Design, synthesis and structure-activity relationship optimization of phenanthridine derivatives as new anti-vitiligo compounds.

Humans have been suffering from vitiligo for a long time. Target vitiligo drugs have yet been approved. Activation of Wnt/ß-catenin signalling has potential in the therapeutic use of vitiligo, so exploring new drugs that specifically directly activate Wnt is worthwhile to obtain new anti-vitiligo agents. In this work, two portions design and synthesis were put into effect. firstly, 17 phenanthridine derivatives with C-4 substitutes were designed and synthesized, which compounds 4, 6, 12, 13 served as H-acceptor with protein showed enhance melanogenesis activity; Secondly, 7 hybrid new scaffolds of compounds were designed and synthesized, scaffold hopping compound 36 that aromatic benzene was replaced pyrazole on ring C showed enhance melanogenesis and tyrosinase activity; The last and most important, a comprehensive optimization and SARs of compound 36 were carried out, compounds 41 and 43 shared phenolic hydroxyl or 3-methyl-pyridine substitutes at C-7 position remarkably improved the capacity of melanogenesis and tyrosinase activity. Compound 43 were identified as new anti-vitiligo agents that specifically activate the Wnt/ß-catenin signalling pathway by targeting Axin. Structure-activity relationship analysis implied that H-acceptor substitutions at the C-4 position and phenolic hydroxyl or pyridine substitutions at the C-7 position would improve the activities of the compounds. These findings reveal a new therapeutic strategy for vitiligo, and compounds 41 and 43 may represent potential compounds for vitiligo treatment.

Phenanthridine Derivative Host Heat Shock Cognate 70 Down-Regulators as Porcine Epidemic Diarrhea Virus Inhibitors.

Porcine epidemic diarrhea virus (PEDV) has become increasingly problematic around the world, not only for its hazards to livestock but also due to the possibility that it is a zoonotic disease. Although vaccine therapy has made some progress toward PEDV control, additional effective therapeutic strategies against PEDV are needed, such as the development of chemotherapeutic agents. The aim of this work was to identify novel anti-PEDV agents by designing and synthesizing a series of phenanthridine derivatives. Among them, three compounds (compounds 1, 2, and 4) were identified as potent anti-PEDV agents exhibiting suppression of host cell heat shock cognate 70 (Hsc70) expression. Mechanism studies revealed that host Hsc70 is involved in the replication of PEDV, and its expression can be suppressed by destabilization of the mRNA, resulting in inhibition of PEDV replication. Activity against PEDV in vivo in PEDV-infected piglets suggested that phenanthridine derivatives are the first host-acting potential anti-PEDV agents.

Aphananoid A is an Anti-Inflammatory Limonoid with a New 5/6/5 Fused Ring Featuring a C24 Carbon Skeleton from Aphanamixis polystachya.

Aphananoid A, a limonoid which features a rare C24 appendage and new 5/6/5 fused-ring framework, was obtained from Aphanamixis polystachya. The planar structure as well as the absolute configuration was identified based on extensive spectroscopic analysis and electronic circular dichroism calculations. The biogenetic pathway of aphananoid A was also speculated, which arises from the triterpene by the 3,4-seco-7,8-seco-6,8 cyclo-7,30-decarbon key pattern. In addition, bioassays indicated that aphananoid A inhibited NO production in the RAW264.7 cell line (46.80 ± 1.93%).

Design, synthesis and structure-activity relationship optimization of phenanthridine derivatives as new Wnt/ß-catenin signalling pathway agonists.

Phenanthridine derivativeHLY78 has previously been identified as the first Wnt/ß-catenin signalling pathway agonist that targets the DAX domain of axin. However, due to the relatively weak activation on the Wnt/ß-catenin signalling pathway, HLY78 is insufficient for further pharmacological study. Herein, the structural optimization of HLY78 and analyses of the structure-activity relationships (SARs) of HLY78-derived phenanthridine derivatives as agonists of the Wnt/ß-catenin signalling pathway are presented. In this work, 36 derivatives were designed and synthesized with some derivatives exhibiting stronger Wnt activity than the activity of HLY78. In particular, one of them, 8-((1,3-dimethy-pyrazol-5-yl)methoxy)-5-ethyl-4-methyl-5,6-dihydro-phenanthridin-9-ol, exhibited strong Wnt active activity and is 10 times more potent than HLY78. The following SAR analysis suggests that a pyrazole group, especially at the C-8 position, is important for Wnt activation; a methyl group at the C-4position seems to be more beneficial for Wnt activation than ethyl; and oxidation of the C-6 position reduces the Wnt activation.

