Role Of Natural Products Research Articles

The use of natural products for improving and maintaining bone health

Bone is a metabolically active tissue throughout life, and bone remodelling maintains bone strength and controls mineral homeostasis. It is carried out by two specialised cell types, the osteoclast, which resorbs and recycles components of old bone matrix, and the osteoblast, which synthesises new bone matrix. After the age of 30, skeletal mass deteriorates as resorption exceeds formation, at a rate of ˜ 3% for males and 8% for females, resulting in increased fragility and susceptibility to fracture. This is osteoporosis, which affects an estimated 75 million people in Europe, USA and Japan. Worldwide, 1 in 3 women and 1 in 5 men over 50 will experience osteoporotic fractures [1]. Current treatment focuses mainly on preventing bone resorption using bisphosphonates, hormone replacement therapy, selective oestrogen receptor modulators (SERMs) and vitamin D analogues, but these simply halt further deterioration of skeletal microarchitecture [2]. Treatments which can increase bone mass and accelerate fracture healing are urgently needed and recent research indicates a role for natural products in the prevention and treatment of osteoporosis, by enhancing osteoblast activity as well as reducing osteoclast activity [2, 3]. Epidemiological evidence suggests a positive association between the accrual and maintenance of bone mass and fruit and vegetable intake, and experimental studies show that this is likely to be due to flavonoids and related polyphenols, which have the advantages of low toxicity whilst providing other health benefits at the same time [2]. Furthermore, natural phytoestrogens are now being compared to SERMs in terms of their binding to oestrogen receptors [4]. This presentation will give an overview of phytochemicals which modulate bone metabolism, including flavonoids, polyphenols, beta-glucans, allyl sulphides and even cannabinoids, from the numerous published experimental studies to the few clinical trials reported.

The role of natural products in crop protection

Agricultural production per unit area of cultivated land has increased dramatically over the past 60 years due to several innovations, including the introduction of modern pest management chemicals. A significant number of these synthetic pesticides were inspired by natural compounds. Synthetic alterations of the natural compounds were made to improve pesticide activity, reduce cost, and in some cases to lengthen half-life. However, there is concern over the potential for environmental damage and adverse toxicological effects of many of some of the currently used synthetic pesticides. Natural compounds used as pesticides generally leave a smaller environmental footprint and many are toxicologically benign. Furthermore, the growing area of organic agriculture will only accept natural pest management chemicals. Thus, there is a resurgence of research effort to discover natural pesticide compounds that can be used like synthetic pesticides. The US EPA categorizes such products as biochemical biopesticides. The discovery process for natural pesticides and specific examples of successes in this area will be discussed.

Thymoquinone protects against cigarette smoke extract‐induced vascular dysfunction through inhibition of the RhoA/Rho‐kinase signaling pathway (849.1)

There is an ever‐growing focus on the role of natural products in modulating reactive oxygen species (ROS) and RhoA/Rho kinase‐mediated vascular disease. Thymoquinone (TQ), a constituent of the volatile oil derived from Nigella sativa seeds, possesses promising antioxidant and vasodilating properties via its effect on multiple signaling pathways; however, the effect of TQ on the RhoA/Rho‐Kinase pathway remains to be investigated. Cigarette smoke extract (CSE)‐exposed rat aortic rings were mounted in a wire myograph and subjected to contraction and relaxation. TQ protected against CSE‐induced impairment of acetylcholine‐induced endothelium‐dependent relaxation, and decreased CSE‐induced ROS generation and glutathione depletion. Preincubation of aortic rings for 20 min with TQ attenuated the CSE‐enhanced phenylephrine‐induced vascular tension in endothelium‐denuded rings. TQ‐pretreated rings showed a decrease in CSE‐induced RhoA activation and phosphorylation of myosin light chain‐20, myosin phosphatase‐targeting subunit 1 and protein kinase CPI‐17. These data indicate that TQ inhibited ROS generation‐induced RhoA/Rho kinase pathway activation, protecting against CSE‐induced vascular dysfunction. This study provides mechanistic insight for understanding the molecular basis and efficacy of TQ on vascular disease management.Grant Funding Source: Supported by NIH #00000784 to JLZ; Egyptian government

