Alkaloids from Corydalis saxicola and their antiproliferative activity against cancer cells.

Eight undescribed alkaloids named corydalisine D-K (1-7), including one isoquinoline benzopyranone alkaloid (1), one benzocyclopentanone alkaloid (2), four benzofuranone alkaloids (3, 4, and 5a/5b) and two protoberberine alkaloids (6 and 7), along with fourteen known ones, were isolated from the Corydalis saxicola. Their structures, including absolute configurations, were unambiguously identified using spectroscopic techniques, single-crystal X-ray diffraction and electron circular dichroism calculation. Compounds 2, 14 and 21 exhibit antiproliferative activity against five cancer cell lines. The aporphine alkaloid demethylsonodione (compound 14), which exhibited the best activity (IC50 = 3.68 ± 0.25 µM), was subjected to further investigation to determine its mechanism of action against the T24 cell line. The molecular mechanism was related to the arrest of cell cycle S-phase, inhibition of CDK2 expression, accumulation of reactive oxygen species (ROS), induction of cell apoptosis, inhibition of cell migration, and activation of p38 MAPK signaling pathway. The results indicated that 14 could be used as a potential candidate agent for further development of anti-bladder transitional cell carcinoma.

Foegraecumoside O and P, a Pair of Triterpenoid Saponins with a 4/5/6 Fused Tricyclic Oleanane Carbon Skeleton from Lysimachia foenum-graecum Hance.

Lysimachia foenum-graecum Hance (Primulaceae) is a medicinal plant used for cold, pain, ascariasis, etc., in China. Triterpenoid saponins have been found to be the main components of this genus. In this work, a pair of oleanane-type triterpenoid saponins with an unprecedented 4/5/6 fused tricyclic skeleton, foegraecumoside O (1) and foegraecumoside P (2) were isolated from the butanol fraction of the aerial parts of L. foenum-graecum. Their structures were determined using chemical methods and extensive spectroscopic analyses, along with quantum chemical calculations. Compound 2 displayed moderate cytotoxicity against HepG2, MGC-803, T24, NCI-H460, A549, and A549/CDDP (drug-resistant lung-cancer cell line) with IC50 at 12.4-19.2 µM in an MTT assay, comparing with the positive control doxorubicin, which had IC50 at 0.53-4.92 µM, but was inactive for A549/CDDP. Furthermore, a possible biosynthetic pathway for forming compounds 1 and 2 was proposed.

Structurally diverse isobutylamides from Zanthoxylum nitidum.

Five pairs of new racemic alkamides (1a/1b and 4a/4b-7a/7b) and two new achiral derivatives (2-3), as well as five known ones (8-12), were purified from the 95% EtOH extract of Zanthoxylum nitidum. Their structures were elucidated based on spectroscopic analyses (NMR and HR-ESI-MS), electronic circular dichroism (ECD) and NMR calculations. The enantiomeric separation was successfully achieved by chiral-phase HPLC-ECD measurements. Among all the isolates, compounds 2, 3, and 10 showed inhibitory effects against five human cancer cell lines, with IC50 values in range of 18.51-48.03 µM.

New alkaloids and their in vitro antitumor activity of Corydalis balansae.

The chemical investigation on Corydalis balansae resulted in the isolation of three previous undescribed compounds (1, 10, and 11) and 17 known compounds. Compound 1 and 2 were obtained as two lignanamide dimers, and compound 11 had a spiro [benzofuranone-benzazepine] skeleton, which was found in Corydalis for the first time. The structures of new compound were determined by the detailed analysis of 1D/2D NMR, UV, and IR data. Absolute configurations of compounds 10 and 11 were defined by their crystal X-ray diffraction data and calculations of electronic circular dichroism (ECD). The CCK-8 method was used to assay the inhibition effect of all the compounds on the growth of Hela, MGC-803, A549, and HepG2 cancer cells. Compound 2, 13, and 14 showed moderate inhibitory activity against the tested cell lines. Compound 2 exhibited potential antitumor activity against MGC-803 cells with an IC50 value of 20.8 µM, while the positive control etoposide was 17.3 µM. Furthermore, results from the cellular-mechanism investigation indicated that compound 2 could induce S-phase cell-cycle arrest and MGC-803 cells apoptosis, which was triggered by the up-regulation of PARP1, caspase-3 and -9, Bax, and down-regulation of Bcl-2. The 2-induced strong apoptosis indicated that compound 2 had good potential as an antitumor lead compound.

