Sesquiterpenes and dimeric sesquiterpenoids from Sarcandra glabra

Terpenoids of plants from Chloranthaceae family: chemistry, bioactivity, and synthesis

Covering: 1976 to December 2023Chloranthaceae is comprised of four extant genera (Chloranthus, Sarcandra, Hedyosmum, and Ascarina), totaling about 80 species, many of which have been widely used as herbal medicines for diverse medical purposes. Chloranthaceae plants represent a rich source of structurally interesting and diverse secondary metabolites, with sesquiterpenoids and diterpenoids being the predominant structural types. Lindenane sesquiterpenoids and their oligomers, chemotaxonomical markers of the family Chloranthaceae, have shown a wide spectrum of bioactivities, attracting significant attention from organic chemists and pharmacologists. Recent achievements also demonstrated the research value of two unique structural types in this plant family, sesquiterpenoid-monoterpenoid heterodimers and meroterpenoids. This review systematically summarizes 682 structurally characterized terpenoids from 22 Chloranthaceae plants and their key biological activities as well as the chemical synthesis of selected terpenoids.

Trisarcglaboids A and B, two cytotoxic lindenane sesquiterpenoid trimers with a unique polymerization mode isolated from Sarcandra glabra

Trisarcglaboids A and B (1 and 2), representing the first example of lindenane sesquiterpenoid trimers repolymerized based on the classical [4 + 2] type dimer, together with known biogenic precursors chlorahololide D (3) and sarcandrolide A (4), were identified as chemical components of the root of Sarcandra glabra. The novel trimeric lindenane sesquiterpenoid skeletons, including their absolute configurations, were characterized using MS, NMR, ECD, and X-ray single crystal diffraction. The proposed Diels-Alder cycloaddition between Δ2(3) of the tiglic acyl group of the classical [4 + 2] type dimer and Δ15(4),5(6) of the third lindenane may serve as the key biogenic step. In addition, compound 1 exerted significant cytotoxicity against five human cancer cell lines with IC50 values ranging from 1 to 7 μM, potentially through blocking Akt phosphorylation and activating the endogenous apoptosis pathway.

Chemistry and bioactivity of lindenane sesquiterpenoids and their oligomers

Covering: 1925 to July 2023Among the sesquiterpenoids with rich structural diversity and potential bioactivities, lindenane sesquiterpenoids (LSs) possess a characteristic cis, trans-3,5,6-carbocyclic skeleton and mainly exist as monomers and diverse oligomers in plants from the Lindera genus and Chloranthaceae family. Since the first identification of lindeneol from Lindera strychnifolia in 1925, 354 natural LSs and their oligomers with anti-inflammatory, antitumor, and anti-infective activities have been discovered. Structurally, two-thirds of LSs exist as oligomers with interesting skeletons through diverse polymeric patterns, especially Diels-Alder [4 + 2] cycloaddition. Fascinated by their diverse bioactivities and intriguing polycyclic architectures, synthetic chemists have engaged in the total synthesis of natural LSs in recent decades. In this review, the research achievements related to LSs from 1925 to July of 2023 are systematically and comprehensively summarized, focusing on the classification of their structures, chemical synthesis, and bioactivities, which will be helpful for further research on LSs and their oligomers.

Lindenane sesquiterpenoid dimers from Chloranthus japonicus improve LDL uptake by regulating PCSK9 and LDLR

UPLC-TOF-MS/MDF directed phytochemical research of Chloranthus japonicus led to the isolation of 46 lindenane sesquiterpenoid dimers, which included 13 new analogs. Their structures with absolute configurations were elucidated by analysis of spectroscopic data. Fourteen compounds with ester chains significantly decreased PCSK9 protein level in medium of HepG2 cells, especially for compounds 14 and 29 (5 µM) with inhibition rates of 69.0% and 72.8%, respectively. Compound 14 in HepG2 cells was evaluated via DiI-LDL uptake assays and found to increase LDL uptake by upregulating LDLR mRNA and protein level. Meanwhile, 14 decreased the secretion of PCSK9 protein in medium and downregulated intracellular PCSK9 protein and mRNA level. The discovery of these natural small molecule compounds provides a novel structure basis for design PCSK9 regulators, making them a promising lead for development of new lipid-lowering agents.

