Two new isoquinoline alkaloids from Hypecoum leptocarpum Hook. f. et Thoms.

Two new isoquinoline alkaloids, hypecocarpinine (1) and leptocaramine (2) along with five known ones including leptopidine (3), corydamine (4), protopine (5), dihydroprotopine (6) and oxohydrastinine (7), were isolated from Hypecoum leptocarpum Hook. f. et Thoms. Structures of the compounds were elucidated using spectroscopic methods, including UV, IR, HR-ESI-MS, 1 D and 2 D NMR. The cytotoxic activities of these compounds were evaluated using MTT assay. The results showed that compounds 2, 4, and 7 have moderate cytotoxicity against human lung cancer (A549) and human gastric carcinoma (MGC-803) cell lines.

Isolation, synthesis and bioactivity evaluation of isoquinoline alkaloids from Corydalis hendersonii Hemsl. against gastric cancer in vitro and in vivo.

Isoquinoline alkaloid displays significant anti-gastric cancer effects due to its unique structure, which is attracting more and more attention for the development of anti-gastric cancer drugs. In this study, we explore the active components against gastric cancer from the Tibetan Medicine Corydalis hendersonii Hemsl, which is rich in isoquinoline alkaloids. 14 compounds including 2 previously undescribed natural products were obtained. Interestingly, an new active compound displays potent anti-gastric cancer activity. After accomplishing the total syntheses of the active compound and its derivatives, the anti-gastric cancer activity of the active compound was further investigated. In vitro experiments revealed that the active compound significantly attenuated the proliferative capacity, caused G2/M phase arrest, inhibited the cell migration and invasion, and induced cell apoptosis. Mechanistically, the active compound could increase the Bax/Bcl-2 ratio, elevate cytochrome c in the cytosol, and activate caspase-9/3, along with inactivating the upstream PI3K/Akt/mTOR signaling pathway. In addition, the active compound could also cause gastric cancer cell death by inhibiting topoisomerase I activity. More importantly, the anti-gastric cancer activity of the active compound was confirmed in MGC-803 xenograft nude mice in vivo. This work not only promotes the exploitation of Corydalis hendersonii Hemsl., but also provides some experience for discovering new entities from natural sources.

Design, synthesis and anti-hepatocellular carcinoma activity of 3-arylisoquinoline alkaloids.

This article describes the syntheses and biological activity of five 3-arylisoquinoline natural products corydamine (1), N-formyl Corydamine (2), hypecumine (3), Decumbenine B (XW) and 2-(1,3-dioxolo [4,5-h]isoquinolin-7-yl)-4,5-dimethoxy-N-methyl-Benzeneethanamine (A), and twelve analogues. Among them, 1, 2, and A were synthesized for the first time. In vitro screening for anti-proliferative activity showed that derivative 1a could significantly inhibit the proliferation of HCC cells (IC50 = 9.82 µM on Huh7 cells and 6.83 µM on LM9 cells), and arrest cell cycle at G2/M phase. The mechanistic studies further suggested compound 1a was a dual inhibitor of Topo I and Topo II, and Topo II inhibitory activity was superior to etoposide. In addition, 1a could significantly inhibit the invasion and migration of cancer cells by inhibiting the expression of MMP-9, and induce apoptosis through inhibiting the activation of the PI3K/Akt/mTOR signaling pathway. Moreover, in vivo studies demonstrated 1a could obviously reduce the growth of xenograft tumor and possessed good pharmacokinetic parameters, which indicated the potential value of 1a in treating liver cancer.

Targeted Separation of COX-2 Inhibitor from Pterocephalus hookeri Using Preparative High-Performance Liquid Chromatography Directed by the Affinity Solid-Phase Extraction HPLC System.

Pterocephalus hookeri, as a kind of popular traditional Tibetan medicine, is reputed to treat inflammatory related diseases. In the present work, a cyclooxygenase-2 functionalized affinity solid-phase extraction HPLC system was developed and combined with preparative-HPLC for rapidly screening and separating cyclooxygenase-2 ligand from P. hookeri extracts. Firstly, ligands of cyclooxygenase-2 were screened from extracts by affinity solid-phase extraction HPLC system. Then directed by the screening results, the recognized potential active compounds were targeted separated. As a result, the major cyclooxygenase-2 inhibitor of P. hookeri was obtained with a purity of >95%, which was identified as sylvestroside I. To test the accuracy of this method, the anti-inflammatory activity of sylvestroside I was inspected in lipopolysaccharide-induced RAW 264.7 cells. The results show that sylvestroside I significantly suppressed the release of prostaglandin E2 with dose-dependent, which was in good agreement with the screening result of the affinity solid-phase method. This method of integration of screening and targeted separation proved to be very efficient for the recognition and isolation of cyclooxygenase-2 inhibitors from natural products.

