Ricerc@Sapienza

Novel diterpenoids were isolated from the extracts of Fabiana densa var. ramulosa and found to display a selective activity against Gram-positive bacterial strains with negligible cytotoxicity toward human keratinocytes. This study highlighted the role played by the acidic group at C18 of the tetracyclic ent-beyerene scaffold for antibacterial effects and how the length and flexibility of the alkyl chain between the two carbonyl groups are crucial factors to increase the antimicrobial activity of the molecules, supporting the development of natural products from F.

Colistin is a last-resort antibiotic for the treatment of multidrug resistant Gram-negative bacterial infections. Recently, a natural ent-beyerene diterpene was identified as a promising inhibitor of the enzyme responsible for colistin resistance mediated by lipid A aminoarabinosylation in Gram-negative bacteria, namely, ArnT (undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase).

The discovery of antibiotics has revolutionized the medicine and treatment of microbial
infections. However, the current scenario has highlighted the difficulties in marketing new
antibiotics and an exponential increase in the appearance of resistant strains. On the other hand,
research in the field of drug-discovery has revaluated the potential of natural products as a unique
source for new biologically active molecules and scaffolds for the medicinal chemistry. In this

An undescribed labdane-like diterpene with a rare spiro-β-lactone function was identified from the ethanol
extract of the male cones of the coniferous tree Wollemia nobilis. This spirolabdadienolide (IUPAC name: syn-ent-
8(17),13-labdadien-19,18-olid-15-oic acid methyl ester; trivial name: wollemolide), was isolated by means of
traditional and high performance chromatography techniques and structurally elucidated through NMR and MS.
In addition, six further known metabolites were evidenced in the extract. Wollemolide, which may be considered

In this article the scientific activity carried out on stemarane diterpenes and diterpenoids, isolated over the world from various natural sources, was reviewed. The structure elucidation of stemarane diterpenes and diterpenoids was reported, in addition to their biogenesis and biosynthesis. Stemarane diterpenes and diterpenoids biotransformations and biological activity was also taken into account. Finally the work leading to the synthesis and enantiosynthesis of stemarane diterpenes and diterpenoids was described.