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Macroalgae or seaweeds are the most abundant marine species occurring all over the world in all kinds of habitats. For several decades, the significance of organic metabolites isolated from marine algae has been demonstrated by their role in drug discovery and applications in clinical trials. The marine environment is a rich source of naturally occurring halogenated compounds. Many marine algae show exceptional biochemistry in the synthesis of brominated organic compounds such as bromophenols, bromoindoles, bromopyrroles, bromoterpenes, and polybrominated diphenyl ethers (PDBEs). Some of these compounds have been reported to have intriguing biochemical properties such as antibacterial, antifungal, and antihistamine activities. The brominated aromatic core containing compounds discussed in this chapter includes substituted diphenyl ethers, bromophenols, benzaldehyde, bromonaphthalene, and indoles. These molecules were reported to have a range of biological activities such as anticancer, antimicrobial, antioxidant, aldose reductase inhibition, etc. PDBE derivatives have also been reported to inhibit enzymes implicated in tumor development and antisclerotic plaque which indicate their potential as promising therapeutic agents. Moreover, 84 brominated terpenes isolated from various marine algae have been summarized along with their biological properties. Most of the terpenes were evaluated for anticancer activities against different human cancer cell lines. Overall this chapter presents a broad survey of bioactive brominated organic molecules isolated from marine algae around the world, as well as literature from 2005 to present day.

Biochemicals produced by nature are always special in terms of their structures, properties, medicinal uses, and many more reasons. Nature has always challenged chemists by producing the complex structural skeletons. As a consequence, an impressive number of modern drugs have been derived from natural sources. These new chemicals may be obtained by the qualitative/quantitative extractions from different plants/crops/animals/microorganisms extract. Over the years, due to the outstanding developments in the field of analytical separation methods coupled with advances in structural characterization techniques, natural products research is leading in fronts as an ocean of novel and interesting chemical scaffolds. This chapter gives an in-depth review of the state-of-the-art techniques for the extraction, isolation, purification, and characterization of metabolites from natural sources. Special attention is focused on discussion of case studies involving isolation of marine, microbial, and terrestrial natural products with the help of suitable examples.

Nature continues to be most important in the delivery of new drugs or lead structures and the oceans are important resources of structurally unique natural products. The major occupation of marine natural product chemists in recent years has been the search for potential pharmaceuticals. As a result, various new classes of potential pharmacophores against various diseases have been identified. Over the past five decades the search for new drugs has expanded, to those produced by marine macroorganisms and their associated microbes obtained from marine sources. Indeed, many of the pharmaceutical, agrochemical, and crop protection industry are based on the exploitation of microbial natural products. Fungi isolated from substrates such as marine plants (algae, sea grasses), invertebrates (ascidians, sponges, tunicates, etc.), vertebrates (fish), sands, sediments, and seawater itself have been found to yield novel bioactive natural products, many of which have highly complex structures, making them difficult to be supplied economically via chemical synthesis. This review chapter covers the literature on novel bioactive metabolites of marine-derived fungi published in years 2010–14. Metabolites from Aspergillus sp., Penicillium sp., Trichoderma sp., Chaetomium globosum, Phomopsis sp., Phoma sp., and Fusarium sp. will be highlighted in this chapter. It also gives a brief overview of progress of the marine fungal chemistry over past 5 years.

Mass spectrometry (MS) has emerged as an invaluable technique with a wide array of applications ranging from forensic, proteomic, and metabolomic to clinical studies. With the development of different ionization techniques and mass analyzers, even challenging samples can be analyzed, thereby making mass spectrometry an important analytical tool in the field of characterization of bioactive molecules ranging from small metabolites to large macromolecular assemblies. MS is the only technique that offers the combination of high sensitivity with structural information. This chapter demonstrates the application of MS in the determination of different classes of bioactive compounds with a special emphasis on peptides, alkaloids, and lipids. A case study has been demonstrated for each class of compounds that might be helpful for early learners in the field of mass spectrometry. This also shall be of interest to the biochemical, biomedical, and pharmaceutical communities, and those working in other branches of analytical bioscience.

Vibrational spectroscopy is a widely used analytical technique that requires a short analysis time, less sample quantity, and provides nondestructive and situ analysis of biological samples. Infrared and Raman spectroscopies have been used for the characterization of organic and inorganic compounds as well as natural products including macromolecules such as polysaccharides, proteins, and highly insoluble melanin pigments. Although the techniques give less precise structural information, they are widely used for fast, nondestructive, and green analysis, which is not possible with the other complementary techniques such as NMR and mass spectroscopies. The technique coupled with NMR and mass can provide a strong platform for natural product analysis. This chapter presents the basic concepts of infrared and Raman spectroscopies and their application to the structure characterization of compounds such as polysaccharides, alkaloids, terpenes, flavonoids, sterols, sideorophores, and insoluble melanin pigments isolated from marine organisms.