南海海绵的结构多样性和生物活性

海绵是重要的海洋生物资源,由于其生态条件特殊,产生的天然产物结构多样、生物活性显著。本文就作者近年对我国南海海绵代谢产物及其生物活性研究的部分结果进行总结,以阐明我国海绵生物资源的结构多样性,为我国海绵作为药用资源的深入研究提供参考依据。     

A clinical armamentarium of marine-derived anti-cancer compounds

The sea, covering 70% of the Earth's surface, offers a considerably broader spectrum of biological diversity than terra firma. Containing approximately 75% of all living organisms, the marine environment offers a rich source of natural products with potential therapeutic application. Marine organisms have evolved the enzymatic capability to produce potent chemical entities that make them promising sources of innovative cytotoxic compounds. Prominent in the identification and development of novel anti-cancer agents from marine sources is the Spanish biotechnology company, PharmaMar, which currently has a large number of oncology products in late preclinical and clinical development. These include: ecteinascidin-743 (ET-743), a marine-derived antitumor agent isolated from the Caribbean tunicate, Ecteinascidia turbinata; aplidine (Aplidin), a cyclopeptide cytotoxic agent derived from the Mediterranean tunicate, Aplidium albicans; kahalalide F, a depsipeptide isolated from the Hawaiian mollusc, Elysia rufescens; and ES-285, a molecule isolated from the mollusc, Spisula polynyma. Many of these innovative compounds have novel mechanisms of anti-tumor action that have yet to be fully elucidated.     

Drugs from the deep: marine natural products as drug candidates

In recent years, marine natural product bioprospecting has yielded a considerable number of drug candidates. Most of these molecules are still in preclinical or early clinical development but some are already on the market, such as cytarabine, or are predicted to be approved soon, such as ET743 (Yondelis). Research into the ecology of marine natural products has shown that many of these compounds function as chemical weapons and have evolved into highly potent inhibitors of physiological processes in the prey, predators or competitors of the marine organisms that use them. Some of the natural products isolated from marine invertebrates have been shown to be, or are suspected to be, of microbial origin and this is now thought to be the case for the majority of such molecules. Marine microorganisms, whose immense genetic and biochemical diversity is only beginning to be appreciated, look likely to become a rich source of novel chemical entities for the discovery of more effective drugs.     

Drug discovery from natural sources

Organic compounds from terrestrial and marine organisms have extensive past and present use in the treatment of many diseases and serve as compounds of interest both in their natural form and as templates for synthetic modification. Over 20 new drugs launched on the market between 2000 and 2005, originating from terrestrial plants, terrestrial microorganisms, marine organisms, and terrestrial vertebrates and invertebrates, are described. These approved substances, representative of very wide chemical diversity, together with several other natural products or their analogs undergoing clinical trials, continue to demonstrate the importance of compounds from natural sources in modern drug discovery efforts.     

Effect of Carrier Excipient and Processing on Stability of Indorenate Hydrochloride/Excipient Mixtures

The purpose of this investigation was to determine the solid-state chemical stability of a model drug, indorenate hydrochloride, as a function of carrier excipient and mixing process. Physical mixtures and granules were prepared by tumble mixing and alcoholic granulation with and without binder. Stability of the mixtures was estimated using differential scanning calorimetry and isothermal degradation studies at 40, 50, and 60°C. Average first-order degradation constants at 25°C, extrapolated from isothermal studies, were much lower for indorenate hydrochloride after tumbling mixing with microcrystalline cellulose (3.45 × 10^{? 5} day^{? 1}) than those obtained after tumbling mixing with lactose (112.0 × 10^{? 5} day^{? 1}). Distribution of the drug on the excipient's surface, through granulation with and without Povidone, increased the average drug degradation rates in granules with microcrystalline cellulose (36.2 × 10^{? 5} day^{? 1}) as well as in granules with lactose (326 × 10^{? 5} day^{? 1}). Partially amorphous lactose (spray-dried lactose) showed higher average degradation rates (310.5 × 10^{? 5} day^{? 1}) than crystalline lactose (199.3 × 10^{? 5} day^{? 1}). It appears that the amorphous portion of the drug as well as that of reacting excipients play a major role in affecting the reaction rate. The calorimetric studies showed a strong solid–solid interaction between indorenate hydrochloride and lactose, suggesting chemical incompatibility. This strong solid–solid interaction was characterized by disappearance of typical transition peaks of lactose at temperatures above 200°C and the development of new peaks at about 130–170°C. No major changes in transition peaks were observed in mixtures of microcrystalline cellulose and indorenate hydrochloride, suggesting chemical compatibility. Calorimetric results allow the prediction of the chemical incompatibility between indorenate hydrochloride and lactose observed in isothermal degradation studies.     

