Effect of gambierol and its tetracyclic and heptacyclic analogues in cultured cerebellar neurons: a structure-activity relationships study

The polycyclic ether class of marine natural products has attracted the attention of researchers due to their complex and large chemical structures and diverse biological activities. Gambierol is a marine polycyclic ether toxin, first isolated along with ciguatoxin congeners from the dinoflagellate Gambierdiscus toxicus. The parent compound gambierol and the analogues evaluated in this work share the main crucial elements for biological activity, previously described to be the C28═C29 double bond within the H ring and the unsaturated side chain [ Fuwa , H. , Kainuma , N. , Tachibana , K. , Tsukano , C. , Satake , M. , and Sasaki , M. ( 2004 ) Diverted total synthesis and biological evaluation of gambierol analogues: Elucidation of crucial structural elements for potent toxicity . Chem. Eur. J. 10 , 4894 - 4909 ]. With the aim to gain a deeper understanding of the cellular mechanisms involved in the biological activity of these compounds, we compared its activity in primary cultured neurons. The three compounds inhibited voltage-gated potassium channels (Kv) in a concentration-dependent manner and with similar potency, caused a small inhibition of voltage-gated sodium channels (Nav), and evoked cytosolic calcium oscillations. Moreover, the three compounds elicited a "loss of function" effect on Kv channels at concentrations of 0.1 nM. Additionally, both the tetracyclic and the heptacyclic derivatives of gambierol elicited synchronous calcium oscillations similar to those previously described for gambierol in cultured cerebellar neurons. Neither gambierol nor its tetracyclic derivative elicited cell toxicity, while the heptacyclic analogue caused a time-dependent decrease in cell viability. Neither the tetracyclic nor the heptacyclic analogues of gambierol exhibited lethality in mice after ip injection of 50 or 80 μg/kg of each compound. Altogether, the results presented in this work support an identical mechanism of action for gambierol and its tetracyclic and heptacyclic analogues and indicate a "loss of function" effect on potassium channels even after administration of the three compounds at subnanomolar concentrations. In addition, because gambierol is known to stabilize the closed state of Kv3 channels, the results presented in this paper may have implications for understanding of channel functions and for future development of therapies against ciguatera poisoning and potassium channel-related diseases.     

6个小分子海洋药物的全合成方法

骨架新颖、活性独特的海洋天然产物是药物先导化合物的重要来源,但由于海洋样品采集困难、一些高活性天然产物在海洋生物体中含量低微,往往难以获取足够量的化合物进行后续药物的深入研究,成为海洋小分子药物研究的瓶颈之一。现代有机合成尤其是海洋天然产物全合成的迅猛发展,为获取复杂小分子海洋活性天然产物提供了一个重要手段。探究复杂小分子海洋天然产物合成的新策略和新方法,建立高效、高选择性的规模化制备技术,是国际海洋药物研究的热点。本文就6个上市的小分子海洋药物的全合成研究作一概述,重点阐述有机合成对于成药分子规模化制备的途径。     

Bis and tris indole alkaloids from marine organisms: new leads for drug discovery

The marine organisms are a rich source of varied natural products with unique functionality. Marine natural products chemistry has undergone an explosive growth during the past three decades. A variety of natural products of new molecular structures with diverse biological activities have been reported from marine flora and fauna, thus ensuring motivation in the search of newer natural products. The bis and trisindole alkaloids are a class of marine natural products that show unique promise in the development of new drug leads. 3-hydroxy staurosporine 51, an indolo carbazole having powerful antiproliferative activity. Hamacanthin A 1 and B 2, pyrazinone alkaloids have significant antimicrobial activity. Coscinamides 60-62 and Chondriamides 63-65 an indolic enamides which have anti-HIV and cytotoxic activity respectively. Gelluisine A 66 and B 67, trisindole alkaloids have strong anti-serotonin activity and strong affinity with somatostatin and neuropeptide Y receptors in receptor-binding assays. This report reviews the literature on these alkaloids of marine origin and highlights the isolation, structure, latest synthesis and specific biological activities including cytotoxicity, antiviral, antiparasitic, serotonin antagonism and other pharmacological activities of sixty-nine bis and trisindole alkaloids.     

