New phenylbutenoids and terpene glycosides from Ginkgo biloba leaves.

Our continued works on the chemical constituents of Ginkgo biloba (G. biloba) leaves has led to the isolation of two novel phenylbutenoids (1, 2), along with five previously unidentified terpene glycosides (3-7). Among them, compounds 1 and 2 represent unique (Z)-phenylbutenoids, 3-6 are megastigmane glycosides, and 7 is identified as a rare bilobanone glycoside (Fig. 1). This study marks the first reported isolation of phenylbutenoid and bilobanone glycoside from G. biloba. The chemical structures of these compounds were elucidated through extensive spectroscopic analysis, including HR-ESI-MS and various 1D and 2D NMR experiments. Furthermore, the absolute configurations of these molecules were determined using Mosher's method, ECD experiments, and Cu-Kα X-ray crystallographic analyses.

Vlasouliodes A-D, four new C30 dimeric sesquiterpenes exhibiting potential inhibition of MCF-7 cells from Vladimiria souliei.

As our ongoing interest to search bioactive dimeric sesquiterpenes from the genus Vladimiria (Asteraceae), the plant of Vladimiria souliei was studied. Based on the repetitive chromatographic fractionation, a chemical investigation on the roots of Vladimiria souliei led to the isolation and the identification of four previously undescribed sesquiterpene dimers, vlasouliodes A-D (1-4). Their chemical structures were elucidated by comprehensive analysis of spectroscopic data, including HRESIMS, 1D and 2D NMR spectroscopic data. The absolute configurations of them were unambiguously established by the experimental and calculated ECD data. In the in vitro biological activity evaluation, 1 and 3 displayed pronounced inhibitory activity against human breast adenocarcinoma cell lines (MCF-7) with IC50 values of 17.12 ± 0.42 µM and 13.12 ± 0.10 µM, respectively. Additionally, treatment with 1 and 3 induced cell apoptosis in MCF-7 cells, down-regulated the expression of Caspase-3 and up-regulated the expression of Cleaved-caspase-3.

Discovery of naturally occurring inhibitors against SARS-CoV-2 3CLpro from Ginkgo biloba leaves via large-scale screening.

3-Chymotrypsin-like protease (3CLpro) is a virally encoded main proteinase that is pivotal for the viral replication across a broad spectrum of coronaviruses. This study aims to discover the naturally occurring SARS-CoV-2 3CLpro inhibitors from herbal constituents, as well as to investigate the inhibitory mechanism of the newly identified efficacious SARS-CoV-2 3CLpro inhibitors. Following screening of the inhibitory potentials of eighty herbal products against SARS-CoV-2 3CLpro, Ginkgo biloba leaves extract (GBLE) was found with the most potent SARS-CoV-2 3CLpro inhibition activity (IC50 = 6.68 µg/mL). Inhibition assays demonstrated that the ginkgolic acids (GAs) and the bioflavones isolated from GBLE displayed relatively strong SARS-CoV-2 3CLpro inhibition activities (IC50 < 10 µM). Among all tested constituents, GA C15:0, GA C17:1 and sciadopitysin displayed potent 3CLpro inhibition activities, with IC50 values of less than 2 µM. Further inhibition kinetic studies and docking simulations clearly demonstrated that two GAs and sciadopitysin strongly inhibit SARS-CoV-2 3CLprovia a reversible and mixed inhibition manner. Collectively, this study found that both GBLE and the major constituents in this herbal product exhibit strong SARS-CoV-2 3CLpro inhibition activities, which offer several promising leading compounds for developing novel anti-COVID-19 medications via targeting on 3CLpro.

Identification and Characterization of Chalcone Isomerase Genes Involved in Flavonoid Production in Dracaena cambodiana.