海洋来源的微管去稳定剂抗肿瘤药物研究进展

摘要：微管是细胞骨架重要组成成分,是筛选抗肿瘤药物的重要靶标。海洋生态系统的极端环境使海洋生物具备产生独特 化学结构和生理活性天然产物的能力,为新药发现提供了物质基础。本文主要综述了1972-2021年从海洋生物中分离鉴定的成 药性较好的微管去稳定剂抗肿瘤药物的研究进展,总结了活性化合物来源、构效关系,临床研究进展,化学全合成及衍生物的 研究情况等,以期为医药工作者提供新的研究思路,推进靶向微管海洋抗肿瘤药物的发展。     

Natural products with anti-HIV activity from marine organisms

In order to combat the human immunodeficiency virus (HIV), diverse strategies have been developed to research on compounds which can be developed as therapeutic agents. Screening of natural products derived from numerous species has afforded metabolites with significant antiviral activity against the HIV. The marine environment representing approximately half of the global biodiversity offers an enormous resource for novel compounds. Currently more than 150 natural products with promising levels of anti-HIV activity have been isolated following bioassay guided protocols from aqueous or organic extracts of marine organisms. Some of the most characteristic marinemetabolites that have exhibited significant anti-HIV activity on different biochemical assays designed for chemotherapeutic strategies are: Cyanovirin-N, a protein from a blue green alga; various sulfated polysaccharides extracted from seaweeds (i.e. Nothogenia fastigiata, Aghardhiella tenera); the peptides tachyplesin and polyphemusin, which are highly abundant in hemocyte debris of the horseshoe crabs Tachypleus tridentatus and Limulus polyphemus; sponge metabolites such as avarol, avarone, ilimaquinone and several phloroglucinols; and a number of metabolites from marine fungi such as equisetin, phomasetin and integric acid. Considering that number of unique metabolites that have been isolated from a small extent of the ocean's biological and chemical diversity, the oceans represent a virtually untapped resource for the discovery of novel bioactive compounds.     

Survival of prokaryotes in a polluted waste dump during remediation by alkaline hydrolysis

A combination of culture-dependent and culture-independent techniques was used to characterize bacterial and archaeal communities in a highly polluted waste dump and to assess the effect of remediation by alkaline hydrolysis on these communities. This waste dump (Breakwater 42), located in Denmark, contains approximately 100 different toxic compounds including large amounts of organophosphorous pesticides such as parathions. The alkaline hydrolysis (12 months at pH >12) decimated bacterial and archaeal abundances, as estimated by 16S rRNA gene–based qPCR, from 2.1 × 10⁴ and 2.9 × 10³ gene copies per gram wet soil respectively to below the detection limit of the qPCR assay. Clone libraries constructed from PCR-amplified 16S rRNA gene fragments showed a significant reduction in bacterial diversity as a result of the alkaline hydrolysis, with preferential survival of Betaproteobacteria, which increased in relative abundance from 0 to 48 %. Many of the bacterial clone sequences and the 27 isolates were related to known xenobiotic degraders. An archaeal clone library from a non-hydrolyzed sample showed the presence of three main clusters, two representing methanogens and one representing marine aerobic ammonia oxidizers. Isolation of alkalitolerant bacterial pure cultures from the hydrolyzed soil confirmed that although alkaline hydrolysis severely reduces microbial community diversity and size certain bacteria survive a prolonged alkaline hydrolysis process. Some of the isolates from the hydrolyzed soil were capable of growing at high pH (pH 10.0) in synthetic media indicating that they could become active in in situ biodegradation upon hydrolysis.     

Chemical diversity of bioactive marine natural products: an illustrative case study

The marine environment contains a number of plants, animals and micro organisms, which, due to the unique adaptations to their habitat, elaborate a wide diversity of natural products with specific bioactivities. These products provide a rich source of chemical diversity that can be used to design and develop new potentially useful therapeutic agents. The huge variety of the structures present in marine organisms has been illustrated through the case study of the sponge Plakortis simplex, whose chemical analysis, started in our laboratories about ten years ago, revealed an incredible variety and abundance of secondary metabolites. The obtained results have been presented with the intention of drawing some conclusions of general relevance. Particularly, the problem of the limited availability of natural compounds for both structural and preliminary pharmacological studies has been discussed, this issue becoming a serious obstacle when the pharmacological research reaches a more advanced stage. Furthermore, the origin of the chemodiversity in Plakortis simplex and, in general, in marine invertebrates has been discussed; in this respect, the possible cooperative role of symbiotic micro-organisms in the biosynthesis of the varied metabolic content typical of these organisms has been considered.     