N-salicyloyl tryptamine derivatives as potential therapeutic agents for Alzheimer's disease with neuroprotective effects.

Alzheimer's disease (AD) has become a serious threat to the developed nations with burgeoning patients and annual costs on health care system in modern society. Neuroinflammation, as one of the specific biochemical factors in the progress of neurodegeneration diseases, performs a crucial role in the pathogenesis and development of AD. Therefore, it is of great significance to develop effective anti-neuroinflammatory strategies for the treatment of AD. N-salicyloyl tryptamine derivatives were previously reported and demonstrated that possessed great potential anti-neuroinflammatory effects and favorable blood-brain barrier (BBB) permeation. Herein, a series of novel N-salicyloyl tryptamine derivatives were synthesized and their anti-AD potential was evaluated both in vitro and in vivo. Among them, L7 performed well anti-neuroinflammatory effects and excellent neuroprotective effects, as well as little toxicity. To lucubrate its potential for the treatment of AD, behavior tests including morris water maze (MWM), eight-arm radial maze, open field test and novel object recognition (NOR) test were carried out and the results showed that L7 could remarkably improve Aß-induced cognitive impairment. Moreover, the mechanism of action of L7 on improving Aß-induced AD was preliminarily investigated, and the results uncovered that the neuroprotective effects of L7 was might exerte via intervening Aß-induced pyroptosis through NLRP3-caspase-1-GSDMD axis and ameliorating neuronal apoptosis by mitochondrial apoptosis pathway. Besides, the distribution of Aß plaques in brain tissues were detected by immunohistochemical (IHC) assay and the results indicated that L7 could significantly attenuate the deposition of Aß plaques in the brain.

Design, synthesis and bioactivity study of evodiamine derivatives as multifunctional agents for the treatment of hepatocellular carcinoma.

Topoisomerase has been found extremely high level of expression in hepatocellular carcinoma (HCC) and proven to promote the proliferation and survival of HCC. Cancer-associated fibroblasts (CAFs) as a kind of key reactive stromal cell that abundantly present in the microenvironment of HCC, could enhance the metastatic ability and drug resistance of HCC. Therefore, developing new drugs that address the above conundrums would be of the upmost significant in the fight against HCC. Evodiamine, as a multi-target natural product, has been found to exert various biological activities such as anti-cancer and anti-hepatic fibrosis via blocking topoisomerase, NF-κB, TGF-ß/HGF, and Smad2/3. Inspired by these facts, 15 evodiamine derivatives were designed and synthesized for HCC treatment by simultaneously targeting Topo I and CAFs. Most of them displayed preferable anti-HCC activities on three HCC cell lines and low cytotoxicity on one normal hepatic cell. In particular, compound 8 showed the best inhibitory effect on HCC cell lines and a good inhibition on Topo I in vitro. Meanwhile, it also induced obvious G2/M arrest and apoptosis, and significantly decreased the migration and invasion capacity of HCC cells. In addition, compound 8 down-regulated the expression of type I collagen in the activated HSC-T6 cells, and induced the apoptosis of activated HSC-T6 cells. In vivo studies demonstrated that compound 8 markedly decreased the volume and weight of tumor (TGI = 40.53%). In vitro and in vivo studies showed that its effects were superior to those of evodiamine. This preliminary attempt may provide a promising strategy for developing anti-HCC lead compounds taking effect through simultaneous inhibition on Topo I and CAFs.

Hydrogen sulfide donors: Therapeutic potential in anti-atherosclerosis.

