Anti-leukemic effect and molecular mechanism of 11-methoxytabersonine from Melodinus cochinchinensis via network pharmacology, ROS-mediated mitochondrial dysfunction and PI3K/Akt signaling pathway.

Melodinus cochinchinensis (Lour.) Merr. is a Yunnan endemic folk medicine. Our previous study showed that 11-methoxytabersonine (11-MT) isolated from M. cochinchinensis has strong cytotoxicity on human T-ALL cells, but its molecular mechanism has not been studied. In current study, the cytotoxicity and possible mechanism of 11-MT on T-cell acute lymphoblastic leukemia was explored using network pharmacology and molecular biology techniques. 11-MT significantly inhibited the cell proliferations on different four human T-ALL cells (MOLT-4, Jurkat, CCRF-CEM, and CEM/C1 cells). 11-MT triggered ROS accumulation, calcium concentration and cell apoptosis, and decreased the mitochondrial membrane potential (MMP) in human T-ALL cells, especially MOLT-4 cells. Western blot analysis showed that it can induce MOLT-4 cell apoptosis by up-regulating PI3K/Akt signaling pathway. Therefore, 11-MT induces human T-ALL cells apoptosis via up-regulation of ROS-mediated mitochondrial dysfunction and down-regulation of PI3K/Akt/mTOR signaling pathway.

Phenolic Constituents, Antioxidant and Cytoprotective Activities, Enzyme Inhibition Abilities of Five Fractions from Vaccinium dunalianum Wight.

The bud of Vaccinium dunalianum Wight has been traditionally consumed as health herbal tea by "Yi" people in Yunnan Province, China, which was locally named "Que Zui tea". This paper studied the chemical constituents of five fractions from Vaccinium dunalianum, and their enzyme inhibitory effects of α-glucosidase and pancreatic lipase, antioxidant activity, and cytoprotective effects on H2O2-induced oxidative damage in HepG2 cells. The methanol extract of V. dunalianum was successively partitioned with petroleum ether (PF), chloroform (CF), ethyl acetate (EF), n-butanol (BF), and aqueous (WF) to obtain five fractions. The chemical profiling of the five fractions was analyzed by ultra-high-performance liquid chromatography coupled with a tandem mass spectrometry (UHPLC-MS/MS), and 18 compounds were tentatively identified. Compared to PF, CF, BF and WF, the EF revealed the highest total phenols (TPC) and total flavonoids (TFC), and displayed the strongest enzyme inhibition ability (α-glucosidase and pancreatic lipase) and antioxidant capacity (DPPH, ABTS and FRAP). Furthermore, these five fractions, especially EF, could effectively inhibit reactive oxygen species (ROS) production and cell apoptosis on H2O2-induced oxidative damage protection in HepG2 cells. This inhibitory effect might be caused by the up-regulation of intracellular antioxidant enzyme activity (CAT, SOD, and GSH). The flavonoids and phenolic acids of V. dunalianum might be the bioactive substances responsible for enzyme inhibitory, antioxidant, and cytoprotective activities.

Phytochemicals and Allelopathy of Induced Water Hyacinth against Microcystis aeruginosa.

Induced water hyacinth with purple roots (PRWH) exerts a significant inhibitory effect on the growth of blue-green algae. Interestingly, its chemical constituents differ from those of wild-type water hyacinth and have not yet been reported. This study aimed to explore the chemical constituents of PRWH and its bioactive components serving as allelopathic agents against blue-green algae. Phytochemical investigation of the bioactive ethyl acetate fraction of a crude methanol extract from PRWH led to the isolation of 56 compounds, including 11 new phenylphenalene derivatives. The structures of these compounds were elucidated by comprehensive analyses through NMR, HRMS, and X-ray techniques. Bioactivity evaluation against Microcystis aeruginosa indicated that compounds 7, 12, 15, 37, 39, 45, and 47 potently inhibited blue-green algae growth.

4,21-Secovincanol, a Novel Immunosuppressive Monoterpenoid Indole Alkaloid from Kopsia Hainanensis.

