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.

Discovery of novel phenanthridone derivatives with anti-streptococcal activity.

To address the growing health threat posed by drug-resistant pathogenic microorganisms, the development of novel antimicrobial medications with multiple mechanisms of action is in urgent demand. With traditional antibacterial drug resources challenging to push forward, developing new antibacterial drugs has become a hot spot in biomedical research. In this study, we tested the antibacterial activity of 119 phenanthridine derivatives via the antibacterial assay and obtained 5 candidates. The cytotoxicity assay showed one phenanthridine derivative, HCK20, was safe for mammalian cells below 125 µM. HCK20 was verified to possess significant antibacterial activity to Streptococcus spp., such as Streptococcus pneumoniae, Streptococcus agalactiae, Streptococcus suis, Streptococcus dysgalactiae, and Streptococcus equi with MICs ranging from 15 to 60 µM. Furthermore, we found that HCK20 probably achieved its bacterial inhibition by influencing the permeability of bacterial cell walls via interacting with Streptococcal penicillin-binding proteins (PBPs). Our results suggest that this phenanthridine derivative, HCK20, has great potential to become a novel antibacterial agent that can be a potent treatment for streptococcal infections.

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.

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.

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.

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%).

Diterpenes with potential treatment of vitiligo from the aerials parts of Euphorbia antiquorum L.

Six new diterpenes Euphonoids A-F including one ingenol (1), three lathyrane (2-5), one ent-abietane (6) and fifteen known derivatives (7-21) were isolated from the aerial parts of Euphorbia antiquorum L. Their structures were elucidated by physical data analysis. Compounds 1, 12, and 16 improve the melanogenesis in B16 cells in vitro.

Two new bioactive lignans from leaves and twigs of Cleistanthus concinnus Croizat.

Two new lignans (1-2), along with five known compounds (3-7) with different structures were isolated from leaves and twigs of Cleistanthus concinnus Croizat. The new lignans were elucidated as (7'R,8'S)-3,3',5'-trimethoxy-4,4'-dihydroxy-7-en-7',9- epoxy-8,8'-lignan (1) and (7'R,8'S)-3,3'-dimethoxy-4,4'-dihydroxy-7-en-7',9-epoxy-8, 8'-lignan (2) by comprehensive spectroscopic analysis including 1D and 2D NMR as well as HREIMS and comparing their NMR data with known compounds in the literature. Among these isolated compounds, compound 1, 2, 3, and 6 were tested for anti- inflammatory effects by inhibiting NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Compound 1, 2, and 6 exhibit NO inhibitory activity.[Formula: see text].

Stelleraguaianone B and C, two new sesquiterpenoids from Stellera chamaejasme L.

Two new sesquiterpenoids were isolated from Stellera chamaejasme L., known as the traditional Chinese herb 'Rui Xiang Lang Du'. The compounds were elucidated as stelleraguaianone B (1) and C (2) by comprehensive spectroscopic analysis, including 1D and 2D NMR as well as HRESIMS, and by comparing their NMR data with known compounds. In addition, the structure of 1 was further confirmed by single-crystal X-ray diffraction analysis. Both the compounds were evaluated for their cytotoxicity on common tumour cell lines in vitro, which revealed that compound 1 exhibits cytotoxic activity on A549 cells, while 2 has no activity.

Structural Revision of Macropodumine A and Structure of 2-Deoxymacropodumine A, Daphniphyllum Alkaloids with 11-Membered Macrolactone Rings.

An unusual Daphniphyllum alkaloid, 2-deoxymacropodumine A (1), possessing an 11-membered macrolactone ring, was obtained from an extract of the stems of Daphniphyllum angustifolium. The structure of 1 was elucidated by 1D and 2D NMR spectroscopic methods and chemical calculations. Based on a comparison of the experimental and calculated NMR data, the structure of macropodumine A (2'), an analogue of 1, was also revised.

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.

Efficient synthesis of new phenanthridine Wnt/ß-catenin signaling pathway agonists.

Previously, HLY78, a lycorine derivative, was identified as the first Wnt/ß-catenin signaling agonist through binding to the DAX domain of Axin, a scaffold of Wnt/ß-catenin complex. In this study, to obtain more potent Wnt/ß-catenin agonist, the structure optimization of HLY78 was carried out by design and synthesis of six phenanthridine derivatives, which afforded five active ones. In particular, 8,9-bis((1,3-dimethyl-1H-pyrazol)methoxy)-5-ethyl-4-methyl-5,6-dihydrophenanthridine showed the most potent activity (0.15/µM) that was increased nearly 30 times as that of the lead HLY78. These compounds may be valuable in future pharmacological or biological studies.

An Explorer of Chemical Biology of Plant Natural Products in Southwest China, Xiaojiang Hao.