Four New Sesquiterpenoids from Zanthoxylum nitidum.

Zanthoxylum nitidum (Roxb.) DC., is one of Guangxi's characteristic national medicines, and is the classic Laoban medicine of Yao people "Ru Shan Hu" and Zhuang medicine "Liang Bei Zhen". It has been used as an anti-inflammatory, analgesic and haemostatic medicine for thousands of years. In this study, four new sesquiterpenoids (1-4), along with six previously described coumarins (5-10), were isolated from 95 % EtOH extract of Zanthoxylum nitidum. Comprehensive spectroscopic analyses (NMR and HR-ESI-MS) were used to elucidate the structures of these isolates. The absolute configurations of nitidumine A-D (1-4) were established by electronic circular dichroism (ECD). Their cytotoxicity of all the isolates against five cancer cell lines (T24, HeLa, MGC-803, A549, and HepG2) was evaluated by MTT experiment and found not to be cytotoxicity.

Pentagalloylglucose suppresses the growth and migration of human nasopharyngeal cancer cells via the GSK3ß/ß-catenin pathway in vitro and in vivo.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a type of malignant squamous cell tumour originating from the nasopharynx epithelium. Pentagalloylglucose (PGG) is a natural polyphenolic compound that exerts anticancer effects in many types of tumours. However, the role and underlying mechanism of PGG in NPC cells have not been fully defined. PURPOSE: This study aimed to investigate the anticancer activity of PGG as well as the potential mechanism in NPC cells. METHODS: The effects of PGG on the proliferation, apoptosis and cell cycle distribution of CNE1 and CNE2 cells were assessed by MTT and flow cytometry assays. Cell migration was evaluated using wound healing and transwell assays. The expression of microtubule-associated protein 1 light chain 3 beta (LC3B) was observed by immunofluorescence staining. Western blotting was used to explore the levels of related proteins and signalling pathway components. Furthermore, the effects of PGG on NPC cell growth were analysed in a xenograft mouse model in vivo using cisplatin as a positive control. RESULTS: PGG dose-dependently inhibited the proliferation of CNE1 and CNE2 cells. PGG regulated the cell cycle by altering p53, cyclin D1, CDK2, and cyclin E1 protein levels. PGG induced apoptosis and autophagy in NPC cells and elevated the Bax/Bcl-2 ratio and the protein levels of LC3B. Moreover, PGG decreased NPC cell migration by increasing E-cadherin and decreasing N-cadherin, vimentin and CD44 protein levels. Mechanistically, PGG treatment downregulated p-mTOR and ß-catenin expression but upregulated p-p38 MAPK and p-GSK3ß expression. In addition, PGG significantly inhibited NPC cell tumour growth and lung metastasis in vivo. CONCLUSION: PGG may suppress cell proliferation, induce apoptosis and autophagy, and decrease the metastatic capacity of NPC cells through the p38 MAPK/mTOR and Wnt/ß-catenin pathways. The present study provides evidence for PGG as a potential therapy for NPC.

New enantiomeric lignans and new meroterpenoids with nitric oxide release inhibitory activity from Piper puberulum.