烯烃关环复分解反应及其在海洋来源抗肿瘤活性大环内酯类化合物全合成中的应用

烯烃关环复分解（Ring-closing olefin metathesis, RCM）反应在天然来源大环内酯的全合成中一般作为关键的一步反应,一直是合成化学家关注的焦点。高活性、结构新颖的海洋来源大环内酯类化合物往往含量低微,从海洋生物中难以大量,这就阻碍了该类化合物后续的生物活性研究。利用有机合成方法全合成该类化合物是解决药源的有效途径。该类化合物全合成中最大的挑战就是如何构建其大环母核骨架。因此,本文主要介绍RCM反应及其近年在海洋来源抗肿瘤活性大环内酯类化合物全合成中的应用。     

Synthetic studies of heterocyclic natural products

Recent reports of the syntheses of heterocyclic natural products that are isolated from bacteria, fungi, plants and marine sources are discussed. This review emphasizes new developments in synthetic methodology and strategies for such products, and the potential biological activity of the metabolites that are described is highlighted. Concepts of conformational analysis, stereoelectronic control and reaction mechanism are all used in the development of new methodology. Despite the variety and scope of synthetic efforts, the synthesis of new organic molecules and the improved synthesis of known molecules remains a major task for organic chemists.     

海洋天然活性物质心血管药理作用的研究进展

从30多年来国内外学者在海洋生物天然活性物质的研究中，对具心血管药理作用的活性产物作系统、概括的报道。从1968年以来获得的55种海洋生物活性物质，对每一种天然产物分别概括其来源、化学成分，并重点阐述其心血管方面的药理作用。系统报道这些海洋天然活性物质的研究成果及进展，对进一步开展海洋心血管药物的研发提供参考。     

Natural peroxy anticancer agents

Present review describes research on novel natural anticancer agents isolated from terrestrial and marine sources. More than 120 cytotoxic anticancer compounds have shown confirmed activity in vitro tumor cell lines bioassay and are of current interest to Natural Cancer Institute for further in vivo evaluation. Intensive searches for new classes of pharmacologically potent agents produced by terrestrial and marine organisms have resulted in the discovery of dozens of compounds possessing high cytotoxic activities. However, only a limited number of them have been tested in pre-clinical and clinical trials. One of the reasons is a limited supply of the active ingredients from the natural sources. However, the pre-clinical and clinical development of many terrestrial and/or marine-derived natural products into pharmaceuticals is often hampered by a limited supply from the natural source. Total synthesis is of vital importance in these situations, allowing for the production of useful quantities of the target compound for further biological evaluation. With computer program PASS some additional biological activities are also predicted, which point toward new possible applications of these compounds. This review emphasizes the role of terrestrial and marine peroxides as an important source of leads for drug discovery.     

具有抗菌活性的海洋真菌天然产物研究新进展

近年来,病原微生物的耐药性已严重威胁到人类健康,从海洋微生物中寻找对耐药菌敏感的化合物成为研究的热点,其中海洋真菌因其能够产生大量结构新颖、活性显著的代谢产物而受到广泛关注。本文按照海洋真菌的来源进行分类,从海洋动物来源真菌、红树林来源真菌、海藻来源真菌、海水来源真菌等4个方面,综述了2014年来发表的具有抗菌活性的海洋真菌来源的新的天然产物,主要介绍天然产物的化学结构和生物活性,化合物结构式曾有文献报道的未包括在内,为具有抗菌活性的海洋真菌天然产物的进一步研究开发提供了参考。     

海洋来源的荧光天然产物

近年来海洋天然产物越来越引起科学家们的关注。由于在珊瑚礁珊瑚和海葵等海洋无脊椎动物中具有荧光现象普遍,许多海洋天然产物除了药用和生物学价值外,还具有突出的荧光特性。本文从来源、发色团结构以及应用等方面进行综述,介绍了Ageladine A、Marmycin A、两种新型羟基蒽醌和Zoanthoxanthins等几种海洋来源的荧光小分子,以及代表性的海洋荧光蛋白GFP家族和藻胆蛋白。它们具有独特的光学性质将在生物医学领域广泛应用。     

Niphatenones, glycerol ethers from the sponge Niphates digitalis block androgen receptor transcriptional activity in prostate cancer cells: structure elucidation, synthesis, and biological activity