A comprehensive review on the chemical constituents, sesquiterpenoid biosynthesis and biological activities of Sarcandra glabra

Sarcandra glabra (Thunb.) Nakai is a perennial evergreen herb categorised within the Sarcandra Gardner genus under the Chloranthaceae family. Indigenous to tropical and subtropical regions of East Asia and India, this species is extensively distributed across China, particularly in the southern regions (Sichuan, Yunnan, and Jiangxi). In addition to its high ornamental value, S. glabra has a rich history of use in traditional Chinese medicine, evident through its empirical prescriptions for various ailments like pneumonia, dysentery, fractures, bruises, numbness, amenorrhea, rheumatism, and other diseases. Besides, modern pharmacological studies have revealed various biological activities, such as antitumour, anti-bacterial, anti-viral anti-inflammatory and immunomodulatory effects. The diverse chemical constituents of S. glabra have fascinated natural product researchers since the 1900s. To date, over 400 compounds including terpenoids, coumarins, lignans, flavonoids, sterols, anthraquinones, organic acids, and organic esters have been isolated and characterised, some featuring unprecedented structures. This review comprehensively examines the current understanding of S. glabra's phytochemistry and pharmacology, with emphasis on the chemistry and biosynthesis of its unique chemotaxonomic marker, the lindenane-type sesquiterpenoids.

Lindenane sesquiterpenoid monomers and oligomers: Chemistry and pharmacological activities

Lindenane sesquiterpenoid monomers and oligomers, characterized by a sterically congested cyclopentane and an unusual trans-5/6 ring junction, are mainly found in Chloranthaceae species and the genus Lindera Thunb (Lauraceae). Numerous studies have shown that lindenane sesquiterpenoid monomers and oligomers exhibit a broad range of biological activities, such as cytotoxicity, anti-inflammation, neuroprotection, antifungal, and anti-malarial activities. This review covers publications from the first identification of lindeneol in 1925-2023 and classifies the lindenane sesquiterpenoid derivatives into sesquiterpenoid monomers, sesquiterpenoid-monoterpene conjugates, sesquiterpenoid homodimers, sesquiterpenoid heterodimers, and trimeric sesquiterpenoids. In addition, their biological activities are summarized. This review will establish a scientific basis and provide guidance for utilizing this unique class of natural products as potential lead compounds to develop their application in treating diseases corresponding to inflammation, cancer, and plasmodium.

Lindenane sesquiterpenoid dimers from Chloranthus holostegius with anti-neuroinflammatory activities in BV-2 microglia

Fifteen undescribed lindenane-type sesquiterpenoid dimers, designated chloranholides F-T (1-15), together with twenty-five known analogs (16-40), were isolated from the whole plants of Chloranthus holostegius. The isolate structures were elucidated by analysis of spectroscopic data and chemical methods, and their absolute configurations were determined by X-ray crystallography and electronic circular dichroism spectra. In anti-neuroinflammatory assays, all isolates were evaluated by examination of their inhibitory effect on nitric oxide (NO) in LPS-stimulated BV-2 cells, and the results showed that 21-24, 26, 30, 32 and 36 significantly inhibited the production of the inflammatory mediator NO, with IC50 values ranging from 3.18 to 11.46 μM, which was better than that of quercetin. Structure-activity relationship analysis revealed that two essential functional groups played an indispensable role in the anti-inflammatory effects. Moreover, 22 and 24 inhibited the LPS-induced upregulation of iNOS and COX-2 enzymes in BV-2 microglia at the protein level.

Chlorahololide D, a Lindenane-Type Sesquiterpenoid Dimer from Chloranthus holostegius Suppressing Breast Cancer Progression

Aimed at discovering small molecules as anticancer drugs or lead compounds from plants, a lindenane-type sesquiterpene dimer, chlorahololide D, was isolated from Chloranthus holostegius. The literature review showed that there were few reports on the antitumor effects and mechanisms of chlorahololide D. Our biological assay suggested that chlorahololide D blocked the growth and triggered apoptosis of MCF-7 cells by stimulating the reactive oxygen species (ROS) levels and arresting the cell cycle at the G2 stage. Further mechanism exploration suggested that chlorahololide D regulated apoptosis-related proteins Bcl-2 and Bax. Moreover, chlorahololide D inhibited cell migration by regulating the FAK signaling pathway. In the zebrafish xenograft model, chlorahololide D was observed to suppress tumor proliferation and migration significantly. Considering the crucial function of angiogenesis in tumor development, the anti-angiogenesis of chlorahololide D was also investigated. All of the research preliminarily revealed that chlorahololide D could become an anti-breast cancer drug.