4,21-Secovincanol (1), a novel C-21/N-4 cleavage monoterpenoid indole alkaloid, along with four analogs (2-5), were obtained from the aerial parts of Kopsia hainanensis. Structurally, compound 1 might be a derivative of epivincanol (2) via C-21/N-4 cleavage. Their structures were confirmed by means of comprehensive spectroscopic data analysis and comparison with the reported data. All isolates significantly inhibited Con A-stimulated mice splenocytes proliferation at 10-40 µM in a dose-dependent manner in vitro. Especially, compound 3 exhibited potent activities comparable to positive control (Dexamethasone, DXM).

Molecular Basis for the Biosynthesis of an Unusual Chain-Fused Polyketide, Gregatin A.

Gregatin A (1) is a fungal polyketide featuring an alkylated furanone core, but the biosynthetic mechanism to furnish the intriguing molecular skeleton has yet to be elucidated. Herein, we have identified the biosynthetic gene cluster of gregatin A (1) in Penicillium sp. sh18 and investigated the mechanism that produces the intriguing structure of 1 by in vivo and in vitro reconstitution of its biosynthesis. Our study established the biosynthetic route leading to 1 and illuminated that 1 is generated by the fusion of two different polyketide chains, which are, amazingly, synthesized by a single polyketide synthase GrgA with the aid of a trans-acting enoylreductase GrgB. Chain fusion, as well as chain hydrolysis, is catalyzed by an α/ß hydrolase, GrgF, hybridizing the C11 and C4 carbon chains by Claisen condensation. Finally, structural analysis and mutational experiments using GrgF provided insight into how the enzyme facilitates the unusual chain-fusing reaction. In unraveling a new biosynthetic strategy involving a bifunctional PKS and a polyketide fusing enzyme, our study expands our knowledge concerning fungal polyketide biosynthesis.

Immunosuppressive Nor-isopimarane Diterpenes from Cultures of the Fungicolous Fungus Xylaria longipes HFG1018.

Eighteen new nor-isopimarane diterpenes, xylarinorditerpenes A-R (1-18), along with two previously reported compounds, 14α,16-epoxy-18-norisopimar-7-en-4α-ol (19) and the labdane-type diterpene agatadiol (20), were isolated from cultures of the fungicolous fungus Xylaria longipes HFG1018 isolated from the wood-rotting basidiomycete Fomitopsis betulinus. The structure elucidation and relative configuration assignments of 1-18 were accomplished by interpretation of spectroscopic data and through computational methods. The absolute configurations of 1, 4, and 16 were determined by single-crystal X-ray diffraction. Compounds 1-16 possess an 18- or 19-nor-isopimarane skeleton, and compounds 17 and 18 possess an 18,19-dinor-isopimarane skeleton. Compounds 2-5, 9, 14, 19, and 20 showed immunosuppressive activity but were devoid of cytotoxicity against the cell proliferation by concanavalin A-induced T lymphocytes and lipopolysaccharide-induced B lymphocytes, with IC50 values varying from 1.0 to 27.2 µM and from 16.1 to 51.8 µM, respectively.

Curtachalasins, immunosuppressive agents from the endophytic fungus Xylaria cf. curta.

Eleven new cytochalasins, curtachalasins F-P (1-11), were isolated from the rice fermentation of endophytic fungus Xylaria cf. curta. Their structures were identified by extensive spectroscopic methods, X-ray diffraction, and quantum chemistry calculations. Curtachalasin P possesses a unique 5/6/6/7 fused ring system. In the bioactivity screening for curtachalasins F-P, A-C, and E (1-15), compounds 1, 3-6, 8-13, and 15 did not show obvious cytotoxicity against primary mouse splenocytes. Furthermore, the immunosuppressive assay against concanavalin A (ConA) induced T lymphocyte cell proliferation and lipopolysaccharide (LPS) induced B lymphocyte cell proliferation showed that compound 1 results in significant selective inhibition on B-cell proliferation (IC50 value of 2.42 µM) and compound 10 has selective inhibition on T-cell proliferation (IC50 value of 12.15 µM). These interesting immunosuppressive properties of this class of compounds provide new clues to fulfill the urgent demand for new immunosuppressive drugs.

Melokhanines A-J, Bioactive Monoterpenoid Indole Alkaloids with Diverse Skeletons from Melodinus khasianus.

