Chloramultilide A, a highly complex sesquiterpenoid dimmer from Chloranthus multistachys

Anti-inflammatory lindenane sesquiterpenoid dimers from the roots of Chloranthus holostegius var. trichoneurus

Two new lindenane-type sesquiterpenoid dimers, chlotrichenes C and D (1 and 2) together with five known lindenane-type sesquiterpenoid dimers (3-7) were isolated from the roots of Chloranthus holostegius var. trichoneurus, a famous natural medicine named as "Sikuaiwa" for subduing swellings and relieving pain. The structures including absolute configuration were elucidated by their 1D and 2D NMR, HRESIMS, and ECD data. Compounds 1 and 2 were classical [4 + 2] lindenane-type sesquiterpenoid dimers that differed from known analogs in oxidation profile, side chain profile, and double bond position. The new isolates and compound 3 exhibited significant inhibitory activity on IL-1β production (IC50: 1-15 μM) in LPS-induced THP-1 cells and other compounds exhibited inhibitory activity on NO production in LPS-induced RAW 264.7 cells (IC50: 24-33 μM).

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 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.

Trichloranoids A–D, antimalarial sesquiterpenoid trimers from Chloranthus spicatus

Four new anti-malarial sesquiterpenoid trimers including two rearranged skeletons were isolated from Chloranthus spicatus. The structurally different but biogenetically related compounds 1, 2 and 5 rationalized the biradical pathway, and vice versa.

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.

Constituents from Chloranthaceae plants and their biological activities

The Chloranthaceae is a small family with only four genera (

Phytochemical and biological studies of Chloranthus medicinal plants

The plants of genus Chloranthus have been investigated in many chemical and pharmacological laboratories due to their complex secondary metabolites and diverse bioactivities. The aim of this review is to provide an up-to-date overview on the chemistry and bioactivity of the compounds isolated, mainly sesquiterpenoids and diterpenoids, from the genus Chloranthus over the past few decades.

Asymmetric total synthesis of onoseriolide, bolivianine, and isobolivianine

In this article, we describe our efforts on the total synthesis of bolivianine (1) and isobolivianine (2), involving the synthesis of onoseriolide (3). The first generation synthesis of bolivianine was completed in 21 steps by following a chiral resolution strategy. Based on the potential biogenetic relationship between bolivianine (1), onoseriolide (3), and β-(E)-ocimene (8), the second generation synthesis of bolivianine was biomimetically achieved from commercially available (+)-verbenone in 14 steps. The improved total synthesis features an unprecedented palladium-catalyzed intramolecular cyclopropanation through an allylic metal carbene, for the construction of the ABC tricyclic system, and a Diels-Alder/intramolecular hetero-Diels-Alder (DA/IMHDA) cascade for installation of the EFG tricyclic skeleton with the correct stereochemistry. Transformation from bolivianine to isobolivianine was facilitated in the presence of acid. The biosynthetic mechanism and the excellent regio- and endo selectivities in the cascade are well supported by theoretical chemistry based on the DFT calculations.

Sesquiterpenoids from Chloranthus multistachys

An 8,9-seco-lindenane disesquiterpenoid, chloramultiol G, four eudesmane sesquiterpenoids, ent-(3R)-3-hydroxyatractylenolide III and multistalactones A-C, and four guaiane sesquiterpenoids, (1R,4S,5R,8S,10S)-zedoalactone A and multistalactones D-F, along with 14 known compounds, were isolated from whole plant tissues of Chloranthus multistachys. Their structures were established by extensive NMR experiments in conjunction with mass spectrometry. Except for chloramultiol G, the absolute stereochemistries of the other eight were confirmed by single-crystal X-ray crystallography and CD spectra. Nine compounds were tested for cytotoxicity against five human tumor cell lines and for antifungal activity against four microorganisms in vitro, but all were inactive.

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.

Spicachlorantins G-J, new lindenane sesquiterpenoid dimers from the roots of Chloranthus spicatus

Four new lindenane sesquiterpenoid dimers, spicachlorantins G-J (1-4), were isolated from the roots of Chloranthus spicatus together with seven known compounds, including chloramultilide A, shizukaol B, shizukaol D, shizukaol F, shizukaol P, chlorahololide D, and cycloshizukaol A. The planar structures of the new compounds were established by 1D-, 2D-NMR, and MS analyses. The absolute configurations of these compounds were determined by analyzing rotating Overhauser enhancement and exchange spectroscopy (ROESY) and circular dichroism (CD) spectra.

Terpenoids from Chloranthus serratus and their anti-inflammatory activities

Seven new terpenoids, including two sesquiterpene dimers (1, 2), two norditerpenoids (3, 4), and three sesquiterpenes (5-7), along with six known sesquiterpene dimers and four known sesquiterpenes were isolated from the whole plant of Chloranthus serratus. Their structures and relative configurations were elucidated on the basis of spectroscopic data analysis. The absolute configuration of 1 was determined by the CD exciton chirality method. These isolates were evaluated for their inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW264.7 cells. Compound 2 and two known compounds, shizukaols B and D, showed significant anti-inflammatory activities, with IC(50) values of 0.22, 0.15, and 7.22 μM, respectively.

Total synthesis of (±)-chloranthalactone A

A total synthesis of (±)-chloranthalactone A was completed. It features substrate-controlled epoxidation of ketone and highly diastereoselective intramolecular cyclopropanation to construct the cis, trans-3/5/6 tricyclic skeleton.

