Limonoids from the roots of Melia azedarach and their anti-inflammatory activity

Twelve undescribed limonoids, meliazedarines J-U (1-12), along with a known one, were isolated from the roots of Melia azedarach. Their structures were elucidated by extensive spectroscopic investigations, X-ray diffraction analyses, and ECD calculations. Compounds 1-8 were identified as ring intact limonoids, while compounds 9-12 were established as ring C-seco ones. The anti-inflammatory potential of compounds 1-4, 6, 8, 9, and 11-13 was evaluated on macrophages. Compounds 1, 3, 4, 6, and 9 significantly suppressed nitric oxide production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, among them compound 3 showed the best inhibitory effect with an IC50 value of 7.07 ± 0.48 μΜ. Furthermore, compound 3 effectively reduced interleukin-1β secretion in LPS plus nigericin-induced THP-1 macrophages by inhibiting NLRP3 inflammasome activation. The results strongly suggested that limonoids from the roots of M. azedarach might be candidates for treating inflammation-related diseases.

Germacrane-type sesquiterpenoids from the flowers of Chrysanthemum indicum with hepatoprotective activity

Two new germacrane-type sesquiterpenoids, chrysanthemolides A (1) and B (2), and four known germacrane-type sesquiterpenoids, hanphyllin (3), 3β-hydroxy-11α,13-dihydro-costunolide (4), costunolide (5), and 6,7-dimethylmethylene-4-aldehyde-1β-hydroxy-10(15)-ene-(4Z)-dicyclodecylene (6), were isolated and identified from the flowers of Chrysanthemum indicum. The structures of the new compounds were elucidated via high resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D and 2D nuclear magnetic resonance (NMR) spectra and electronic circular dichroism (ECD). Meanwhile, all the isolates were tested for their hepatoprotective activity in tert-butyl hydroperoxide (t-BHP) injured AML12 cells. Compounds 1, 2, and 4 showed significant protective effects at 40 μM, comparable with the positive control resveratrol at 10 μM. As the most potent one, compound 1 was chosen for further studies. Compound 1 dose-dependently increased the viability of t-BHP-injured AML12 cells. Furthermore, compound 1 decreased reactive oxygen species accumulation, while increased glutathione level, heme oxygenase-1 level and superoxide dismutase activity, through anchoring in the binding site of Kelch domain of the Kelch-like ECH-associated protein 1 (Keap1) to promote the dissociation of nuclear factor erythroid 2-related factor 2 from Keap1 and translocation to nuclei. In summary, germacrane-type sesquiterpenoids from C. indicum might be further developed to protect liver against oxidative damage.

14-Deoxygarcinol improves insulin sensitivity in high-fat diet-induced obese mice via mitigating NF-κB/Sirtuin 2-NLRP3-mediated adipose tissue remodeling

Interleukin (IL)-1β is a culprit of adipose tissue inflammation, which in turn causes systematic inflammation and insulin resistance in obese individuals. IL-1β is mainly produced in monocytes and macrophages and marginally in adipocytes, through cleavage of the inactive pro-IL-1β precursor by caspase-1, which is activated via the NLRP3 inflammasome complex. The nuclear factor-κB (NF-κB) transcription factor is the master regulator of inflammatory responses. Brindle berry (Garcinia cambogia) has been widely used as health products for treating obesity and related metabolic disorders, but its active principles remain unclear. We previously found a series of polyisoprenylated benzophenones from brindle berry with anti-inflammatory activities. In this study we investigated whether 14-deoxygarcinol (DOG), a major polyisoprenylated benzophenone from brindle berry, alleviated adipose tissue inflammation and insulin sensitivity in high-fat diet fed mice. The mice were administered DOG (2.5, 5 mg · kg-1 · d-1, i.p.) for 4 weeks. We showed that DOG injection dose-dependently improved insulin resistance and hyperlipidemia, but not adiposity in high-fat diet-fed mice. We found that DOG injection significantly alleviated adipose tissue inflammation via preventing macrophage infiltration and pro-inflammatory polarization of macrophages, and adipose tissue fibrosis via reducing the abnormal deposition of extracellular matrix. In LPS plus nigericin-stimulated THP-1 macrophages, DOG (1.25, 2.5, 5 μM) dose-dependently suppressed the activation of NLRP3 inflammasome and NF-κB signaling pathway. We demonstrated that DOG bound to and activated the deacetylase Sirtuin 2, which in turn deacetylated and inactivated NLRP3 inflammasome to reduce IL-1β secretion. Moreover, DOG (1.25, 2.5, 5 μM) dose-dependently mitigated inflammatory responses in macrophage conditioned media-treated adipocytes and suppressed macrophage migration toward adipocytes. Taken together, DOG might be a drug candidate to treat metabolic disorders through modulation of adipose tissue remodeling.

Triterpenoids from the fruits of Melia azedarach L. and their cytotoxic activities

Eleven undescribed tetracyclic triterpenoids, meliazedarachins A-K, along with twenty-six known compounds were isolated from the fruits of Melia azedarach L.. Their structures were determined by HRESIMS, UV, IR, NMR, X-ray diffraction, electronic circular dichroism (ECD) spectra, and the modified Mosher's method. The cytotoxic activities of all the isolates were measured. Meliazedarachin K and mesendanin N showed cytotoxicity against five human cancer cell lines with IC₅₀ values ranging from 9.02 to 31.31 μM. Meliazedarachin K showed significant cytotoxicity against HCT116 cell line with IC₅₀ value of 9.02 ± 0.84 μM. 21α-methylmelianodiol showed significant cytotoxicity against HCT116 and RKO cell lines with IC₅₀ values of 10.16 ± 1.22 and 8.57 ± 0.80 μM, respectively.