Extracts of the marine sponge Niphates digitalis collected in Dominica showed strong activity in a cell-based assay designed to detect antagonists of the androgen receptor (AR) that could act as lead compounds for the development of a new class of drugs to treat castration recurrent prostate cancer (CRPC). Assay-guided fractionation showed that niphatenones A (3) and B (4), two new glycerol ether lipids, were the active components of the extracts. The structures of 3 and 4 were elucidated by analysis of NMR and MS data and confimed via total synthesis. Biological evaluation of synthetic analogues of the niphatenones has shown that the enantiomers 7 and 8 are more potent than the natural products in the screening assay and defined preliminary SAR for the new AR antagonist pharmacophore, including the finding that the Michael acceptor enone functionality is not required for activity. Niphatenone B (4) and its enantiomer 8 blocked androgen-induced proliferation of LNCaP prostate cancer cells but had no effect on the proliferation of PC3 prostate cancer cells that do not express functional AR, consistent with activity as AR antagonists. Use of the propargyl ether 44 and Click chemistry showed that niphatenone B binds covalently to the activation function-1 (AF1) region of the AR N-terminus domain (NTD).     

来源于海洋链霉菌属的宜他霉素

如今,医院（HA）相关型和社区（CA）相关型的耐甲氧西林金黄色葡萄球菌（MRSA）的大量出现使人们不顾一切地去寻找有效的新型抗生素。然而,陆地资源的减少,使人们将目光转向了有待开发的海洋资源。在浩瀚的海洋中存在着大量令人激动、活性独特、结构新颖的次级代谢产物,它们已成为发现重要先导药物和新的生物作用机制的主要源泉。本文将综述来源于海洋链霉菌属放线菌CNS-575且具有很强抗MRSA活性的宜他霉素,主要从其来源、化学性质、结构、活性以及未来开发价值进行论述。     

Synthesis and biological evaluation of imidazoquinoxalinones, imidazole analogues of pyrroloiminoquinone marine natural products

This report describes the synthesis and biological activity of imidazoquinoxalines, benzimidazole-based analogues of indole-based pyrroloiminoquinone marine natural products. Our analogues consist of series 1, which possesses the ethylene tether and extended amidine feature found in the pyrroloiminoquinone natural products, and series 2, which also has the ethylene tether but with an electrostatically stabilized iminoquinone rather than a resonance stabilized iminoquinone (i.e., extended amidine). The biological properties of series 1 analogues, bearing electron-rich side chain rings (indole and phenol), display cytostatic and cytotoxic properties similar to that of the pyrroloiminoquinone natural products. In contrast, COMPARE analysis suggests that analogues bearing benzyl and phenethyl side chains possess a different cytotoxicity mechanism. Hollow fiber assays of analogs of 1 indicate promising antitumor activity and acceptable levels of toxicity. One analogue of 2 is active only against breast cancer cell lines, but the cellular target is as yet unknown.     

Enhancing marine natural product structural diversity and bioactivity through semisynthesis and biocatalysis

In the last several decades the plants, animals and microbes from the marine environment have revealed a portion of what is clearly a tremendous resource for structurally diverse and bioactive secondary metabolites. Many of these extraordinarily sophisticated and bioactive natural products can be isolated in significant quantities without great difficulty. As a result these readily available bioactive natural products provide valuable starting materials for the rational generation of libraries of compounds prepared through semisynthesis and biocatalysis. A review of our work using marine natural products to generate rationally designed compound libraries and their biological activity against infectious diseases, cancer and neurological targets is presented. The marine natural products utilized to date as starting materials consist of compounds from a variety of structural classes and include: aureol, puupehenone, sarcophine, palinurin, and the manzamine alkaloids. The possibility to generate diverse bioactive products beginning with a marine natural product scaffold is a direct result of improvements made in the technologies to harvest samples from the ocean, purify and characterize complex natural products quickly and complete chemical reactions and biotransformations in parallel. As a result the vast resources of the ocean can now be utilized routinely to design and produce countless products to be evaluated as part of drug discovery and development programs.     