Six new lignans with various type of linkage between two C6-C3 fragments (1a, 1b, 2a, 2b, 3, 4), two new meroterpenoids (5, 6) and 24 known compounds (7-30) were isolated from an EtOH extract of the stems and leaves of Piper puberulum. The absolute configurations of enantiomers 1a and 1b were determined by single-crystal X-ray diffraction analysis, 2a and 2b were determined by comparing their calculated and experimental ECD spectra. Biogenetically, all the new lignans may come from the polymerization of two molecules of hydroxychavicol (30). In the anti-neuroinflammation activity assay, the IC50 values of fifteen compounds were lower than those of the positive control minocycline, and compound 1a showed good activity, but its enantiomer 1b showed no activity. Compound 1a have notable anti-neuroinflammatory activity, and can significantly decrease mRNA levels of proinflammatory cytokines (IL-1ß, IL-6, TNF-α) in a dose-dependent manner.

Acetylated Rhamnose Triterpenoid Saponins from Glechoma longituba Analyzed by LC-Q-TOFMS.

The aim of the present work is to isolate a series of triterpene derivatives with rhamnosyl linking acetyl groups from Glechoma longituba according to the structural characteristics of previously described triterpene saponins. The extract ion chromatography spectrum of the crude extract of G. longituba was detected and analyzed by HPLC-HR-ESI-MS to determine possible components, and these metabolites were traced and separated by combining high-resolution mass spectrometry and predicted liquid chromatography retention time. Three 11α, 12α-epoxypentacyclic oleanolic acid triterpene saponins (glechomanosides H-J) and one ursane triterpene aldehyde saponin with a C-28 aldehyde group were isolated from G. longituba. The structure of these compounds was confirmed by NMR and compared with those of previously characterized compounds. The strategy described in this report enables a rapid, reliable, and complete analysis of glycoside compounds containing different numbers of acetyl groups at different positions on the sugar.

The neurotrophic and antineuroinflammatory effects of phenylpropanoids from Zanthoxylum nitidum var. tomentosum (Rutaceae).

Three novel lignans (1, 5 and 6) and two novel quinic acids (16 and 17) along with 15 known phenylpropanoids were obtained from the ethanol extract of Zanthoxylum nitidum var. tomentosum (Rutaceae). Their structures were confirmed by comprehensive spectroscopic data (NMR and HRESIMS), and the absolute configurations of all novel compounds were elucidated based on electronic circular dichroism (ECD) spectroscopic data. The production of nitric oxide (NO) in BV-2 microglial cells induced through lipopolysaccharide (LPS) was used to evaluate in vitro anti-neuroinflammatory activity of compounds 1-20. Compound 2, 3, 7 and 16 showed excellent inhibition of LPS-induced NO production. The structure-activity relationships of the isolates were investigated. In addition, the mechanism of action of 2 was elucidated by RT-PCR and Western blotting analysis, which indicated that it reduced neuroinflammatory mainly through NLRP3/caspase1 signaling pathways in LPS-induced BV2 microglial cells.

Flavonol glycosides and phenylpropanoid glycosides with inhibitory effects on microglial nitric oxide production from Neoshirakia japonica.

Five new flavonol glycosides (1-5), one new phenylpropanoid glycoside (6), and nine known glycosides (7-15) were isolated from the stems and leaves of Neoshirakia japonica. The structures of the new compounds were determined by detailed analysis of spectroscopic data (HRESIMS, 1D and 2D NMR) and acid hydrolysis experiment. The antineuroinflammatory effects of all the isolates were evaluated by inhibiting NO production against LPS-induced BV-2 microglial cells. Compounds 1, 8, and 9 showed more potent inhibitory activities with IC50 values of 2.7, 5.5, and 4.1 µM, respectively, than that of the positive control minocycline (IC50 = 15.6 µM), while compounds 7 (IC50 = 17.0 µM) and 10 (IC50 = 24.3 µM) also displayed inhibitory activities to a certain degree.

Diterpenoids and triterpenoids from Triadica rotundifolia and their effects on microglial nitric oxide production.