Atherosclerosis (AS), an important cause of high mortality of cardiovascular disease, involves numerous pathophysiological processes, including endothelial cell damage, oxidative stress, inflammation, lipid deposition, vascular smooth muscle proliferation and migration, macrophage-derived foam cell formation, and platelet aggregation, and seriously endangers human health and safe of life. Hydrogen sulfide (H2S) was discovered as the third gaseous signaling molecule following nitric oxide (NO) and carbon monoxide (CO), and has been proposed to exert potentially significant effects in many physiological processes, especially in atherosclerosis. Compelling evidence suggests that malfunction of CSE/H2S pathway and downregulation of endogenous H2S level contribute to the pathogenesis of atherosclerosis, whereas exogenous supplementation of H2S can ameliorate many of atherogenic processes. The current knowledge on the anti-atherogenic role of H2S comes from the use of H2S donors and CSE or CBS inhibitors, or another more accurate genetic technology, including gene knockout and gene therapy studies. Among them H2S releasing donors have vast therapeutic potential in anti-atherosclerosis and are promising as one of the clinical strategies for atherosclerosis treatment. Based on the recent studies on therapeutic effects and mechanisms of H2S donors, this review focuses on the most recent advances of therapeutic potential of H2S donors in anti-atherosclerosis, especially synthetic organic donors, because sulfide salts can release H2S rapidly and lead to various adverse effects. In addition, the future of this domain is prospected.

Design, synthesis and bioactivity study of N-salicyloyl tryptamine derivatives as multifunctional agents for the treatment of neuroinflammation.

Because of the complex etiology in neuroinflammatory process, the design of multifunctional agents is a potent strategy to cure neuroinflammatory diseases including AD and PD. Herein, based on the combination principles, 23 of N-salicyloyl tryptamine derivatives as multifunctional agents were designed and their new application for anti-neuroinflammation was disclosed. In cyclooxygenase assay, two compounds 3 and 16 displayed extremely preferable COX-2 inhibition than N-salicyloyl tryptamine. In LPS-induced C6 and BV2 cell models, some compounds decreased the production of proinflammatory mediators NO, PGE2, TNF-α, iNOS, COX-2 and ROS, while increased the production of IL-10. Among them, compound 3 and 16 showed approximately six-fold better inhibition on nitric oxide production than N-salicyloyl tryptamine in C6. Besides, compounds 3, 13 and 16 attenuated the activation of BV2 and C6 cells. More importantly, in vivo, compounds 3 and 16 reduced GFAP and Iba-1 levels in the hippocampus, and displayed neuroprotection in Nissl staining. Besides, both compounds 3 and 16 had high safety (LD50 > 1000 mg/kg). Longer plasma half-life of compounds 3 and 16 than melatonin supported combination strategy. All these results demonstrated that N-salicyloyl tryptamine derivatives are potential anti-neuroinflammation agents for the treatment of neurodegenerative disorder.

A concise synthesis and biological study of evodiamine and its analogues.

Efficient access to evodiamine and its analogues is presented via Lewis acid catalysis. In this reaction, three chemical bonds and two heterocyclic-fused rings are constructed in one step. The reaction shows good functional group tolerance and atom economy, and various heteroatom-containing evodiamine analogues are obtained in moderate to excellent yields even on a gram scale. An anti-tumor study in vitro demonstrates compound 2b possesses potent efficacy against hepatoma cell line (IC50 = 5.7 µM).

Antihypoxic activities of constituents from Arenaria kansuensis.

BACKGROUND: In previous investigation, we have identified antioxidative effects of water-soluble ethanolic extracts (named as AKE) from Arenaria kansuensis and inferred that these extracts or their constituents may also have antihypoxic activity. A. kansuensis has been widely used in traditional Tibetan medicine for altitude sickness (AS) and has been known as the herb of anti-inflammatory and hypoxia resistance for a long time. PURPOSE: The purpose of this study is to evaluate protective effects of AKE and its major constituents against hypoxia-induced lethality in mice and RSC96 cells. STUDY DESIGN AND METHODS: Hypoxia-induced lethality in mice was investigated by 3 experimental animal models of hypoxia. Meanwhile, we established a RSC96 cell model of hypoxia which applied to screen and assess the anti-hypoxic activity of compounds isolated from A. kansuensis. RESULTS: Results indicated that AKE dose-dependently prolonged survival time of hypoxia induced lethality in mice compared to vehicle group and exhibited significantly anti-hypoxic effect. AKE also enhanced the number of red blood cells (RBC) and the concentration of hemoglobin (HB). 8 compounds were bio-guided separated and purified from AKE based on the animal model and cell model of hypoxia. Among which pyrocatechol (C16) and tricin 7-O-ß-d-glucopyranoside (C13) were confirmed to express better protective effects on cell damage induced by hypoxia, suggesting that these two compounds are major active constituents of AKE for anti-hypoxia. CONCLUSION: This study demonstrated that pyrocatechol and tricin 7-O-ß-d-glucopyranoside could be therapeutic candidates for treatment of AS. It is the first time to find the major active constituents of AKE for anti-hypoxia. Meanwhile, a RSC96 cell model of hypoxia was established to screen anti-hypoxic activity of compounds for the first time.