Chemoattraction of the pearlfish Encheliophis vermicularis to the sea cucumber Holothuria leucospilota

The specificity of the relationship between Indo-Pacific pearlfish (family Carapidae) and their hosts, the sea cucumbers (Holothuridae), was examined in Okinawa, Japan. While some species of pearlfishes lived in several species of sea cucumbers, one species, Encheliophis vermicularis, was very specific and was only found in Holothuria leucospilota. The role of natural products in this relationship was then examined in maze tests, and highly polar (water soluble) substances in the coelomic fluid, body wall, and Cuvierian tubules of H. leucospilota were found to attract the pearlfish. Coelomic extracts were active at low concentrations and holothurins A and B found within these extracts were implicated as the active factors in maze tests. The possible role of these products in other symbiotic relationships between pearlfishes and sea cucumbers, some of which seem species-specific, now needs to be examined.

Herbal medicines for the treatment of nonalcoholic steatohepatitis: current scenario and future prospects.

Nonalcoholic steatohepatitis (NASH) is a multifactorial disease and has close correlations with other metabolic disorders. This makes its treatment difficult using a single pharmacological drug. Use of plant extract/decoction or polyherbal formulation to treat various liver diseases is very well mentioned in various traditional systems of medicine (Ayurveda, Japanese or traditional Chinese Medicine, and Kampo medicine). Medicinal herbs are known for their multifaceted implications and thus can form an effective treatment schedule against NASH. Till date, several plant extracts, polyherbal formulations, and phytochemicals have been evaluated for their possible therapeutic potential in preventing onset and progression of NASH in experimental models, but clinical studies using the same are sparse. Herbal extracts with antioxidants, antidiabetic, and antihyperlipidemic properties have been shown to ameliorate symptoms of NASH. This review article is a meticulous compilation of our current knowledge on the role of natural products in alleviating NASH and possible lacunae in research that needs to be addressed.

Natural products in synthesis and biosynthesis

This is the second Thematic Series in the Beilstein Journal of Organic Chemistry focused on natural products. While the first Thematic Series summarized recent research work on the biosynthesis and function of natural products [1–2], the present Thematic Series deals with synthetic and biosynthetic aspects. Why the research interest in natural products? Natural products are structurally fascinating as is spectacularly demonstrated by the prominent examples of maitotoxin [3], the largest non-polymer secondary metabolite known to date, or calicheamycin (Fig. 1), which possibly holds the record in carrying the most diverse functional groups including an enediyne subunit, a deoxysugar, an aminosugar, a hydroxylamine linkage between two sugar subunits, a carbamate, an aromatic iodide, a thioester, and a trisulfide [4]. Natural products have also been used by humankind since ancient times and are part of our traditions and culture, as is evident from the widespread consumption of coffee, tea, tobacco and cocoa, drugs that all contain alkaloids with stimulating effects. More importantly, starting from their usage in traditional medicine natural products – and today also compounds inspired by natural products – are indispensable in the treatment of various threatening infectious diseases. The rapid spreading of antibiotic resistances and the comeback of some infectious diseases already claimed to be eliminated should sharpen our minds for the beneficial roles of natural products in medicine as well as their responsible use. This should be a strong appeal upon the responsibility of both researchers and decision makers in the academic sciences and the pharmaceutical industry. Figure 1 Calicheamycin. Why should we have a look at the synthetic and biosynthetic aspects of natural products in this Thematic Series? Of course, the chemistry of nature and as it is used by chemists is one and the same and makes use of the same intrinsic reactivity of molecules. It is fascinating to see that a particular chemical reaction, believed to be invented by man, is in fact already used for millions – sometimes even billions – of years by Mother Nature. An interesting example is the discovery of the Diels–Alder reaction in the 1920s and its later enhancement into an enantioselective reaction by the development of chiral catalysts. But a Diels–Alder reaction also occurs in the biosynthesis of lovastatin and is likely catalysed by a Diels–Alderase [5], a natural analogue of man-made chiral catalysts! Beyond such fascinating examples of comparing natural to artificial systems it is their interplay that may provide the best solutions to some of the most urgent problems of our time. A perfect example is artemisinin, a terpenoid natural product from Artemisia annua, which is highly efficient in the treatment of malaria. The problem is that the plant produces only small and variable amounts, thereby making the isolation procedure difficult and expensive. Neither biotechnology nor chemistry were able to provide a solution on their own, but the combination of the heterologous production of an advanced intermediate in yeast [6] and its further elaboration by chemical synthesis [7] procures sufficient quantities of artemisinin at a reasonable price. An impressive demonstration of the effectiveness of multi-disciplinary research. I would like to thank the highly professional team of the Beilstein-Institut for a very pleasant cooperation on this Thematic Series. I wish you, the reader, joy and fun with this Thematic Series and – at the best – a new impetus for your own future research! Jeroen S. Dickschat Braunschweig, September 2013