Hypermonins A and B, two 6-norpolyprenylated acylphloroglucinols with unprecedented skeletons from Hypericum monogynum.

Two new 6-norpolycyclic polyprenylated acylphloroglucinols (PPAPs), hypermonins A (1) and B (2), featuring an undescribed decahydroindeno[1,7-bc]furan ring system, were isolated from the leaves and twigs of Hypericum monogynum. These compounds are a pair of epimers with opposite configurations at the C-5 position. Their structures, including their absolute configurations, were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway of 1 and 2 was also proposed. Compound 1 exhibited a significant protective effect against corticosterone-induced injury in PC12 cells.

Design, Synthesis, and Structural Optimization of Lycorine-Derived Phenanthridine Derivatives as Wnt/ß-Catenin Signaling Pathway Agonists.

Lycorine is a benzylphenethylamine-type alkaloid member of the Amaryllidaceae family. A lycorine derivative, HLY78, was previously identified as a new Wnt/ß-catenin signaling pathway agonist that targets the DAX domain of axin. Herein, the structural optimization of HLY78 and analyses of the structure-activity relationships of lycorine-derived phenanthridine derivatives as agonists of the Wnt/ß-catenin signaling pathway are presented. This research suggests that triazole groups are important pharmacophores for Wnt activation; triazole groups at C-8 and C-9 of phenanthridine compounds markedly enhanced Wnt activation. A C-11-C-12 single bond is also important for Wnt activation. On the basis of these findings, two Wnt agonists were designed and synthesized. The results for these agonists indicated that the combination of a 4-ethyldihydrophenanthridine skeleton and a triazole substituent improves Wnt activation. These compounds may be useful in further pharmacological or biological studies.

Bioactive Limonoid Constituents of Munronia henryi.

Fourteen new limonoids, munronins A-N (1-14), and eight known limonoids (15-22) were isolated from the whole plants of Munronia henryi. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry, and the structure of 8 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 represents the first limonoid found with a novel 7-oxabicyclo[2.2.1]heptane moiety produced by incorporating C-11 and C-14 via an oxygen atom. All compounds were evaluated for their anti-tobacco mosaic virus (TMV) activity and in vitro cytotoxicity against the human cancer HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines. Among them, compounds 2, 8, 9, 10, 11, 12, 18, and 20 showed significant anti-TMV activity, with IC50 values in the range 19.6-44.4 µg/mL. Compounds 1 and 18 exhibited cytotoxic effects for all five cancer cell lines, with IC50 values between 0.4 and 4.8 µM.

Alkaloids with Different Carbon Units from Myrioneuron faberi.

Three new Myrioneuron alkaloids, myrifamines A-C (1-3), with unique skeletons were isolated from Myrioneuron faberi. The absolute configuration of 1 was confirmed by single-crystal X-ray diffraction analysis, and the stereochemistry of the other two alkaloids was determined using a combination of ROESY experiments and calculated and experimental electronic circular dichroism spectra. Myrifamine C (3) is the first example of a symmetric dimer among the Myrioneuron alkaloids. Known alkaloids myrionamide (4) and schoberine (5) were also isolated, and experimental NMR and X-ray diffraction data suggest their structural revision. Compound 2 showed significant inhibitory activity toward the hepatitis C virus in vitro, with a therapeutic index (CC50/EC50) greater than 108.7.

Cyclohexane-fused octahydroquinolizine alkaloids from Myrioneuron faberi with activity against hepatitis C virus.

Investigation of the alkaloids from Myrioneuron faberi, a plant unique to China, gave four pairs of enantiomers (1-4). (±)-ß-Myrifabral A (1) and (±)-α-myrifabral A (2) formed an inseparable mixture of anomers (cluster A), as did (±)-ß-myrifabral B (3) and (±)-α-myrifabral B (4) (cluster B). Their structures were determined by X-ray diffraction and NMR analysis. Compounds 1-4 possessed novel cyclohexane-fused octahydroquinolizine skeletons and represent the first quinolizidine alkaloids from the genus Myrioneuron. The epimers of cluster A (1 and 2) were modified and separated. In vitro, clusters A and B and their derivatives inhibited replication of hepatitis C virus (HCV, IC50 0.9 to 4.7 µM) with cytotoxicity lower than that of telaprevir.

