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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 3.26 μmol·L-1, respectively.

Fortuneicyclidins A (1) and B (2), a pair of epimeric pyrrolizidine alkaloids containing an unprecedented 7-azatetracyclo[5.4.3.0.02,8]tridecane core, were isolated from the seeds of Cephalotaxus fortunei, along with two biogenetically relative known analogues, 3 and 4. The structures were determined by multiple spectral techniques and chemical derivatization methods. Compound 1 showed inhibitory activity against α-glucosidase.

Eight new germacranolides, minusolides A–H (1–8), along with two known analogues, 9 and 10, were isolated from the whole plant of Carpesium minus. Their structures were elucidated by spectroscopic ...

Five new spirocyclic polycyclic polyprenylated acylphloroglucinols, Hyperpatulones C-G (1–5), were obtained from the leaves of Hypericum patulum. Their structures were characterized by the comprehensive analysis of their IR, NMR, CD spectra and HRESIMS data. All the new compounds were evaluated for the α-glycosidase inhibitory activities. Among them, compounds 3–5 showed α-glucosidase inhibitory activities, with IC50 values of 14.06–37.69 μM.

(±)-Melipatulinones A–C (1–3), three unique enantiomeric pairs of lignan–phloroglucinol hybrids along with the biogenetically related compound melipatulignan A (4), were isolated from the leaves of Melicope patulinervia. Melipatulinones A (1) and B (2) share a novel spiro[hydrobenzofuran-2,3′-furan] 5/5/6 tricyclic ring system, while melipatulinone C (3) features an unprecedented spiro[cyclopenta[b]hydrofuran-2,3′-furan] 5/5/5 tricyclic framework. Their structures were determined by spectroscopic methods, electronic circular dichroism (ECD) calculations, and X-ray diffraction. Compounds 1–3 exhibited a pancreatic lipase inhibitory effect.

Taxodisones A and B, C30-terpenes with an unprecedented tetracyclo[12.4.0.0.2,709,14]octodecane core, were isolated from the seeds of Taxodium distichum. Their structures, including their configurations, were unambiguously determined. Their biomimetic synthesis suggests that they stem from diterpenes and monoterpenes, and not from squalene or oxidosqualene. In addition, their bioactivities were also evaluated.

Two uncommon C37 heterodimeric diterpenoids, taicrypnacids A (1) and B (2), and a known labdane-type diterpenoid (3) were isolated from the leaves of Taiwania cryptomerioides. Several techniques, such as comprehensive spectroscopic analysis, chemical conversion, X-ray crystallography, and ECD data, were employed to define the structures. The two new compounds displayed cytotoxicity against human breast cancer (MCF-7), osteosarcoma (U-2 OS), and human colon carcinoma (HCT-116) cell lines, while the methyl ester 1a showed no activity. Compound 1 induced Ca2+-ROS pathway-mediated endoplasmic reticulum stress, and excessive stress led to cell death by activating apoptosis and autophagy.

Artemisianins A-D (1–4), four stereoisomers of sesquiterpenoid dimers, forming via [4+2] cycloaddition from a 1, 10-seco-guaianolide dienophile and a guaianolide diene, along with two biosynthetically related precurors 5 and 6, were isolated from the famous traditional Chinese medicine Artemisia argyi. The structures of 1–4, including their absolute configurations, were elucidated by extensive spectroscopic data and ECD/TDDFT calculation analysis. Compounds 1–4 exhibited cytotoxicity with IC50 values ranging from 7.2 to 23.3 μM. The accumulation of Ca2+ in cytoplasm and enlarged endoplasmic reticulum (ER) indicated that 1 mediated HT-29 cancer cell apoptosis through improvement of ER-stress, which was further proved by unfolded protein response (UPR) pathway on basis of the upregulation of IRE1α, p-PERK, ATF6, and CHOP.

