Class Of Diterpenoids Research Articles

A chromosome-level genome assembly reveals that tandem-duplicated CYP706V oxidase genes control oridonin biosynthesis in the shoot apex of Isodon rubescens

The ent-kaurenoids (e.g., oridonin and enmein) from the Isodon genus (Lamiaceae) are one class of diterpenoids with rich structural diversity and intriguing pharmaceutical activity. In contrast to the well-established gibberellin pathway, oxidative modifications diversifying the ent-kaurene skeleton in Isodon have remained undetermined for half a century. Here we report a chromosome-level genome assembly of I. rubescens, a well-recognized oridonin producer long favored by Asian people as a traditional herb with antitumor effects. The shoot apex was confirmed to be the actual region actively producing ent-kaurene diterpenoids. Through comparative genomics and phylogenetic analyses, we discovered a cluster of tandem-duplicated CYP706V oxygenase-encoding genes located on an ancient genomic block widely distributed in eudicots, whereas almost exclusively emerged in Isodon plants. In the shoot apex, IrCYP706V2 and IrCYP706V7 oxidized the ent-kaurene core in the initial stage of oridonin biosynthesis. Loss of CYP706Vs in other Lamiaceae plants offered an explanation for the specific kaurenoid production in Isodon plants. Moreover, we found that the Isodon genomes encode multiple diterpenoid synthases that are potentially involved in generating diterpenoid diversity. These findings provided new insights into the evolution of the lineage-specific diterpenoid pathway and laid a foundation for improving production of bioactive ent-kaurene-type diterpenoids by molecular breeding and synthetic biology approaches.

Antimicrobial and Cytotoxic Cyathane-Xylosides from Cultures of the Basidiomycete Dentipellis fragilis.

In our continued search for biologically active metabolites from cultures of rare Basidiomycota species, we found eight previously undescribed cyathane-xylosides from submerged cultures of Dentipellis fragilis, which were named dentifragilins A–H. In addition, the known cyathane derivatives striatal D and laxitextine A were isolated. All compounds were characterized by high-resolution electrospray ionization mass spectrometry (HR-ESIMS) as well as by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Several of the compounds exhibited significant activities in standardized cell-based assays for the determination of antimicrobial and cytotoxic effects. The discovery of cyathanes in the genus Dentipellis has chemotaxonomic implications, as this class of diterpenoids has already been shown to be characteristic for mycelial cultures of the related genera Hericium and Laxitextum, which are classified as Dentipellis in the family Hericiaceae.

ChemInform Abstract: 20‐Nor‐isopimarane Cycloethers from the Deep‐Sea Sediment‐Derived Fungus Aspergillus wentii SD‐310.

AbstractAsperethers A—E (I—IV), five new 20‐nor‐isopimarane diterpenoids, are isolated from the title fungus.

Antituberculosis activity of alkylated mulinane diterpenoids

Natural azorellane and mulinane diterpenoids show antituberculosis activity, which is increased by methylation of their free carboxyl group. We have systematically investigated the effect of alkylation in this class of diterpenoids and found that the profile of bioactivity is relatively unaffected by the introduction of short alkyl groups, both linear and branched. In this investigation, three semisynthetic diterpenoids, 13 hydroxy-mulin-11-en-20-oic acid n-propyl ester ( 3) and the n-propyl ( 19) and n-butyl ( 20) esters of isomulinic acid, showed the strongest antituberculosis activity (MIC = 6.25 μg/mL) against a drug-resistant strain of Mycobacterium tuberculosis.

Zythiostromic acids, diterpenoids from an antifungal Zythiostroma species associated with aspen

Three new cleistanthane type diterpenes, zythiostromic acid A, zythiostromic acid B and zythiostromolid, have been isolated from liquid cultures of a Zythiostroma sp., a fungus associated with aspen. Their structures were determined both by spectroscopic methods and chemical correlation. This class of diterpenoids has previously been reported only from plant sources.

The first seco-asbestinin: A novel class of diterpene from the Caribbean gorgonian Briareum asbestinum (Pallas)

The hexane extract of the Caribbean gorgonian octocoral Briareum asbestinum was found to contain traces of a novel seco-asbestinin diterpenoid. The structure of 1, the first representative of this novel class of diterpenoids, was assigned on the basis of extensive NMR analyses and by comparison with analogous spectral data from related asbestinane diterpenoids. Confirmation of structure 1 was achieved by partial synthesis from known asbestinin-6 ( 2).

Metabolites of Cyathus helenae. A New Class of Diterpenoids

Allocyathin B3 and cyathin A3, metabolites of the bird's nest fungus Cyathus helenae Brodie are shown to possess structures [Formula: see text] and [Formula: see text], respectively. In the solid state allocyathin B3 exists in the hydroxyketone form 2a, while cyathin A3 is in the hemiketal form 6a. In each case acetylation gives the diacetyl derivative of the hydroxyketone form whereas treatment with methanolic HCl gives an internal ketal. Allocyathin B3 and cyathin A3 have been correlated by hydrogénation to the common product 13a, and by transformation of each to the aldehyde 12a. These compounds are representatives of a new class of diterpenoids. Their biogenesis from geranylgeranyl pyrophosphate is discussed.