Biflavonoids from the twigs and leaves of Cephalotaxus oliveri Mast. and their α-glucosidase inhibitory activity

Three new biflavonoids, umcephabiovins C - E (1 - 3), along with fourteen known compounds were isolated from the twigs and leaves of Cephalotaxus oliveri. Their structures and configurations were elucidated by UV, IR, NMR, ECD, and HR-ESI-MS spectra. Compounds 1 - 3 exhibited significant α-glucosidase inhibitory activity with IC₅₀ values of 7.05 ± 2.66, 24.45 ± 4.73, and 1.84 ± 1.14 μM, respectively. Compound 11 showed moderate cytotoxicity against the BaF3/T315I cell line.

Honokiol: A naturally occurring lignan with pleiotropic bioactivities

Honokiol is the dominant biphenolic compound isolated from the Magnolia tree, and has long been considered as the active constituent of the traditional Chinese herb, 'Houpo', which is widely used to treat symptoms due to 'stagnation of qi'. Pharmacological studies have shown that honokiol possesses a wide range of bioactivities without obvious toxicity. Honokiol protects the liver, kidneys, nervous system, and cardiovascular system through reducing oxidative stress and relieving inflammation. Moreover, honokiol shows anti-diabetic property through enhancing insulin sensitivity, and anti-obese property through promoting browning of adipocytes. In vivo and in vitro studies indicated that honokiol functions as an anti-cancer agent through multiple mechanisms: inhibiting angiogenesis, promoting cell apoptosis, and regulating cell cycle. A variety of therapeutic effects of honokiol may be associated with its physiochemical properties, which make honokiol readily cross the blood brain barrier and the blood-cerebrospinal fluid barrier, with high bioavailability. In the future, more clinical researches on honokiol are needed to fully authenticate its therapeutic values.

Phanginin R Induces Cytoprotective Autophagy via JNK/c-Jun Signaling Pathway in Non-Small Cell Lung Cancer A549 Cells

BACKGROUND

Cassane-type diterpenoids are widely distributed in the medical plants of genus Caesalpinia. To date, plenty of cassane diterpenoids have been isolated from the genus Caesalpinia, and some of them were documented to exhibit multiple biological activities. However, the effects of these compounds on autophagy have never been reported.

OBJECTIVE

To investigate the effects and mechanisms of the cassane diterpenoids including Phanginin R (PR) on autophagy in Non-Small Cell Lung Cancer (NSCLC) A549 cells.

METHODS

Western blot analysis and immunofluorescence assay were performed to investigate the effects of the compounds on autophagic flux in A549 cells. The pathway inhibitor and siRNA interference were used to investigate the mechanism of PR. MTT assay was performed to detect cell viability.

RESULTS

PR treatment upregulated the expression of phosphatidylethanolamine-modified microtubule-associated protein Light-Chain 3 (LC3-II) in A549 cells. Immunofluorescence assay showed that PR treatment increased the production of red-fluorescent puncta in mRFP-GFP-LC3 plasmid-transfected cells, indicating PR promoted autophagic flux in A549 cells. PR treatment activated the c-Jun N-terminal Kinase (JNK) signaling pathway while it did not affect the classical Akt/mammalian Target of Rapamycin (mTOR) pathway. Pretreatment with the JNK inhibitor SP600125 or siRNA targeting JNK or c-Jun suppressed PR-induced autophagy. In addition, cotreatment with the autophagy inhibitor Chloroquine (CQ) or inhibition of the JNK/c-Jun signaling pathway increased PR-induced cytotoxicity.

CONCLUSION

PR induced cytoprotective autophagy in NSCLC A549 cells via the JNK/c-Jun signaling pathway, and autophagy inhibition could further improve the anti-cancer potential of PR.

Nagilactone E increases PD-L1 expression through activation of c-Jun in lung cancer cells

Nagilactone E (NLE), a natural product with anticancer activities, is isolated from Podocarpus nagi. In this study, we reported that NLE increased programmed death ligand 1 (PD-L1) expressions at both protein and mRNA levels in human lung cancer cells, and enhanced its localization on the cell membrane. Mechanistically, NLE increased the phosphorylation and expression of c-Jun, and promoted the localization of c-Jun in the nucleus, while silencing of c-Jun by small interfering RNA (siRNA) reduced NLE-induced PD-L1. Further study showed that NLE activated the c-Jun N-terminal kinases (JNK), the upstream of c-Jun, and its inhibitor SP600125 reversed the NLE-increased PD-L1. Moreover, NLE-induced PD-L1 increased the binding intensity of PD-1 on the cell surface. In summary, NLE upregulates the expression of PD-L1 in lung cancer cells through the activation of JNK-c-Jun axis, which has the potential to combine with the PD-1/PD-L1 antibody therapies in lung cancer.

Identification of nagilactone E as a protein synthesis inhibitor with anticancer activity

Norditerpenoids and dinorditerpenoids represent diterpenoids widely distributed in the genus Podocarpus with notable chemical structures and biological activities. We previously reported that nagilactone E (NLE), a dinorditerpenoid isolated from Podocarpus nagi, possessed anticancer effects against lung cancer cells in vitro. In this study we investigated the in vivo effect of NLE against lung cancer as well as the underlying mechanisms. We administered NLE (10 mg·kg^-1·d^-1, ip) to CB-17/SCID mice bearing human lung cancer cell line A549 xenograft for 3 weeks. We found that NLE administration significantly suppressed the tumor growth without obvious adverse effects. Thereafter, RNA sequencing (RNA-seq) analysis was performed to study the mechanisms of NLE. The effects of NLE on A549 cells have been illustrated by GO and pathway enrichment analyses. CMap dataset analysis supported NLE to be a potential protein synthesis inhibitor. The inhibitory effect of NLE on synthesis of total de novo protein was confirmed in Click-iT assay. Using the pcDNA3-RLUC-POLIRES-FLUC luciferase assay we further demonstrated that NLE inhibited both cap-dependent and cap-independent translation. Finally, molecular docking revealed the low-energy binding conformations of NLE and its potential target RIOK2. In conclusion, NLE is a protein synthesis inhibitor with anticancer activity.

