Sulfur-containing secondary metabolites

The general metabolism of sulfur, extensively described in many texts of biological sciences, is not considered in this article some topics (e.g. metallo-enzymes) are discussed elsewhere in this volume (Chapter 11.2). Our focus is on sulfur-containing secondary metabolites in microorganisms and plants. In view of the vast literature, we can only provide an eclectic account citing recent work where possible. 

Overview of Structural Types for Sulfur-Containing Secondary Metabolites... 

Plants of the genus Allium, e.g. garlic Allium sativum), leek Allium amp-eloprasum), and onion Allium cepa), produce a bewildering variety of sulfur compounds. Selenium analogs for some of these have also been found (Section 11.1.3.6). Much work has focused on garlic (contains more than 100 such materials) and onion.56,66,67 Key compounds for formation of the Allium sulfur-containing secondary metabolites are sulfoxides of cysteine derivatives,... 

Few sulfur-containing secondary metabolites have been isolated from green algae. As well as the sulfated triter-penic alcohols mentioned previously, two biologically active atypical compounds were characterized. The first compound is a bis-alkykanthate, whose function is very rare in the natural environment and is toxic to mosquito larvae. The second compound is a cyclic disulfide inhibitor... 

In 1977, a survey of low molecular weight sulphur-containing compounds in Nature ,4 noted that these secondary metabolites had little more in common than the possession of one or more sulfur atoms. The reader was left with a kaleidoscopic impression of almost 80 chemical structures. A comprehensive review today would require many hundreds of sulfur-containing chemical structures. 

While many sulfur-containing fungal secondary metabolites are known, they are found less frequently than in plants. There is a structural range from CH2S6, 1,2,3,4,5,6-hexathiapane, from Lentinus edodes, to C82Hii4N2oOi7S, a 13-unit peptide containing methionine from Saccharomyces cerevesiae,13... 

ABSTRACT This chapter provides a comprehensive overview of the sulfur-containing natural products that are non-sulfated and have been isolated from marine organisms. The overview covers the published literature from 1985 to 1999. A total of 482 compounds and 371 references are recorded. These secondary metabolites are organized in sections according to structural classifications by sulfur functional groups and by structural families of compounds. Comments on structural characterization, biogenesis, and biological activity have also been included. 

Thiopeptide antibiotics, thiazolyl peptides, naturally occurring sulfur-containing, highly modified, macrocyclic peptides. They share a number of structural motifs, including several heterocycles such as thiazoles, a dehydropiperidine, a pyridine, oxazoles, and indoles. Nearly aU of the thiopeptide antibiotics act as inhibitors of protein synthesis in bacteria. They are secondary metabolites produced by actino-mycetes, largely by the genus Streptomyces. A representative member of this family is thiostrepton [M. C. Bagleyetal., Chem. Rev. 2005, 105, 685]. 

Three major classes of secondary metabolites are involved in these phytochemicals, which are alkaloids, terpenes, and phenoUcs [16]. There are many phytochemicals recognized with health benefits such as sulfur-containing compounds of garlic family, various terpenoids, and polyphenols (anthocyanins, flavones, flavanols, isoflavones, stilbenes, ellagic acid, etc.). 

The distribution of sulfur-containing metabolites among marine organisms is even more general than that of organohalogen compounds, insofar as sulfur appears as much in the primary metabolites - polysaccharides - as in the secondary metabolites. Sulfated compotmds are... 

The secondary metabolites of Medusozoa are broadly similar to those of the Hexacorallia (Anthozoa), that is, there are only small amounts of terpenes, few nitrogen derivatives and, in Tridentata (Hydrozoa), atypical sulfur-containing derivatives. Among the categories of metabolites that could be considered characteristic of the class Hydrozoa are aromatic compounds derived from anthracene and the bioluminescent substances formd in some jellyfish, such as aequorin (see Chapter 4). 

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