Design,Synthesis and Bioactivity Study of Marine Alkaloid Neobacillamide-A Derivatives

The Janus kinases(JAKs)are a family of intracellular tyrosine kinases that play an essential role in many basic biological processes,such as apoptosis and inflammation.Thus any dysfunction of the proteins in this pathway may lead to a variety of diseases,including cancer and diseases that affect the immune system,such as severe combined immune deficient(SCID).Marine biological resources have become an important source in new drug research and development due to their diversity,complexity and speciality.In this study,Marine alkaloid Neobacillamide A was isolated from the greedy and stubborn sponge symbiotic Bacillus atrophicus C89 in the South China Sea.Totally 24 novel marine alkaloid Neobacillamide A derivatives were designed and synthesized,which were evaluated for their inhibitory activity against JAK/STAT signaling pathway and their cytotoxicity to A549 cells.Compounds 13c,13o,14d,14g and 14h showed potent JAK/STAT inhibition capability(concentration of 25μmol L^(-1),all inhibitory potencies were above 60%),especially compound 14g exhibited superior JAK/STAT inhibition effect(89.70%inhibition).In addition,all these compounds with a concentration of 25μmol L^(-1)displayed weak or no cytotoxicity to A549 cells,which means that these Neobacillamide A derivatives with JAK/STAT inhibition capability may have potential anti-inflammatory function.

The Antioxidant Effects of Complexes of Tilapia Fish Skin Collagen and Different Marine Oligosaccharides

An excess of reactive oxygen species (ROS) leads to a variety of chronic health problems.As potent antioxidants, marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently, there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However, only few studies are available on the antioxidant activities of such complexes, in terms of their ROS scavenging capability.In this study, we combined different marine oligosaccharides (isolated and purified) with collagen peptides derived from tilapia fish skin, and evaluated the an-tioxidant activity of the marine peptide-oligosaccharide complexes vis-à-vis the activity of their original component molecules.Bio-chemical and cellular assays were performed to measure the scavenging effects on 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl and superoxide radicals, and to evaluate the influences on the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the level of malondialdehyde (MDA) in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested, two complexes, namely MA1000+CP and κ-ca3000+CP, turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood, this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical, cosmetics and food industries.

Efficient Syntheses of Permethylated Derivatives of Neolamellarin A,a Pyrrolic Marine Natural Product

The pyrrole-derived alkaloids with marine origin, especially their permethyl derivatives, have unique structures and promising biological activities. Marine natural product neolamellarins are a collection of lamellarin-like phenolic pyrrole compounds, which can inhibit hypoxia-induced HIF-1 activation. Many pyrrole-derived lamellarin-like alkaloids show potent MDR reversing activity. In this study, five permethylated derivatives of neolamellarin A were synthesized with their MDR reversing activity studied in order to identify new MDR reversal agents. A convergent strategy was adopted to synthesize the permethylated derivatives of neolamellarin A. Pyrrole was first converted into a corresponding N-trisisopropylsilyl(TIPS)-substituted derivative, then through iodination afforded 3,4-diiodinated pyrrole compound. The key intermediate, 3,4-disubstituent-1H-pyrrole, was obtained through desilylation of 3,4-disubstituent-1-TIPS pyrrole, which was prepared from 3,4-diiodinated pyrrole derivative and aryl boronic acid ester through Suzuki cross-coupling reaction between them. Then, the intermediate, 3,4-disubstituent-1H-pyrrole, reacted with fresh phenylacetyl chloride under n-Bu Li/THF condition afforded the target compounds. Finally, we obtained five novel pyrrolic compounds, permethylated derivatives of neolamellarin A 16a-e, in 30%–37% yield through five step reactions. The bioactivity testing of these compounds are in process.

