A manzamine-derived compound as a potential therapeutic agent for glioma by inducing apoptosis and cell cycle arrest.

Glioma is a severe disease with a poor prognosis despite aggressive surgical resection and traditional chemotherapies. Therefore, new anti-neoplastic drugs are urgently needed. Bioactive compounds from natural products are potential sources of antiproliferative molecules, among which manzamine compounds extracted from the Formosan marine sponge Haliclona sp. have shown considerable promise as anticancer drugs. In the present study, the anti-neoplastic effect and mechanism of the manzamine derivative 1-(9'-propyl-3'-carbazole)-1, 2, 3, 4-tetrahydro-ß-carboline (PCTC) were investigated using in vitro cell lines and an in vivo subcutaneous animal model. Both cytotoxic and anti-proliferative effects were shown in human and murine glioma cell lines (A172, U87MG, and GL261), together with enhanced expressions of apoptotic enzymes and intracellular reactive oxygen species, and blockage of the G1/S phase of the cell cycle. In addition, combined treatment of GL261 cells with PCTC and temozolomide had a synergic antiproliferative effect. Significant safety, efficacy, and survival benefits were also demonstrated with PCTC treatment in the murine subcutaneous GL261 model. In conclusion, PCTC could effectively promote cell death through apoptosis and cell cycle arrest in glioma cell lines, and provide survival benefits in the animal model. Therefore, PCTC may be a clinically beneficial therapy for glioblastoma.

Sesquiterpene Lactone Deoxyelephantopin Isolated from Elephantopus scaber and Its Derivative DETD-35 Suppress BRAFV600E Mutant Melanoma Lung Metastasis in Mice.

Melanoma is a highly metastatic disease with an increasing rate of incidence worldwide. It is treatment refractory and has poor clinical prognosis; therefore, the development of new therapeutic agents for metastatic melanoma are urgently required. In this study, we created a lung-seeking A375LM5IF4g/Luc BRAFV600E mutant melanoma cell clone and investigated the bioefficacy of a plant sesquiterpene lactone deoxyelephantopin (DET) and its novel semi-synthetic derivative, DETD-35, in suppressing metastatic A375LM5IF4g/Luc melanoma growth in vitro and in a xenograft mouse model. DET and DETD-35 treatment inhibited A375LM5IF4g/Luc cell proliferation, and induced G2/M cell-cycle arrest and apoptosis. Furthermore, A375LM5IF4g/Luc exhibited clonogenic, metastatic and invasive abilities, and several A375LM5IF4g/Luc metastasis markers, N-cadherin, MMP2, vimentin and integrin α4 were significantly suppressed by treatment with either compound. Interestingly, DET- and DETD-35-induced Reactive Oxygen Species (ROS) generation and glutathione (GSH) depletion were found to be upstream events important for the in vitro activities, because exogenous GSH supplementation blunted DET and DETD-35 effects on A375LM5IF4g/Luc cells. DET and DETD-35 also induced mitochondrial DNA mutation, superoxide production, mitochondrial bioenergetics dysfunction, and mitochondrial protein deregulation. Most importantly, DET and DETD-35 inhibited lung metastasis of A375LM5IF4g/Luc in NOD/SCID mice through inhibiting pulmonary vascular permeability and melanoma cell (Mel-A+) proliferation, angiogenesis (VEGF+, CD31+) and EMT (N-cadherin) in the tumor microenvironment in the lungs. These findings indicate that DET and DETD-35 may be useful in the intervention of lung metastatic BRAFV600E mutant melanoma.

Design and synthesis of ß-carboline and combretastatin derivatives as anti-neutrophilic inflammatory agents.

A series of ß-carboline derivatives was synthesized by the Pictet-Spengler reaction with or without the combretastatin skeleton. The structures of these derivatives were elucidated by spectroscopic techniques. All synthesized compounds were evaluated for their anti-inflammatory activity in human neutrophils. Among them, two compounds, NTU-228 and HK-72, showed significant inhibitory effects on N-formyl-Met-Leu-Phe (fMLF)-induced superoxide anion generation in human neutrophils with IC50 values of 5.58 ± 0.56 and 2.81 ± 0.07 µM, respectively. Neither NTU-228 nor HK-72 caused cytotoxicity in human neutrophils. NTU-228 inhibited the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and intracellular Ca2+ levels ([Ca2+]i) in fMLF-activated human neutrophils. Additionally, HK-72 selectively inhibited the fMLF-induced phosphorylation of p38 and [Ca2+]i in human neutrophils. Molecular docking analysis showed a favorable binding affinity of HK-72 toward p38 MAPK. The proposed synthetic strategy opens up new opportunities for the synthesis of novel potential candidates against neutrophilic inflammation.