Spiramine derivatives induce apoptosis of Bax(-/-)/Bak(-/-) cell and cancer cells.

Spiramine C-D, the atisine-type diterpenoid alkaloids isolated from the Chinese herbal medicine Spiraea japonica complex, are shown to have anti-inflammatory effects in vitro. In this study, we report that spiramine derivatives of spiramine C-D bearing α,ß-unsaturated ketone induce apoptosis of Bax(-/-)/Bak(-/-) MEFs cell, which is positively corresponding their cytotoxicity of tumor cell lines including multidrug resistance MCF-7/ADR. The results indicated that oxazolidine ring is necessary, and derivatives bearing double 'Michael reaction acceptor' group would significantly increased activities both of inducing apoptosis of Bax(-/-)/Bak(-/-) cells and cytotoxicity of tumor cells. The result indicated that spiramine derivative with α,ß-unsaturated ketone group is a new anti-cancer agent with a capability of inducing apoptosis of cancer cells in Bax/Bak-independent manner.

Limonoids from Aphanamixis polystachya and their antifeedant activity.

Eight new aphanamixoid-type aphanamixoids (C-J, 1-8) and six new prieurianin-type limonoids, aphanamixoids K-P (9-14), along with 10 known terpenoids were isolated from Aphanamixis polystachya, and their structures were established by spectroscopic data analysis. Among the new limonoids, 13 compounds exhibited antifeedant activity against the generalist Helicoverpa armigera, a plant-feeding insect, at various concentration levels. In particular, compounds 1, 4, and 5 showed potent activities with EC50 values of 0.017, 0.008, and 0.012 µmol/cm(2), respectively. On the basis of a preliminary structure-activity relationship analysis, some potential active sites in the aphanamixoid-type limonoid molecules are proposed.

Potential SARS-CoV-2 Mpro steroid inhibitors from Aphanamixis polystachya (Wall.) R. N. Parker.

Herein, six previously undescribed steroids (1-6), were isolated from leaves and twigs of Aphanamixis polystachya (Wall.) R. N. Parker (Meliaceae). Their structures were elucidated by comprehensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR, UV, and IR. Antiviral activity of these compounds were evaluated. Compounds 1-6 showed varying degrees of inhibitory activity against the severe acute respiratory syndrome coronavirus 2 main protease (SARS-CoV-2 Mpro) at 200 µM.

Diterpenoids target SARS-CoV-2 RdRp from the roots of Euphorbia fischeriana Steud.

Introduction: Currently, the development of new antiviral drugs against COVID-19 remains of significant importance. In traditional Chinese medicine, the herb Euphorbia fischeriana Steud is often used for antiviral treatment, yet its therapeutic effect against the COVID-19 has been scarcely studied. Therefore, this study focuses on the roots of E. fischeriana Steud, exploring its chemical composition, antiviral activity against COVID-19, and the underlying basis of its antiviral activity. Methods: Isolation and purification of phytochemicals from E. fischeriana Steud. The elucidation of their configurations was achieved through a comprehensive suite of 1D and 2D NMR spectroscopic analyses as well as X-ray diffraction. Performed cytopathic effect assays of SARS-CoV-2 using Vero E6 cells. Used molecular docking to screen for small molecule ligands with binding to SARS-CoV-2 RdRp. Microscale thermophoresis (MST) was used to determine the dissociation constant Kd. Results: Ultimately, nine new ent-atisane-type diterpenoid compounds were isolated from E. fischeriana Steud, named Eupfisenoids A-I (compounds 1-9). The compound of 1 was established as a C-19-degraded ent-atisane-type diterpenoid. During the evaluation of these compounds for their antiviral activity against COVID-19, compound 1 exhibited significant antiviral activity. Furthermore, with the aid of computer virtual screening and microscale thermophoresis (MST) technology, it was found that this compound could directly bind to the RNA-dependent RNA polymerase (RdRp, NSP12) of the COVID-19, a key enzyme in virus replication. This suggests that the compound inhibits virus replication by targeting RdRp. Discussion: Through this research, not only has our understanding of the antiviral components and material basis of E. fischeriana Steud been enriched, but also the potential of atisane-type diterpenoid compounds as antiviral agents against COVID-19 has been discovered. The findings mentioned above will provide valuable insights for the development of drugs against COVID-19.

Daphmacrimines A-K, Daphniphyllum alkaloids from Daphniphyllum macropodum Miq.