Advances in marine natural products of the indole and annelated indole series: chemical and biological aspects

Marine natural products, form a field of scientific endeavour, that has recently grown considerably. The isolation, biological evaluation, chemical properties and synthetic elaborations of products of marine organisms have attracted the attention of organic chemists, medicinal chemists, biologists and pharmacists. In this context a structurally and biologically highly interesting class is represented by the marine natural products containing an indole moiety in a pure substituted form or in an anellated form. The present review summarizes primarily the actual results concerning these products as new pharmacologically attractive lead compounds for drug design. The chemistry, biological evaluation and synthetic aspects are discussed. The spectrum of compounds represented comprises simply substituted indoles, peptidic products, dimeric indoles, anellated indoles and a variety of carbazoles. Most of them exhibit significant cytotoxicities.     

Natural marine anti-inflammatory products

The marine environment has been shown to be the source of a great diversity of chemical structures with promising biological activities. The isolation, biological evaluation, chemical properties and synthetic elaborations of the products of marine organisms and microorganisms have attracted the attention of organic chemists, medicinal chemists, biologists and pharmacists. Marine organisms and microorganisms have provided a large proportion of the natural anti-inflammatory products over the last years. Marine organisms include green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates, echinoderms, miscellaneous marine organisms and marine microorganisms and phytoplankton. This review describes current progress in the development of a selection of new anti-inflammatory agents from marine sources. The chemistry and biological evaluation are discussed.     

Marine peptides and related compounds in clinical trial

Advances in the sophisticated instruments for the isolation and characterization of marine natural products, and development in the biological assay systems, have resulted in the discovery of various compounds of biomedical application. Marine natural products have been a source of new leads for the treatment of many deadly diseases such as cancer, acquired immuno-deficiency syndrome (AIDS) etc. The compounds of marine origin are diverse in structural class from simple linear peptides to complex macrocyclic polyethers. Number of marine peptides have been isolated in recent years which exhibit potent biological activities, and many of the compounds showed promising anticancer activity. Didemnin was the first marine peptide that entered in human clinical trials in US for the treatment of cancer, and other anticancer peptides such as kahalalide F, hemiasterlin, dolastatins, cemadotin, soblidotin, didemnins and aplidine have entered in the clinical trials. Clinical status of anticancer marine derived peptides have been discussed and reviewed.     

海洋天然产物研究与新药开发

近年来海洋天然产物越来越引起科学家们的关注。在浩瀚的海洋中存在着大量超乎人们想象的化学结构新颖、生物活性多样、作用机制独特的次生代谢产物。海洋天然产物已成为发现重要先导药物的主要源泉。本文主要探讨近年来发现的重要的海洋天然活性产物以及在新药开发中所起的作用。     

玫瑰茄的药理作用于临床应用

玫瑰茄广泛分布于全球热带和亚热带地区.其花药食两用,富含维生素C、氨基酸、有机酸、黄酮类、花青苷类等多种成分,亦作为天然色素的资源植物.玫瑰茄除具有消除疲劳、清热解暑的功效外,还具有降压、调血脂、抗肥胖、保肝、抗糖尿病并发症等多种药理作用,用于心脏病、神经疾病和癌症等的治疗.综述了玫瑰茄的药理作用及临床研究进展,为其广泛应用提供参考.     

海洋真菌来源的抗植物病原菌活性天然产物

近年来,海洋真菌来源的天然产物因其化学结构新颖和活性显著而受到广泛关注,其中许多代谢产物对植物病原菌具有较强的抗菌性。本文综述了从2002年-2018年5月间报道的33个新的抗植物病原菌活性天然产物的来源、结构及其生物活性。     

海洋微生物活性代谢产物的研究进展

研究海洋微生物活性物质 ,不但能发现结构新颖的化合物 ,而且能寻找到新的强效抗生素和抗病毒等活性的新药以及其它有用物质 ,这一新兴领域的研究在理论上和维护人类健康方面都有重大意义。本文综述了 2 0 0 0年以来对海洋微生物 (包括海洋细菌、蓝细菌、放线菌、真菌 )活性代谢产物的研究进展 ,共引用文献 6 9篇 ,包括 12 9个活性代谢产物。重点描述了这些化合物的相关生理活性 ,产生它们的微生物及微生物的采集地。