The Influence of Toll-like Receptor (TLR-) Agonists on Lysozyme Activity and TNFα-Secretion in THP-1 cells

TLRs (Toll-like receptors) are part of the innate immune system and play a major role in the recognition of pathogens. They participate in the stimulation of monocytes and macrophages by activation of NF-κB and C/EBPβ, two transcription factors that are implicated in lysozyme and TNF-alpha expression. Aim of this study was to investigate the influence of TLR-agonists and other natural compounds on cytokine secretion and lysozyme activity in a comparative assay. To explore the importance of differentiation THP-1 cells were pre-treated with PMA and IFNy. Stimulation of undifferentiated cells with natural products including various bacterial antigens, diterpenes and alkamides had almost no effect on TNF-alpha secretion and lysozyme activity whereas secretion of IL-6 and IL-10 as well as intercellular adhesion was clearly affected. Differentiated THP-1 cells were much more sensitive to further stimulation yet revealed an opposing effect on lysozyme activity and TNF-alpha secretion. The results suggest a coordinated activation of intercellular adhesion and cytokine production in the differentiation process from monocytes to macrophages and highlights the role of natural products as putative immunmodulatory agents.

Bioactive Natural Products

Bioactive natural products have never ceased to play an important role in the search of novel therapeutic agents. Natural products from the nature such as the plant and marine sources form an integral part of the living system, and they have existed ever since the beginning of life.Therefore, it is undeniable that works related to natural products continue to develop in many aspects involving researchers from various scientific backgrounds. This special issue is dedicated to compile twelve articles on chemical and biological aspects of research developments in natural products. Traditional medicinal plants still play a significant role in health maintenance and well-being that contribute to the economic growth. This is well described by R. A. Street et al. in his review on the commercially traditional medicinal plants of South Africa. The potential nutritional value of Ilex paraguariensis fruits, a native tree from Northeastern Argentina, as source of novel foods andmedicine, is discussed by Laura Cogoi et al. The article by K. Yokota et al. explains the application of ultraperformance liquid chromatography tandem mass spectrometry (UPLC) to determine the proportions of terminal and extension units of A-type and B-type highly polymeric proanthocyanidins. A. Giorgi et al. report on the analysis of volatile organic compounds from a Brazilian flora by Headspace Solid-Phase Microextraction coupled with Gas Chromatography and Mass Spectrometry (HS-SPME GC/MS) and its antioxidant property and repellent activity against Aedes aegypti L. The paper by J. Li et al. discussed the optimum conditions for the extraction of natural pigment from purple sweet potato as an alternative natural source of food coloring. The inhibitory activity of plant and marine sources in cancer research are discussed in two papers. Z.-C. Kang et al. demonstrated the inhibitory effects of the aqueous extract from guava twigs on mutation and oxidative damage, and S. N. Fedorov et al. described the inhibitory effects of marine and algae extracts, thus supporting the role of natural products in the management of cancer. The role of natural products in the treatment of Alzheimer’s disease has yet to be fully exploited. The study by T. Zhao et al. demonstrated the potential inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) of β-carboline and quinoline alkaloids from the plants of genus Peganum. X. Ding et al. showed that the flavonoids from the leaves of Ginkgo biloba, a traditional Chinese medicinal plant, were found to inhibit AChE by enhancing acetylcholine levels and its potential insecticidal activity against brown planthopper. Natural product synthesis also contributes to the development of new therapeutic agents. T. S. Zhivotova et al. illustrated the synthesis of 2,5-bi-substituted derivatives of 1,3,4tiadiazol-2,5-ditiol and some of their biological properties. A. Rusina et al. report on the synthesis of complex c-glycosides of genistein and their antiproliferative activities. Recent advances in molecular docking have enabled researchers to investigate the inhibitory activity of bioactive compounds. This is described by L. Hai-Boi et al. on the mechanism of selective inhibition of yohimbine and its derivatives on adrenoceptor α2 subtypes.