The new melokhanines A-J (1-10) and 22 known (11-32) alkaloids were isolated from the twigs and leaves of Melodinus khasianus. The new compounds and their absolute configurations were elucidated by extensive analysis of spectroscopic, X-ray diffraction, and computational data. Melokhanine A (1), composed of a hydroxyindolinone linked to an octahydrofuro[2,3-b]pyridine moiety, is an unprecedented monoterpenoid indole alkaloid. Melokhanines B-H (2-8) possess a new 6/5/5/6/6 pentacyclic indole alkaloid skeleton. Alkaloids 1-16, 25-27, 31, and 32 showed the best antibacterial activity against Pseudomonas aeruginosa (MIC range 2-22 µM). Among the seven dermatophytes tested, compound 1 showed significant inhibitory activity against Microsporum canis, M. ferrugineum, and Trichophyton ajelloi (MIC range 38-150 µM), i.e., half the efficacy of the positive control, griseofulvin.

A potent antibacterial indole alkaloid from Psychotria pilifera.

A new strychnine alkaloid, 16,17,19,20-tetrahydro-2,16-dehydro-18-deoxyisostrychnine (1), and fourteen known alkaloids were isolated from the leaves of Psychotria pilifera. Their structures were identified on the basis of extensive spectroscopic analysis, as well as by comparison with the reported spectroscopic data. The new alkaloid (1) exhibited potent antibacterial activity against Escherichia coli, equivalent to cefotaxime with MIC value of 0.781 µg/ml.

Dysoxydensins A-G, seven new clerodane diterpenoids from Dysoxylum densiflorum.

Seven new clerodane diterpenoids, dysoxydensins A-G (1-7), together with six known clerodanes, were isolated from Dysoxylum densiflorum. The structures of all the compounds were elucidated by extensive spectroscopic analysis. These compounds were evaluated for their cytotoxic activities against five human cancer cell lines, and compounds 2, 3, and 5 showed moderate cytotoxic activities.

Cinchona alkaloids from Cinchona succirubra and Cinchona ledgeriana.

Seven new cinchona alkaloids, cinchonanines A-G (1-7), and 29 known alkaloids were isolated from the barks of Cinchona surrirubra and C. ledgeriana collected from Yunnan Province in China. The new structures were elucidated by extensive spectroscopic analysis. All compounds were evaluated for their cytotoxicity against five human cancer cell lines. Compounds 2, 13, 14, and 15 showed moderate cytotoxicity.

Melosuavines A-H, cytotoxic bisindole alkaloid derivatives from Melodinus suaveolens.

Eight new bisindole alkaloids, melosuavines A-C (1-3), having an aspidosperma-scandine linkage, melosuavines D-F (4-6), possessing an aspidosperma-aspidosperma skeleton, and melosuavines G and H (7 and 8) of the aspidosperma-venalatonine type, tenuicausine (9), and melodinine J (10) were isolated from the twigs and leaves of Melodinus suaveolens. The structures of 1-8 were elucidated by extensive spectroscopic methods, and compounds 9 and 10 were identified by comparison with data in the literature. The relative configuration 9 was determined from the ROESY spectrum, and some NMR signals were reassigned. Compounds 1, 2, 4-6, 8, and 10 exhibited low micromolar cytotoxicity against one or more of five human cancer cell lines.

Cytotoxic indole alkaloids from Tabernaemontana divaricata.

Five new vobasinyl-ibogan-type bisindole alkaloids, tabernaricatines A-E (1-5), two new monomers, tabernaricatines F and G (6 and 7), and 24 known indole alkaloids were isolated from the aerial parts of Tabernaemontana divaricata. Alkaloids 1 and 2 are the first vobasinyl-ibogan-type alkaloids possessing a six-membered ring via an ether linkage between C-17 and C-21. All compounds except for 3 were evaluated for their cytotoxicity against five human cancer cell lines; conophylline showed significant bioactivity against HL-60, SMMC-7721, A-549, MCF-7, and SW480 cells with IC50 values of 0.17, 0.35, 0.21, 1.02, and 1.49 µM, respectively.

Indole alkaloids from leaves and twigs of Rauvolfia verticillata.