Abietane diterpenoids with anti-inflammatory activities from Callicarpa bodinieri

Nine undescribed abietane diterpenoids (1-9) and eleven known abietane analogs (10-20) were isolated from Callicarpa bodinieri. Their structures were characterized by interpreting spectroscopic data, X-ray crystallography, and ECD analysis. The anti-inflammatory activities of these compounds were tested by evaluation of their inhibitory effect on NO production by lipopolysaccharide in RAW 264.7 macrophages, and compounds 3 and 8 exhibited potent anti-inflammatory activities with IC50 values of 36.35 ± 1.12 and 37.21 ± 0.92 μM. The western blotting studies demonstrated that compound 3 inhibited the expression of nitric oxide synthase and p65 that involved in the NF-κB pathway.

Anti-Inflammatory Lindenane Sesquiterpenoid Dimers from the Roots of Sarcandra glabra

Sarglaroids A-H (1-8), eight new lindenane dimers, and a monomer sarglaroid I (9), along with fourteen known analogues (10-23), were isolated from the roots of Sarcandra glabra. The planar structures and the absolute configurations were elucidated by HR-MS, NMR, ECD calculations, and X-ray diffraction crystallography. Sarglaroid A (1) was identified as a rare 8,9-seco lindenane dimer with a unique 5/5/5 tricyclic system. The biological evaluation showed that compounds 1 and 13 potently inhibited NO production with IC50 values at 19.8 ± 1.06 and 10.7 ± 0.25 μM, respectively, and had no cytotoxicity to RAW264.7 cells. Compound 6 significantly inhibited the LPS-/ATP-induced IL-1β release by inactivating the NLRP3 inflammasome through inhibiting the initiation and assembly by affecting the K+ efflux. Compounds 2 and 3 inhibited the proliferation of MCF-7 and MDA-MB-231 with IC50 values ranging from 5.4 to 10.2 μM.

Lindenane-Type Sesquiterpene Dimers Mitigate Lipopolysaccharide-Induced Inflammation by Inhibiting Toll-Like Receptor Signaling

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns and trigger an inflammatory response via the myeloid differential factor 88 (MyD88)-dependent and toll-interleukin-1 receptor domain-containing adapter-inducing interferon-β (TRIF)-dependent pathways. Lindenane type sesquiterpene dimers (LSDs) are characteristic metabolites of plants belonging to the genus Sarcandra (Chloranthaceae). The aim of this study was to evaluate the potential anti-inflammatory effects of the LSDs shizukaol D (1) and sarcandrolide E (2) on lipopolysaccharides (LPS)-stimulated RAW264.7 macrophages in vitro, and explore the underlying mechanisms. Both LSDs neutralized the LPS-induced morphological changes and production of nitric oxide (NO), as determined by CCK-8 assay and Griess assay, respectively. Furthermore, shizukaol D (1) and sarcandrolide E (2) downregulated interferon β (IFNβ), tumor necrosis factor α (TNFα) and interleukin-1β (IL-1β) mRNA levels as measured by reverse transcription polymerase chain reaction (RT-PCR), and inhibited the phosphorylation of nuclear factor kappa B p65 (p65), nuclear factor kappa-Bα (IκBα), Jun N-terminal kinase (JNK), extracellular regulated kinase (ERK), mitogen-activated protein kinase p38 (p38), MyD88, IL-1RI-associated protein kinase 1 (IRAK1), and transforming growth factor-β-activated kinase 1 (TAK1) proteins in the Western blotting assay. In conclusion, LSDs can alleviate the inflammatory response by inhibiting the TLR/MyD88 signalling pathway.

Sarglamides A-E, Indolidinoid-Monoterpenoid Hybrids with Anti-neuroinflammatory Activity from a Sarcandra Species

Sarglamides A-E (1-5), representing the first example of heterodimers of a trans-N-cinnamoylindolidinoid and α-phelladrene derivatives, were isolated from Sarcandra glabra subsp. brachystachys. Particularly, compounds 4 and 5 possess unprecedented cagelike 6/6/5/6/5- and 6/6/6/6/5-fused pentacyclic scaffolds, respectively. Their structures were established by spectroscopic analysis, X-ray crystallography, quantum-chemical calculations, and chemical conversions. Plausible biosynthetic pathways of 1-5 involving the coisolated enantiomers 6a and 6b were proposed. Compounds 3-7 showed inhibitory activity against lipopolysaccharide-induced inflammation in BV-2 microglial cells.