Cablinosides A and B, Two Glycosidic Phenylacetic Acid Derivatives from the Leaves of Pogostemon cablin

A pair of new glycosidic epimers, cablinosides A (1a) and B (1b) were isolated from the leaves of Pogostemon cablin. The structures with absolute configurations of 1a and 1b were elucidated by extensive NMR investigation, and quantum chemical CD calculations. The epimer mixture 1 showed moderate α-glucosidase inhibitory activity and no significant cytotoxic activity against HepG2 cells.

Cycloartane triterpenoids from Actaea vaginata with anti-inflammatory effects in LPS-stimulated RAW264.7 macrophages

Five undescribed cycloartane triterpenoids, including two cycloartane trinor-triterpenoids, were isolated from a 70% ethanol extract of the whole plant of Actaea vaginata (Ranunculaceae), together with thirteen known cycloartane triterpenoids. Their structures were determined by spectroscopic techniques and quantum chemical calculations for intramolecular noncovalent interactions with reduced density gradient method. All compounds were evaluated for their anti-inflammatory effects by a lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production model in RAW264.7 macrophage cells, and some showed potent inhibitory effects with IC₅₀ values ranging from 5.0 to 24.4 μM. Further mechanism studies showed that one compound dose-dependently suppressed LPS-induced NO production and pro-inflammatory cytokines secretion, and decreased the expression of iNOS, through inhibiting NF-κB activation.

Tautomerism and bioactivities of curcumenol, a common sesquiterpenoid widely existing in edible plants

Curcumenol was firstly revealed as a pair of hemiacetal-ketone tautomers in solutions by using temperature variation 1H-NMR experiments, 2D NMR, and chemical methods. Quantum chemical calculation allowed the explanation of its spectroscopic behavior. An antioxidative SAR study on its derivatives verified the tautomeric bio-significance. Curcumenol also remarkably enhanced myogenic differentiation and mitochondrial function.

Triterpenoids from Cyclocarya paliurus that Enhance Glucose Uptake in 3T3-L1 Adipocytes

Four previously undescribed compounds, including three rarely occurring seco-dammarane triterpenoid glycosides and a pentacyclic triterpenic acid, were isolated from a 70% ethanol extract of the leaves of Cyclocarya paliurus (Juglandaceae), along with eleven known triterpenoids. Their structures were determined by spectroscopic techniques, including 2D NMR and HRESIMS, as well as chemical methods. Among them, several triterpenoids enhanced insulin stimulated glucose uptake in both 3T3-L1 adipocytes and C2C12 myotubes. Furthermore, compound 1 dose-dependently increased glucose uptake through activating AMP-activated protein kinase (AMPK)-p38 pathway. Collectively, triterpenoids from C. paliurus could be developed as insulin sensitizers, which might have therapeutic potential for insulin resistance and hyperglycemia.

Nagilactone E suppresses TGF-β1-induced epithelial-mesenchymal transition, migration and invasion in non-small cell lung cancer cells

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related death around the world. Epithelial-mesenchymal transition (EMT) has been documented to increase motility and invasiveness of cancer cells, which promotes cancer metastasis.

PURPOSE

This study aims to investigate the inhibitory effects and mechanisms of the dinorditerpenoids and norditerpenoids isolated from the seeds of Podocarpus nagi against transforming growth factor (TGF)-β1-induced EMT.

METHODS

A series of dinorditerpenoids and norditerpenoids were isolated from the seeds of P. nagi. Western blot and quantitative real-time PCR assays were performed to determine the expression levels of relative proteins and mRNA, along with immunofluorescence, Smad-binding element (SBE)-luciferase and chromatin immunoprecipitation (ChIP) assays for the mechanism study. Transwell assays were conducted to determine the effect of the compounds on cell migration and invasion.

RESULTS

Nagilactone E (NLE) showed the superior inhibitory effect against TGF-β1-induced EMT. NLE treatment dramatically inhibited TGF-β1-induced expression of EMT markers in A549 cells. Mechanism study indicated that NLE markedly suppressed TGF-β1-induced Smad2 and Smad3 activation and nuclear translocation. SBE-luciferase and ChIP assays showed that NLE inhibited the combining of Smad3 to SBE in the promoters of the cell signaling factors. NLE co-treatment attenuated TGF-β1-induced up-regulation of the protein and mRNA levels of TGF-β receptor TβRI. Furthermore, NLE inhibited TGF-β1-stimulated cell migration and invasion, as well as up-regulation of the key signaling proteins related with migration and invasion.

CONCLUSION

NLE inhibited TGF-β/Smad signaling pathway, thereafter suppressed TGF-β1-induced EMT, migration and invasion in NSCLC A549 cells.

Anticancer carbazole alkaloids and coumarins from Clausena plants: A review

Pharmaceutical research has focused on the discovery and development of anticancer drugs. Clinical application of chemotherapy drugs is limited due to their severe side effects. In this regard, new naturally occurring anticancer drugs have gained increasing attention because of their potential effectiveness and safety. Fruits and vegetables are promising sources of anticancer remedy. Clausena (family Rutaceae) is a genus of flowering plants and includes several kinds of edible fruits and vegetables. Phytochemical and pharmacological studies show that carbazole alkaloids and coumarins from Clausena plants exhibit anticancer activity. This review summarizes research progresses made in the anticancer properties of plants belonging to Clausena; in particular, compounds with direct cytotoxicity, cell cycle arrest, apoptosis induction, and immune potentiation effects are discussed. This review reveals the potential use of plants from Clausena in preventing and treating cancer and provides a basis for development of relevant therapeutic agents.

