The role of germacrene D as a precursor in sesquiterpene biosynthesis: investigations of acid catalyzed, photochemically and thermally induced rearrangements.

The genesis of the purple dye from shellfish, its composition, origin,intermediates, analysis and synthesis of the components, 6,6’-dibromoindigo, 6-bromoindigo and 6,6’-dibromoindirubin are reviewed Keywords: 6,6’-dibromoindigo, 6-bromoindigo, 6,6’-dibromoindirubin, tyrindoxyl,tyriverdin, tyrindoleninone, tyrindolinone, synthesis, structure, properties Introduction 6,6’-Dibromoindigo is a major component of the historic pigment Tyrian purple, also known asRoyal purple, shellfish purple and Purple of the Ancients. Arguably, it is the oldest known pigment,the longest lasting, the subject of the first chemical industry, the most expensive and the best known.The colour is derived exclusively from marine shellfish of the Muricidae and Thaisidae families. Thelong history, stretching back well into the pre-chemical era, and embracing chemistry, biology andsociology, contains not a few misconceptions and erroneous conclusions. This review attempts to setthe record straight.This molluscan dye has been known since pre-Roman times and in the Mediterranean region thereis evidence for the industry around the 13th century B.C. [1] at Sarepta, now Sarafand, Lebanon. Theancient industry was distributed world-wide [2]. Surviving details of the ancient process areinsufficient to explain the chemistry involved and this is the subject of continuing speculation. But it isclear that the dye does not exist in the mollusc and is generated from precursors, sometimes termed

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Tyrian Purple: 6,6’-Dibromoindigo and Related Compounds

A volatile metabolite of actinomycetes, 2-methylisoborneol

An antibiotic-producing pseudomonad was isolated from a seawater sample from a La Jolla, Calif., tidepool. The pseudomonad produces two novel antibacterial compounds, 2-n-pentyl-4-quinolinol and 2-n-heptyl-4-quinolinol. It also synthesizes indole-3-carboxaldehyde, 6-bromoindole-3-carboxaldehyde, and the known antibiotic p-hydroxybenzaldehyde. Each of these compounds was identified by analysis of spectral data, and the structures were confirmed by synthesis or comparison with authentic samples.

Antibiotic Metabolites from a Marine Pseudomonad

The phylum Mollusca represents an enormous diversity of species with eight distinct classes. This review provides a taxonomic breakdown of the published research on marine molluscan natural products and the medicinal products currently derived from molluscs, in order to identify priority targets and strategies for future research. Some marine gastropods and bivalves have been of great interest to natural products chemists, yielding a diversity of chemical classes and several drug leads currently in clinical trials. Molluscs also feature prominently in a broad range of traditional natural medicines, although the active ingredients in the taxa involved are typically unknown. Overall secondary metabolites have only been investigated from a tiny proportion (<1%) of molluscan species. At the class level, the number of species subject to chemical studies mirrors species richness and our relative knowledge of the biology of different taxa. The majority of molluscan natural products research is focused within one of the major groups of gastropods, the opisthobranchs (a subgroup of Heterobranchia), which are primarily comprised of soft-bodied marine molluscs. Conversely, most molluscan medicines are derived from shelled gastropods and bivalves. The complete disregard for several minor classes of molluscs is unjustified based on their evolutionary history and unique life styles, which may have led to novel pathways for secondary metabolism. The Polyplacophora, in particular, have been identified as worthy of future investigation given their use in traditional South African medicines and their abundance in littoral ecosystems. As bioactive compounds are not always constitutively expressed in molluscs, future research should be targeted towards biosynthetic organs and inducible defence reactions for specific medicinal applications. Given the lack of an acquired immune system, the use of bioactive secondary metabolites is likely to be ubiquitous throughout the Mollusca and broadening the search field may uncover interesting novel chemistry.

https://tekhelet.com/pdf/Benkendorff-Biological-2010.pdf

M.D. Sutherland

Papers

Pigments of Marine animals VIII Precursors of 66 tp-dibromoindigotin (Tyrian purple) from the molluse Dicathais orbita Gmelin

Further skeletal variety in the toxic furanosesquiterpene ketones in the myoporum genus

Constitution and biogenesis of two new sesquiterpenes

The structure of Spinochrome B

The hydrocyanation of free and polymer-bound benzoquinone