Six new Cephalotaxus alkaloids, including five cephalotaxine-type alkaloids, and one homoerythrina-type alkaloid, along with six known analogues, were isolated from the seeds of Cephalotaxus fortunei. Their structures were elucidated by combination of spectroscopic data analyses, time-dependent density functional theory (TDDFT) ECD calculation, and single-crystal X-ray diffraction. Cephalofortine B represents the first example of C-5 epi-cephalotaxine-type alkaloid. All isolated compounds were tested for cytotoxicities against HCT-116, A375, and SK-Mel-28 cell lines. Cephalofortine E showed moderate activity against HCT-116 cell line, with an IC50 value of 7.46 ± 0.77 μM.

Harringtonolide (HO), a natural product isolated from Cephalotaxus harringtonia, exhibits potent antiproliferative activity. However, little information has been reported on the systematic structure−activity relationship (SAR) of HO derivatives. Modifications on tropone, lactone, and allyl positions of HO (1) were carried out to provide 17 derivatives (2–13, 11a–11f). The in vitro antiproliferative activity against four cancer cell lines (HCT-116, A375, A549, and Huh-7) and one normal cell line (L-02) was tested. Amongst these novel derivatives, compound 6 exhibited comparable cell growth inhibitory activity to HO and displayed better selectivity index (SI = 56.5) between Huh-7 and L-02 cells. The SAR results revealed that the tropone and lactone moieties are essential for the cytotoxic activities, which provided useful suggestions for further structural optimization of HO.

Two new phthalide dimers (1 and 2) were obtained from the rhizomes of Ligusticum sinense Oliv., along with three known dimeric phthalides (3–5). Their structures were determined with the aid of the spectroscopic data, and their absolute configurations were elucidated based on the comparison of calculated and experimental electronic circular dichroism (ECD) spectra. All the compounds were evaluated in vitro for their inhibitory activities against NO production in LPS-treated RAW264.7 macrophages. Among them, compounds 1 and 3 showed potent NO prohibitive activity with IC50 values at 4.86 ± 0.29 μM and 4.87 ± 0.32 μM, respectively.

(±)-Patulignans A–C (1–3), three unique pairs of lignan enantiomers were isolated from the leaves of Melicope patulinervia. Patulignan A (1) possesses an unprecedented dimethyloxonane moiety in nature, meanwhile patulignans B (2) and C (3) are epimers carrying a novel dimethyl-1,6-dioxaspiro[4.5]decane skeleton. Their structures were established by spectroscopy methods and electronic circular dichroism (ECD) calculations. Compounds 1–3 showed significant inhibitory activity against α-glucosidase.

Five novel formyl-phloroglucinol-β-caryophyllene meroterpenoids, namely littordials A–E (1–5), were isolated from the leaves of Psidium littorale. Their structures were established by spectroscopic data and computational methods, and the structure of 1 was confirmed by X-ray crystallography. Littordials A–E feature unusual acyl phloroglucinol units, and 5 possesses a rare 6/7/9/4-fused tetracyclic ring system. Compounds 2, 3 and 5 exhibited cytotoxic activities on two cancer cell lines (MDA-MB-231 and B16) with IC50 values from 6.6 ± 1.5 to 9.2 ± 1.7 μM.

A pair of novel C23 terpenoid epimers, officinalins A (1) and B (2), together with a biogenetically related known diterpenoid (3), was isolated from the leaves of Salvia officinalis. The epimers feature an unprecedented carbon skeleton with a tetracycline-[9.6.0.03,8.012,16]-heptadecane core and a peroxide bridge. Their structures were unequivocally established by extensive spectroscopic analyses, including electronic circular dichroism (ECD) calculations and ROESY correlation analogy with model compounds for the configuration assignment. Possible biosynthetic pathways of 1 and 2 were proposed. Compound 1 exhibited potent NO inhibitory activity with an IC50 value of 2.02 ± 0.87 μM.