Simultaneous Quantification of Three Curcuminoids and Three Volatile Components of Curcuma longa Using Pressurized Liquid Extraction and High-Performance Liquid Chromatography

A high-performance liquid chromatography (HPLC) method was investigated for the simultaneous quantification of two chemical types of bioactive compounds in the rhizome of Curcuma longa Linn. (turmeric), including three curcuminoids: Curcumin, bisdemethoxycurcumin, and demethoxycurcumin; and three volatile components: ar-turmerone, β-turmerone, and α-turmerone. In the present study, the sample extraction system was optimized by a pressurized liquid extraction (PLE) process for further HPLC analysis. The established HPLC analysis conditions were achieved using a Zorbax SB-C18 column (250 mm × 4.6 mm i.d., 5 μm) and a gradient mobile phase comprised of acetonitrile and 0.4% (v/v) aqueous acetic acid with an eluting rate of 1.0 mL/min. The curcuminoids and volatile components were detected at 430 nm and 240 nm, respectively. Moreover, the method was validated in terms of linearity, sensitivity, precision, stability and accuracy. The validated method was successfully applied to evaluate the quality of twelve commercial turmeric samples.

Isolation, Structural Elucidation, and α-Glucosidase Inhibitory Activities of Triterpenoid Lactones and Their Relevant Biogenetic Constituents from Ganoderma resinaceum

Ganoderma resinaceum has been used as an ethnomedicine for lowering blood sugar. To clarify the bioactive chemical constituents contributing to lower blood sugar, chemical investigation on the fruiting bodies of Ganoderma resinaceum was conducted by chromatographic techniques, and led to the isolation of 14 compounds. Their structures were elucidated as triterpenoid lactones (1–4 and 8) and ganoderma acids (5–7 and 9–14) based on the analysis of extensive spectroscopy (mass spectrometry (MS), nuclear magnetic resonance (NMR), infrared (IR), and ultraviolet (UV)) and comparison with literature data. Compounds 3, 5, 6, and 9–14 were evaluated for α-glucosidase inhibitory activity. Compounds 1–7 are new compounds. Compounds 1–4 and 8 were characteristic of an oxaspirolactone moiety, consisting of a five-membered ether ring, a five-membered lactone ring, and a characteristic C-23 spiro carbon. It is rare for natural products that such an oxaspirolactone moiety occurred in the lanostane-type triterpenoids. Compounds 5–7 and 9–14 may be important intermediates of the biosynthetic pathways of 1–4 and 8. Compounds 1 and 2 showed more potent inhibitory activity against α-glucosidase compared with the positive control drug acarbose with IC₅₀ value of 0.75 ± 0.018 mM and 1.64 ± 0.022 mM, respectively.

Downregulation of Cyclin B1 mediates nagilactone E-induced G2 phase cell cycle arrest in non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is one of the most common forms and leading causes of cancer-related mortality worldwide, and discovery of new effective drugs still remains imperative to improve the survival rate. Nagilactone E (NLE) is a natural product isolated from Podocarpus nagi seeds, which has been used as raw materials for edible oil and industrial oil extraction. This study aimed to investigate the anticancer potential of NLE against NSCLC A549 and NCI-H1975 cells. MTT assay revealed that NLE inhibited the proliferation of A549 and NCI-H1975 cells with IC₅₀s of 5.18 ± 0.49 and 3.57 ± 0.29 μM, respectively. NLE treatment inhibited clone formation in both cancer cell lines. Cell cycle analysis indicated that NLE treatment effectively induced G2 phase cell cycle arrest in A549 and NCI-H1975 cells. NLE downregulated the phosphorylation of cdc2 (Tyr15) and cdc25C (Ser216) as well as the expression level of the protein kinase Wee1 in concentration- and time-dependent manners. In addition, NLE treatment decreased the protein level of Cyclin B1 as well as its nuclear localization, which might decrease the activity of the Cyclin B1/cdc2 complex and induce G2 phase arrest. Long-term NLE treatment also induced caspase-dependent cell apoptosis, as evidenced by increase in Annexin V positive cells and the cleavage of PARP. To sum, NLE inhibited proliferation, induced G2 phase arrest, and triggered caspase-dependent apoptosis in NSCLC cells, suggesting it to be a potential leading compound for cancer treatment.

Techniques for extraction and isolation of natural products: a comprehensive review

Natural medicines were the only option for the prevention and treatment of human diseases for thousands of years. Natural products are important sources for drug development. The amounts of bioactive natural products in natural medicines are always fairly low. Today, it is very crucial to develop effective and selective methods for the extraction and isolation of those bioactive natural products. This paper intends to provide a comprehensive view of a variety of methods used in the extraction and isolation of natural products. This paper also presents the advantage, disadvantage and practical examples of conventional and modern techniques involved in natural products research.

Coptidis rhizoma and its main bioactive components: recent advances in chemical investigation, quality evaluation and pharmacological activity

Background

Coptidis rhizoma (CR) is the dried rhizome of Coptis chinensis Franch., C. deltoidea C. Y. Cheng et Hsiao or C. teeta Wall. (Ranunculaceae) and is commonly used in Traditional Chinese Medicine for the treatment of various diseases including bacillary dysentery, typhoid, tuberculosis, epidemic cerebrospinal meningitis, empyrosis, pertussis, and other illnesses.

Methods

A literature survey was conducted via SciFinder, ScieneDirect, PubMed, Springer, and Wiley databases. A total of 139 selected references were classified on the basis of their research scopes, including chemical investigation, quality evaluation and pharmacological studies.

Results

Many types of secondary metabolites including alkaloids, lignans, phenylpropanoids, flavonoids, phenolic compounds, saccharides, and steroids have been isolated from CR. Among them, protoberberine-type alkaloids, such as berberine, palmatine, coptisine, epiberberine, jatrorrhizine, columamine, are the main components of CR. Quantitative determination of these alkaloids is a very important aspect in the quality evaluation of CR. In recent years, with the advances in isolation and detection technologies, many new instruments and methods have been developed for the quantitative and qualitative analysis of the main alkaloids from CR. The quality control of CR has provided safety for pharmacological applications. These quality evaluation methods are also frequently employed to screen the active components from CR. Various investigations have shown that CR and its main alkaloids exhibited many powerful pharmacological effects including anti-inflammatory, anti-cancer, anti-diabetic, neuroprotective, cardioprotective, hypoglycemic, anti-Alzheimer and hepatoprotective activities.