Coumarins from Sarcandra glabra (Thunb.) Nakai and Acetylcholinesterase Inhibiting Activity

Nine coumarins including a pair of new enantiomers ( 1a / 1b ) and seven known compounds ( 2-8 ) were isolated from Sarcandra glabra (Thunb.) Nakai. Among them, compounds 1a and 1b were naturally occurring coumarin-phenylpropanoid conjugate enantiomers. Their structures were identified by NMR and ECD calculations. Compounds 1-8 were tested for acetylcholinesterase (AchE) inhibiting activity. The results of the enzymology experiment showed that compound 3 demonstrated obvious AchE inhibitory activity which showed an IC 50 value of 1.982 ± 0.003 μ M, and the binding sites were predicted by molecular docking.

Sarglaromatics A-E: A Class of Naphthalene-Like Architecture Fused Norlindenane Sesquiterpene Dimers from Sarcandra glabra

Sarglaromatics A-E (1-5, respectively), five unprecedented naphthalene-like architecture-fused norlindenane sesquiterpene dimers, were discovered from the roots of Sarcandra glabra. The unique naphthalene core skeleton was obtained from classical lindenane [4 + 2] dimers via a free-radical-mediated C11-C11' bond formation reaction and 12'-decarboxylation. The highly fused octonary ring skeleton was elucidated by HRMS, NMR, ECD, quantum chemical calculations, and biogenetic inspiration. Compounds 1 and 2 showed significant anti-nonalcoholic steatohepatitis (NASH) activity by inhibiting lipid deposition in L02 cells.

Sarcanolides C–E: Three new lindenane sesquiterpenoid dimers with anti-inflammatory activities from Sarcandra glabra

Three new lindenane-type sesquiterpenoid dimers, sarcanolides C–E (1–3), were isolated from the roots of Sarcandra glabra. Sarcanolide C (1) possesses a unique decacyclic scaffold with an unusual orthoformate unit. The...

The Traditional Uses, Phytochemistry and Pharmacology of Sarcandra glabra (Thunb.) Nakai, a Chinese Herb With Potential for Development: Review

Sarcandra glabra (Thunb.) Nakai is a folk medicine with a long history in China, which has been applied to treat sore throat, abscess, even tumor and so on. Meanwhile, it is also used as tea in some areas. At present, more than 200 chemical compounds have been isolated and identified from it, such as, sesquiterpenes, flavonoids, phenolic acids, coumarins and so on. Pharmacological studies have already confirmed that the extracts of S. glabra have many effects, such as antibacterial, antiviral, anti-inflammatory, anti-tumor, and anti-thrombocytopenia, especially the effects of anti-tumor and anti-thrombocytopenia are confirmed in clinic. Therefore, this paper systematically summarized the traditional uses, botany, phytochemistry, pharmacology, and toxicity of S. glabra, in order to provide a beneficial reference of its further research.

Horienoids A and B, Two Heterocoupled Sesquiterpenoid Dimers from Hedyosmum orientale

Two eudesmane-guaiane/lindenane heterocoupled sesquiterpenoid dimers, horienoids A (1) and B (2) with new carbon skeletons, from Hedyosmum orientale were characterized by a combined method. Compound 1 featured a unique 2,10-dioxabicyclo[6.2.1]undecane core moiety with an anti-Bredt bridgehead double bond. Their biogenetic pathways were proposed to involve Diels-Alder and cascade rearrangement reactions as the key steps. Compound 2 exhibited a potent anti-inflammatory effect on LPS-induced BV-2 microglial cells.

Monoterpene-flavonoid conjugates from Sarcandra glabra and their autophagy modulating activities

Fourteen new monoterpene-flavonoid conjugates including four monoterpene-conjugated chalcones (glabratins A-D, 1-4), seven monoterpene-conjugated dihydrochalcones (glabratins E-K, 5-11), and three monoterpene-conjugated flavanones (glabratins L-N, 12-14), together with four known analogues (15-18) were isolated from the aerial parts of Sarcandra glabra. The structures and the absolute configurations of these compounds were elucidated by the spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compounds 1, 4-6, 9-14, and 18 showed obvious cell autophagy-inducing activities at 25 μM in HEK293 cells. Furthermore, the bioassay results also showed that 18 induced cell autophagy in a dose dependent manner. Our findings revealed a rare class of monoterpene-flavonoid conjugates in nature and firstly reported their autophagy-inducing activities.