Fragment-based screening with natural products for novel anti-parasitic disease drug discovery

ABSTRACT

Introduction: Fragment-based drug discovery can identify relatively simple compounds with low binding affinity due to fewer binding interactions with protein targets. FBDD reduces the library size and provides simpler starting points for subsequent chemical optimization of initial hits. A much greater proportion of chemical space can be sampled in fragment-based screening compared to larger molecules with typical molecular weights (MWs) of 250–500 g mol^?1 used in high-throughput screening (HTS) libraries.

Areas covered: The authors cover the role of natural products in fragment-based drug discovery against parasitic disease targets. They review the approaches to develop fragment-based libraries either using natural products or natural product-like compounds. The authors present approaches to fragment-based drug discovery against parasitic diseases and compare these libraries with the 3D attributes of natural products.

Expert opinion: To effectively use the three-dimensional properties and the chemical diversity of natural products in fragment-based drug discovery against parasitic diseases, there needs to be a mind-shift. Library design, in the medicinal chemistry area, has acknowledged that escaping flat-land is very important to increase the chances of clinical success. Attempts to increase sp³ richness in fragment libraries are acknowledged. Sufficient low molecular weight natural products are known to create true natural product fragment libraries.     

Strategies for discovering drugs from previously unexplored natural products

Natural products are the most consistently successful source of drug leads. Despite this, their use in drug discovery has fallen out of favour. Natural products continue to provide greater structural diversity than standard combinatorial chemistry and so they offer major opportunities for finding novel low molecular weight lead structures that are active against a wide range of assay targets. As less than 10% of the world's biodiversity has been tested for biological activity, many more useful natural lead compounds are awaiting discovery. The challenge is how to access this natural chemical diversity.     

南极海洋丝状真菌多样性及其次级代谢产物的研究进展

海洋真菌由于能够产生结构新颖,活性独特的次级代谢产物,现已成为药物先导化合物的重要来源。南极海洋独特而严酷的自然环境使得真菌在生物物种、活性代谢产物等方面表现出明显的多样性和新颖性,正在成为微生物药物研究新的重要资源。本文对近年来国内外南极海洋丝状真菌多样性及其次级代谢产物的研究进展进行综述。     

Identification of antidepressant drug leads through the evaluation of marine natural products with neuropsychiatric pharmacophores

The marine environment is a valuable resource for drug discovery due to its diversity of life and associated secondary metabolites. However, there is very little published data on the potential application of marine natural products to treat neuropsychiatric disorders. Many natural products derived from chemically defended organisms in the marine environment have pharmacophores related to serotonin or clinically utilized antidepressant drugs. Therefore, in the present study, compounds selected for their structural similarity to serotonin or established antidepressants were evaluated for antidepressant-like activity using the forced swim and tail suspension tests in mice. The antidepressant positive controls, citalopram (selective serotonin reuptake inhibitor) and despiramine (tricyclic antidepressant) both dose-dependently reduced immobility time in the forced swim and tail suspension tests. Two marine natural product compounds tested, aaptamine and 5,6-dibromo-N,N-dimethyltryptamine, also produced significant antidepressant-like activity in the forced swim test. In the tail suspension test, the antidepressant-like effects of 5,6-dibromo-N,N-dimethyltryptamine were confirmed, whereas aaptamine failed to produce significant results. None of the tested compounds induced hyperlocomotion, indicating that nonspecific stimulant effects could not account for the observed antidepressant-like actions of the compounds. These studies highlight the potential to rationally select marine derived compounds for treating depression and other neuropsychiatric disorders.     

The role of pharmacognosy in modern medicine and pharmacy

This review details the contribution to modern medicine and pharmacy made by natural products and drugs derived from natural products, with an emphasis on essential medicines and new introductions to the market. Areas covered include recent advances in the development of drugs derived from marine organisms, microbes, terrestrial animals, and vascular plants, and current issues regarding botanical medicines. The role of natural products in drug discovery and development is evaluated, particularly with regard to their value as sources of drug leads with "drug-like" properties. A rationale for the success of natural products research in providing new drugs and drug prototypes is presented, drawing on lines of evidence from chemical informatics and chemical ecology. Several innovative strategies for natural products drug discovery and evaluation of botanical medicines are also reviewed.     