Erythritol Attenuates Postprandial Blood Glucose by Inhibiting α-Glucosidase.

Diabetes mellitus (DM) is a serious metabolic disorder, where impaired postprandial blood glucose regulation often leads to severe health complications. The natural chemical erythritol is a C4 polyol approved by the U.S. Food and Drug Administration for use as a sweetener. Here, we examined a potential role for erythritol in the control of postprandial blood glucose levels in DM. An anti-postprandial hyperglycemia effect upon erythritol administration (500 mg kg-1) was demonstrated in alloxan-induced DM model mice by monitoring changes in blood glucose after intragastric administration of drugs and starch. We also found that erythritol most likely exerts its anti-postprandial hyperglycemic activities by inhibiting α-glucosidase in a competitive manner. This was supported by enzyme activity assays and molecular modeling experiments. In the latter experiments, it was possible to successfully dock erythritol into the catalytic pocket of α-glucosidase, with the resultant interaction likely driven by electrostatic interactions involving Asp215, Asp69, and Arg446 residues. This study suggests that erythritol may not only serve as a glucose substitute but also be a useful agent in the treatment of DM to help manage postprandial blood glucose levels.

Phenolics from Lagotis brevituba Maxim.

A phytochemical investigation on Lagotis brevituba led to the isolation and characterisation of 11 phenolic compounds: p-hydroxy-benzoic acid 1, methyl 3,4-dihydroxybenzoate 2, vanillic acid 3, protocatechuic acid 4, caffeic acid 5, glucose ester of (E)-ferulic acid 6, p-coumaric acid 7, vanillin 8, diosmetin-7-O-ß-d-glucoside 9, chrysoeriol 10 and luteolin 11. Their structures were elucidated using spectroscopic methods and by comparison with data in the literature. Compounds 1-6 were first obtained from the genus Lagotis, and compounds 1-9 were isolated from L. brevituba for the first time. Compound 4 and 11 displayed remarkable antioxidant activities against DPPH radical (IC50 = 5.60 ± 0.09, 27.5 ± 0.06 mg/L, respectively), which were superior to positive control rutin. And compound 11 was also superior to rutin in ABTS assay (IC50 = 2.04 ± 0.13 mg/L).

Anti-hepatitis, antioxidant activities and bioactive compounds of Dracocephalum heterophyllum extracts.

BACKGROUND: Dracocephalum heterophyllum was a traditional Tibetan medicine possesses various pharmacological effects involved in anti-inflammatory, antibacterial activities. However, its anti-hepatitis, antioxidant activity and bioactive compounds have not been reported, the objective of this research work was to investigate the pharmacological activity and bioactive compounds of D. heterophyllum extracts. RESULTS: In the present study, the anti-hepatics and antioxidant activities of four D. heterophyllum extracts (i.e. petroleum ether extracts, ethyl acetate extracts, n-BuOH extracts, and water extracts) were conducted. The main chemical constituent of petroleum ether and ethyl acetate extracts were also isolated using chromatographic techniques and identified by NMR spectroscopic methods. The anti-hepatitis assay showed that the petroleum ether and ethyl acetate extracts of D. heterophyllum significantly prolonged the mean survival times and reduced the mortality of mouse hepatitis model induced by concanavalin A (ConA). The levels of alanine transaminase, aspartate transaminase in blood serum could be decreased obviously by ethyl acetate extracts compared with ConA group (P < 0.01). The histological analysis demonstrated that the ethyl acetate extracts could inhibit apoptosis and necrosis caused by ConA. In addition, the antioxidant activities of the four extracts of D. heterophyllum were measured by DPPH assay, ABTS assay, anti-lipidperoxidation assay, ferric reducing antioxidant power assay, ferrous metal ions chelating assay and determination of total phenolic contents. The results showed that the ethyl acetate extract had the highest antioxidant activities, followed by petroleum ether extract. Finally, nine mainly compounds were isolated from the Petroleum ether and ethyl acetate extracts, including four triterpenes: oleanolic acid (1), ursolic acid (2), pomolic acid (3), 2α- hydroxyl ursolic acid (4), three flavonoids: apigenin-7-O-rutinoside (5), luteolin (8), diosmetin (9) and two phenolic acids: rosmarinic acid (6), methyl rosmarinate (7). CONCLUSION: The Ethyl acetate extract of D. heterophyllum had the highest anti-hepatitis and antioxidants activities, followed by petroleum ether extract. The bioactive substances may be triterpenes, flavonoids and phenolic acids, the ethyl acetate extracts of D. heterophyllum may be possible candidates in developing anti-hepatitis medicine.