Antileukemic effect of caffeic acid 3,4-dihydroxyphenetyl ester. Evidences for its mechanisms of action

BACKGROUND

Caffeic acid 3,4-dihydroxyphenethyl ester (CADPE) is a natural polyphenolic ester isolated as a minor component from a water extract of the Chinese medicine Zhongjiefeng [Sarcandra glabra (Thunb.) Nakai (Chloranthaceae)] and has previously shown to have activity against solid tumors through the modulation of multiple targets or signal pathways. However, the activity and potential mechanism of CADPE against leukemia cells have not yet been characterized.

PURPOSE

To investigate whether and how CADPE kills leukemia cells.

METHOD

(1) The activity of CADPE inhibiting the growth of different leukemia cell lines was evaluated by MTT assay; (2) Cell cycle arrest and apoptosis induced by CADPE were determined by flow cytometry with FlowJo software for quantification; (3) The protein levels were analyzed by Western blot and ubiquitin-binding c-Myc was acquired by co-immunoprecipitation.

RESULTS

CADPE exerted potent activity against different leukemia cell lines with low toxicity in normal cells. In terms of mechanism of action, CADPE promoted ubiquitin-proteasome-dependent degradation of c-Myc through activating glycogen synthase kinase-3β (GSK3β) and downregulating deubiquitinating enzyme USP28 to trigger the interaction of c-Myc with ubiquitin ligase Fbw7, resulting in the downregulation of cell cycle regulators and anti-apoptotic proteins and consequently, cell cycle arrest and cell apoptosis.

CONCLUSION

CADPE is a novel c-Myc inhibitor with high activity and a unique mechanism for killing leukemia cells.

Atypical Lindenane-Type Sesquiterpenes from Lindera myrrha

Two new lindenane sesquiterpenes were obtained from the roots of Lindera myrrha. These compounds were structurally elucidated by HRMS data, extensive NMR analyses, and comparison between experimental and theoretical ¹³C-NMR data. Myrrhalindenane A is the first monomeric seco-d lindenane displaying a non-rearranged, cyclohexanic C-ring. Myrrhalindenane B is the second occurrence of an angular lindenane-sesquiterpene related to a C₆-C₇ lactonization.

Reanalysis of Lindenatriene, a Building Block for the Synthesis of Lindenane Oligomers

Lindenane oligomers isolated from Chloranthus pose significant challenges for chemical synthesis. The structure of a proposed biosynthetic monomer, lindenatriene, was recently called into question. Its attempted synthesis produced a compound whose 1H NMR spectrum differed significantly from the spectrum of a monomer produced by oligomer pyrolysis. Here we propose that the original structural assignment after pyrolysis was correct and instead the spectra of synthetic materials were misinterpreted. Reanalysis of 2D NMR data suggest that lindenatriene isomerizes (formal [1,7]-hydrogen shift) upon treatment with base.

TiCl4-n-Bu3N-mediated cascade annulation of ketones with α-ketoesters: a facile synthesis of highly substituted fused γ-alkylidene-butenolides

A facile protocol for the synthesis of highly substituted fused γ-alkylidene butenolides using direct annulation of ketones with α-ketoesters, which proceeds through TiCl4-n-Bu3N mediated aldol addition followed by an intramolecular enol-lactonization/cyclization cascade, is reported. Diverse 6-5, 7-5 and 8-5 fused bicyclic γ-ylidene butenolides and highly substituted monocyclic analogs related to biologically relevant natural products were prepared from readily accessible ketone and α-ketoester building blocks. The highly step-economic cascade nature, good substrate scope, easy access to complex products with good to excellent yields, gram-scalability, demonstration of synthetic utility, and unambiguous structural confirmation through X-ray crystallography analyses and analogy are the salient features of this work.

Chloraserrtone A, a Sesquiterpenoid Dimer from Chloranthus serratus

Chloraserrtone A (1), a new sesquiterpenoid dimer with two lindenane-type sesquiterpenoid monomers bridged by two six-membered rings, was obtained from Chloranthus serratus. A combination of UV, IR, NMR, HRESIMS, and X-ray diffraction data were used to elucidate the structure of 1. Compound 1 represents the first lindenane-type sesquiterpenoid dimer with extremely unique C-15-C-15', C-4-C-6', and C-6-C-11' linkages to form two six-membered rings between the monomeric units. A plausible biosynthesis toward chloraserrtone A is proposed. This new compound (1), together with the known lindenane dimers (2-11), were assessed for their inhibitory effects on lipopolysaccharide-induced NO production in RAW264.7 cells. Compound 6 showed activity with an IC₅₀ value of 3.7 μM.