Five new prenylated acetophenones, melicoptelins A-E (1–5), along with one known congener (6) were isolated from the roots of Melicope ptelefolia. Among them, compounds 2a/2b, 3a/3b, and 4a/4b were obtained as inseparable interconverting mixtures of keto and enol tautomers. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D, 2D NMR and HRESIMS. Compouds 2a/2b, 4a/4b and 5 exhibit protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC50 values of 34.4, 55.2 and 66.6 μM, respectively.

Peyronellones A and B (1 and 2), a pair of rare tetracyclic caged adducts of azaphilone with pyruvic acid, along with four new analogues (3–6), were isolated from solid cultures of the endophytic fungus Peyronellaea glomerata. Their structures were elucidated through spectroscopic analysis, and their absolute configurations were unambiguously determined by a combination of single-crystal X-ray crystallography, Rh2(OCOCF3)4-induced ECD experiments, ECD calculations, and modified Mosher methods. Compound 2 (5 μM) was found to have a significant hypoxia-protective effect that improved the survival rate of hypoxia/reoxygenation-treated human umbilical vein endothelial cells from 35% to 70%, which was equal to the potency of the positive control, verapamil. Flow cytometry analysis suggested 2 could inhibit H/R-induced late-stage apoptosis of this cell line.

The reactivity-based screening (RBS) was developed for directed discovery of cytotoxic withanolides. In this study, a thiol probe, 4-chlorobenzenethiol, was used to selectively attack cytotoxic withanolides containing potential pharmacophore, 2(3)-en-1-one in ring A (AEO) and 5β,6β-epoxy in ring B (BE), from the plant extract of Physalis angulata var. villosa. The screening was performed based on the potential mechanism of 4-chlorobenzenethiol nucleophilic addition to AEO, followed by detection of adducts using liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS). Guided by RBS, eleven target withanolides, including five new compounds, physagulides R-V (10–14) and six known ones (2, 7–9, 15, 16) were discovered. All of them exhibited cytotoxicity against the both tested cell lines, especially, compounds 2, 7, 8 and 14 showed potent activities with IC50 values of 1.57–6.29 μM. The results suggested that RBS was efficient and accurate for rapid identification of cytotoxic withanolides and could guide isolation of target components from the complex medicinal plant extract.

Ten new highly oxidized monomeric (1–8) and dimeric guaianolides (9 and 10), along with two known guaianolide derivatives (11 and 12), were isolated from the aerial parts of Chrysanthemum indicum using a bioassay-guided fractionation procedure. The new compounds were characterized by the basic analysis of the spectroscopic data obtained, and the absolute configurations were determined by both empirical approaches and ECD calculations. Inhibitory effects of 1–12 on nitric oxide production were investigated in lipopolysaccaride (LPS)-mediated RAW 264.7 cells, and most of them (1–8 and 11) displayed IC50 values in the range 1.4–9.7 μM. Moreover, a mechanistic study revealed that the potential anti-inflammatory activity of compound 1 appears to be mediated via suppression of an LPS-induced NF-κB pathway and down-regulation of MAPK activation.

Biogenesis-inspired chemical research of the leaves of Taiwania cryptomerioides afforded four unprecedented dimeric diterpenes, featuring a tetracyclic [7. 75, 9. 4. 05, 10. 08, 9] octodecane core: taiwanoids A-D (1-4). The structures of these compounds were determined on the basis of comprehensive spectral analysis, chemical conversions and X-ray crystallography. A possible biosynthetic pathway for compounds 1-4 was proposed. Compounds 2 and 3 exerted a 5.37 and 6.26-fold potentiation effect on bortezmib (BTZ) susceptibility at a tested concentration of 20 μM, respectively.