ChemInform Abstract: Biosynthetic Medicinal Chemistry of Natural Product Drugs

AbstractReview: 104 refs.

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.

The Role of Natural Products in the Discovery of New Drug Candidates for the Treatment of Neurodegenerative Disorders I: Parkinsons Disease

Neurodegenerative disorders such as Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS) are currently incurable pathologies with huge social and economic impacts closely related to the increasing of life expectancy in modern times. Although the clinical and neuropathological aspects of these debilitating disorders are distinct, they share a pattern of neurodegeneration in anatomically or functionally related regions. For each disease, presently available treatments only address symptoms and do not alter the course or progression of the underlying diseases. In this context, the search for new effective chemical entities, capable of acting on diverse biochemical targets, with new mechanisms of action and low toxicity are genuine challenges to research groups and the pharmaceutical industry. This medical need has led to the reemerging of modern natural products chemistry that has yielded sophisticated and complex new lead molecules for drug discovery and development. In this review we discuss some of the main contributions of the natural products chemistry that covers multiple and varied plant species. Advances in the discovery of active constituents of plants, herbs, and extracts prescribed by traditional medicine practices for the treatment of senile neurodegenerative disorders, especially for PD, in the period after the 2000s is reviewed. The most important contributions from the 1990s are also discussed. The review also focuses on the pharmacological mechanisms of action that might underlie the purported beneficial improvements in memory and cognition, neurovascular function, and in neuroprotection. It is concluded that natural product chemistry brings tremendous diversity and historical precedent to a huge area of unmet medical need.

The Role of Natural Products in the Discovery of New Drug Candidates for the Treatment of Neurodegenerative Disorders II: Alzheimers Disease

The present review is part II in a series (part I focuses on Parkinson's Disease) that addresses the value of natural product chemistry in the discovery of medicines for the treatment of neurodegenerative disorders. Data reviewed document that a host of products from plant species and derivatives have neuroprotectant effects in vitro and in vivo. In addition, besides neuroprotection, natural products also demonstrate biological effects that target biochemical pathways underlying associated symptoms of neurdegnerative disorders that include cognitive impairments, energy/fatigue, mood, and anxiety. This part of the review series focuses specifically upon Alzheimer's Disease (AD). AD is postulated to result from extracellular formation of amyloid plaques and intracellular deposits of neurofibrilary tangles in the hippocampus, cerebral cortex and other areas of the brain essential for cognitive function. Plaques are formed mostly from the deposition β-amyloid (Aβ), a peptide derived from the amyloid precursor protein (APP). Filamentous tangles are formed from paired helical filaments composed of neurofilament and hyperphosphorilated tau protein, a microtubule-associated protein. In addition, environmental factors can engender the production of cytokines that are closely related to the installation of an inflammatory process that contributes to neuronal death and the development and the progression of AD. In this review we focus on the recent main contribuitions of natural products chemistry to the discovery of new chemical entities usefull to the control and prevention of AD installation and progression. More than sixteen plant species, including Ginseng, Celastrus paniculatus, Centella asiatica, Curcuma longa, Ginkgo biloba, Huperzia serrata, Lycoris radiate, Galanthus nivalis, Magnolia officinalis, Polygala tenuifolia, Salvia lavandulaefolia, Salvia miltiorrhiza, Coptis chinensis, Crocus sativus, Evodia rutaecarpa, Sanguisorba officinalis, Veratrum grandiflorum and Picrorhiza kurvoa, are discussed as potential sources of active extracts. In addition, more than sixty secondary metabolites are under evaluation for their efficacy on controlling symptoms and to impede the development and progression of AD.