Dragon's blood is a traditional medicine in which flavonoids are the main bioactive compounds; however, the underlying formation mechanism of dragon's blood remains largely poorly understood. Chalcone isomerase (CHI) is the key enzyme in the flavonoid biosynthesis pathway. However, CHI family genes are not well understood in Dracaena cambodiana Pierre ex Gagnep, an important source plant of dragon's blood. In this study, 11 CHI family genes were identified from D. cambodiana, and they were classified into three types. Evolutionary and transcriptional profiling analysis revealed that DcCHI1 and DcCHI4 might be involved in flavonoid production. Both DcCHI1 and DcCHI4 displayed low expression levels in stem under normal growth conditions and were induced by methyl jasmonate (MeJA), 6-benzyl aminopurine (6-BA, synthetic cytokinin), ultraviolet-B (UV-B), and wounding. The recombinant proteins DcCHI1 and DcCHI4 were expressed in Escherichia coli and purified by His-Bind resin chromatography. Enzyme activity assay indicated that DcCHI1 catalyzed the formation of naringenin from naringenin chalcone, while DcCHI4 lacked this catalytic activity. Overexpression of DcCHI1 or DcCHI4 enhanced the flavonoid production in D. cambodiana and tobacco. These findings implied that DcCHI1 and DcCHI4 play important roles in flavonoid production. Thus, our study will not only contribute to better understand the function and expression regulation of CHI family genes involved in flavonoid production in D. cambodiana but also lay the foundation for developing the effective inducer of dragon's blood.

Five new C17/C15 sesquiterpene lactone dimers from Carpesium abrotanoides.

Five new unusual C17/C15 sesquiterpene lactone dimers, carabrodilactones A-E (1-5), along with four known common C15/C15 SLDs, carpedilactones A and B (6 and 7), faberidilactone A (8), and faberidilactone C (9), were isolated from the whole plants of Carpesium abrotanoides. The structures of 1-5 featured a flexible C-11/C-13' linked single bond between two sesquiterpene units and a tailed acetyl connected to the C-13 position. The preferential conformation of 1-5 was elucidated by the diagnostic NMR data of geminal proton of H-13. The biogenetic pathway of 1-5 was proposed to involve Stetter and Michael addition reactions. In addition, compound 1 exhibited significant cytotoxicities against the four cell lines (A549, HCT116, MDA-MB, and BEL7404 cells) with IC50 value in the range of 3.08-8.05 µM, while compounds 2-5 showed weak cytotoxicities.

Triterpenoid saponins from the roots of Psammosilene tunicoides.

Seven oleanane-type triterpenoid saponins, tunicosaponins B-D (1-3), F-I (4-7), along with eight known triterpenoid saponins (8-15), were isolated from the roots of Psammosilene tunicoides. The structures of compounds 1-7 were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and chemical methods. Triterpene glycosides have been considered as major active constituents of P. tunicoides. This work provides a more complete insight into the saponin constituents of P. tunicoides.

A new bilobalide isomer and two cis-coumaroylated flavonol glycosides from Ginkgo biloba leaves.

A new bilobalide isomer (1), together with two flavonol glycosides (2, 3), have been isolated and elucidated from the extract of Ginkgo biloba leaves. Significantly, 1 was a new sesquiterpene lactone with two lactone ring groups, both 2 and 3 were two flavonol glycosides with a same cis-coumaroylated fragment. Their chemical structures were elucidated by NMR and MS spectroscopic date and the absolute configuration of 1 was specific established by Cu-Kα X-ray crystallographic analyses. However, 1-3 showed no obvious anti-platelet aggregation activity.

Lineariifolianoids M-O, three rare sesquiterpene lactone dimers inhibiting NO production from Inula lineariifolia.

Three rare squiterpene lactone dimers lineariifolianoids M-O (1-3) were isolated from Inula lineariifolia for the first time. Their structures and absolute configuration were established on the basis of by NMR and MS spectroscopic data and X-ray crystallography. Furthermore, those three compounds exhibited significant inhibitory activity against LPS-induced NO production in RAW 264.7 macrophages with IC50 values of 1.421, 1.087 and 1.243 µM, respectively.

Identification of Carpesium cernuum extract as a tumor migration inhibitor based on its biological response profiling in breast cancer cells.