An unusual stress metabolite induced by CuCl(2) and other constituents from the leaves of Chloranthus anhuiensis

A 6-eremophilene derivative 2 with an unusual pendant was produced as phytoalexin in the fresh leaves of Chloranthus anhuiensis K. F. Wu in response to abiotic stress elicitation by CuCl(2). The phytoalexin was characterized as a sesquiterpene with a (2,6-dimethoxy-4-hydroxy)benzyl moiety pendant. Two new sesquiterpenes, (3R,4S,5R,10S,11S)-3-hydroxy-8-oxo-6-eremophilen-12-oic acid (1) and (3R,4S,5R,6R,8R,10S)-3,6,8-trihydroxy-7(11)-eremophilen-12,8-olide (3), one new sesquiterpene glycoside, anhuienoside A (4), one new caffeoyl phenylethanoid diglycoside with an unusual cyclic structure, anhuienoside B (5), and one new tyramine derivative, N-acetyltyramine 1-O-beta-d-glucoside (6), and three known compounds were also isolated. Their structures and relative configurations were established by spectroscopic means. The absolute configurations of 1-3 were defined mainly by comparison of quantum chemical TDDFT calculated and experimental ECD spectra.

Four sesquiterpenoids from Chloranthus multistachys

Four new sesquiterpenoids, chlomultins A-D (1-4), were isolated from the whole plant of Chloranthus multistachys. Their structures were established on the basis of spectroscopic analysis.

Chloramultiols A-F, lindenane-type sesquiterpenoid dimers from Chloranthus multistachys

Six new highly complex lindenane-type sesquiterpenoid dimers, chloramultiols A-F (1-6), along with six known analogues, were isolated from the whole plant of Chloranthus multistachys. The structures of 1-6 were elucidated on the basis of mass spectrometry (MS) and 1D and 2D NMR spectroscopic analysis. Among them, compounds 1 and 6 contain a unique 18-membered macrocyclic triester ring. All compounds isolated were evaluated for the inhibition of the growth of five tumor cell lines.

Terpenoids from Chloranthus multistachys

Two new diterpenoids, ent-17-hydroxyl-16beta-methoxyl-kauran-3-one (1) and ent-17-acetoxyl-16beta-methoxyl-kauran-3-one (2), along with nine known compounds (3-12), ent-17-hydroxyl-kaur-15-en-3-one (3), ent-3beta-acetoxyl-kaur-15-en-16beta, 17-diol (4), ent-kauran-3beta, 16beta, 17-triol (5), ent-3beta-acetoxyl-kauran-16beta, 17-diol (6), ent-kauran-16beta, 17-diol (7), abbeokutone (8), ent-17alpha-acetyl-16beta-hydroxyl- kauran-3-one (9), shizukaol F (10), cycloshizukaol A (11) and curcolonol (12), were isolated from Chloranthus multistachys (Chloranthaceae). Their structures were elucidated by spectroscopic spectra.

Sesquiterpenoids and phenylpropanoids from Chloranthus serratus

Seven new sesquiterpenoids, chlorantenes A-G (1-7), two new phenylpropanoids (8 and 9), and six known sesquiterpenoids were isolated from the whole plants of Chloranthus serratus. Their structures were elucidated on the basis of spectroscopic analyses. Chlorantene A (1) was a sesquiterpene with a unique C-4 and C-10 linkage, and chlorantene B (2) possessed a nitro group at C-1. The structure of a eudesmane-type sesquiterpene previously isolated from Chloranthus henryi was revised as its 4-epimer (3a).

Sesquiterpene furan compound CJ-01, a novel chitin synthase 2 inhibitor from Chloranthus japonicus SIEB

A novel sesquiterpene furan compound CJ-01 was isolated from the methanol extract of the whole plant of Chloranthus japonicus SIEB. by monitoring the inhibitory activity of chitin synthase 2 from Saccharomyces cerevisiae. Based on spectroscopic analysis, the structure of compound CJ-01 was determined as 3,4,8a-trimethyl-4a,7,8,8a-tetrahydro-4a-naphto[2,3-b]furan-9-one. The compound inhibited chitin synthase 2 of Saccharomyces cerevisiae in a dose-dependent manner with an IC50 of 39.6 microg/ml, whereas it exhibited no inhibitory activities against chitin synthase 1 and 3 of S. cerevisiae up to 280 microg/ml. CJ-01 has 1.7-fold stronger inhibitory activity than polyoxin D (IC50=70 microg/ml), a well-known chitin synthase inhibitor. These results indicate that the compound is a specific inhibitor of chitin synthase 2 from S. cerevisiae. In addition, CJ-01 showed antifungal activities against various human and phytopathogenic fungi. Therefore, the compound might be an interesting lead to develop effective antifungal agents.

Complex sesquiterpenoids with tyrosinase inhibitory activity from the leaves of Chloranthus tianmushanensis

Investigation of the leaves of Chloranthus tianmushanensis resulted in the isolation and characterization of two new sesquiterpene dimers with a rare 18-membered triester ring, tianmushanol (1) and 8-O-methyltianmushanol (2), and four known sesquiterpenes. Their structures were established by spectroscopic means. The inhibitory activities against tyrosinase of all isolates were also evaluated.

Lindenane sesquiterpene dimers from Chloranthus fortunei

Five new lindenane sesquiterpene dimers ( 1- 5), named shizukaols K-O, and eight known sesquiterpene dimers were isolated from the roots of Chloranthus fortunei. The structures of 1- 5 were elucidated using spectroscopic data, mainly 1D NMR, 2D NMR, and mass spectra.

Mono- and Di-sesquiterpenoids from Chloranthus spicatus

Three new dimeric sesquiterpenoids, chloramultilides B-D ( 1- 3), along with 10 known sesquiterpenoids, were isolated from the whole plant of Chloranthus spicatus. Their structures were established by physical data (1D and 2D NMR, MS). The structure and absolute configuration of 1 was confirmed by X-ray crystallography. Compound 1 exhibited moderate in vitro antifungal activity.