Four new diterpenoids (1-4), three new triterpenoids (12-14), and seven known diterpenoids (5-11) were obtained from an aqueous EtOH extract of the aerial parts of Triadica rotundifolia. The structures of new compounds were determined by spectroscopic techniques. Their absolute configurations were verified via single-crystal X-ray diffraction data, Mo2(OAc)4 induced electronic circular dichroism (ECD), and ECD calculations. The antineuroinflammatory effects of the isolates were assessed by inhibiting NO production in LPS-induced BV-2 microglial cells. Compared with the positive control minocycline (IC50 = 16.1 µM), compounds 3, 8, 11 showed moderate inhibitory activities with IC50 values of 35.9, 17.0, 31.5 µM, respectively.

Potential anti-diabetic isoprenoids and a long-chain δ-lactone from frangipani (Plumeria rubra).

A decoction of Plumeria rubra flowers has been used traditionally for the treatment of diabetes in China and Mexico. Chemical investigations on the bioactive constituents of these flowers led to the isolation of 30 compounds, including the four new compounds, one iridoiod (1), two triterpenoids (4, 5), and a long-chain δ-lactone (16). In addition, 26 known compounds (2, 3, 6-15, 17-30) are also reported. All of these compounds were identified on the basis of spectroscopic data interpretation and the absolute configurations of compound 4, 5, 16 were determined by Mosher's method. Compounds 1-4, 7, 8 and 16 showed moderate to significant inhibitory activities against α-glucosidase and protein tyrosine phosphatase 1B, with 4 having IC50 values of 19.45 µM and 0.21 µM, respectively.

Anti-inflammatory activity of isobutylamides from zanthoxylum nitidum var. tomentosum.

Inflammation is a very common and important basic pathological process. There is still a great need for the isolation of effective anti-inflammatory agents from plants. In this paper, five new isobutylamides, zanthoxylumamides E-I (1-5), and four known isobutylamides (6-9) were isolated from Zanthoxylum nitidum var. tomentosum (Rutaceae). Chiral resolution of seven racemic isobutylamides (1-4 and 6-8) was successfully performed, and the absolute configurations of two stereoisomers of 1-4 were validated by ECD and NMR. The obtained isobutylamides were evaluated in vitro anti-inflammatory activity with the lipopolysaccharide (LPS)-stimulated production of nitric oxide (NO) in murine macrophage RAW264.7 cells. Compound 8 exhibited significant inhibition of LPS-induced NO production. The underlying molecular mechanisms of the anti-inflammatory activity of 8 revealed that it suppressed the NO production through the modulation of myeloid differentiation factor 88 (MyD88) and interferon regulatory factor 3 (IRF3) signaling pathways.

Quassinoids with Insecticidal Activity against Diaphorina citri Kuwayama and Neuroprotective Activities from Picrasma quassioides.

Six new quassinoids, named kumulactone F (1), kumulactone G (2), kumulactone H (4), kumulactone I (5), kumulactone J (6), and kumulactone K (7), a pair of undescribed epimers α- and ß-nigakihemiacetal G (3), 15 known quassinoids (8-22), and a mixture of the known compounds α- and ß-neoquassin (23) were separated from the dried stems of the medical plants Picrasma quassioides. The chemical structures of all of the new compounds were established by spectroscopic data analyses (HR-ESI-MS, 1D and 2D NMR spectroscopy, and electronic circular dichroism (ECD)). Biologically, compounds 9 and 21 showed toxicity toward the Asian citrus psyllid Diaphorina citri Kuwayama with potent activity even equal to that of the positive control (Abamectin), compound 11 exhibited an excellent neuroprotective effect against SH-SY5Y cells which were pretreated by H2O2 with potent activity equal to that of the positive control (Trolox), and none of them showed cytotoxic activity toward the HeLa or A549 cell lines (IC50 > 100 µM).

Glechomanamides A-C, Germacrane Sesquiterpenoids with an Unusual Δ8-7,12-Lactam Moiety from Salvia scapiformis and Their Antiangiogenic Activity.

