This volume highlights some recent developments on plants used widely as botanical dietary supplements and herbal medicines, especially in terms of knowledge of the chemical types and diverse biological activities of their constituents, as well as laboratory approaches for their quality control and taxonomic identification. In the first chapter, the biologically active secondary metabolites are described of selected botanicals that have a wide current use in the United States, with recent information provided also on their in vitro and in vivo biological activities. The second chapter constitutes an updated survey of the different chromatographic, spectroscopic, and metabolomics techniques that can be utilized for the quality control of botanical products. The penultimate chapter covers different nomenclatural systems that are of use for the taxonomic identification of source plants used in botanical products. Finally, deoxyribonucleic acid molecular barcoding techniques for the identification for plants used as dietary supplements are covered.

The volumes of this classic series, now referred to simply as "Zechmeister" after its founder, L. Zechmeister, have appeared under the Springer imprint ever since the series was founded in 1938. The volumes contain contributions on various topics related to the origin, distribution, chemistry, synthesis, biochemistry, function or use of various classes of naturally occurring substances ranging from small molecules to biopolymers. Each contribution is written by a recognized authority in his field and provides a comprehensive and up-to-date review of the topic in question. Addressed to biologists, technologists and chemists alike, the series can be used by the expert as a source of information and literature citations and by the non-expert as a means of orientation in a rapidly developing discipline.

The first chapter describes the oldest method of communication between living systems in Nature, the chemical language. Plants, due to their lack of mobility, have developed the most sophisticated way of chemical communication. Despite that many examples involve this chemical communication process - allelopathy, there is still a lack of information about specific allelochemicals released into the environment, their purpose, as well as in-depth studies on the chemistry underground. These findings are critical to gain a better understanding of the role of these compounds and open up a wide range of possibilities and applications, especially in agriculture and phytomedicine. The most relevant aspects regarding the chemical language of plants, namely, kind of allelochemicals have been investigated, as well as their releasing mechanisms and their purpose, are described in this chapter. The second chapter is focused on the natural products obtained from Hypericum L., a genus of the family Hypericaceae within the dicotyledones. Hypericum has been valued for its important biological and chemical properties and its use in the treatment of depression and as an antibacterial has been well documented in primary literature and ethnobotanical reports. The present contribution gives a comprehensive summary of the chemical constituents and biological effects of this genus. A comprehensive account of the chemical constituents including phloroglucinol derivatives, xanthones, dianthrones, and flavonoids is included. These compounds show a diverse range of biological activities that include antimicrobial, cytotoxic, antidepressant-like, and antinociceptive effects. The third chapter addresses microtubule stabilizers, which are a mainstay in the treatment of many solid cancers and are often used in combination with molecularly targeted anticancer agents and immunotherapeutics. The taccalonolides are a unique class of such microtubule stabilizers isolated from plants of Tacca species that circumvent clinically relevant mechanisms of drug resistance. Although initial reports suggested that the microtubule stabilizing activity of the taccalonolides is independent of direct tubulin binding, additional studies have found that potent C-22,23 epoxidated taccalonolides covalently bind the Aspartate 226 residue of β-tubulin and that this interaction is critical for their microtubule stabilizing activity. Some taccalonolides have demonstrated in vivo antitumor efficacy in drug-resistant tumor models with exquisite potency and long-lasting antitumor efficacy as a result of their irreversible target engagement. The recent identification of a site on the taccalonolide scaffold that is amenable to modification has provided evidence of the specificity of the taccalonolide-tubulin interaction and the opportunity to further optimize the targeted delivery of the taccalonolides to further improve their anticancer efficacy and potential for clinical development.

The book summarizes important aspects of cheminformatics that are relevant for natural product research. It highlights cheminformatics tools that help to match natural products with their respective biological targets or off-targets, and discusses the potential and limitations of this approach.

In this book, chemical studies are described mainly from literature reports appearing since 2000, inclusive of investigations performed by the present authors, on the diversity in secondary metabolites of Ligularia growing in the Hengduan Mountains area of China, focusing on eremophilane sesquiterpenoids and other metabolites. More than 100 Ligularia species and their related genera in the plant family Senecioneae plants (Cremanthodium, Cacalia, Senecio, and others) grow in East Asia. For many years, researchers have studied the chemical constituents of these plants, and terpenoids, flavonoids, steroids, alkaloids, and aromatic compounds have been isolated. Among these, in particular, numerous sesquiterpenoids were reported. Within this book terpenoids and aromatic compounds (total 1049), both previously unknown and known, are presented. Finally, genetic studies and synthesis investigations are briefly reviewed.

The first chapter in volume 111 summarizes research on the sesterterpenoids, which are known as a relatively small group of natural products. However, they express a variety of simple to complicated chemical structures. This chapter focuses on the chemical structures of sesterterpenoids and how their structures are synthesized in Nature. The second chapter is devoted to marine-derived fungi, which play an important role in the search for structurally unique secondary metabolites, some of which show promising pharmacological activities that make them useful leads for drug discovery. Marine natural product research in China in general has made enormous progress in the last two decades as described in this chapter on fungal metabolites. This contribution covers 613 new natural products reported from 2001 to 2017 from marine-derived fungi obtained from algae, sponges, corals, and other marine organisms from Chinese waters.

The first contribution reviews the occurrence of xanthine alkaloids in the plant kingdom and the elucidation of the caffeine biosynthesis pathway, providing details of the N-methyltransferases, belonging to the motif B' methyltransferase family which catalyze three steps in the four step pathway leading from xanthosine to caffeine. The second contribution in this book provides a background on the molecule and related compounds and update knowledge on the most recent advances in Iboga alkaloids. The third contribution presents a comprehensive analysis of frequently occurring errors with respect to 13C NMR spectroscopic data and proposes a straightforward protocol to eliminate a high percentage of the most obvious errors.