BACKGROUND: Breast cancer is one of the most lethal cancers in women when it reaches the metastatic stage. The plant Carpesium cernuum has been used as an anti-inflammatory, analgesic, and detoxifying agent in Chinese folk medicine. However, the inhibitory activity and molecular mechanisms of Carpesium cernuum in breast cancer cells have not been investigated. METHODS: RNA sequencing experiments were performed to elucidate the cellular pathways affected by Carpesium cernuum extract (CCE). Cell viability and EdU incorporation assays were conducted to determine the effect of CCE on cell proliferation. The inhibitory effects of CCE on the expression levels of target genes were confirmed by qRT-PCR and Western blot. Cell migration and invasion were analysed with transwell chamber assays. RESULTS: Proliferation assays indicated that CCE inhibited cell proliferation in multiple cancer cell lines and the IC50 value of CCE was the smallest in MDA-MB-231 cells. Transcriptome analysis showed that CCE significantly affected the cell adhesion pathway. Further experiments revealed that CCE suppressed cell migration and invasion. The inhibitory effect on migration was likely mediated by targeting TIMP1, MMP9, CD44 and COL4A2. The main active components of CCE were isolated, and CCE-derived sesquiterpene lactone substances could reproduce the inhibitory effect of CCE on cell migration and invasion. CONCLUSIONS: Overall, both molecular and phenotypic assays showed that CCE has potential in the treatment of breast cancer, especially for the treatment of breast cancer metastasis. CCE-derived sesquiterpene lactone substances are the foundation for the tumor inhibitory effect of CCE.

Hybrid multidimensional data acquisition and data processing strategy for comprehensive characterization of known, unknown and isomeric compounds from the compound Dan Zhi Tablet by UPLC-TWIMS-QTOFMS.

The compound Dan Zhi Tablet (DZT), a reputable traditional Chinese medicine prescription, is widely used for the treatment of ischemic stroke in clinic. However, its systematic chemical constituents have rarely been elucidated, which hampers its quality evaluation, the study of bioactive constituents and the mechanism of action interpretation. In this study, we developed a combination of multidimensional data acquisition and data processing strategy with the aim to globally and comprehensively identify the chemical constituents in DZT based on UPLC-TWIMS-QTOFMS. First, multidimensional acquisition modes (MSE, Fast DDA and HDMSE) were performed on UPLC-TWIMS-QTOFMS. Second, targeted characterizations of the known compounds and their analogues present in DZT were carried out on the basis of the corresponding commercial standards or Mass2Motifs. Third, untargeted identification of unknown compounds in DZT was performed by extracting shared Mass2Motifs from the raw fragmentation spectra. Finally, the coeluting isomers were characterized using a precursor and/or product ion mobility. Consequently, 202 compounds were detected from DZT: 29 of them were unambiguously identified by comparison with reference compounds, 29 unknown compounds were discovered in specific medicinal materials, and ten pairs of coeluting isomers, which could not be distinguished using conventional MSE or Fast-DDA, were resolved using HDMSE only. This strategy was successfully used for the rapid and global identification of complex compounds including known, unknown and coeluting isomeric compounds in DZT and provided helpful chemical information for further quality control, pharmacology and active mechanism research on DZT.

Metabolite profiling of traditional Chinese medicine formula Dan Zhi Tablet: An integrated strategy based on UPLC-QTOF/MS combined with multivariate statistical analysis.