Seven new indole alkaloids, rauverines A-G (1-7), and 19 known indole alkaloids were isolated from the leaves and twigs of Rauvolfia verticillata. All compounds showed no cytotoxicity against five human cancer cell lines, human myeloid leukemia (HL-60), hepatocellular carcinoma (SMMC-7721), lung cancer (A-549), breast cancer (MCF-7), and colon cancer (SW480) cells.

Melodinines M-U, cytotoxic alkaloids from Melodinus suaveolens.

Nine new alkaloids, melodinines M-U (1-9), and 11 known alkaloids were isolated from Melodinus suaveolens. The new structures were elucidated by extensive NMR and mass spectroscopic analyses and comparison to known compounds. All compounds were evaluated for their cytotoxicity against five human cancer cell lines. Compounds 6, 11, and 16 showed significant cytotoxicity.

Hypoglycemic and hypolipidemic effects of Epigynum auritum in high fat diet and streptozotocin-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Epigynum auritum is mainly distributed in Southwest China, and has been used as a "dai" folk medicine with promising Besides, the leaves and barks of E. auritum have detoxifying, analgesic and relieving swelling effects. Previous studies evidenced that E. auritum was rich in pregnanes and their glycosides. However, the hypoglycemic and hypolipidemic effects of the extract from E. auritum (EAE) and its molecular mechanism are still not studied. AIM OF THE STUDY: The aim of this study is to investigate the hypoglycemic and hypolipidemic effects of EAE on high-fat diet and streptozocin-induced type 2 diabetic rats. MATERIALS AND METHODS: The high-fat diet and streptozocin induced type 2 diabetic model was established. The diabetic rats were treated with 70% ethanol extract of E. auritum (100 and 300 mg/kg/d) or metformin (DMBG, 100 mg/kg/d) every day for 4 weeks. Fasting blood glucose was recorded weekly. The phenotypic changes were evaluated by the measurement of biochemical indexes and immunohistochemical. The expressions of signaling-related proteins were explored by western blotting. RESULTS: EAE could effectively regulate the metabolism of glucose and lipids in diabetic rats by increasing insulin sensitivity. In addition, EAE ameliorated the oxidative stress damage and further mitigated the liver, kidney, and pancreatic damage. Mechanism research results show that EAE treatment increased the phosphorylation of Akt, AMPK and GSK-3ß, up-regulated the expression of GLUT-2, GLUT-4 and PPAR-α, and reduced PPAR-γ and FAS expressions. CONCLUSION: EAE exhibited significant hypoglycemic and hypolipidemic effects in HFD/STZ-induced diabetes rats. The mechanism may be related to the effective upregulation of AMPK/Akt/GSK-3ß pathway and the decreased expression of PPAR-γ and FAS. It could be a promising natural product with potential value for the development of drugs to prevent or treat type 2 diabetic.

Phenolic constituents, antioxidant activity and neuroprotective effects of ethanol extracts of fruits, leaves and flower buds from Vaccinium dunalianum Wight.

Vaccinium dunalianum Wight is an important healthy tea resource in China with health benefits. The chemical compositions and the possible bioactive substances in its fruits, leaves and flower buds extracts (FE, LE and FBE) were identified and characterized by UHPLC-HRMS/MS. Consequently, FE, LE and FBE were rich in phenolic and flavonoid compounds. Among them, 21 compounds were identified, and the main components were chlorogenic acid, quinic acid and 6'-O-caffeoylarbutin. Furthermore, their neuroprotection and mechanism on H2O2-induced neurotoxicity in PC12 cells were investigated. All the different concentrations of FE, LE and FBE were apparently inhibited the H2O2-induced ROS generation and apoptosis on PC12 cells. FBE showed stronger neuroprotective activity against H2O2-induced PC12 cell damage than those of FE and LE. The mechanism of neuroprotective effect might be related to the upregulation of endogenous antioxidant enzymes expressions and activation of the Nrf2/HO-1 signaling pathway.

Que Zui tea ameliorates hepatic lipid accumulation and oxidative stress in high fat diet induced nonalcoholic fatty liver disease.