Development and Validation of UHPLC-MS/MS Method for Quantifying of Agarotriose:An Application for Pharmacokinetic,Tissue Distribution,and Excretion Studies in Rats

A sensitive,rapid,and robust ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)method was established for the first time to quantify agarotriose(A3)in rat plasma,tissues,urine,and feces.A3 and stachyose(internal standard)were separated by a BEH amide column at 65℃under the mobile phase of 10 mmol L^(-1)ammonium ace-tate-acetonitrile(42:58,v/v)with 350µLmin-1.The acquisition of transitions was carried out in multiple reaction monitoring(MRM)pattern operating with positive ionization at m/z 509.16>329.15 for A3 and m/z 689.15>527.11 for stachyose.The linearity ranges of A3 were 10 to 5000nmolL^(-1)for plasma,20 to 10000nmolL^(-1)for tissues,and 40 to 20000nmolL^(-1)for urine and feces.The accuracy and precision ranged from 90.9%to 111.6%and 0.7%to 10.1%,respectively.The stability was between 86.1%and 102.5%.The extraction recovery was consistent and reproducible.The matrix effect ranged from 1.5%to 11.4%.The pharmacokinetic,tissue dis-tribution,and excretion studies were successfully conducted with the validated method.Results showed that A3 could be absorbed by rats,and the absolute bioavailability was 6.7%.Furthermore,it was rapidly distributed in rat tissues and mainly eliminated via feces excretion(67.0%)after oral administration.For intravenous bolus,85.5%was recovered,and renal excretion was the primary path-way(77.6%)for cumulative recovery.

Isolation and Neuroprotective Activity of Phenolic Derivatives from the Marine-Derived Fungus Penicillium janthinellum

A new phenolic compound, 6-(2-acetyl-3,5-dihydroxybenzyl)-4-hydroxy-3-methyl-2H-pyran-2-one(1), along with other six known phenolic derivatives(2-7), were isolated from the mangrove rhizosphere fungus Penicillium janthinellum HK1-6 cultured in potato dextrose broth medium containing 30 g L^(-1) of natural sea salt. The structure of the new compound(1) was elucidated by comprehensive analysis of spectroscopic data including 1D and 2D NMR spectra. The proposed biosynthetic pathway of compound 1 was also studied in this research. Interestingly, a brominated phenolic derivative, aryl bromide(compound 8), was obtained from this fungal strain cultured in medium containing 30 g L^-1 of NaBr instead of natural sea salt. Compound 8 is proposed as a new natural product and formed through bromination of compound 7 when the fungus was cultured with NaBr. The neuroprotective effect of compound 1 on oxygen-glucose deprivation(OGD)-induced injury was investigated in rat spinal cord astrocytes. MTT assay demonstrated that compound 1 can attenuate OGD-induced cell viability loss in rat spinal cord astrocytes.

First total synthesis of marine alkaloid hyrtiosulawesine

Hyrtiosulawesine was isolated from Indonesian specimens of the marine sponges Hyrtios erectus and H.reticulatu in 2002.We report here the first total synthesis of hyrtiosulawesine using an efficient and convenient synthetic strategy which could be widely used in the synthesis of otherβ-carboline compounds.All structures of new compounds were confirmed by 1H NMR,13C NMR and HRMS.

The hydrophobic cluster on the surface of protein is the key structural basis for the SDS-resistance of chondroitinase VhChlABC

The application of chondroitinase requires consideration of the complex microenvironment of the target.Our previous research reported a marine-derived sodium dodecyl sulfate(SDS)-resistant chondroitinase VhChlABC.This study further investigated the mechanism of VhChlABC resistance to SDS.Focusing on the hydrophobic cluster on its strong hydrophilic surface,it was found that the reduction of hydrophobicity of surface residues Ala181,Met182,Met183,Ala184,Val185,and Ile305 significantly reduced the SDS resistance and stability.Molecular dynamics(MD)simulation and molecular docking analysis showed that I305G had more conformational flexibility around residue 305 than wild type(WT),which was more conducive to SDS insertion and binding.The affinity of A181G,M182A,M183A,V185A and I305G to SDS was significantly higher than that of WT.In conclusion,the surface hydrophobic microenvironment composed of six residues was the structural basis for SDS resistance.This feature could prevent the binding of SDS and the destruction of hydrophobic packaging by increasing the rigid conformation of protein and reducing the binding force of SDS-protein.The study provides a new idea for the rational design of SDS-resistant proteins and may further promote chondroitinase research in the targeted therapy of lung diseases under the pressure of pulmonary surfactant.