Metabolites derived from traditional Chinese medicine (TCM) are becoming active substances of pharmacologically as well as promising sources for discovering new drugs. However, detection and identification of constituents in vivo remains a challenge for TCM, due to massive endogenous interference and low abundance of metabolites in biological matrix. Traditional Chinese medicine formula Dan Zhi Tablet (DZT), a well-established TCM formula developed based on years of clinical experiences, was widely used to treat cerebral infraction disease. In this study, an integrated strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was adopted to comprehensively identify the prototype and metabolite constituents of DZT. The potential constituents were screened by cross orthogonal partial least-squares discriminant analysis (OPLS-DA). Automatic matching analysis was performed on UNIFI platform based on the function of predicting metabolites. Using this strategy, a total of 170 compounds, including 51 prototype constituents and 119 metabolites were unambiguously or tentatively identified in rat plasma. Furthermore, 31 compounds have also been detected in rat cerebrospinal fluid. The metabolism reactions included phase I reactions (hydroxylation, hydrolysis, deglycosylation, hydrogenation, demethylation and dehydroxylation) and phase II reactions (conjugation with glutatione, cysteine, acetylcysteine, glucuronide, sulfate). It is the first systematic metabolic study of DZT in vivo and some metabolites were also reported for the first time, which could provide a scientific basis for explaining the multiple functions of DZT. More importantly, the integrated strategy also shows promising perspectives in the identification of the metabolites in TCM from a complicated biological matrix.

Podocarpane trinorditerpenes from Celastrus angulatus and their biological activities.

Five new podocarpane trinorditerpenes (1-5) and a dimeric trinorditerpene with an unprecedented skeleton bearing a 1,4-benzodioxane moiety (6) along with seven known compounds (7-13) were isolated from the stems of Celastrus angulatus (Celastraceae). These compounds' structures were elucidated by comprehensive spectroscopic analysis. In addition, the absolute configuration of 1 was determined by single crystal X-ray diffraction analysis. Compounds 3, 4, 7, and 12 exhibited moderate inhibitory activity against LPS-induced NF-κB activation in murine macrophage RAW264.7 cells at IC50 values of 25.08, 18.64, 15.33 and 3.89 µM, respectively. However, compound 6 exhibited potent cytotoxicity against the A549 and MDA-MB-231 human tumour cell lines with IC50 values of 4.47 µM and 5.86 µM, respectively. Compound 9 exhibited potent cytotoxicity against the HCT116 and BEL7404 human tumour cell lines with IC50 values of 6.77 µM and 9.45 µM, respectively.

New chromane and chromene meroterpenoids from flowers of Rhododendron rubiginosum Franch. var. rubiginosum.

Six new chromane and chromene meroterpenoids rubiginosins A-F (1-2, and 4-7), together with three known ones, rubiginosin G (3) and anthopogochromenes A and B (8-9),were isolated from the flowers of Rhododendron rubiginosum Franch. var. rubiginosum. Among them, 1-4 were the chromane ones derived from an intramolecular [2 + 2] cycloaddition of their respective chromene precursors, making a 6/6/6/4- or 6/6/5/4-ring fused scaffold. The absolute configuration of the chiral center at C-2 of 1-9 was determined as S by chromane/chromene helicity rule and X-ray crystallograph. Notably, more attention should be paid to 6-carboxyl derivatives, since the 6-carboxyl derivatives showed an abnormal diagnostic Cotton effect (CE) with respect to their normal diagnostic CE. Compounds 1-9 were tested for cytotoxicity against four cell lines (A549, HCT116, SK-HEP-1, and HL-60), and only 1, 3, 5, and 9 showed moderate cytotoxicity, while others were inactive, discovering the 6-carboxyl is crucial for their low cytotoxicity.

[Chemical constituents from ethyl acetate-soluble extraction of Valeriana jatamansi].

Application of a combination of various chromatographic techniques including column chromatography over silica gel, Sephadex LH-20, macroporous adsorbent resin, and reversed-phase HPLC, led to the isolation of 173 compounds including irdidoids, monoterpenes, sesquiterpenes, triterpenes, lignans, flavonoids, and simple aromatic derivatives from the ethyl acetate-soluble fraction of the whole plants of Valeriana jatamansi(Valerianaceae), and their structures were elucidated by spectroscopic methods including 1D, 2D NMR UV, IR, and MS techniques. Among them, 77 compounds were new. In previous reports, we have described the isolation, structure elucidation, and bioactivities of 68 new and 25 known compounds. As a consequence, we herein reported the isolation and structure elucidation of the remaining 9 new and 71 known compounds, the structure revision of valeriotriate A(8a), as well as cytotoxicity of some compounds.

