Natural Product Molecular Fossils

Chemistry and Analysis of Organic Compounds in Dinosaurs

This review provides an overview of organic compounds detected in non-avian dinosaur fossils to date. This was enabled by the development of sensitive analytical techniques. Non-destructive methods and procedures restricted to the sample surface, e.g., light and electron microscopy, infrared (IR) and Raman spectroscopy, as well as more invasive approaches including liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), time-of-flight secondary ion mass spectrometry, and immunological methods were employed. Organic compounds detected in samples of dinosaur fossils include pigments (heme, biliverdin, protoporphyrin IX, melanin), and proteins, such as collagens and keratins. The origin and nature of the observed protein signals is, however, in some cases, controversially discussed. Molecular taphonomy approaches can support the development of suitable analytical methods to confirm reported findings and to identify further organic compounds in dinosaur and other fossils in the future. The chemical properties of the various organic compounds detected in dinosaurs, and the techniques utilized for the identification and analysis of each of the compounds will be discussed.

An enumeration of natural products from microbial, marine and terrestrial sources

The discovery of a new drug is a multidisciplinary and very costly task. One of the major steps is the identification of a lead compound, i.e. a compound with a certain degree of potency and that can be chemically modified to improve its activity, metabolic properties, and pharmacokinetics profiles. Terrestrial sources (plants and fungi), microbes and marine organisms are abundant resources for the discovery of new structurally diverse and biologically active compounds. In this chapter, an attempt has been made to quantify the numbers of known published chemical structures (available in chemical databases) from natural sources. Emphasis has been laid on the number of unique compounds, the most abundant compound classes and the distribution of compounds in terrestrial and marine habitats. It was observed, from the recent investigations, that ~500,000 known natural products (NPs) exist in the literature. About 70 % of all NPs come from plants, terpenoids being the most represented compound class (except in bacteria, where amino acids, peptides, and polyketides are the most abundant compound classes). About 2,000 NPs have been co-crystallized in PDB structures.

Plant triterpenoids with bond-missing skeletons: biogenesis, distribution and bioactivity

Covering: up to December 2018 The polycyclic ABCD(E) framework of triterpenoids can miss a single endocyclic C-C bond as a result of a modification of the cyclization cascade that triggers their formation (interrupted- or diverted cascades), or can be the result of post-cyclization ring cleavage by late-stage oxidative modifications (seco-triterpenoids). Because of mechanistic and biogenetic differences, ring opening associated with loss of a skeletal fragment, as in nor-seco-triterpenoids (limonoids, quassinoids), will not be covered, nor will compounds where ring opening is part of a fragmentation cascade or of a multiple diversion from it. Even with these limitations, 342 bond-missing triterpenoids could be retrieved from the literature, with transversal distribution in the plant kingdom. Their structural diversity translates into a variety of biological targets, with dominance of potential applications in the realm of cancer, neuroprotection, and anti-infective therapy. In addition to the bioactivity and chemotaxonomic relevance of bond-missing triterpenoids, current knowledge on the genetic basis of interrupted- and diverted oxidosqualene cyclases will be summarized. This untapped source of enzymes could be useful to selectively modify triterpenoids by metabolic engineering, circumventing the bottlenecks of their isolation (poor yield or inadequate supply chain) to explore new areas of their chemical space.

A new byciclic monoterpene glucoside and a new biflavone from the male reproduction organs of Wollemia nobilis

In this work, the fifth part of an ongoing phytochemical study on Wollemia nobilis was reported. The attention was now focused on the male reproduction organs of which the content in both primary and secondary metabolites was analyzed. Twenty compounds, belonging to seven different classes of natural compounds, were identified from the ethanolic extract by means of Column Chromatography and NMR and MS Spectroscopy. They all represent new compounds for the studied organ whereas some of them are also new constituents of the genus or even previously undescribed phytochemicals. Their presence was able to display a general overview of these organs from the phytochemical standpoint and to provide more elements in confirmation with the current botanical classification of the species. Moreover, they add a further experimental evidence of the tendency of this species to accumulate different metabolites in different organs. This characteristic as well as the occurrence of several compounds with added value, make this plant a possible candidate for large scale cultivation with extractive purposes to obtain useful phytochemicals for botanicals and pharmaceutical fields. Moreover, they offer the opportunity to develop an additional method of conservation and protection for this endangered and very rare species.

Naturally occurring aromatic steroids and their biological activities

The present review describes the distribution and biological activities of natural mono-, di-, and triaromatic steroids. It is shown that the producers of aromatic steroids are microorganisms, fungi, and marine invertebrates, and also they were found in plants, animals, marine sediments, and karst deposits. Eighty biologically active aromatic steroids likely have an anti-tumor, anti-inflammatory, and neuroprotection activity with a confidence of 78 to 92%. The structures and predicted biological activities of aromatic steroids are available. This review emphasizes the role of aromatic steroids as an important source and potential leads for drug discovery and they are of great interest to chemists, physicians, biologists, pharmacologists, and the pharmaceutical industry.