Seven new phloroglucinol derivatives, uraliones L-R (1-7), were isolated from the whole plant of Hypericum urialum. The structures of new compounds were unambiguously elucidated by comprehensive spectroscopic analysis, and the absolute configurations of the vic-diol groups were determined by Mo2(OAc)4-induced electronic circular dichroism experiments. Their capability to reversal the multidrug resistance in doxorubicin-induced resistant MCF-7/DOX sublines showed that compounds 1, 5, 6, 7 exerted a potential effect of doxorubicin susceptibility.

Artemisians A-D (1-4), the first examples of [4 + 2] Diels-Alder type adducts presumably biosynthesized from a rare 1, 10-4, 5-diseco-guaianolide and a guaianolide diene, along with their possible precursor 5, were isolated from the traditional Chinese medicine Artemisia argyi. The structures of 1-4 were elucidated by extensive spectroscopic analyses and calculated electronic circular dichroism. Compound 2, with an IC50 value of 3.21 μM, exhibited significant antiproliferative activity via apoptosis induction and G2/M arrest in MDA-MB-468 cells.

Six novel calyxins, named calyxin T-W, ent-calyxin T and ent-calyxin U were isolated from the seeds of Alpinia katsumadai Hayata. Their relative configurations were elucidated by means of detailed UV, IR, NMR and MS spectroscopic data. Their absolute configurations were assigned by collaborative studies on single crystal X-ray diffraction analysis, Mosher's method, electronic circular dichroism (ECD), optical rotation and theoretical calculations. These compounds are Friedel-Cranft alkylation adducts composed of coexisted diarylheptanoids and flavanone from the seeds of Alpinia katsumadai. The antiproliferative activity of the six compounds against NCI-H460, HeLa, SMMC-7721 and HCT-116 cell lines was also reported, and most of them showed moderate to strong activities.

A pair of new tetranorlabdane diterpenoid epimers, named elettarins A (1) and B (2), together with five known labdane diterpenes (3–7), were isolated from Elettaria cardamomum Maton. The structures of elettarins A and B were established based on spectroscopic data (HRESIMS, 1D/2D NMR), and ECD experimentation. All isolates were evaluated for their inhibitory activities against nitric oxide (NO) production on BV-2 microglia cells.

Xylopiana A (1), a dimeric guaiane with an unprecedented pentacyclo[5.2.1.01,2.04,5′.05,4′]decane-3,2′-dione core, and three biosynthetically related intermediates, compounds 2–4, were isolated from the leaves of Xylopia vielana. Their structures and absolute configurations were determined by a combination of spectroscopic data, X-ray crystallography, electronic circular dichroism calculations, and chemical conversion. The structure of known vielanin A was revised to be compound 3. Compound 4 exerted a 3.7-fold potentiation effect on doxorubicin susceptibility at the tested concentration of 10 μM.

Six new obovatol trimeric neolignans, houpulignans A–F (1–6) were isolated from the leaves of Magnolia officinalis var. biloba. Their structures were determined on the basis of the interpretation of HRESIMS, NMR data, and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are the first examples of neolignans derived from three units of obovatol bearing a rare 1,4-benzodioxepane moiety. Compound 3 possesses a benzodihydropyran ring, meanwhile three units of obovatol in 4–6 are connected by an alkyl chain. Compounds 1–3 inhibited NO production in LPS-stimulated RAW264.7 cells with IC50 values of 8.01, 20.21, and 4.05 µM, respectively.

A synthesis-inspired chemical investigation of the leaves of Melicope ptelefolia led to the isolation of evodialones A–D (1–4), four rearranged acetophenone stereoisomers possessing a prenylated acylcyclopentenone skeleton with three stereogenic carbons. Evodialones C and D (3 and 4) are new minor constituents. The chiral-phase HPLC resolution gave (+)-1–4 and (−)-1–4, eight enantiomers forming a complete stereoisomer library. Their absolute configurations were elucidated via extensive spectroscopic data and a modified Mosher’s method. The relationship between the chiral structures and their NMR and ECD data is discussed. Compounds (±)-1, -2, and -4 have significant protective effects on high-glucose-induced oxidative stress in human vein endothelial cells.