Nature's chemicals. The natural products that shaped our world

Nature's chemicals. The natural products that shaped our world

Assessment of selected Yemeni medicinal plants for their in vitro antimicrobial, anticancer, and antioxidant activities

Context: The role of natural products as a source for remedies has been recognized since the beginning of mankind. Nevertheless, a minority of folkloricly used medicinal plants have been evaluated for their pharmacological activities.Objectives: The purpose of this study is to evaluate 33 selected Yemeni plants for their in vitro anticancer, antimicrobial, and antioxidant activities.Materials and methods: The plants were extracted with methanol and hot water. The obtained 66 extracts were tested for their in vitro cytotoxic activity using the neutral red uptake assay against two cancer cell lines (5637 and MCF-7). The antimicrobial activity was determined using the agar diffusion method and MIC-determination. The DPPH radical method was used for the determination of antioxidant activity.Results: Interesting cytotoxic activity was observed for Hypoestes forskalei (Vahl) R. Br. (Acanthaceae), Lycium shawii Roem. & Schult. (Solanaceae), Pergularia tomentosa L. (Asclepiadaceae), Psiadia punctulata (DC.) Vatke (Compositae), Pulicaria petiolaris Jaub. & Spach (Compositae) and Rosmarinus officinalis L. (Labiatae) (IC50 values < 50 μg/mL). Antimicrobial activity with MIC values ≤ 125 μg/mL was exhibited against Gram-positive bacteria by Chrozophora oblongifolia (Del.) A.Juss. ex Spreng. (Euphorbiaceae), Myrtus communis L. (Myrtaceae), Phragmanthera regularis (Steud. ex Sprague) M.G. Gilbert (Loranthaceae) and R. officinalis. Antioxidant activity was observed for C. oblongifolia, M. communis, and P. regularis.Conclusion: The results justified the use of some investigated plants in the Yemeni ethnomedicine. These findings demonstrated that some of the investigated plants could be a source of new cytotoxic and antibiotic compounds; however, further work is needed.

Fungal metabolites: structural diversity as incentive for anticancer drug development

Natural products play an important role in the development of anticancer drugs. To date, predominantly metabolites from plants and bacteria served as lead structures for anticancer agents. Fungal metabolites and derivatives thereof are much less investigated for their potential in cancer therapy. There are, however, some promising candidates derived from fungi in clinical phases I and II studies. This review gives an overview on the role of natural products in cancer therapy and summarises some of the latest results of our group in this area.

Welcome to “Ion Channels: Key Therapeutic Targets”

Welcome to “Ion Channels: Key Therapeutic Targets”

Plant-derived natural products: synthesis, function, and application

The chemical composition of plants.- to the Different Classes of Natural Products.- Natural Products from Seaweeds.- Use of Secondary Metabolite Variation in Crop Improvement.- Approaches to the Analysis of Plant-Derived Natural Products.- Opportunities and Challenges for Ethnobotany at the Start of the Twenty-First Century.- Secondary metabolite biosynthesis.- to the Different Classes of Biosynthetic Enzymes.- Methods for Molecular Identification of Biosynthetic Enzymes in Plants.- Regulation of Secondary Metabolism by Jasmonate Hormones.- Metabolite Channeling and Multi-enzyme Complexes.- Glycosylation of Secondary Metabolites and Xenobiotics.- Handling Dangerous Molecules: Transport and Compartmentation of Plant Natural Products.- Participation of Phytochemicals in Plant Development and Growth.- Biological activity.- Biological Activity of Defence-Related Plant Secondary Metabolites.- The Role of Natural Products in Plant-Microbe Interactions.- Role of Natural Products in Nature: Plant-Insect Interactions.- Oligosaccharide Signalling Molecules.- Biological Activity of Allelochemicals.- Health Benefits of Dietary Plant Natural Products.- Floral Scents and Fruit Aromas Inspired by Nature.- New trends.- Bioengineering.- Genome Wide Approaches in Natural Product Research.- Metabolomics and the Detection of Unintended Effects in Genetically Modified Crops.- Recent Advances in Traditional Medicines and Dietary Supplements.- Plant-derived natural products as leads for drug discovery.- Speciality Non-food Crops.