Cumingianoside A, a Phyto-Triterpenoid Saponin Inhibits Acquired BRAF Inhibitor Resistant Melanoma Growth via Programmed Cell Death.

Mutated proto-oncogene BRAF is a bona fide therapeutic target for melanomas. Regrettably, melanoma acquires resistance to BRAF inhibitors, e.g., vemurafenib (PLX4032) casting doubt on this promising melanoma targeted therapy. In this study, we explored the bioactivity of triterpenoid saponin cumingianoside A (CUMA), isolated from leaves and twigs of Dysoxylum cumingianum against PLX4032-resistant BRAFV 600E mutant melanoma A375-R in vitro and in vivo. Our data show that CUMA treatment inhibited A375-R melanoma cell proliferation in a time- and dose-dependent manner. CUMA also suppressed the activity of CDK1/cyclin B1 complex and led to G2/M-phase arrest of A375-R cells. Furthermore, CUMA treatment resulted in induction of apoptosis as shown by the increased activation of caspase 3 and caspase 7, and the proteolytic cleavage of poly(ADP-ribose) polymerase (PARP). We also observed that CUMA induced autophagy-like activity in A375-R cells, as shown by the increased expression of autophagy-related genes and increased formation of autophagosomes. Moreover, we found that CUMA treatment induced ER stress response and co-treatment with an ER stress inhibitor (4-PBA) could attenuate apoptosis induced by CUMA. Importantly, orally administered CUMA as a single agent or in combination with PLX4032 exhibited strong tumor growth inhibition in a PLX4032-resistant A375-R xenograft mouse model, and with little toxicity. This is the first report to explore the anti-tumor activity of CUMA in vitro and in vivo mechanistically, and our results imply that this triterpenoid saponin may be suitable for development into an anti-melanoma agent.

Macrophage Migration Inhibitory Factor Acts as the Potential Target of a Newly Synthesized Compound, 1-(9'-methyl-3'-carbazole)-3, 4-dihydro-ß-carboline.

For a newly synthesized compound, identifying its target protein is a slow but pivotal step toward understand its pharmacologic mechanism. In this study, we systemically synthesized novel manzamine derivatives and chose 1-(9'-methyl-3'-carbazole)-3, 4-dihydro-ß-carboline (MCDC) as an example to identify its target protein and function. MCDC had potent toxicity against several cancer cells. To identify its target protein, we first used a docking screen to predict macrophage migration inhibitory factor (MIF) as the potential target. Biochemical experiments, including mutation analysis and hydrogen-deuterium exchange assays, validated the binding of MCDC to MIF. Furthermore, MCDC was shown by microarrays to interfere with the cell cycle of breast cancer MCF7 cells. The activated signaling pathways included AKT phosphorylation and S phase-related proteins. Our results showed MIF as a potential direct target of a newly synthesized manzamine derivative, MCDC, and its pharmacologic mechanisms.

Tetranortriterpenes and Limonoids from the Roots of Aphanamixis polystachya.

Phytochemical investigation of the acetone extract from the roots of Aphanamixis polystachya resulted in isolation of four new tetranortriterpenes (1-4) in addition to one protolimonoid (methyl-1ξ,7R-diacetoxy-23R,25-dihydroxy-20S,24R-21,24-epoxy-3,4-seco-apotirucall-4(28),14(15)-diene-3-oate (5)), five known limonoids (rohituka 3 (6), rohituka 7 (7), nymania 1 (8), rubrin G (9), prieurianin (10)) and a steroid (2,3-dihydroxy-5-pregnan-16-one (11)). Their structures were determined by spectroscopic analyses, including 2D-NMR (COSY, HMQC, HMBC, and NOESY) and high-resolution electrospray ionization mass spectrometry (HRESIMS). Cytotoxic and anti-inflammatory activities of these compounds were evaluated. Compounds 4 and 5 showed significant inhibition against superoxide generation and elastase release by human neutrophils in response to (formyl-l-methionyl-l-leucyl-l-phenylalanine/cytochalasin B) (FMLP/CB).

Nitrogen-Containing Diterpenoids, Sesquiterpenoids, and Nor-Diterpenoids from Cespitularia taeniata.

Two new nitrogen-containing verticillene diterpenoids, cespilamides A and B (1 and 2), three new nitrogen-containing sesquiterpenoids, cespilamides C-E (3-5), and five new norverticillene and verticillene diterpenoids, cespitaenins A-E (6-10), were isolated from the Taiwanese soft coral Cespitularia taeniata. Compound 1 possesses an unusual oxazo ring system at C-10 while compound 2 displays an unprecedented C-C bond cleavage between C-10 and C-11 with an N-ethylphenyl group at C-10. Biogenetic pathways of 1 and 2 are proposed. The absolute configuration of 1 was confirmed by Mosher's method and molecular mechanics calculations (MM2). The cytotoxicities of compounds 1-10 were evaluated against a small panel of human cancer cell lines.

