis and electronic circular dichroism(ECD)calculations.Compounds 1-2 were rare N-containing eudesmane-type sesquiterpenoids.Compound 3 exhibited inhibitory activity against nitric oxide(NO)production in lipopolysaccharides(LPS)-induced RAW 264.7 cells with IC_(50) values at 20.00±1.30μmol·L^(-1).These findings provide scientific evidence for sesquiterpenoids as the material foundation of S.glabra.

Bioactive A-ring rearranged limonoids from the root barks of Walsura robusta

Screening active natural products, rapid identification, and accurate isolation are of great important for modern natural lead compounds discovery1. We hereby reported the isolation of seven new neotecleanin-type limonoids(1–7), seven new limonoids with 5-oxatricyclo[5.4.0.11,4]hendecane ring system(8–14), and two new precursors(15–16) together with four known limonoids(17–20) from the root barks of Walsura robusta. Their structures, including their absolute configurations, were elucidated based on analyses of HR-ESI-MS, 1D/2D NMR, ECD spectrum calculations and singlecrystal X-ray diffraction techniques. Compounds 2, 8, 9, 11, 13, 14, 18 showed significant anti-inflammatory activities in LPS-induced RAW 264.7 cell line, BV2 microglial cells, and Propionibacterium acnes-stimulated THP-1 human monocytic cells. Walrobsin M(11) exhibited anti-inflammatory activity with IC50 value of 7.9670.36 μmol/L, and down-regulated phosphorylation levels of ERK and p38 in a dose-dependent manner.

Two new nimbolinin-and trichilin-class limonoids isolated from the fruits of Melia azedarach

Two new furan fragment isomerized limonoids, meliazedalides A and B(compounds 1 and 2), were isolated from the fruits of Melia azedarach Linn.. Their chemical structures were elucidated on the basis of HR-ESI-MS and 1D and 2D NMR data, which belonged to nimbolinin-and trichilin-class, respectively. Compound 2 exhibited weak inhibitory effect on NO production in lipopolysaccharide(LPS)-activated RAW 264.7 macrophages with IC_(50) being 37.41 μmol·L^(–1).

Rapid identification of stigmastane-type steroid saponins from Vernonia amygdalina leaf based onα-glucosidase inhibiting activity and molecular networking

Steroid saponins are secondary metabolites with multiple medicinal values that are found in large quantities in natural medicines,especially Vernonia amygdalina,a famous nature medicine for the treatment of tonsillitis,diabetes,pneumonia.The current study was designed to combine molecular networking(MN)with diagnostic ions for rapid identification ofΔ^(7,9(11))stigmastane-type saponins which were theα-glucosidase inhibitory active substances in V.amygdalina.First,theα-glucosidase inhibitory activities of fiveΔ^(7,9(11))stigmastane-type steroid saponins that were previously isolated were screened,which indicated that theΔ^(7,9(11))stigmastane-type steroid saponin was one of the active constituents responsible for ameliorating diabetes.Furthermore,a strategy was proposed to identify stigmastane-type steroid saponins and verify the plausibility of derived fragmentation pathways by applying MN,MolNetEnhancer and unsupervised substructure annotation(MS2LDA).Based on this strategy,other sevenΔ^(7,9(11))stigmastane-type steroid saponins were identified from this plant.Our research provide scientific evidence for the antidiabetic potential of the steroid saponin-rich extract of V.amygdalina leaf.

Type B polycyclic polyprenylated acylphloroglucinols from the roots of Hypericum beanii

Two new type B polycyclic polyprenylated acylphloroglucinols(PPAPs)(1 and 2)and a known biogenetic precursor hyperbeanol Q(3)were isolated from the root extract of Hypericum beanii,a medicinal plant widespread in southwest China.Their chemical structures were elucidated by 1 D/2 D NMR and HRESIMS data analysis,and absolute configurations were determined through detailed electric circular dichroism(ECD)analysis including ECD exciton chirality,Mo2(OAc)4-induced ECD,and ECD comparison.Of these compounds,hyperbeone A(1)is a typical[3.3.1]-type B PPAP with an unusual C-1 geranyl side chain,and hyperberin C(2)possesses a rare bicyclo[5.3.1]hendecane core.Taking compound 3 as a starting point,a plausible biosynthetic pathway to the bicyclic type B frameworks of 1 and 2 was proposed.