Nitric oxide: pros and cons in tumor progression

Nitric oxide (NO), synthesized by NO synthase, is a mediator involved in different processes varying from neurotransmission, to affecting the vasculature. The role of NO in tumor development is multifaceted and depends on a variety of conditions that exist with in the cell. This review will discuss the pros and cons of NO in tumor progression and provide an overview of their significant part in metabolism, angiogenesis and their role in the activation of macrophages as well as tumor-associated macrophages. The role of natural products in the regulation of NO will also be discussed.

Chemical antifouling defences of sea stars: effects of the natural products hexadecanoic acid, cholesterol, lathosterol and sitosterol

The role of natural products in keeping the surfaces of the sea stars Linckia laevigata, Fromia indica, Cryptasterina pentagona and Archaster typicus free of fouling organisms was investi- gated. Conditioned seawater of these sea stars did not have any effects on the settlement of the eco- logically relevant diatoms Amphora sp. and Nitzschia closterium and the bryozoan Bugula neritina. However, dichloromethane, methanol and aqueous extracts of whole sea stars at 100, 10, 1 and 0.1 µg cm -2 had concentration-dependent effects on the settlement of these fouling species and the poly- chaete Hydroides elegans. Based on bioassay-guided fractionation and analysis with proton nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry (GC-MS), the most bioactive fractions contained several fatty acids and sterols. To determine whether the compounds responsible for the observed antifouling effects were present on the surface of all 4 sea star species, surface-associated compounds were tested against Amphora sp., N. closterium, B. neritina and H. elegans. These compounds reduced the settlement of at least 2 of the 4 fouling species for each sea star species. Using surface extractions and GC-MS analysis, the most abundant surface-associated fatty acids and sterols of each sea star species were identified and quantified. Hexadecanoic acid, cholesterol, lathosterol and sitosterol were tested at surface-associated concentrations, ranging from 1000 to 1 ng cm -2 , in settlement assays. Whereas the settlement of B. neritina was not affected by any of the compounds, hexadecanoic acid, cholesterol and lathosterol significantly reduced the settle- ment of N. closterium at surface-associated concentrations.

Antarctic marine chemical ecology: what is next?

AbstractAntarctic ecosystems are exposed to unique environmental characteristics resulting in communities structured both by biotic interactions such as predation and competition, as well as abiotic factors such as seasonality and ice‐scouring. It is important to understand how ecological factors may trigger chemical mechanisms in marine Antarctic organisms as a response for survival. However, very little is known yet about the evolution of chemical compounds in Antarctic organisms. Investigations in chemical ecology have demonstrated over the last several years that defensive metabolites have evolved in numerous representative Antarctic species. This contradicts earlier theories concerning biogeographic variation in predation and chemical defenses. As reviewed here, a number of interesting natural products have been isolated from Antarctic organisms. However, we believe many more are still to be discovered. Currently, many groups such as microorganisms, planktonic organisms and deep‐sea fauna remain almost totally unknown regarding their natural products. Furthermore, for many described compounds, ecological roles have yet to be evaluated. In fact, much of the research carried out to date has been conducted in the laboratory, and only in a few cases in an ecologically relevant context. Therefore, there is a need to extend the experiments to the field, as done in tropical and temperate marine ecosystems, or at least, to test the activity of the chemicals in natural conditions and ecologically meaningful interactions. Defense against predators is always one of the main topics when talking about the roles of natural products in species interactions, but many other interesting aspects, such as competition, chemoattraction, fouling avoidance and ultraviolet (UV) protection, also deserve further attention. In our opinion, challenging future developments are to be expected for Antarctic marine chemical ecology in the years to come.