Three new germacrane sesquiterpenoid-type alkaloids with an unusual Δ8-7,12-lactam moiety, glechomanamides A-C (1-3), and two pairs of 7,12-hemiketal sesquiterpenoid epimers (4a/b, 5a/b) were isolated from Salvia scapiformis. Their structures were elucidated by spectroscopic methods including HRESIMS, IR, UV, and 1D and 2D NMR and also confirmed by single-crystal X-ray diffraction analysis. The chemical transformation of compounds 1-5 in a solution environment was analyzed by 2D NMR spectroscopy. The aza acetallactams (1-3) were stable in organic solvent, while single crystals of the hemiacetal esters (4a/b, 5a/b) underwent a tautomeric equilibrium after being dissolved. Single crystals of 4a, 4b, and 5a were obtained for the first time as their naturally occurring forms. Glechomanamide B (2) exhibited antiangiogenic activity by suppression of vascular endothelial growth factor (VEGF)-induced tube formation through modulation of VEGF receptor 2 (VEGFR2)-mediated signaling pathways in human umbilical vascular endothelial cells (HUVECs). In addition, compound 2 also showed the significant suppression of mRNA expression associated with glycolysis and angiogenesis biomarkers in high glucose (30 mM)-induced HUVECs. These findings suggest that compound 2 might be a potential lead compound candidate for the management of diabetic retinopathy.

Five 11α, 12α-epoxy pentacyclic triterpenoid saponins with antithrombus activities from Glechoma longituba.

The present study reports the phytochemical investigation of n-butanol-soluble extracts of Glechoma longituba. Five new oleanane-type triterpenoid saponins with an 11α, 12α-epoxy unit, named glechomanosides A - E, were isolated from the n-butanol soluble fraction of G. longituba. Their chemical structures were established using HRESIMS, IR, 1D NMR, and 2D NMR techniques. The compounds were all evaluated for their antithrombus activities by monitoring thrombin time (TT), prothrombin time (PT), activated partial thromboplastin time (APTT), and antiplatelet aggregation assays. These results suggest that G. longituba might be a candidate plant source of an interesting antithrombotic activity.

NF-κB inhibitory and cytotoxic activities of hexacyclic triterpene acid constituents from Glechoma longituba.

BACKGROUND: Non-Small-Cell Lung Cancer (NSCLC) is the most-frequent cause of cancer death, and novel chemotherapeutic drugs for treating NSCLC are urgently needed. 2α, 3α, 23-trihydroxy-13α, 27-cyclours-11-en-28-oic acid (euscaphic acid G) is a new hexacyclic triterpene acid isolated by our group from Glechoma longituba (Nakai) Kupr. However, the underlying mechanisms responsible for the anticancer effects of hexacyclic triterpene acid have not been elucidated. PURPOSE: In the present work, we evaluated growth inhibitory effect of the new isolated hexacyclic triterpene acid and explored the underlying molecular mechanisms. METHODS/STUDY DESIGNS: Herbs were extracted and constituents were purified by chromatographic separation, including silica gel, ODS, MCI, Sephadex LH-20 and preparative HPLC. The compound structures were elucidated by the use of UV, NMR and MS spectral data. The anticancer activity of euscaphic acid G was evaluated by MTT assay. Cell cycle, apoptosis, reactive oxygen species and mitochondrial membrane potential were determined by flow cytometry. To display the possible mechanism of euscaphic acid G on NCI-H460 cells, RT-PCR, immunofluorescence and Western blot analysis were carried out. RESULTS: A new hexacyclic triterpene acid, euscaphic acid G, together with fifteen known triterpenoids, was isolated from the aerial parts of G. longituba. Our results showed that euscaphic acid G exerted strong anti-proliferative activity against NCI-H460 cells in a concentration- and time-dependent manner. Flow cytometry demonstrated euscaphic acid G arrested the cell cycle at G1 phase, induced cellular apoptosis, accompanied by ROS generation and mitochondrial membrane potential reduction. Mechanistic studies revealed that euscaphic acid G treatment inhibited IKKα/ß phosphorylation and IκBα phosphorylation, which subsequently caused the blockage of NF-κB p65 phosphorylation and nuclear translocation. CONCLUSION: In conclusion, these results suggested that euscaphic acid G from G. longituba showed potential anticancer effects against lung cancer cells via inducing cell cycle arrest and apoptosis, at least partly, through NF-κB signaling pathways.