New oligomeric neolignans from the leaves of Magnolia officinalis var. biloba

Six new oligomeric neolignans including two trimeric neolignans(1 and 2)and four dimeric neolignans(3–6)were isolated from the leaves of Magnolia officinalis var.biloba.Their structures were determined based on HR-ESIMS and NMR data,as well as electronic circular dichroism(ECD)calculations.Compound 1 is formed from two obovatol moieties directly linked to an aromatic ring of the remaining obovatol moiety,which is an unprecedented type of linkage between monomers.All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells.Compounds 1 and 3 showed significantly inhibitory activities with IC50 values of 6.04 and 3.26μmol·L^(−1),respectively.

LIX1-like protein drives hepatic stellate cell activation to promote liver fibrosis by regulation of chemokine mRNA stability

Dear Editor,Hepatic stellate cells(HSCs)play a key role in the fibrotic response,thus inactivating activated HSC could be a potential therapy for fibrosis.^(1,2) CCL20 expressed by HSCs and macrophages,may serve as a mediator of in flammation and fibrosis.^(3) LIX1L is a putative RNA-binding protein(RBP)that may play an important role in post-transcriptional gene regulation.^(4) However,the biological function of LIX1L in liver fibrosis remains unclear,we therefore aimed to characterize its functions in HSC activation and liver fibrosis.

Improving cancer immunotherapy via co-delivering checkpoint blockade and thrombospondin-1 downregulator

The use of checkpoint-blockade antibodies is still restricted in several malignancies due to the modest efficacy,despite considerable success in anti-tumor immunotherapy.The poor response of cancer cells to immune destruction is an essential contributor to the failure of checkpoint therapy.We hypothesized that combining checkpoint therapy with natural-product chemosensitizer could enhance immune response.Herein,a targeted diterpenoid derivative was integrated with the checkpoint blockade(anti-CTLA-4)to improve immunotherapy using thermo sensitive liposomes as carriers.In vivo,the liposomes enabled the co-delivery of the two drug payloads into the tumor.Consequently,the regulatory T cell proliferation was restrained,the cytotoxic T cell infiltration was enhanced,and the profound immunotherapeutic effect was achieved.In addition,the immunotherapeutic effect of another clinically used checkpoint antibody,anti-PD-1,also benefited from the diterpenoid derivative.Of note,our mechanism study revealed that the targeted diterpenoid derivative increased the sensitivity of cancer cells to immune attack via THBS1 downregulation and the resultant destruction of THBS1-CD47 interaction.Collectively,co-delivering THBS1 inhibitor and checkpoint blockade is promising to boost cancer immunotherapy.We first time discovered that THBS1 suppression could strengthen checkpoint therapy.

Polyphyllin I promotes cell death via suppressing UPR-mediated CHOP ubiquitination and degradation in non-small cell lung cancer

Polyphyllin I(PPI)purified from Polyphylla rhizomes displays puissant cytotoxicity in many kinds of cancers.Several researches investigated its anti-cancer activity.But novel mechanisms are still worth investigation.This study aimed to explore PPI-induced endoplasmic reticulum(ER)stress as well as the underlying mechanism in non-small cell lung cancer(NSCLC).Cell viability or colony-forming was detected by MTT or crystal violet respectively.Cell cycle,apoptosis,reactive oxygen species(ROS)and mitochondrial membrane potential were assessed by flow cytometry.Gene and protein levels were evaluated by q RT-PCR and immunoblotting respectively.Protein interaction was determined by immunoprecipitation or immunofluorescence assay.Gene overexpression or silencing was carried out by transient transfection with plasmids or small interfering RNAs.The Cancer Genome Atlas(TCGA)database was used for Gene Set Enrichment Analysis(GSEA),survival analysis,gene expression statistics or pathway enrichment assay.PPI inhibited the propagation of NSCLC cells,increased non-viable apoptotic cells,arrested cell cycle at G2/M phase,induced ROS levels but failed to decrease mitochondrial membrane potential.High levels of GRP78 indicates poor prognosis in NSCLC patients.PPI selectively suppressed unfolded protein response(UPR)-induced GRP78 expression,subsequently protected CHOP from GRP78-mediated ubiquitination and degradation.We demonstrated that the natural product PPI,obtained from traditional herbal medicine,deserves for further study as a valuable candidate for lead compound in the chemotherapy of NSCLC.