Five rare C32 sesquiterpene lactone dimers with anti-inflammation activity from Vladimiria souliei.

Five rare sesquiterpene lactone dimers, vlasouliolides E-I, were isolated from Vladimiria souliei. Their chemical structures were elucidated by spectroscopic analysis. Furthermore, 2 and 4 were unambiguously confirmed by Cu-Kα X-ray crystallographic analysis. Compounds 1, 2, 4 and 5 exhibited significant anti-inflammatory activity against LPS-induced NO production in RAW 264.7 cells with IC50 values of 1.88, 4.89, 7.24 and 2.46µM, respectively. Additionally, compounds 1 and 2 were revealed with potent inhibitory activity of the phosphorylation progress of NF-κB P65.

Identification, characterization and expression analysis of genes involved in steroidal saponin biosynthesis in Dracaena cambodiana.

Dracaena cambodiana is a traditional medicinal plant used for producing dragon's blood. The plants and dragon's blood of D. cambodiana contain a rich variety of steroidal saponins. However, little is known about steroidal saponin biosynthesis and its regulation in D. cambodiana. Here, 122 genes encoding enzymes involved in steroidal saponin biosynthesis were identified based on transcriptome data, with 29 of them containing complete open reading frames (ORF). Transcript expression analysis revealed that several genes related to steroidal saponin biosynthesis showed distinct tissue-specific expression patterns; the expression levels of genes encoding the key enzymes involved in the biosynthesis and early modification of steroidal saponins were significantly down-regulated in the stems in response to the inducer of dragon's blood, exhibiting positive correlations with the content of steroidal saponins. These results provide insights on the steroidal saponins biosynthetic pathway and mechanisms underlying induced formation of dragon's blood in D. cambodiana.

Identification of 11(13)-dehydroivaxillin as a potent therapeutic agent against non-Hodgkin's lymphoma.

Despite great advancements in the treatment of non-Hodgkin lymphoma (NHL), sensitivity of different subtypes to therapy varies. Targeting the aberrant activation NF-κB signaling pathways in lymphoid malignancies is a promising strategy. Here, we report that 11(13)-dehydroivaxillin (DHI), a natural compound isolated from the Carpesium genus, induces growth inhibition and apoptosis of NHL cells. Multiple signaling cascades are influenced by DHI in NHL cells. PI3K/AKT and ERK are activated or inhibited in a cell type dependent manner, whereas NF-κB signaling pathway was inhibited in all the NHL cells tested. Applying the cellular thermal shift assay, we further demonstrated that DHI directly interacts with IKKα/IKKß in NHL cells. Interestingly, DHI treatment also reduced the IKKα/IKKß protein level in NHL cells. Consistent with this finding, knockdown of IKKα/IKKß inhibits cell proliferation and enhances DHI-induced proliferation inhibition. Overexpression of p65, p52 or RelB partially reverses DHI-induced cell growth inhibition. Furthermore, DHI treatment significantly inhibits the growth of NHL cell xenografts. In conclusion, we demonstrate that DHI exerts anti-NHL effect in vitro and in vivo, through a cumulative effect on NF-κB and other pathways. DHI may serve as a promising lead compound for the therapy of NHL.

A Natural CCR2 Antagonist Relieves Tumor-associated Macrophage-mediated Immunosuppression to Produce a Therapeutic Effect for Liver Cancer.