Inhibition potential of phenolic constituents from the aerial parts of Tetrastigma hemsleyanum against soluble epoxide hydrolase and nitric oxide synthase.

The aerial parts of Tetrastigma hemsleyanum (APTH) have been used as a functional tea in China. The purpose of the current study was to identify the bioactive constituents with inhibitory activity against soluble epoxide hydrolase (sEH) and inducible nitric oxide synthase (iNOS), which are jointly considered potential therapeutic targets for vascular system diseases. In the present study, 39 compounds (1-39) were isolated from the APTH. Among them, compounds 8, 10, 12, 16, 17, 19, and 32 displayed potential activities, with IC50 values ranging from 4.5 to 9.5 µM, respectively, and all in non-competitive inhibition mode. Compounds 5, 10, 12, 19, and 32 displayed potent iNOS inhibitory effects, with IC50 values ranging from 15.6 to 47.3 µM. The results obtained in this work contribute to a better understanding of the pharmacological activities of T. hemsleyanum and its potential application as a functional food.

New inhibitors of matrix metalloproteinases 9 (MMP-9): Lignans from Selaginella moellendorffii.

Matrix metalloproteinase 9 (MMP-9) is one of the structurally related zinc-dependent endopeptidases families and provides a new target for cancer therapy owing to its pivotal role in metastatic tumors. In this paper, fourteen lignans, including three novel lignans, named selamoellenin B-D (1-3), and eleven known lignan derivatives (4-14) were isolated from the plant of Selaginella moellendorffii. Among them, compound 3 is optically active, which was enantiomerically seperated to afford a pair of enantiomers, (-)-3 and (+)-3. Their structures were elucidated by extensive spectroscopic analyses. Their cytotoxic activities were evaluated against four human cancer cell lines. Among them, five compounds (4, 5, 6, 11 and 13) exhibited great potent cytotoxicity and their structure-activity relationships were also discussed. All compounds except for 3 lignan analogues with low cytotoxicity were selected for further in vitro enzyme inhibition, surface plasmon resonance (SPR), and molecular docking assays based on the MMPs target. The results shown that, compound 11 have the best inhibitory effect and can be considered as a potential drug candidate targeting at MMP-9 for cancer therapy.

Alkaloids from Tetrastigma hemsleyanum and Their Anti-Inflammatory Effects on LPS-Induced RAW264.7 Cells.

Alkaloids 1⁻10 were isolated from the aerial parts of Tetrastigma hemsleyanum (APTH) and obtained from species of the genus Tetrastigma for the first time. The chemical structures of the isolated compounds were identified by NMR, UV, and MS analyses. Their anti-inflammatory activities were investigated by measuring nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Among all the isolates, compounds 6, 7 and 10 showed potent inhibitory activity against LPS-stimulated NO production in RAW264.7 cells (IC50: 31.9, 25.2 and 6.3 µM, respectively). Furthermore, APTH and S-(−)-trolline (10) inhibited induction of inflammatory cytokines or mediators such as interleukin-1ß (IL-1ß) and inducible nitric oxide synthase (iNOS) via suppression of nuclear factor κB (NF-κB) translocation into the nucleus. In addition, 10 suppressed extracellular signal-regulated protein kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) phosphorylation in a dose-dependent manner. These results conclusively demonstrated that compound 10 displays anti-inflammatory activity via suppression of NF-κB activation and the ERK-MAPK signaling pathway in LPS-stimulated RAW264.7 cells.