New therapeutic approaches by using microorganism-derived compounds

The role of natural products as a source for remedies has been recognized since ancient times. Despite major scientific and technological progress in combinatorial chemistry, drugs derived from natural product still make an enormous contribution to drug discovery today. Nature is an attractive source of new therapeutic candidate compounds since a tremendous chemical diversity is found in millions of species of plants, animals, marine organisms and microorganisms. Microorganisms such as bacteria and fungi have been invaluable to discover drugs and lead compounds. These microorganisms produce a large variety of antimicrobial agents which have evolved to give their hosts an advantage over their competitors in the microbiological world. The screening of microorganisms became highly popular after the discovery of penicillin but in recent years the list of antibacterial agents (bacteria- or fungi-derived) has increased considerably with the arrival of cephalosporins, tetracyclines, aminoglycosides, rifamycins, and chloramphenicol. Although most of the drugs derived from microorganisms are used in antibacterial therapy, some microbial metabolites have provided lead compounds in other fields of medicine. For example: the fungal metabolite lovastatin, which was the lead compound for a series of drugs that lower cholesterol levels, the ciclosporin (fungal metabolite) currently used to suppress the immune response after transplantation operations and sirolimus- a bacterium-derived macrolide- used in the treatment of some cancers. The aim of this review is to analyze the current uses and the future applications in therapeutic treatments of microorganism-derived products (MdPs) and discuss the results obtained in the some clinical trials.     

Marine bacteria and fungi as promising source for new antibiotics

Natural products and derivatives thereof are of considerable importance in the discovery of new pharmaceuticals, for example, for the treatment of cancer, diabetes, inflammation diseases, and infection diseases caused by bacteria, fungi, viruses, or parasites. The great biodiversity of marine microorganisms is reflected in their huge chemical diversity, which provides a rich source of biologically active compounds. An increasing interest in marine microorganisms as promising producers of new compounds with potential medical applications has raised increasing interest in the sustainable exploration of marine microbial resources for the discovery of new antibiotics, which is highlighted. The bottlenecks in the development of drugs using the large marine natural product pipeline are also discussed.     

Natural Products in Drug Discovery and Development. 27-28 June 2005, London, UK

The meeting covered many aspects of the use of natural products in drug discovery and development. The historical and current contributions of natural products to the main classes of medicines, technical improvements to the supply of marine microbial products by fermentation and molecular biology and the value of natural chemical diversity for providing patentable, drug-like lead molecules were among the topics discussed. Several compounds in current clinical trials were described; these included several anticancer compounds and two compounds in development by Phytopharm plc, PYM-50028 (Cogane) and PYM-50018 (Myogane), for the treatment of neurodegenerative disease.     

Applied metabolomics in drug discovery

ABSTRACT

Introduction: The metabolic profile is a direct signature of phenotype and biochemical activity following any perturbation. Metabolites are small molecules present in a biological system including natural products as well as drugs and their metabolism by-products depending on the biological system studied. Metabolomics can provide activity information about possible novel drugs and drug scaffolds, indicate interesting targets for drug development and suggest binding partners of compounds. Furthermore, metabolomics can be used for the discovery of novel natural products and in drug development. Metabolomics can enhance the discovery and testing of new drugs and provide insight into the on- and off-target effects of drugs.

Areas covered: This review focuses primarily on the application of metabolomics in the discovery of active drugs from natural products and the analysis of chemical libraries and the computational analysis of metabolic networks.

Expert opinion: Metabolomics methodology, both experimental and analytical is fast developing. At the same time, databases of compounds are ever growing with the inclusion of more molecular and spectral information. An increasing number of systems are being represented by very detailed metabolic network models. Combining these experimental and computational tools with high throughput drug testing and drug discovery techniques can provide new promising compounds and leads.     

Marine natural products targeting phospholipases A2

Phospholipases A₂ (PLA₂s) form a family of enzymes catalyzing the hydrolysis of membrane phospholipids into arachidonic acid, which is the major precursor of pro-inflammatory eicosanoids. As a result, PLA₂s have been considered as potential targets in anti-inflammatory drug discovery.Marine natural products are a rich source of bioactive compounds, including PLA₂ inhibitors. Here, we review the properties of marine PLA₂ inhibitors identified since the first discovery of PLA₂ inhibitory activity in the marine natural product manoalide in the mid 1980s.