Daphmacrimines A-K (1-11) were isolated from the leaves and stems of Daphniphyllum macropodum Miq. Their structures and stereochemistries were determined by extensive techniques, including HRESIMS, NMR, ECD, IR, and single-crystal X-ray crystallography. Daphmacrimines A-D (1-4) are unprecedented Daphniphyllum alkaloids with a 2-oxazolidinone ring. Daphmacrimine I (9) contains a nitrile group, which is relatively rare in naturally occurring alkaloids. The abilities of daphmacrimines A-D and daphmacrimines G-K to enhance lysosomal biogenesis were evaluated through LysoTracker Red staining. Daphmacrimine K (11) can induce lysosomal biogenesis and promote autophagic flux.

Evaluation of anti-HCV activity and SAR study of (+)-lycoricidine through targeting of host heat-stress cognate 70 (Hsc70).

The anti hepatitis C virus (HCV) activity of (+)-lycoricidine (1) was evaluated for the first time in this letter, yielding an EC50 value of 0.55 nmol/mL and an selection index (SI) value of 12.72. Further studies indicated that 1 induced this effect by down-regulating host heat-stress cognate 70 (Hsc70) expression. In addition, 20 derivatives were designed and synthesised to investigate the basic structure-activity relationship (SAR) of the title compound. Several of these derivatives exhibit a good inhibition of HCV, such as compound 3 (EC50=0.68 nmol/mL, SI=33.86), compound 2d (EC50=15 nmol/mL, SI=12) and compound 5 (EC50=33 nmol/mL, SI >10.91). Meanwhile, the experimental data suggest that the modification of certain groups of (+)-lycoricidine can reduce the cytotoxicity of the compounds.

Two new sphingolipids from the leaves of Piper betle L.

Two new sphingolipids, pipercerebrosides A (1) and B (2), were isolated from the leaves of Piper betle L. Their structures, including absolute configurations, were determined by spectroscopic analysis and chemical degradation. These two compounds did not show significant cytotoxic activity against the cancer cell lines K562 and HL-60 in a MTT assay.

Five new limonoids isolated from Walsura robusta.

Five new toosendanin limonoids with highly oxidative furan ring walsurobustones A-D (1-4), and one new furan ring degraded limonoid walsurobustone E (5) together with one known compound toonapubesic acid B (6) were isolated from the leaves of Walsura robusta. Their structures were elucidated by NMR and MS data. Especially, the absolute configuration of toonapubesic acid B (6) was confirmed by X-ray diffraction study. Compounds 1-6 exhibited good cytotoxicity against the cancer cell lines HL-60, SMMC-7721, A-549, MCF-7, and SW480.

Two new cytotoxic cycloartane triterpenoids from Aphanamixis polystachya (Wall.) R. N. Parker.

Two new cycloartane triterpenoids, (24 R)-cycloartane-3ß,24,25,30-tetrol (1) and (24 R)-24,25,30-trihydroxy-9,19-cycloartane-3-one (2), along with three known compounds (3-5) were isolated from leaves and twigs of Aphanamixis polystachya. The new compounds were elucidated based on comprehensive spectroscopic analysis, including 1 D, 2 D NMR and HREIMS. The in vitro cytotoxic activities evaluation of five human cancer cell lines revealed that compound 1 exhibited cytotoxic activity on all of tested human cancer cell lines, while compound 2 only had specific activity on SMMC-7721 cell line.

Novel nucleocapsid protein-targeting phenanthridine inhibitors of SARS-CoV-2.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unprecedented in human history. As a major structural protein, nucleocapsid protein (NPro) is critical to the replication of SARS-CoV-2. In this work, 17 NPro-targeting phenanthridine derivatives were rationally designed and synthesized, based on the crystal structure of NPro. Most of these compounds can interact with SARS-CoV-2 NPro tightly and inhibit the replication of SARS-CoV-2 in vitro. Compounds 12 and 16 exhibited the most potent anti-viral activities with 50% effective concentration values of 3.69 and 2.18 µM, respectively. Furthermore, site-directed mutagenesis of NPro and Surface Plasmon Resonance (SPR) assays revealed that 12 and 16 target N-terminal domain (NTD) of NPro by binding to Tyr109. This work found two potent anti-SARS-CoV-2 bioactive compounds and also indicated that SARS-CoV-2 NPro-NTD can be a target for new anti-virus agents.

Total synthesis of baicalein.

In this paper, a simple and novel synthesis of baicalein is described. This transformation features the novel synthesis of helilandin B and a different way to demethylate. The overall yield of 59% is acceptable.