Randainins A-D, Based on Unique Diterpenoid Architectures, from Callicarpa randaiensis.

Four new compounds, randainins A-D (1-4), were isolated from the leaves and twigs of Callicarpa randaiensis, which is an endemic species in Taiwan. Compounds 1 and 2 are diterpenoids with an unusual trans-7/5 ring system, whereas compounds 3 and 4 are diterpenoids possessing a trans-5/7 ring scaffold. The structures of the new compounds were established based on NMR and MS data analyses. Anti-inflammatory activities and cytotoxicity were tested and evaluated for these compounds. Compound 4 exhibited moderate inhibition of superoxide-anion generation with an IC50 value of 21.5 ± 2.5 µM.

New briarane diterpenoids from Taiwanese soft coral Briareum violacea.

Ten new briarane diterpenoids, briaviolides A-J (1-10), together with six known briaranes, solenolides A and D, excavatolide A, briaexcavatolide I, 4ß-acetoxy-9-deacetystylatulide lactone and 9-deacetylstylatulide lactone, were isolated from the Taiwanese soft coral, Briareum violacea. Their structures were determined on the basis of spectroscopic data ((1)H- and (13)C-NMR, (1)H-(1)H COSY, HSQC, HMBC and NOESY), HR-MS and chemical methods. The absolute configuration of briaviolide A (1) was determined by X-ray crystallographic analysis. Compounds 5, 9 and derivative 11 showed moderate inhibitory activities on superoxide-anion generation and elastase release by human neutrophils in response to N-formyl-methionyl-leucyl-phenylalanine/ Cytochalasin B (fMLP/CB).

Seven new sesquiterpenoids from the fruits of Schisandra sphenanthera.

Fractionation of the EtOH extract from the fruits of Schisandra sphenanthera resulted in the isolation of seven new sesquiterpenoids, 1-7, in addition to the known metabolites 8-23. Among them, schiscupatetralin A (1) possesses an unprecedented structure with a CC bond between cuparenol and tetralin. The isolated new compounds were evaluated for their anti-HSV-1 and anti-inflammatory activities. The results revealed that compound 4 exhibited anti-HSV-1 activity, while compound 6 showed a significant anti-inflammatory activity.

Cespitulones A and B, cytotoxic diterpenoids of a new structure class from the soft coral Cespitularia taeniata.

Two novel diterpenoids, cespitulones A (1) and B (2), were isolated from extracts of the soft coral Cespitularia taeniata. Both compounds possess an unprecedented bicyclo [10.3.1] ring system with C-C bond connections between C-10 and C-20, and between C-20 and C-11. Their structures were elucidated on the basis of extensive spectroscopic analyses. Compound 1 exhibited significant cytotoxicity against human medulloblastoma and colon adenocarcinoma cancer cells.

Four new briarane diterpenoids from Taiwanese gorgonian Junceella fragilis.

Four new 8-hydroxybriarane diterpenoids, frajunolides P-S (1-4), together with umbraculolide A, juncenolide C, junceellonoid A and juncin R, were isolated from the acetone extract of the gorgonian Junceella fragilis, collected from the southeast coast of Taiwan. Compound 1 contains an unusual pivaloyloxy group at C-2, while 3 is a rare compound having a chlorine atom on the olefinic carbon (C-6). The structures of the isolated compounds were established by extensive spectroscopic analysis, including 1D- and 2D-NMR, as well as HRMS data. Compound 1 was further confirmed by X-ray crystallographic analysis. In the anti-inflammatory test, compounds 1 and 2 exhibited moderate inhibition on superoxide anion generation and elastase release by human neutrophils in response to formylmethionylleucyl-phenylalanine/dihydrocytochalasin B (fMLP/CB).

New Lignans from the Leaves and Stems of Kadsura philippinensis.

Three novel C19 homolignans, taiwankadsurins D (1), E (2) and F (4), and two new C18 lignans kadsuphilins N (3) and O (5) were isolated from the aerial parts of Taiwanese medicinal plant Kadsura philippinensis. The structures of compounds 1-5 were determined by spectroscopic analyses, especially 2D NMR techniques. The structure of compound 5 was further confirmed by X-ray crystallographic analysis. Compounds 1 and 2 have a 3,4-{1'-[(Z)-2''-methoxy-2''-oxoethylidene]}-pentano(2,3-dihydrobenzo[b]furano)-3-(2'''-methoxycarbonyl-2'''-hydroxy-2''',3'-epoxide) skeleton.

Hyperinakin, a new anti-inflammatory phloroglucinol derivative from Hypericum nakamurai.