Spirolindemers A and B,Lindenane Sesquiterpenoid Oligomers Equipped with Oxaspiro[4.5]decane from Chloranthus henryi

Spirolindemers A and B,unprecedented lindenane sesquiterpenoid dimer(1)and trimer(2)equipped with oxaspiro[4.5]decane unit,were discovered from the medicinal plant Chloranthus henryi.Their structures including absolute configurations were achieved by HRMS,NMR,ECD,X-ray diffraction analyses,and quantum chemical calculations.Biogenetically,hetero-and homo-Diels-Alder additions may dominate the formation of oxaspiro[4.5]decane and spiro[4.5]decane skeletons,respectively.Compound 1 showed anti-inflammatory activity by inhibiting the expression of iNOS and COX-2.

Hyperbenzones A and B,two 1,2-seco and rearranged polycyclic polyprenylated acylphloroglucinols from Hypericum beanii

Two novel seco-polycyclic polyprenylated acylphloroglucinols(PPAPs),hyperbenzones A(1)and B(2),were isolated from the roots of Hypericum beanii,together with one known biosynthetic congener 3.Compound 1 incorporates a 6/5/5 ring system with an unprecedented spiro[bicyclo[3.3.0]octane-3,1'-cyclohexane]-2,2'-dione motif.The structures of 1 and 2 were determined by a combination of high resolution electrospray ionization mass spectroscopy(HRESIMS),nuclear magnetic resonance(NMR)spectroscopic analyses,gage-independent atomic orbital(GIAO)NMR chemical shift calculation with DP4+analyses,electronic circular dichroism(ECD)calculation,and X-ray diffraction analysis.A 1,2-seco retroClaisen rearrangement from a bicyclo[3.3.1]nonane PPAP precursor and following chemodivergent radical cascade cyclizations are proposed as the key steps in the biosynthetic pathway to yield compounds 1 and2.Biological investigations indicated that compounds 1 and 3 could decrease intracellular lipid accumulation in a palmitic acid-induced nonalcoholic steatohepatitis(NASH)cell model.

Chlospicenes A and B,cyclopropane cracked lindenane sesquiterpenoid dimers with anti-nonalcoholic steatohepatitis activity from Chloranthus henryi

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.

Two new phenolic glycosides isolated from Ginkgo seeds

Two new phenolic glycosides, 7S, 8R-urolignoside-9′-O-β-D-glucoside(1) and scrophenoside G(2), were isolated and identified from the seeds of Ginkgo biloba L., a famous traditional medicine and functional food around the world. Their structures were elucidated by spectroscopic methods(1D and 2D NMR, HR-ESI-MS, and CD), and the comparisons of spectroscopic data with the reported values in the literature.

具有褶皱导电路径的本征体弹性导体用于柔性电磁屏蔽和肿瘤消融

弹性导体在可穿戴电子设备和软机器人中至关重要.理想的本征弹性体导体在大形变下显示出均匀的三维导电网络结构和稳定的电阻变化.其面临的一个挑战是,由于体弹性导体在形变下导电路径断开,电阻变化很大.我们的策略是将具有互连微孔的泡沫进行预拉伸,通过碳纳米管在微孔表面自组装形成导电层,随后释放预应变,从而在导电网络中引入褶皱结构.在拉伸过程中,褶皱和微孔的变形都有助于电阻的稳定(在70%应变下电阻变化2.0%).微观结构和有限元分析表明,由于导电层中的缺陷,可以获得不同形貌的二维褶皱结构.我们展示了其在全方位电气互连、可拉伸电磁屏蔽和电热肿瘤消融方面的应用.