Conclusion

This review summarizes the recent phytochemical investigations, quality evaluation methods, the biological studies focusing on CR as well as its main alkaloids.

Garcinone E induces apoptosis and inhibits migration and invasion in ovarian cancer cells

Ovarian cancer remains the most lethal gynecological malignant tumor. In this study, 24 xanthones were isolated and identified from the pericarps of mangosteen (Garcinia mangostana), and their anti-proliferative activities were tested in ovarian cancer cells. Garcinone E (GE) was found to exhibit excellent anti-proliferative effects among the tested xanthones. It significantly inhibited the proliferation in HEY, A2780, and A2780/Taxol cells as evidenced by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, Hoechst 33342 staining, annexin V/PI staining, and JC-1 staining. It induced endoplasmic reticulum (ER) stress and activated the protective inositol-requiring kinase (IRE)-1α pathway. Knocking down IRE-1α further activated the caspase cascade and caused an increase in cell death. Moreover, GE eliminated the migratory ability of HEY cells by reducing the expression of RhoA and Rac. It also blocked the invasion, which might be related to downregulation of matrix metalloproteinases (MMPs), i.e., MMP-9 and MMP-2, and upregulation of tissue inhibitors of metalloproteinase (TIMP) -1 and TIMP-2. In summary, GE exerts anticancer activities by inducing apoptosis and suppressing migration and invasion in ovarian cancer cells, which indicates its therapeutic potential for ovarian cancer.

Norditerpenoids and Dinorditerpenoids from the Seeds of Podocarpus nagi as Cytotoxic Agents and Autophagy Inducers

Nine new norditerpenoids and dinorditerpenoids, 2-oxonagilactone A (1), 7β-hydroxynagilactone D (2), nagilactones K and L (3 and 4), 3β-hydroxynagilactone L (5), 2β-hydroxynagilactone L (6), 3-epi-15-hydroxynagilactone D (7), 1α-chloro-2β,3β,15-trihydroxynagilactone L (8), and 15-hydroxynagilactone L (9), were isolated from the seeds of Podocarpus nagi, along with eight known analogues. The structures of the new compounds were established based on detailed NMR and HRESIMS analysis, as well as from their ECD spectra. The absolute configuration of the known compound 1-deoxy-2α-hydroxynagilactone A (16) was confirmed by single-crystal X-ray diffraction. All of the isolates were tested for their cytotoxic activities against cancer cells. The results indicated that compounds 4 and 6, as well as several known compounds, displayed cytotoxicity against A2780 and HEY cancer cells. Among the new compounds, 2β-hydroxynagilactone L (6) showed IC₅₀ values of less than 2.5 μM against the two cell lines used. Furthermore, compound 6 induced autophagic flux in A2780 cells, as evidenced by an enhanced expression level of the autophagy marker phosphatidylethanolamine-modified microtubule-associated protein light-chain 3 (LC3-II) and increased mRFP-GFP-LC3 puncta. Also, compound 6 activated the c-Jun N-terminal kinase (JNK) pathway, while pretreatment with the JNK inhibitor SP600125 decreased compound 6-induced autophagy.

Cucurbitane Glucosides from the Crude Extract of Siraitia grosvenorii with Moderate Effects on PGC-1α Promoter Activity

Seven new cucurbitane glucosides, 11-oxomogrosides III E and IV (1 and 2), 11-oxoisomogroside V (3), 7-oxomogrosides III E and IV (4 and 5), and mogrosides VI A and VI B (6 and 7), were separated from the crude extract of Siraitia grosvenorii. The new structures were defined by analysis of their ¹H and ¹³C NMR, 2D NMR, and HRESIMS data. Especially, the band-selective constant time HSQC and band-selective constant time HMBC techniques were recuited to elucidate the structures of the complex glucoside moieties. Using the PGC-1α promoter driven luciferase reporter assay, the isolated compounds were examined for PGC-1α promoter activity.

Dicarabrol A, dicarabrone C and dipulchellin A, unique sesquiterpene lactone dimers from Carpesium abrotanoides

Three sesquiterpene lactone dimers with an unprecedented skeleton were isolated from the whole plants of Carpesium abrotanoides.

Clausoxamine, an alkaloid possessing a 1,3-oxazine-4-one ring from the seeds of Clausena lansium and the anti-obesity effect of lansiumamide B

One alkaloid with an unprecedented skeleton and one alkaloid with anti-obesity effect were isolated from the seeds of Clausena lansium.

Chikusetsusaponin IVa methyl ester induces G1 cell cycle arrest, triggers apoptosis and inhibits migration and invasion in ovarian cancer cells

BACKGROUND

Panacis Japonici Rhizoma (PJR) is one of the most famous Chinese medical herbs that is known for exhibiting potential anti-cancer effects.

PURPOSE

This study aims to isolate and investigate the anti-cancer potential of saponins from PJR in ovarian cancer cells.

METHODS

The compounds were separated by comprehensive chromatographic methods. By comparison of the 1H- and 13C NMR data, as well as the HR-ESI-MS data, with the corresponding references, the structures of compounds were determined. MTT assay was performed to evaluate cell viability, along with flow cytometry for cell cycle analysis. JC-1 staining, Annexin V-PI double staining as well as Hoechst 33; 342 staining were used for detecting cell apoptosis. Western blot analysis was conducted to determine the relative protein level. Transwell assays were performed to investigate the effect of the saponin on cell migration and invasion and zymography experiments were used to detect the enzymatic activities.