Novel Diketopiperazine Dihydroorotate Dehydrogenase Inhibitors Purified from Traditional Tibetan Animal Medicine Osteon Myospalacem Baileyi.

Traditional Tibetan medicine provides an abundant source of knowledge on human ailments and their treatment. As such, it is necessary to explore their active single compounds used to treat these ailments to discover lead compounds with good pharmacologic properties. In this present work, animal medicine, Osteon Myospalacem Baileyi extracts have been separated using a two-dimensional preparative chromatographic method to obtain single compounds with high purity as part of the following pharmacological research. Five high-purity cyclic dipeptides from chromatography work were studied for their dihydroorotate dehydrogenase inhibitory activity on recombinant human dihydroorotate dehydrogenase enzyme and compound Fr. 1-4 was found to contain satisfying inhibition activity. The molecular modeling study suggests that the active compound Fr. 1-4 may have a teriflunomide-like binding mode. Then, the energy decomposition study suggests that the hydrogen bond between Fr. 1-4 and Arg136 can improve the binding mode to indirectly increase the van der Waals binding energy. All the results above together come to the conclusion that the 2, 5-diketopiperazine structure group can interact with the polar residues well in the active pocket using electrostatic power. If some proper hydrophobic groups can be added to the sides of the 2, 5-diketopiperazine group, it is believed that better 2, 5-diketopiperazine dihydroorotate dehydrogenase inhibitors will be found in the future.

[Fast determination of phenolic acids in Lycium ruthenicum murr juice by solid phase extraction and HPLC].

OBJECTIVE: To establish a quantitative method for determination of gallic acid, original catechins, catechins, chlorogenic acid, caffeic acid, syringic acid in Lycium ruthenicum. METHOD: The sample was separated on an ODS column (4. 6 mm x 250 mm, 5 pnm), eluted with methanol and water containing 0. 1% acid with detected wavelength at 280 nm, and flow rate at 1. 0 mL x min(-1). RESULT: The linearity of six components were good (r = 0.9999). The average recoveries (n=5) of the six constituents were 97. 70% (RSD 2.3%), 99.64% (RSD 1.8%), 100.7% (RSD 2.1%), 99.98% (RSD 2.6%), 99.60% (RSD 2.2%), 99.04% (RSD 2.4%), respectively. CONCLUSION: The method is rapid and precise. It can be used for quality control of Lycium ruthenicum juice.

[RP-hPLC determination of flavonoids in several flowers].

OBJECTIVE: To develvp a RP-HPLC method for the determination of flavonoids in fifteen kinds of flowers such as Iris lacteal pall, prunus persica and rosa chinensis. METHOD: The contents of quercetin, kaempferol and isorhamntin in fifteen kinds of flowers were extracted with methanol. The analysis was performed on a Kromasil C18 column (4.6 mm x250 mm, 5 microm) with methanol-0.1% phosphoric acid (50:50) as mobile phase. RESULT: The quercetin, kaempferol and isorhamntin were separated well, and the result shows that the content of quercetin in the Iris lactea Pall was the highest (1.536%), the contene of kaempferol in Persica persice was the highest (0.572%), and the content of isorhamntin in chrysamthemum morifolium was up to 0.290%. CONCLUSION: The contents of flavonoids in these flowers were by determined RP-HPLC for the first time and the method can be used for quantitative determination of flavonoids in the flowers.