Promotive Effects of Alginate-Derived Oligosaccharides on the Inducing Drought Resistance of Tomato

In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Ly-copersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6 molL-1 PEG-6000 solution for 6 h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

Structure and Anti-influenza A(H1N1) Virus Activity of Three Polysaccharides from Eucheuma denticulatum

Three polysaccharides(EW,EH and EA) were prepared from a red alga Eucheuma denticulatum by sequential extraction with cold water,hot water and sodium hydroxide water solution.Their monosaccharide compositions,relative molecular mass and structural characterization were determined by gas chromatography,high performance 1iquid chromatography,fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods.EW was hybrid ι/κ/ν-carrageenan(70 ι/17κ/13ν-carrabiose),EH was mainly ι-carrageenan,and EA was mainly α-1,4-Glucan(88%) but mixed with small amount of ι-carrageenan(12%).The relative molecular mass of EW,EH and EA was 480,580 and 510 kDa,respectively.The anti-influenza A(H1N1) virus activity of these three polysaccharides was evaluated using the Madin-Darby canine kidney cells model.EW showed good anti-H1N1 virus activity,its IC 50 was 276.5 μg mL-1,and the inhibition rate to H1N1 virus was 52% when its concentration was 250 μg mL-1.The IC 50 of ι-carrageenan EH was 366.4 μg mL-1,whereas EA showed lower anti-H1N1 virus activity(IC 50 >430 μg mL-1).Available data obtained give positive evidence that the hybrid carrageenan EW from Eucheuma denticulatum can be used as potential anti-H1N1 virus inhibitor in future.

Preparation of κ-carra-Oligosaccharides with Microwave Assisted Acid Hydrolysis Method

A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization(DP) of oligosaccharides was detected by high performance thin layer chromatography(HPTLC) and polyacrylamide gel electrophoresis(PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg m L-1; the reaction solution was adjusted to p H 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15℃ min. Oligosaccharides were separated by a Superdex 30 column(2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry(ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.

Evaluation of Antitumor,Immunomodulatory and Free Radical Scavenging Effects of A New Herbal Prescription Seaweed Complex Preparation

Seaweed Complex Preparation(SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs,and it has been used for treatment of lung cancer,liver cancer and digestive cancer.However,little information is available about the pharmacodynamic basis.The antitumor,immunomodulatory and free radical scavenging effects of SCP were evaluated in this study.Transplanted tumor in vivo method was used to determine the antitumor effect.The effects on splenocyte proliferation and phagocytosis of macrophages in tumor-bearing mice were measured by the MTT method and the phagocytizing cock red blood cell(CRBC) method respectively.The scavenging activities of SCP on DPPH and hydroxyl radicals in vitro were investigated.It was found that the medium-dose and high-dose of SCP could significantly inhibit the growth of transplanted hepatic tumor of murine hepatocarcinoma cell line H22,and promote proliferation of splenocytes and phagocytosis of macrophages.SCP possessed noticeable scavenging activities on DPPH and hydroxyl radicals.The antitumor effects of SCP might be achieved by improving immune system and scavenging free radicals,which is in accordance with the viewpoint of traditional Chinese medicine in promoting the body resistance and eliminating pathogenic factors for cancer treatment.