RESULTS

Eleven saponins were isolated from PJR and their anti-proliferative effects were evaluated in human ovarian cancer cells. Chikusetsusaponin IVa methyl ester (1) exhibited the highest anti-proliferative potential among these isolates with the IC50 values at less than 10 µM in both ovarian cancer A2780 and HEY cell lines. Compound 1 induced G1 cell cycle arrest accompanied with an S phase decrease, and down-regulated the expression of cyclin D1, CDK2, and CDK6. Further study showed that compound 1 effectively decreased the cell mitochondrial membrane potential, increased the annexin V positive cells and nuclear chromatin condensation, as well as enhanced the expression of cleaved PARP, Bax and cleaved-caspase 3 while decreasing that of Bcl-2. Moreover, compound 1 suppressed the migration and invasion of HEY and A2780 cells, down-regulated the expression of Cdc42, Rac, RohA, MMP2 and MMP9, and decreased the enzymatic activities of MMP2 and MMP9.

CONCLUSION

These results provide a comprehensive evaluation of compound 1 as a potential agent for the treatment of ovarian cancer.

In Vitro Study on Anti-Hepatitis C Virus Activity of Spatholobus suberectus Dunn

Hepatitis C virus (HCV) infects 200 million people worldwide, and 75% of HCV cases progress into chronic infections, which consequently cause cirrhosis and hepatocellular carcinoma. HCV infection is treated with currently considered standard drugs, including direct anti-viral agents (DAAs), alone or in combination with peginterferon-α plus ribavirin. However, sustained viral responses vary in different cohorts, and high costs limit the broad use of DAAs. In this study, the ethanol and water extracts of 12 herbs from Lingnan in China were examined in terms of their inhibitory effect on HCV replication. Among the examined extracts, Spatholobus suberectus ethanol extracts suppressed HCV replication. By comparison, Extracts from Fructus lycii, Radix astragali (root), Rubus chingii Hu (fruit), Flos chrysanthemi Indici (flower), Cassia obtusifolia (seed), Lonicera japonica Thunb (flower), Forsythia suspense Thunb (fruit), Poria cocos (sclerotia), Carthamus tinctorius L. (flower), Crataegus pinnatifida Bge. (fruit), and Leonurus japonicas Houtt. (leaf) extracts failed to show a similar activity. Active S. suberectus fractions containing tannins as the major component also inhibited the in vitro translation of HCV RNA. The combination treatments of single compounds, such as epigallocatechin gallate and epicatechin gallate, were not as potent as crude S. suberectus fractions; therefore, crude S. suberectus extract may be a potential alternative treatment against HCV either alone or in combination with other agents.

Naturally Occurring Diterpenoid Dimers: Source, Biosynthesis, Chemistry and Bioactivities

Diterpenoid dimers are rare in nature and mainly found in higher plants including the families Acanthaceae, Annonaceae, Asteraceae, Calceolariaceae, Chrysobalanaceae, Cupressaceae, Euphorbiaceae, Fabaceae, Lamiaceae, Liliaceae, Meliaceae, Rhizophoraceae, Taxaceae, Velloziaceae, and Zingiberaceae. In addition, a few diterpenoid dimers have been also reported from fungi (Psathyrellaceae), liverworts (Scapaniaceae), and a gorgonian (Gorgoniidae). They feature a wide variety of structures due to different core skeletons, linkage patterns, substituents, and configurations. Accordingly, diterpenoid dimers exhibit a broad range of bioactivities, including cytotoxic, anti-inflammatory, antimicrobial, antimalarial, and antifouling properties, which have attracted more and more research interests in the past decades. This review with 176 metabolites from 109 references provides a comprehensive and up-to-date overview of the source, biosynthesis, structure, synthesis, and bioactivities of diterpenoid dimers.

Novel Diterpenoids from the Twigs of Podocarpus nagi

Phytochemical investigation of the twigs of Podocarpus nagi (Podocarpaceae) led to the isolation of two new abietane-type diterpenoids, named 1β,16-dihydroxylambertic acid (1) and 3β,16-dihydroxylambertic acid (2), along with two new ent-pimarane-type diterpenoids, named ent-2β,15,16,18-tetrahydroxypimar-8(14)-ene (3) and ent-15-oxo-2β,16,18-trihydroxypimar-8(14)-ene (4). Their respective structures were elucidated on the basis of spectroscopic analyses, including 1D- and 2D-NMR, IR, CD, and HR-ESI-MS. This is the first time ent-pimarane-type diterpenoids from the genus Podocarpus has been reported. All four new compounds were tested for cytotoxic activity. The MTT assay results showed that compounds 3 and 4 significantly inhibited the proliferation of human cervical cancer Hela cells, human lung cancer A549 cells, and human breast cancer MCF-7 cells at a concentration of 10 μM. Furthermore, using the lipopolysaccharide (LPS)-stimulated RAW264.7 cells, compounds 2 and 4 were found to significantly inhibit nitrogen oxide (NO) production with IC50 values of 26.5 ± 6.1 and 17.1 ± 1.5 μM, respectively.

Cytotoxic and Pro-Apoptotic Effects of Cassane Diterpenoids from the Seeds of Caesalpinia sappan in Cancer Cells

The chemical study on the seeds of Caesalpinia sappan led to the isolation of five new cassane diterpenoids, phanginins R‒T (1–3) and caesalsappanins M and N (4 and 5), together with seven known compounds 6–12. Their structures were elucidated on the basis of NMR and HRESIMS analyses. The absolute configurations of compounds 1 and 4 were determined by the corresponding CD spectra. All the isolated compounds were tested for their cytotoxicity against ovarian cancer A2780 and HEY, gastric cancer AGS, and non-small cell lung cancer A549 cells. Compound 1 displayed significant toxicity against the four cell lines with the IC₅₀ values of 9.9 ± 1.6 µM, 12.2 ± 6.5 µM, 5.3 ± 1.9 µM, and 12.3 ± 3.1 µM, respectively. Compound 1 induced G1 phase cell cycle arrest in A2780 cells. Furthermore, compound 1 dose-dependently induced A2780 cells apoptosis as evidenced by Hoechst 33342 staining, Annexin V positive cells, the up-regulated cleaved-PARP and the enhanced Bax/Bcl-2 ratio. What’s more, compound 1 also promoted the expression of the tumor suppressor p53 protein. These findings indicate that cassane diterpenoids might have potential as anti-cancer agents, and further in vivo animal studies and structural modification investigation are needed.