Nine new spirocyclic acylphloroglucinol derivatives, hyperpatulols A-I (1-9), were characterized from the flowers of Hypericum patulum. Their structures were elucidated by the basic analysis of the obtained spectroscopic data, and their absolute configurations were assigned by both the electronic circular dichroism (ECD) exciton chirality method and ECD calculation. The evaluation of their anti-migration effects on U2-OS human osteosarcoma cells showed that compound 4 exhibited moderate inhibitory activity in a dose-dependent manner. Further pharmacological studies revealed that 4 could regulate the expression of the proteins Vimentin and E-cadherin.

Taxodinoid A (1), an unprecedented bis-diterpenic anhydride featuring a 6/6/7/6/6/6 heptacyclic core skeletons, and three novel pyrane-fused abietane-type diterpene dimers (2–4), were obtained from the seeds of Taxodium distichum. Their structures were elucidated by spectroscopic data, X-ray crystallograph and electronic circular dichroism calculation. A biosynthetic pathway and suppressing migration activity against U2 OS cells were also discussed.

Tooniliatone A (1), a novel limonoid with an unprecedented 6/5/6/5 tetracarbocyclic skeleton was isolated from Toona ciliata Roem. var. yunnanensis. Its rearranged ring-seco backbone was proposed to biosynthetically originate from co-isolated known toonacilin (3) via a rare electron-deficient alkene electrophilic cyclization and 1,2-alkyl shift sequence. The acid-catalyzed biomimetic conversion of 3 not only successfully afforded 1 but also another novel 6/5/6/5 tetracarbocyclic skeleton, tooniliatone B (2). The priority of 2 in this biomimetic conversion, the existence of 1 and the absence of 2 in the crude extract suggested the biosynthetic selectivity of 1 from 3. The divergent biomimetic sequence, based on a carbocation from an epoxide moiety, provided an inspiration for constructing complex polycyclic carbon skeletons.

A new peroxide of xanthone ( 1 ), together with five analogues ( 2 – 6 ), was obtained from horseradish peroxidase (HRP) catalysed biotransformation of α -mangostin. In order to increase the yield of compound 1 , the environmental pH was succinctly adjusted, and as a result, compound 1 was formed with considerable selectivity. The anticancer potential of compound 1 , a pentacyclic xanthone with a 1,2-dioxolane ring, was investigated due to its potent cytotoxic activity. The results showed that apoptosis induced by compound 1 in human hepatocellular carcinoma (HepG2) cell was associated with activation of caspase-dependent apoptotic pathway, the generation of reactive oxygen species (ROS) and the activation of c-Jun N-terminal kinases (JNK). In summary, compound 1 with a peroxide group was biosynthesized in considerable yield through pH-switched biotransformation catalysed by HRP, which could be further developed as a promising candidate in the treatment of liver cancer.

An off-on fluorescent probe (CuCIN), coumarin-naphthol linked by an imine group, for detecting Cu2+ in DMSO-HEPES buffer (1:99, v/v) solution was successfully developed. Mechanism studies suggested that CuCIN firstly formed a complex with Cu2+ in a 1:2 metal-to-ligand ratio, and then 60-fold fluorescence enhancement was observed when Cu2+ promoted the imine hydrolysis to release the fluorescence compound 7-diethylaminocoumarin-3-aldehyde. This probe displayed desired properties such as high selectivity toward other metal ions, low detection limit (12.7 nM) and low cytotoxicity. Bio-imaging study revealed that the new probe CuCIN could be applied for imaging living cells with good cell permeability. We hope to apply this probe in the biomedical research field for the imaging of disease-relevant Cu2+.

Tow new arylalkenyl α,β-unsaturated δ-lactones named cryptoconcatones K (1) and L (2) were obtained from the leaves and twigs of Cryptocarya concinna. Their structures were established on the basis of spectroscopic data (MS, 1D and 2D NMR). Compounds 1 and 2 showed cytotoxic activities with IC50 values of 4.5 and 3.9 μM against Huh7 cancer cell line, respectively.