Properties of Polysaccharides in Several Seaweeds from Atlantic Canada and Their Potential Anti-Influenza Viral Activities

To explore the polysaccharides from selected seaweeds of Atlantic Canada and to evaluate their potential anti-influenza virus activities, polysaccharides were isolated from several Atlantic Canadian seaweeds, including three red algae (Polysiphonia lanosa, Furcellaria lumbricalis, and Palmaria palmata), two brown algae (Ascophyllum nodosum and Fucus vesiculosus), and one green alga (Ulva lactuca) by sequential extraction with cold water, hot water, and alkali solutions. These polysaccharides were ana-lyzed for monosaccharide composition and other general chemical properties, and they were evaluated for anti-influenza virus activities. Total sugar contents in these polysaccharides ranged from 15.4% (in U. lactuca) to 91.4% (in F. lumbricalis); sulfation level was as high as 17.6% in a polysaccharide from U. lactuca, whereas it could not be detected in an alikali-extract from P. palmaria. For polysaccharides from red seaweeds, the main sugar units were sulfated galactans (agar or carrageenan) for P. lanosa, F. lumbricalis, and xylans for P. palmata. In brown seaweeds, the polysaccharides largely contained sulfated fucans, whereas the polysaccharides in green seaweed were mainly composed of heteroglycuronans. Screening for antiviral activity against influenza A/PR/8/34 (H1N1) virus revealed that brown algal polysaccharides were particularly effective. Seaweeds from Atlantic Canada are a good source of marine polysaccharides with potential antiviral properties.

Preparation, Characterization and Pharmacokinetics of Fluorescence Labeled Propylene Glycol Alginate Sodium Sulfate

A rapid and sensitive fluorescence labeling method was developed and validated for the microanalysis of a sulfated polysaccharide drug,namely propylene glycol alginate sodium sulfate(PSS), in rat plasma. Fluorescein isothiocyanate(FITC) was selected to label PSS, and 1, 6-diaminohexane was used to link PSS and FITC in order to prepare FITC-labeled PSS(F-PSS) through a reductive amination reaction. F-PSS was identified by UV-Vis, FT-IR and 1H-NMR spectrum. The cell stability and cytotoxicity of F-PSS were tested in Madin-Darby canine kidney(MDCK) cells. The results indicated that the labeling efficiency of F-PSS was 0.522% ± 0.0248% and the absolute bioavailability was 8.39%. F-PSS was stable in MDCK cells without obvious cytotoxicity. The method was sensitive and reliable; it showed a good linearity, precision, recovery and stability. The FITC labeling method can be applied to investigating the absorption and metabolism of PSS and other polysaccharides in biological samples.

Polyphosphorous acid catalyzed cyclization in the synthesis of cryptolepine derivatives

11-Oxo-10,11-dihydroxy-5H-indolo [3,2， b ]quinoline7 羧基的酸被 polyphosphorous 酸明确地获得有最佳的反应条件的催化环合。生物试金证明它潜在地禁止 proteasomal 在 vitro 的像糜蛋白酶的活动并且压制乳癌房间生长。

Edible seaweed-derived constituents: an undisclosed source of neuroprotective compounds

Edible marine algae,or seaweeds,are a rich source of several bioactive compounds including phytosterols,carotenoids,and polysaccharides.Over the last decades,seaweed-derived constituents turned out to not only reside in the systemic circulation,but are able to cross the blood-brain barrier to exert neuro-active functions both in homeostatic and pathological conditions.Therefore,seaweed-derived constituents have gained increasing interest for their neuro-immunomodulatory and neuroprotective properties,rendering them interesting candidates for the management of several neurodegenerative disorders.In particular seaweed-derived phytosterols gained interest for the treatment of neurodegenerative disorders as they potentiate neuroplasticity,enhance phagocytic clearance of neurotoxic peptides and have anti-inflammatory properties.Though,the anti-inflammatory and anti-oxidative properties of other constituents including carotenoids,phenols and polysaccharides have recently gained more interest.In this review,we provide an overview of a selection of the described neuro-active properties of seaweed-derived constituents with a focus on phytosterols.