Ophiopogon japonicus--A phytochemical, ethnomedicinal and pharmacological review

ETHNOPHARMACOLOGICAL RELEVANCE

Ophiopogonis Radix (Maidong in Chinese), the root of Ophiopogon japonicus, is widely used in local medicines of China, Japan and some south-eastern Asian countries. According to the traditional Chinese medicine (TCM) principle, Ophiopogonis Radix nourishes the yin, promotes body fluid production, moistens the lung, eases the mind and clears away heart fire. This review summarizes the achievements of the investigations in botany, phytochemistry, quality control, traditional uses, pharmacological activities and clinical studies on O. japonicus; this review also describes the shortcomings of studies on this herbal drug and thus serves as the basis of further scientific research and development of this traditional herbal drug.

MATERIALS AND METHODS

O. japonicus-related information was collected from various resources, including books on Chinese herbs and the Internet databases, such as Google Scholar, SciFinder, Web of Science, Elsevier, ACS, PubMed and China Knowledge Resource Integrated (CNKI).

RESULTS

O. japonicus is widely distributed in East Asia, especially in China. Numerous compounds were identified from this plant. The main components of O. japonicus include steroidal saponins, homoisoflavonoids and polysaccharides, which exhibited various pharmacological activities, such as cardiovascular protection, anti-inflammation, anticancer, anti-oxidation, immunomodulation, cough relief, antimicrobial, and anti-diabetes.

CONCLUSIONS

O. japonicus is a common traditional Chinese herbal drug used as the main ingredient in many prescriptions. Modern researches verified that O. japonicus can be used either as a healthy food or a therapeutic agent for disease prevention and treatment. The molecular mechanisms and chemical principles of this herbal medicine should be further explored.

Anti-proliferative activities of terpenoids isolated from Alisma orientalis and their structure-activity relationships

This study aimed to isolate terpenoids from Alisma orientalis (Sam.) Juzep. and elucidate their antiproliferative activities, as well as structure-activity relationships. Fourteen protostane-type triterpenoids were isolated from the rhizome of A. orientalis. Among these triterpenoids, alisol A (1), alisol A 24-acetate (2), alisol B (3), alisol B 23-acetate (4), and alisol G (8) presented inhibitory effects on cancer cell lines tested. Compounds 3 and 4 showed the highest potential; IC50 values for HepG2, MDA-MB-231, and MCF-7 cells were 16.28, 14.47, and 6.66 μM for 3 and 18.01, 15.97, and 13.56 μM for 4, respectively. Based on these results, we concluded that the degree of C-16 oxidation and the double bond between C-13 and C-17 may be significant in anti-proliferative activities. Further study showed that 3 and 4 effectively induced apoptosis, as confirmed by flow cytometry. Increased intracellular calcium concentration and endoplasmic reticulum stress were detected after treatment with 4 in HepG2 cells. Although compounds 1 and 2 induced minimal apoptosis, they evidently delayed the G2/M phase in HepG2 cells. Further study showed that 1-4 also enhanced LC3II expression, indicating autophagy is occured.

Chemical constituents from the heartwood of Haematoxylon campechianum as protein tyrosine kinase inhibitors

In a previous study, we showed that a series of homoisoflavonoids from the stems of Haematoxylon campechianum possess potent protein tyrosine kinase inhibitory activity. In a further chemical investigation of the heartwood of H. campechianum, three new homoisoflavonoids, epihematoxylol B (2), 10-O-methylhematoxylol B (3), and 10-O-methylepihematoxylol B (4), were isolated and identified, together with 15 known compounds, including three homoisoflavonoids, three flavonoids, six lignans, and three unsaturated fatty acids. The structures of the new compounds were established on the basis of 1D- and 2D-NMR and other spectroscopic analyses. Using ELISA method, the new compounds and selected known compounds were tested for protein tyrosine kinase inhibitory activity targeting kinase insert domain receptor. Epihematoxylol B (2) and the known compounds, hematoxylol B (1) and hematoxylin (5), exhibited inhibitory rates of 92.22.3, 71.31.1, and 94.81.6, respectively, at 10 μM concentration.

New insights into the anti-obesity activity of xanthones from Garcinia mangostana

This article reviews the anti-adipogenic, anti-inflammatory and antioxidant activities of xanthones from Garcinia mangostana.

Naturally occurring homoisoflavonoids and their pharmacological activities

Homoisoflavonoids, a special subclass of flavonoids, are rarely found in nature, mainly existing in Fabaceae and Asparagaceae families and being less common in Polygonaceae, Portulacaceae, Orchidaceae, and Gentianaceae families. Until now, approximately 240 natural occurring homoisoflavonoids have been identified from roots, barks, heartwood, bulbs, leaves, and seeds of the plants from the above mentioned families, which have often been used in traditional medicine. Homoisoflavonoids have been reported with a broad range of bioactivities, including anti-microbial, anti-mutagenic, anti-oxidant, immunomodulatory, anti-diabetic, cytotoxic, anti-angiogenic, vasorelaxant, and anti-inflammatory effects. To organize this review, the homoisoflavonoids were classified into five groups based on their structures: sappanin-type (I), scillascillin-type (II), brazilin-type (III), caesalpin-type (IV), and protosappanin-type (V). The structures of natural occurring homoisoflavonoids are described, and their proposed biosynthetic pathway and recent pharmacological studies are discussed. The main purpose of this review is to provide a comprehensive and up-to-date state of knowledge from phytochemical and pharmacological studies performed on homoisoflavonoids during the past decades. Homoisoflavonoids might have a large potential for further investigations of their bioactivities in order to identify important leads.