In this study, the protective effects of hot water (QW) and aqueous-ethanol extracts (QA) from Que Zui tea on non-alcoholic fatty liver disease (NAFLD) were investigated. Quantitative and qualitative analysis revealed that QW and QA were rich in polyphenols, especially 6'-O-caffeoylarbutin. Both QW and QA significantly reduced body weight and liver index, increased serum levels of high density lipoprotein cholesterol (HDL-C), and decreased the levels of total cholesterol (TC), triglyceride (TG), nonesterified free fatty acids (NEFA) and low density lipoprotein cholesterol (LDL-C) in NAFLD rats induced high fat diet. Furthermore, the contents of TC, TG, NEFA, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the liver tissues were inhibited after QW and QA administration. Histopathological examination showed that QW and QA significantly reduced liver lipid accumulation of NAFLD rats. In addition, QW and QA could enhance increase the activity of antioxidant (glutathione, superoxide dismutase and catalase) in the liver by regulation Nrf2 signaling pathway, thereby alleviating liver damage caused by lipid peroxidation. QW and QA activated AMPK/PPAR-α signaling pathway by increasing the expression of adiponectin and its receptor AdipoR2, thereby reducing fat production and enhancing fatty acid ß oxidation. These data suggested that QW and QA had the potential to in the prevention and treatment of NAFLD.

6'-O-Caffeoylarbutin from Que Zui tea ameliorates acetaminophen-induced liver injury via enhancing antioxidant ability and regulating the PI3K signaling pathway.

Que Zui tea (QT), a traditional herbal tea in China, has a significant hepatoprotective effect. 6'-O-Caffeoylarbutin (CA) is the most abundant chemical compound in the QT. However, the hepatoprotective effect of CA has not been investigated. This study is aimed to evaluate the protective effect of CA on acetaminophen (APAP) induced hepatotoxicity in vivo and in vitro and its possible underlying mechanism. In APAP-induced HepG-2 cells, CA inhibited intracellular ROS accumulation and cell apoptosis, and improved the expression of antioxidants including SOD, CAT and GSH. In APAP-administrated mice, CA pretreatment remarkably ameliorated the histopathological damage and inflammatory response, and antioxidant enzyme activity in the serum and liver tissues. Moreover, the immunohistochemistry and immunofluorescence assay results revealed that the CA markedly reduced ROS production and apoptosis, and activated antioxidant transcription factor Nrf2 in the liver. Meanwhile, molecular docking results showed that the strong binding force of CA and PI3K was due to the higher number of hydrogen- and π-bonds with active site residues. Notably, CA pretreatment significantly regulated the expression of PI3K, Akt, Nrf2, NQO1, HO-1, Bcl-2, Bax, caspase-3, and caspase-9 proteins in APAP-treated liver tissues. These data demonstrated that CA had a protective effect against APAP-induced hepatotoxicity via regulating the PI3K/Akt and Nrf2 signaling pathway.

Potent immunosuppressive and anti-inflammatory bisindole alkaloids from Melodinus fusiformis.

Phytochemical investigation of Melodinus fusiformis led to a new aspidosperma-aspidosperma bisindole alkaloid (BIA), bis-19ß-hydroxyvenalstonidine (1), together with three known BIAs (2-4). The structures were established by extensive analysis of their HRESIMS, NMR data, and comparing with the reported data. BIA 1 is an almost symmetrical structure, linked by C3-C14' bond, while BIAs 2-4 are reported for the first time from the plant. The cytotoxic, immunosuppressive and anti-inflammatory activities of BIAs 1-4 were evaluated in vitro. BIAs 1, 3 and 4 showed good toxicity against MOLT-4 cell lines with IC50 values in the range of 1.5-17.5 -M. BIA 2 exhibited the strongest inhibitory effect against MCF-7 cell lines with an IC50 value of 7.1 µM. BIA 1 significantly inhibited Con A-stimulated mice splenocytes proliferation equal to that of the positive control (DXM) in a concentration-dependent manner. BIAs 1 and 2 were able to decrease the NO production in LPS-induced RAW 264.7 cells at 30 µM concentration. BIA 2 showed similar inhibition of nitric oxide release, compared to that of DXM. Furthermore, BIA 2 remarkably inhibited the levels of IL-6 and TNF-α compared to the LPS induced group. Interestingly, BIA 2 displayed an inhibitory effect on TNF-α production similar to that of dexamethasone at a concentration of 20 µM.