Chemical Characteristics and Anticoagulant Activities of Two Sulfated Polysaccharides from Enteromorpha linza (Chlorophyta)

Two sulfated polysaccharides, designated MP and SP, were extracted from the marine green alga Enteromorpha linza using hot water and then purified using ion-exchange and size-exclusion chromatography. The anticoagulant activities of MP and SP were examined by determination of their activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT) using human plasma. Results showed that MP and SP were composed of abundant rhamnose with small amounts of xylose and glucuronic acid, whereas SP also contained a small amount of galactose. Approximate molecular weights of MP and SP were 535 and 502 kDa, respectively. As compared with SP, MP had higher contents of sulfate ester (19.0%) and uronic acid (14.9%). The MP mainly consisted of (1→4)-linked rhamnose residues with partially sulfated groups at the C-3 position, and small amounts of (1→3, 4)-linked rhamnose, (1→2, 4)-linked rhamnose, (1→4)-linked glucuronic acid and (1→4)-linked xylose residues. The SP contained abundant (1→4)-linked rhamnose with minor amounts of (1→3)-linked rhamnose, (1→3, 4)-linked rhamnose, (1→2, 4)-linked rhamnose, (1→4)-linked glucuronic acid, (1→4)-linked xylose, and (1→3)-linked galactose residues. The sulfate groups were mainly located at C-3 of (1→4)-linked rhamnose residues. Both MP and SP, in particular the former, effectively prolonged APTT and TT. This work demonstrates that MP and SP have unique structural characteristics distinct from those of other sulfated polysaccharides from Enteromorpha. The MP is a potential source of anticoagulant, and the difference in anticoagulant activities of the two sulfated polysaccharides is directly linked to the discrepancy of their chemical features.

Effects of Sulfate Chitosan Derivatives on Nonalcoholic Fatty Liver Disease

Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.

First total synthesis of eudistalbin A

Eudistalbin A 从海洋的有被膜的 eudistoma 相册被孤立并且拥有细胞毒素的活动(ED50 < 3.2 渭 g /mL ) 在对 KB 人的口腔的 carinoma 细胞的生长的 vitro。合成 eudistalbin A 显示出有势力对有用新陈代谢的试金 MTT 的 2.1 渭 m ol/L 的 IC50 价值的胸癌房间线 MDA-231 的禁止的活动。新混合物的所有结构被 1H NMR， 13C NMR， HRMS 和光旋转证实。

Inhibitory effects and mechanisms of high molecular-weight phlorotannins from Sargassum thunbergii on ADP-induced platelet aggregation

We evaluated the effects of high molecular-weight phlorotannins from Sargassum thunbergii(STP) on ADP-induced platelet aggregation and arachidonic acid(AA) metabolism in New Zealand white rabbits and Wistar rats.The inhibition of STP on platelet aggregation was investigated using a turbidimetric method,and the levels of the terminal products of AA metabolism were measured using the corresponding kits for maleic dialdehyde(MDA),thromboxane B2(TXB2) and 6-keto-prostaglandin F1α(6-keto-PGF1α) by colorimetry and radioimmunoassay,as appropriate.We found that STP could inhibit ADP-induced platelet aggregation,and the inhibitory ratio was 91.50% at the STP concentration of 4.0 mg/mL.Furthermore,STP markedly affected AA metabolism by decreasing the synthesis of MDA(P<0.01) and increasing the synthesis of 6-keto-PGF1α,thus changing the plasma TXB2/6-keto-PGF1α balance when the platelets were activated(P<0.01).Therefore,STP altered AA metabolism and these findings partly revealed the molecular mechanism by which STP inhibits ADP-induced platelet aggregation.

Synthesis and Pharmacokinetic Property Improvement of Deuterated Plinabulin 9

Plinabulin,a potent microtubule-targeting agent,is derived from marine natural diketopiperazine ‘phenylahistin'.To develop novel plinabulin analogue that could display better pharmacokinetic properties and less side effects,deuterated plinabulin 9 was synthesized and evaluated in vitro and in vivo.In comparison with plinabulin,in vivo pharmacokinetic studies indicated that the deuterated derivative 9 could alter blood circulation behavior obviously,which was proved by increased area under the plasma concentration-time curve(AUC_(0–∞)),reduced clearance(CL),and prolonged total body mean residence time(MRT).The derivative 9 also has higher inhibition rates against Bx PC-3,Jurkat and A-431 tumor cell lines as compared with its prototype plinabulin.Therefore,the deuterated compound 9 might be developed as a potential agent for different cancer treatments.