Xiaojiang Hao, who obtained Master Degree from Kunming Institute of Botany (KIB), Chinese Academy of Sciences (CAS) in 1985, and Doctor in Pharmacy degree in Pharmacy from Institute for Chemical Research, Kyoto University, in 1990, was born in Chongqing in July, 1951. In 1991, he returned to KIB, CAS, as an Associate professor and served as the chair of the Department of Phytochemistry. In 1994, he was promoted to a full professor at the current institute. He served as the Deputy Director of KIB and the Director of Open Laboratory of Phytochemistry from 1995 to 1997, and the Director of KIB from 1997 to 2005. Professor Hao has published more than 450 peer-reviewed SCI papers, which have been cited over 6000 times. He has obtained one PCT patent and 23 patents in China. Due to his tremendous efforts, one candidate drug, phenchlobenpyrrone, has entered the Phase II clinical trail for the treatment of Alzheimer's disease. Moreover, he won the First Prize of Natural Sciences in Yunnan Province for three times, and Ho Leung Ho Lee Fund Science and Technology Innovation Award in 2017.

Anti-TMV Effects of Amaryllidaceae Alkaloids Isolated from the Bulbs of Lycoris radiata and Lycoricidine Derivatives.

Fifteen known amaryllidaceae alkaloids were isolated from the bulbs of Lycoris radiata. Some of the compounds and lycoricidine derivatives had been screened for the activities against tobacco mosaic virus (TMV) by the conventional half-leaf method. Lycoricidine derivatives were also carried out the assay of effect on systemic infection of TMV by western-blot and RT-PCR analysis. The tested compounds showed moderate inactivation effect, whereas the lycoricidine derivatives showed good protective effect. The protective inhibitory activity of compounds L1 (N-methyl-2,3,4-trimethoxylycoricidine) (60.8%) and L3 (N-methyl-2-methoxy-3,4-acetonidelycoricidine) (62.0%) was almost similar to the positive control, Ningnanmycin (66.4%). RT-PCR and Western-blot analysis displayed that compounds L1, L3, L5 (N-allyl-2,3,4-triallyloxylycoricidine) exhibited antiviral activity, which was evidenced by reducing TMV-CP gene replication and TMV-CP protein expression. Additionally, defensive enzyme activities confirmed that compound L1 could increase the activity of PAL, POD, SOD to improve disease resistance of tobacco.

Cytotoxic indole alkaloids from Melodinus khasianus and Melodinus tenuicaudatus.

Four new indole alkaloids, melodinusines A-D (1, 2, 6, and 7), along with 26 known indole alkaloids, were isolated from Melodinus tenuicaudatus and Melodinus khasianus (Melodinus genus). Among them, 1 and 2 are aspidospermine-aspidospermine-type bisindole alkaloids while 7 is a novel melodinus-type alkaloid. Their structures were established on the basis of comprehensive spectroscopic data analysis and the structure of 7 was further confirmed by single-crystal X-ray diffraction analysis. Their cytotoxic activities against five human cancer cell lines, HL-60, SMMC-7721, A-549, MCF-7, and SW480 were also evaluated.

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.

Two novel diterpenoid heterodimers, Bisebracteolasins A and B, from Euphorbia ebracteolata Hayata, and the cancer chemotherapeutic potential of Bisebracteolasin A.

Rare ent-abietane-rosane diterpenoid heterodimers, Bisebracteolasins A and B (1 and 2, respectively), were isolated from the roots of Euphorbia ebracteolata Hayata. Their structures and absolute configurations were elucidated from spectroscopic data and X-ray diffraction analysis. Compounds 1 and 2 exhibited moderate cytotoxic effects against five cancer cell lines. Compound 1 showed more effective antiproliferative activities against human tumour cells, HL-60 and SMMC-7721, with IC50 values of 2.61 and 4.08 µM, respectively, than 2. Both compounds 1 and 2 inhibit the colorectal cancer stem cell line P6C with IC50 values of 16.48 and 34.76 µM, respectively. Moreover, preliminary biological tests showed compound 1 exhibited inhibitory activity towards tumoursphere formation and migration of the P6C cell line. Overall, we identified two novel diterpenoid heterodimers, and Bisebracteolasin A exhibits therapeutic potential in impeding tumour growth and metastatic ability of cancer stem cells.

(±)-Perforison A, A Pair of New Chromone Enantiomers from Harrisonia perforata.

(+)-Perforison A and (-)-perforison A, a new pair of chromone enantiomers, along with four known compounds, were isolated from the leaves and stems of Harrisonia perforata. Their structures and absolute configurations were determined on the basis of extensive analysis of spectroscopic data and electronic circular dichroism (ECD) calculations. The cytotoxic activities in vitro of these compounds were evaluated, but none showed significant activity.