Seven new cadinane-type sesquiterpenoids (1–7) were isolated from the rhizomes of Stahlianthus involucratus. The planar structures of 1–7 were elucidated on the basis of extensive spectroscopic and HRMS data. The absolute configuration of 1 was determined by the single-crystal X-ray diffraction, whereas those of C-9 in 3, C-9 in 4, C-6 in 6, and the 1,2-diol in 7 were deduced via the CD data of the in situ formed [Rh2(OCOCF3)4] complex, and Mo2(OAc)4-induced CD analysis, respectively.

Rhodomyrtials A and B (1 and 2), two unprecedented triketone-sesquiterpene-triketone adducts, along with five biogenetically related intermediates, rhodomentone A (3) and tomentodiones A-D (4-7), were isolated from the leaves of Rhodomyrtus tomentosa. Their structures and absolute configurations were determined by a combination of NMR spectroscopy, chemical conversion, and X-ray diffraction analysis. Compounds 1 and 2 were biomimetically synthesized via 5 and 4, respectively, rather than 3, revealing their key ordering of biosynthetic events and confirming their structural assignments. Compound 7 exhibited potent metastatic inhibitory activity against DLD-1 cells by suppressing the activation of matrix metalloproteinase (MMP)-2 and MMP-9.

Two new polycyclic polyprenylated acylphloroglucinols, attenuatumione G (1) and attenuatumione H (2), together with five known compounds (3–7) have been isolated from the whole plant of Hypericum attenuatum. Their structures were elucidated by spectroscopic data including HRESIMS, 1D- and 2D-NMR. In biological assays, compound 2 showed moderate cytotoxic activities against Hep-G2 (IC50 9.11 μM) and MCF-7 (IC50 16.24 μM), compound 4 exhibited significant cytotoxic activity with IC50 value of 5.32 μM against Hep-G2, and both compounds 5 and 6 revealed significant nitric oxide production inhibitory activity with IC50 values of 5.52 and 8.46 μM, respectively.

Nine new withaphysalin-type withanolides (1–9), named physaminimins (G-O) were isolated from the whole plants of Physalis minima Linn. The structures of these compounds were elucidated based on spectroscopic methods (1D NMR, HSQC, HMBC, ROESY) and HRESIMS. Physaminimins G, H, and K showed inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a macrophage (RAW264.7) cells with IC50 values of 17.41 ± 1.04, 36.33 ± 1.95 and 21.48 ± 1.67 μM, respectively.

Four new lignans, patulinones A−D (1–4) and three new acetophenone derivatives, patulinones E−G (5–7) were isolated from the leaves of Melicope patulinervia. Their structures were elucidated on the basis of the interpretation of HR-ESIMS, NMR, CD data. All the isolated compounds were evaluated for α-glucosidase inhibitory activity. Of the isolates, compound 4 was found to exhibit the strongest inhibition against α-glucosidase with IC50 value of 6.02 ± 0.46 μM.

Hyperpatulones A (1) and B (2), two new polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from the leaves of Hypericum patulum. Their unusual 6,7,5-tricyclic system with a peroxide bridge structures were elucidated by comprehensive analysis of their spectroscopic and HRESIMS data. The absolute configuration of hyperpatulone A was determined by comparison between experimental and calculated electron circular dichroism (ECD) spectra. Compounds 1 and 2 exhibited moderate α-glucosidase inhibitory activity with IC50 values of 81.45 ± 1.04 and 12.81 ± 2.13 μM, respectively. Molecular docking studies of 1 and 2 with human maltase-glucoamylase (MGAM) revealing that 2 showed higher shape complementarity with the binding pocket.