Hepatocellular carcinoma (HCC) is a common malignant tumor in the digestive tract with limited therapeutic choices. Although sorafenib, an orally administered multikinase inhibitor, has produced survival benefits for patients with advanced HCC, favorable clinical outcomes are limited due to individual differences and resistance. The application of immunotherapy, a promising approach for HCC is urgently needed. Macrophage infiltration, mediated by the CCL2/CCR2 axis, is a potential immunotherapeutic target. Here, we report that a natural product from Abies georgei, named 747 and related in structure to kaempferol, exhibits sensitivity and selectivity as a CCR2 antagonist. The specificity of 747 on CCR2 was demonstrated via calcium flux, the binding domain of CCR2 was identified in an extracellular loop by chimera binding assay, and in vivo antagonistic activity of 747 was confirmed through a thioglycollate-induced peritonitis model. In animals, 747 elevated the number of CD8+ T cells in tumors via blocking tumor-infiltrating macrophage-mediated immunosuppression and inhibited orthotopic and subcutaneous tumor growth in a CD8+ T cell-dependent manner. Further, 747 enhanced the therapeutic efficacy of low-dose sorafenib without obvious toxicity, through elevating the numbers of intra-tumoral CD8+ T cells and increasing death of tumor cells. Thus, we have discovered a natural CCR2 antagonist and have provided a new perspective on development of this antagonist for treatment of HCC. In mouse models of HCC, 747 enhanced the tumor immunosuppressive microenvironment and potentiated the therapeutic effect of sorafenib, indicating that the combination of an immunomodulator with a chemotherapeutic drug could be a new approach for treating HCC.

Chlorajaponols A-F, sesquiterpenoids from Chloranthus japonicus and their in vitro anti-inflammatory and anti-tumor activities.

Two new eudesmane sesquiterpenoids, chlorajaponols A-B (1-2), two new guaiane sesquiterpenoids, chlorajaponols C-D (3-4), a new germacrane sesquiterpenoid, chlorajaponol E (5), and a new lindenane sesquiterpenoid, chlorajaponol F (6), along with 8 known sesquiterpenoids and 6 known disesquiterpenoids, were isolated from the whole plant of Chloranthus japonicus. Their structures were established by extensive analysis of NMR spectroscopic data in combination with mass spectrometry. The structures of compounds 1-4 were confirmed by single crystal X-ray diffraction (CuKα radiation). The possible biogenetic pathways of compounds 1-6 were discussed. Chlorajaponol B (2) showed significant inhibition against nitric oxide (NO) release in LPS-induced RAW264.7 macrophages with the IC50 value of 9.56±0.71µM, comparable to that of positive control amino guanidine (8.50±0.35µM). Shizukaol C (18) strongly suppressed the proliferation of three human tumor cell lines MGC803, HepG2, and HL-60 with IC50 values of 4.60±1.05µM, 3.17±0.66µM, and 1.57±0.27µM, respectively.

Total sesquiterpene lactones prepared from Inula helenium L. has potentials in prevention and therapy of rheumatoid arthritis.

BACKGROUNDS: Inula helenium L. is an herb with anti-inflammatory properties. Sesquiterpene lactones (SLs), mainly alantolactone (AL) and isoalantolactone (IAL), are considered as its active ingredients. However, the anti-inflammatory effects of SL-containing extracts of I. helenium have not been explored. Here we prepared total SLs from I. helenium (TSL-IHL), analyzed its chemical constituents, and performed cellular and animal studies to evaluate its anti-inflammatory activities. MATERIALS AND METHODS: The chemical profile of TSL-IHL was analyzed by HPLC-UV. Its in vitro effects on the activation of signaling pathways and expression of inflammatory genes were examined by western blotting and quantitative real-time PCR, respectively, and compared with those of AL and IAL. Its in vivo anti-inflammatory effects were evaluated in adjuvant- and collagen-induced arthritis rat models. RESULTS: Chemical analysis showed that AL and IAL represent major constituents of TSL-IHL. TSL-IHL, as well as AL and IAL, could inhibit TNF-α-induced activation of NF-κB and MAPK pathways in b. End3 cells, suppress the expressions of MMP-3, MCP-1, and IL-1 in TNF-α-stimulated synovial fibroblasts, and IL-1, IL-6, and iNOS in LPS-activated RAW 264.7 cells in a dose-dependent manner in the range of 0.6-2.4µg/mL. Oral administration of TSL-IHL at 12.5-50mg/kg could dose-dependently alleviate the arthritic severity and paw swelling in either developing or developed phases of arthritis of rats induced by adjuvant or collagen CONCLUSIONS: These results indicated potentials of TSL-IHL in prevention and therapy of rheumatoid arthritis.