Alkaloids: Chemistry and Biology最新文献

The pyrazole and indazole alkaloids include two different but related groups of naturally occurring substances with interesting structural variations and their biological properties are obtained from the secondary metabolites. In the present book chapter we describe the chemistry and biology of these alkaloids, including their biosynthetic pathway, isolation, structural properties, and variety of biological effects. An overview of the separation and structural elucidation of pyrazole and indazole alkaloids from several natural sources is presented at the beginning, demonstrating the diversity of these molecules across the kingdoms of plants. We also look at synthetic approaches to these structures. The main focus is on the biological activities of pyrazole and indazole alkaloids, which include pharmacological activities such as antibacterial, anti-inflammatory, and anticancer properties. A thorough review of the relevant literature is presented, providing insight into the essential structural motifs that govern their interactions with biological targets. In addition, the possible medicinal uses of these alkaloids are examined, highlighting their importance in the search for new drugs. Thus, the present chapter provides a comprehensive analysis of pyrazole and indazole alkaloids with an emphasis on their chemical structures and biological activities. It serves as a valuable resource for professionals in pharmacology and drug development, offering insights into the potential therapeutic applications of these compounds. By describing the intricate relationship between the chemistry and biology of these alkaloids, the chapter contributes to the field of natural product chemistry and to the discovery and synthesis of new drugs and treatments. This synthesis of current knowledge furthers scientific understanding and underscores the importance of alkaloids in medical research and pharmaceutical innovation.

Over the past 70 years, marine biodiversity has been recognised as a rich source of unique chemical compounds with wide-ranging applications in the blue bioeconomy. Among marine organisms, sponges have historically been a key focus of marine biodiscovery due to their high potential for yielding novel compounds. More recently, attention has also turned to their associated microbiota-including bacteria, fungi, and cyanobacteria-which have emerged as more sustainable sources of bioactive metabolites. Despite this shift, the marine biodiscovery pipeline continues to feature a significant number of unique metabolites derived from sponges. One notable class of compounds is guanidine alkaloids, which are relatively rare in terrestrial organisms but widely diverse in marine sponges. These can be broadly categorised into two main groups: basic guanidine alkaloids and 2-aminoimidazole alkaloids. In this review, we examine the chemical diversity of sponge-derived guanidine alkaloids reported in the literature since the beginning of marine biodiscovery in the 1950s. This analysis reveals shared metabolic characteristics across different guanidine alkaloid groups, organised according to sponge taxonomic orders, and underscores their remarkable potential as sources of novel marine drugs. Although current research increasingly focuses on marine microbiota, sponges-as complex holobionts-continue to represent an exceptional reservoir of chemical diversity. A deeper functional understanding of the interactions between sponge hosts and their microbial symbionts is likely to play a critical role in translating this rich chemical arsenal into new marine therapeutics in the near future.

Natural products containing the hydroxylamine group are discussed. These include acyclic hydroxylamines, isoxazolidines, 1,2-oxazines, diketopiperazines, endocyclic hydroxylamines with larger ring sizes, N-hydroxy and N-methoxypyrroles, -indoles, -carbazoles and -carbolines, pyridones, other rings with an exocyclic hydroxylamine, O-acylhydroxylamines and compounds that may be regarded as unprecedented or having little precedent. Isolation, characterization, biosynthesis and synthesis are covered.

The Stemonaceae family has been included in the Chinese Pharmacopoeia as an antitussive drug, and the alkaloids contained within this family have attracted much attention due to their diverse biological activities and unique structures. From 1962 to 2024, 262 Stemona alkaloids had been isolated and identification. However, the process of exploitation is hindered by the presence of low extraction and separation rates. In recent years, there has been a significant advancement in the synthesis of Stemona alkaloids, with approximately 19 % of them realizing the total synthesis. Here, we reviewed Stemona alkaloids into eight distinct classifications with Pilli's seminal classification approach, and systematically summarized synthesis pathways by the type of reactions to construct the core skeleton. To provide a comprehensive overview of the application of Stemona alkaloids, we have also summarized the biological activities of these alkaloids.

Naphthylisoquinoline alkaloids are a fascinating class of natural biaryl compounds. They show characteristic mono- and dimeric scaffolds, with chiral axes and stereogenic centers. Since the appearance of the last comprehensive overview on these secondary plant metabolites in this series in 1995, the number of discovered representatives has tremendously increased to more than 280 examples known today. Many novel-type compounds have meanwhile been discovered, among them naphthylisoquinoline-related follow-up products like e.g., the first seco-type (i.e., ring-opened) and ring-contracted analogues. As highlighted in this review, the knowledge on the broad structural chemodiversity of naphthylisoquinoline alkaloids has been decisively driven forward by extensive phytochemical studies on the metabolite pattern of Ancistrocladus abbreviatus from Coastal West Africa, which is a particularly "creative" plant. These investigations furnished a considerable number of more than 80-mostly new-natural products from this single species, with promising antiplasmodial activities and with pronounced cytotoxic effects against human leukemia, pancreatic, cervical, and breast cancer cells. Another unique feature of naphthylisoquinoline alkaloids is their unprecedented biosynthetic origin from polyketidic precursors and not, as usual for isoquinoline alkaloids, from aromatic amino acids-a striking example of biosynthetic convergence in nature. Furthermore, remarkable botanical results are presented on the natural producers of naphthylisoquinoline alkaloids, the paleotropical Dioncophyllaceae and Ancistrocladaceae lianas, including first investigations on the chemoecological role of these plant metabolites and their storage and accumulation in particular plant organs.

The sarpagine-ajmaline type monoterpenoid indole alkaloids are among the most important groups of natural alkaloids, and the complex polycyclic and cage-like architectures present significant synthetic challenges. Because of their characteristic indole-fused azabicyclo[3.3.1]nonane structures and prominent biological activities, sarpagine-ajmaline related alkaloids have captured the attention of organic synthetic chemists for decades. In this chapter, the strategies employed in the synthesis of sarpagine-ajmaline related alkaloids are outlined, and the synthetic progress during the period of 2019-2023 is provided in detail. To provide potential targets for future synthetic endeavors, some sarpagine/ajmaline type alkaloids isolated in recent years with novel structures and biological activities are also summarized.

Indolactam alkaloids are a family of aromatic toxins produced by various actinobacteria and the cyanobacterium, Moorena producens. The best characterized examples include the teleocidins, lyngbyatoxins, olivoretins, blastmycetins, and pendolmycins, which share a nine-membered lactam core, comprised from l-tryptophanol and l-valine. Contact with indolactam alkaloids has been linked to severe dermatitis (swimmers itch), while accidental ingestion may lead to illness and fatalities. Indolactam alkaloids are also potent tumor promotors, due to their activation of protein kinase C isozymes. This chapter reviews the current literature on indolactam alkaloids, from their discovery in the early 1960s up to 2024. Topics covered include the isolation, structural elucidation, biosynthesis, bioactivity, and total synthesis of the indolactam alkaloid core.