Nanomolar Antimalarial Agents against Chloroquine-Resistant Plasmodium falciparum from Medicinal Plants and Their Structure-Activity Relationships

Inspired by the discovery of the antimalarial drug artemisinin from a traditional Chinese medicine (TCM), a natural product library of 44 lindenane-type sesquiterpenoids was assessed for activities against the Dd2 chloroquine-resistant strain of the malaria parasite Plasmodium falciparum. These compounds were mainly isolated from plants of the Chloranthus genus, many species of which are named "Sikuaiwa" in TCM and have long been used to treat malaria. The compounds consisted of 41 sesquiterpenoid dimers and three monomers, including the 12 new dimers 1-12 isolated from Chloranthus fortunei. The results showed that 16 dimers exhibited potent antiplasmodial activities (<100 nM); in particular, compounds 1, 14, and 19 exhibited low nanomolar activities with IC₅₀ values ranging from 1 to 7 nM, which is comparable to the potency of artemisinin, and selectivity index values toward mammalian cells greater than 500. A comprehensive structure-activity relationship study indicated that three functional groups are essential and two motifs can be modified.

Chlojaponilactone B from Chloranthus japonicus: Suppression of Inflammatory Responses via Inhibition of the NF-κB Signaling Pathway

Bioassay-guided fractionation of an ethanolic extract of Chloranthus japonicus led to the isolation of the known lindenane-type sesquiterpenoid chlojaponilactone B (1). This compound exhibited pronounced inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. Further anti-inflammatory assays showed that 1 suppressed the levels of some key inflammation mediators, such as iNOS, TNF-α, and IL-6, in a dose-dependent manner, and reduced the ear thickness and neutrophil infiltration in 12-O-tetradecanoylphorbol-13-acetate (TPA)-stimulated mice. A mechanistic study revealed that compound 1 exerted its anti-inflammatory effects via the suppression of the NF-κB signaling pathway, which inhibited NF-κB-dependent transcriptional activity, IκBα phosphorylation, and p65 nuclear translocation. In contrast, chlojaponilactone B (1) was found to exert little influence on the MAPK signaling pathway.

Constituents from Chloranthaceae plants and their biological activities

The Chloranthaceae is a small family with only four genera (

Synthesis and Applications of Hajos-Parrish Ketone Isomers

Numerous natural products possess ring systems and functionality for which Hajos-Parrish ketone isomers with a transposed methyl group (termed "iso-Hajos-Parrish ketones") would be of value. However, such building blocks have not been exploited to the same degree as the more typical Hajos-Parrish hydrindane. An efficient three-step synthesis of such materials was fueled by a simple method for the rapid preparation of highly functionalized cyclopentenones, several of which are new chemical entities that would be challenging to access through other approaches. Furthermore, one iso-Hajos-Parrish ketone was converted into two distinct natural product analogues and one natural product. As one indication of the value of these new building blocks, that latter target was obtained in 10 steps, having previously been accessed in 18 steps using the Hajos-Parrish ketone.

Chlojapolactone A, an unprecedented 1,3-dioxolane linked-lindenane sesquiterpenoid dimer from Chloranthus japonicus

Chlojapolactone A (1), a novel lindenane sesquiterpenoid dimer with an unprecedented 1,3-dioxolane linkage, was isolated from Chloranthus japonicus.

An entry to vinylcyclopropane through palladium-catalyzed intramolecular cyclopropanation of alkenes with unstabilized allylic tosylhydrazones

Intramolecular cyclopropanation of unstabilized allylic tosylhydrazones with different alkenes was developed in the presence of a Pd catalyst.

Discovery of structurally diverse and bioactive compounds from plant resources in China

This review describes the major discoveries of structurally diverse and/or biologically significant compounds from plant resources in China, mainly from the traditional Chinese medicines (TCMs) since the establishment of our research group in 1999. In the past decade, a large array of biologically significant and novel structures has been identified from plant resources (or TCM) in our laboratory. The structural modification of several biologically important compounds led to more than 400 derivatives, some of which exhibited significantly improved activities and provided opportunities to elucidate the structure-activity relationship of the related compound class. These findings are important for drug discovery and help us understand the biological basis for the traditional applications of these plants in TCM.