Hypatulone A (1), an acylphloroglucinol possessing an unprecedented homoadamantane architecture based on a tricyclo-[4.3.1.13,8]-undecane core and a unique 5/5/7/6/6 pentacyclic ring system, together with its biogenetic precursor hyperbeanol B (2), was isolated from Hypericum patulum. The structure of 1 was elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation. Its plausible biosynthetic pathway via Wagner–Meerwein rearrangement was proposed. 1 exhibited nitric oxide inhibitory effect on LPS-induced RAW264.7 cell line (IC50 18.8 ± 1.75 μM).

Investigation into the chemical diversity of Artemisia argyi led to the discovery of four new (1–4) and one known (5) guaianolide sesquitenpenoid dimers linked via ester bond, and five other known mono-sesquiterpenoids (6–10). Their structures were determined via extensive spectroscopic data, and the absolute configurations of these compounds were elucidated by calculated ECD analysis and chemical method. The dimeric sesquiterpenoids exhibited NO production inhibitory activity with IC50 values ranging from 7.02 to 32.1 μM. The studies further suggested that compound 2 inhibited inflammatory responses via suppression of the expression of iNOS, resulting from activation of nuclear factor-kappaB (NF-κB) and phosphorylation of MAPKs (ERK and p38).

Five previously undescribed 4,5-seco-abietane rearrange diterpenoids (1–5, Prionidipene A-E) were isolated from the aerial parts of Salvia prionitis, along with thirteen known seco-abietane diterpenoids (6–18). The structures of 1–5 were elucidated mainly based on analysis of NMR and MS data. The absolute configurations of 1–3 were determined by evaluation of experimental and calculated electronic circular dichroism (ECD) spectra. Putative biosynthetic pathways toward the formation of 1 and 2 are proposed. The nitric oxide (NO) production inhibitory effects of all isolates in lipopolysaccharide (LPS)-induced in RAW 264.7 cells were evaluated. Interestingly, compounds 4 and 9 with a furan-ring showed potent inhibitory activity with IC50 values of 14.56 and 15.11 μM, respectively.

Ten new withanolides (1–10) and three artificial withanolides (11–13) were isolated from the aerial parts of Tubocapsicum anomalum, together with five known analogues (14–18). Their structures were determined on the basis of extensive spectroscopic and chemical methods. They include seven acnistin–type (1–4, 11, 14 and 15), three withajardin–type (5–7), and eight normal–type (8–10, 12, 13 and 16–18) withanolides. Of normal–type withanolides, a chemical conversion from the 16α,17α–epoxywithanolide (16) to Δ13,14–16α–hydroxywithanolide (18) was achieved by Wagner–Meerwein rearrangement. All isolates were evaluated for their cytotoxicity against four human tumor cell lines (HCT–116, HepG2, MCF–7 and A375). Among them, compounds 1–3, 6–8, 14, 16–18 showed cytotoxic activity with IC50 values of 0.24–8.71 μM.

Thirteen undescribed dimeric guaianes were isolated from the leaves of Xylopia vielana Pierre. Their structures were elucidated by NMR spectroscopy and mass spectrometry, and the absolute configurations of vielanins G-Q were determined by a combination of the circular dichroism (CD) exciton chirality method, chemical conversion, and electronic CD (ECD) spectroscopy analysis. Vielaninors A and B are the first examples of trinor-guaiane-dimers. Multidrug resistance reversal activity assay of the isolates was evaluated in doxorubicin-resistant human breast cancer cells. Vielanins H, K-M, P, and Q were noncytotoxic and enhanced the cytotoxicity of doxorubicin by 2.1–41.6-fold at 10 μM.