Phytochemical investigation of Hypericum nakamurai (Masamune) Robson has led to the isolation of three phloroglucinol derivatives 1-3. The structures of these compounds were determined by the analysis of their spectroscopic data (IR, mass and UV), and by the application of 1-D and 2-D-NMR techniques. Hyperinakin (1) is a new compound. The anti-inflammatory activities of compounds 1-3 were also tested and evaluated. A biogenetic pathway for compounds 1-3 was also proposed.

Schisarisanlactones A and B: a new class of nortriterpenoids from the fruits of Schisandra arisanensis.

Two novel highly oxygenated nortriterpenoids, schisarisanlactones A (1) and B (2), have been isolated from the fruits of Schisandra arisanensis, an endemic plant of Taiwan. Compounds 1 and 2 possess an unprecedented 5/5/7/5/5-fused pentacyclic ring system. The structures of both compounds were determined on the basis of spectroscopic analyses, especially 2D NMR and MS. A plausible biogenetic pathway of 1 was proposed. Schisarisanlactone A (1) showed significant anti-HIV activity.

Anti-liver fibrotic lignans from the fruits of Schisandra arisanensis and Schisandra sphenanthera.

Three new polyoxygenated C(18)-dibenzocyclooctadiene lignans, arisanschinins M and N (1 and 2) and schisphenin A (3), together with eight related metabolites (4-11), were isolated from the fruits of Schisandra arisanensis and Schisandra sphenanthera, respectively. The structures of 1-3 were elucidated on the basis of extensive spectroscopic and 2D NMR (HSQC, HMBC, and NOESY) analyses. The configuration of the biphenyl moiety in the octadiene ring was determined by circular dichroism (CD). Compound 1 possessed an unprecedented 3-(1-hydroxypropan-2-yl)-3-methyl-1,4-dioxo-2-one lactonide ring system attaching at C-6/C-14. Pharmacological studies revealed that compounds 3, 4, 6, 7, and 10 exhibited significant anti-hepatic fibrosis activity, while 9 and 11 showed cytotoxicity against HSC-T6 cells. The biogenetic pathway for compound 1 was also proposed.

New Briarane diterpenoids from the gorgonian coral Junceella juncea.

Chemical investigation of Junceella juncea has resulted in the isolation of three new briaranes designated juncenolides M-O (1-3). The structures of these compounds were determined by spectroscopic analysis including 2D-NMR (COSY, HMBC and NOESY) and HRMS. Compound 1 is a new chlorinated briarane while compound 3 contains a rare methyl ester at C-16. The anti-inflammatory activities tested on superoxide anion generation and elastase release by human neutrophils in response to FMLP/CB were evaluated.

Bioactive diterpenes from Callicarpa longissima.

Investigation of the leaves and twigs of Callicarpa longissima resulted in the isolation of four new compounds (1-4), callilongisins A-D, and five known compounds, ursolic acid, 3-oxoanticopalic acid, (E)-6ß-hydroxylabda-8(17),13-dien-15-oic acid, 5-hydroxy-3,6,7,4'-tetramethoxyflavone, and artemetin. Compounds 1-3 are 3,4-seco-abietane-type diterpenoids, and compound 4 is an analogue of a labdenoic-type diterpene. The structure of compound 1 was confirmed by X-ray crystallographic analysis. Cytotoxicity against a human prostate cancer cell line (PC3) and anti-inflammatory activities of the isolated compounds were evaluated.

New verticillane diterpenoids from Cespitularia taeniata.

Chemical investigation of Cespitularia taeniata has led to the isolation of three new verticillanes, cespitulins E-G (1-3, resp.). The structures of these compounds were elucidated by spectroscopic analysis, especially HR-MS and 2D-NMR techniques. Compound 1 possesses a rare norverticillane skeleton with two adjacent OH groups at C(5) and C(6), while the seco-compound 2 with an aldehyde group at C(9) results from an unusual bond cleavage between C(9) and C(10). Pharmacological studies revealed that compound 3 exhibited significant activities on superoxide-anion generation and elastase release by human neutrophils in response to FMLP/CB. A plausible biogenetic pathway for compound 2 is also discussed.

Frajunolides L-O, four new 8-Hydroxybriarane diterpenoids from the Gorgonian Junceella fragilis.

Four new 8-hydroxybriarane diterpenoids, frajunolides L-O (1-4), were isolated from the Taiwanese gorgonian Junceella fragilis. The structures of compounds 1-4 were elucidated based on spectroscopic analysis, especially 2D NMR ((1)H-(1)H COSY, HSQC, HMBC and NOESY) and HRMS. Compounds 1 and 4 showed weak anti-inflammatory activity as tested by superoxide anion generation and elastase release by human neutrophil in response to fMLP/CB. Compound 3 showed selective inhibition on elastase release in vitro.