Knockdown of PU.1 AS lncRNA inhibits adipogenesis through enhancing PU.1 mRNA translation

PU.1 is an Ets family transcription factor involved in the myelo-lymphoid differentiation. We have previously demonstrated that PU.1 is also expressed in the adipocyte lineage. However, the expression levels of PU.1 mRNA and protein in preadipocytes do not match the levels in mature adipocytes. PU.1 mRNA level is higher in preadipocytes, whereas its protein is expressed in the adipocytes but not in the preadipocytes. The underlying mechanism remains elusive. Here, we find that miR-155 knockdown or overexpression has no effect on the levels of PU.1 mRNA and protein in preadipocytes or adipocytes. MiR-155 regulates adipogenesis not through PU.1, but via C/EBPβ which is another target of miR-155. We also checked the expression levels of PU.1 mRNA and antisense long non-coding RNA (AS lncRNA). Interestingly, compared with the level of PU.1 mRNA, the level of PU.1 AS lncRNA is much higher in preadipocytes, whereas it is opposite in the adipocytes. We further discover that PU.1 AS lncRNA binds to its mRNA forming an mRNA/AS lncRNA compound. The knockdown of PU.1 AS by siRNA inhibits adipogenesis and promotes PU.1 protein expression in both preadipocytes and adipocytes. Furthermore, the repression of PU.1 AS decreases the expression and secretion of adiponectin. We also find that the effect of retroviral-mediated PU.1 AS knockdown on adipogenesis is consistent with that of PU.1 AS knockdown by siRNA. Taken together, our results suggest that PU.1 AS lncRNA promotes adipogenesis through preventing PU.1 mRNA translation via binding to PU.1 mRNA to form mRNA/AS lncRNA duplex in preadipocytes.

Rapid structural determination of alkaloids in a crude extract of Stemona saxorum by high-performance liquid chromatography/electrospray ionization coupled with tandem mass spectrometry

The electrospray ionization (ESI) mass spectrometric behavior of five Stemona alkaloids, stemokerrin, oxystemokerrin, oxystemokerrilactone, oxystemokerrin N-oxide and stemokerrin N-oxide, was studied using an ESI tandem mass technique (MS(n)). These compounds, isolated from Stemona saxorum endemic in Vietnam, represent a class of alkaloids containing a pyrido[1,2-a]azepine A,B-ring core with a 1-hydroxypropyl side chain attached to C-4. Their fragmentation pathways were elucidated by ESI-MS(n) results and the elemental composition of the major product ions was confirmed by accurate mass measurement. In order to rationalize some fragmentation pathways, the relative Gibbs free energies of some product ions were estimated using the B3LYP/6-31+G(d) method. Based on the ESI-MS(n) results of five reference compounds, a reversed-phase high-performance liquid chromatography with tandem mass spectrometry (RP-HPLC/MS(n)) method was developed for the characterization of Stemona alkaloids with a pyrido[1,2-a]azepine A,B-ring core from the extract of S. saxorum. A total of 41 components were rapidly identified or tentatively characterized, of which 12 compounds were identified as Stemona alkaloids with a pyrido[1,2-a]azepine A,B-ring core, including four new compounds. This method is convenient and sensitive, especially for minor components in complex natural product extracts.

Naturally occurring homoisoflavonoids function as potent protein tyrosine kinase inhibitors by c-Src-based high-throughput screening

Protein tyrosine kinase (PTK) inhibitors represent emerging therapeutics for cancer chemoprevention. In our study, hematoxylin (26) was identified as one of the most remarkable c-Src inhibitors in an orthogonal compound-mixing library (32200 compounds) by using an ELISA-based automated high-throughput screening (HTS) strategy. Interestingly, hematoxylin was found to be an ATP competitive broad-spectrum PTK inhibitor in vitro, with IC50 values ranging from nanomolar to micromolar level. Further studies showed that such inhibition was associated with the PTK phosphorylation and subsequent downstream signaling pathways. The structure-activity relationship assessment of the PTK inhibitory potency of hematoxylin analogues isolated from Heamatoxylon campechianum was in good agreement with the result of concurrent molecular docking simulation: the catechol moiety in ring A and the hematoxylin-like three-dimensional structure were essential for c-Src-targeted activities. Hematoxylin and its natural analogues were substantially validated to function as a new class of PTK inhibitors.

Antitussive stemoninine alkaloids from the roots of Stemona tuberosa

Investigation of the roots of Stemona tuberosa afforded five minor constituents, stemoenonine (1), 9a- O-methylstemoenonine (2), oxystemoenonine (3), 1,9a- seco-stemoenonine (4), and oxystemoninine (5), along with the known compound stemoninoamide (6). Their structures were elucidated by 1D and 2D NMR spectra and other spectroscopic studies. Alkaloids 1, 2, and 6, as well as the representative stemoninine-type alkaloid, stemoninine (7), were screened for antitussive activity in the citric acid-induced guinea pig cough model. Compounds 6 and 7 exhibited strong antitussive activity after oral and intraperitoneal administrations.

Terpenoids from the stems of Cipadessa baccifera

In our systematical investigation on Chinese Meliaceae plants, the stems of Cipadessa baccifera collected in Yunnan province were studied. Two new tetranortriterpenoids, cipadessalide ( 1) and rubralin D ( 2), one new pregnane, 3beta,4beta-dihydroxy-2beta-acetoxypregnan-16-one ( 3), and two new sesquiterpenoids, bacciferins A ( 4) and B ( 5), along with 10 known compounds were isolated. Their structures were elucidated by 1D and 2D NMR spectra and other spectroscopic studies, as well as chemical conversion.

Antibacterial stilbenoids from the roots of Stemona tuberosa

Twelve dihydrostilbenes, stilbostemins N-Y (1-12), and a phenanthraquinone, stemanthraquinone (13), were isolated and identified from roots of Stemona tuberosa, along with five known dihydrostilbenes. Their structures were established on the basis of 1D and 2D NMR and other spectroscopic analyses. Dihydrostilbene 8 exhibited strong activity against Bacillus pumilus (MIT 12.5-25 microg/mL). Many tested compounds exhibited moderate antibacterial activities.