Withanolides are a large group of steroidal lactones found in Solanaceae plants that exhibit potential anticancer activities. In the present study, eight new withanolides, physagulides A–H (1–8), along with ten known analogues (9–18), were isolated and identified from the whole plants of Physalis angulata var. villosa. All compounds were evaluated for their cytotoxicity against three human cancer cell lines, human hepatoma (HepG2), human breast carcinoma (MCF-7) and human osteosarcoma (MG-63) cells. Compounds 9, 10, 14, 17 and 18 exhibited cytotoxicity on all cell lines with half maximal inhibitory concentration (IC50) values of 0.06–6.73 μM, comparable to those of the reference agent cisplatin. One of the potent compounds, physagulide I (9) arrested cells in the G2/M phase and activated caspase-dependent apoptotic pathways. Furthermore, apoptosis induced by physagulide I in MG-63 cells was associated with the generation of reactive oxygen species (ROS) and the activation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinases (JNK). These results suggest that physagulide I may be a promising agent for the treatment of cancer.

Involudispirones A (1) and B (2), a pair of cytotoxic sesterterpene stereoisomers containing a 1,2-dioxadispiro[5.2.5.2]hexadecane ring, were isolated from the rhizomes of Stahlianthus involucratus. Their structures and absolute configurations were established on the basis of spectroscopic data and chemical conversion. Both 1 and 2 are cytotoxic.

A pair of 2,3-seco cafestol-type diterpenoid epimers, frutilactones A (1) and B (2) were isolated from twigs of Tricalysia fruticosa. Their structures were elucidated by comprehensively employing spectroscopic methods (MS and 1D/2D NMR) and ECD. Their inhibitory effects on nitric oxide production in lipopolysaccharide-activated macrophages were evaluated, and a possible biogenetic pathway was also proposed.

A total of 14 new diterpene dimers, aphanamenes C-P ()1-14, with four known homologous compounds were isolated from the root barks of Aphanamixis grandifolia Bl. The structures of these compounds were elucidated by spectroscopic analyses, and their absolute configurations were determined using the CD exciton chirality method. In addition, all the compounds exhibited significant inhibition of lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophages, with IC50 values between 7.75 and 38.23 μM.

(±)-Calliviminones A (1) and B (2), two Diels–Alder adducts of polymethylated phloroglucinol and myrcene with unprecedented spiro-[5.5] undecene skeleton, were isolated from the fruits of Callistemon viminalis. Structural elucidation was accomplished by NMR spectra studies, and the biomimetic synthesis of compounds 1 and 2 confirmed the pivotal role of Diels–Alder reaction in the plausible biosynthetic pathway. Compounds 1 and 2 were also the first example of Carbon Diels–Alder adducts between phloroglucinol and terpene. Bioactivity scan indicated that 1 and 2 showed moderate inhibition on NO production on lipopolysaccharide-induced RAW264.7 macrophages.

Three new syncarpic acid-conjugated sesquiterpenoids, tomentodiones E–G (1–3), and six new syncarpic acid-conjugated monoterpenoids, tomentodiones H–M (4–9), were isolated from the leaves of Rhodomyrtus tomentosa. Compounds 1–3 represent the first examples of β-calacorene-based meroterpenoids. Their structures and absolute configurations were determined by a combination of NMR and ECD spectroscopy and X-ray diffraction analysis. On the basis of ECD data analysis for isolated and synthesized compounds, an empirical rule was proposed to determine the absolute configuration at C-7′ of syncarpic acid-conjugated terpenoids. Additionally, a study of the reversal effect of multidrug resistance in doxorubicin-resistant human breast cancer cells showed that the noncytotoxic (+)-4 exerted the strongest potentiation effect of doxorubicin susceptibility, with an enhancement of 16.5-fold at a concentration of 30 μM.

Seven new taxane diterpenoids taxumarienes A–G (1–7) were isolated from the leaves of Taxus mairei, along with seven known analogous (8–14). The structures of the new compounds were elucidated based on the analysis of NMR and MS spectroscopy. All isolates were evaluated for their α-glucosidase inhibitory activities. Among them, taxumarienes A (1) and F (6) showed potent effect with IC50 values of 5.9 ± 1.30 μM and 3.7 ± 0.75 μM, respectively.