Synthesis of Bioconjugate Sesterterpenoids with Phospholipids and Polyunsaturated Fatty Acids

Synthesis of ether lipids: natural compounds and analogues

Ether lipids are compounds present in many living organisms including humans that feature an ether bond linkage at the sn-1 position of the glycerol. This class of lipids features singular structural roles and biological functions. Alkyl ether lipids and alkenyl ether lipids (also identified as plasmalogens) correspond to the two sub-classes of naturally occurring ether lipids. In 1979 the discovery of the structure of the platelet-activating factor (PAF) that belongs to the alkyl ether class of lipids increased the interest in these bioactive lipids and further promoted the synthesis of non-natural ether lipids that was initiated in the late 60's with the development of edelfosine (an anticancer drug). More recently, ohmline, a glyco glycero ether lipid that modulates selectively SK3 ion channels and reduces in vivo the occurrence of bone metastases, and other glyco glycero ether also identified as GAEL (glycosylated antitumor ether lipids) that exhibit promising anticancer properties renew the interest in this class of compounds. Indeed, ether lipid represent a new and promising class of compounds featuring the capacity to modulate selectively the activity of some membrane proteins or, for other compounds, feature antiproliferative properties via an original mechanism of action. The increasing interest in studying ether lipids for fundamental and applied researches invited to review the methodologies developed to prepare ether lipids. In this review we focus on the synthetic method used for the preparation of alkyl ether lipids either naturally occurring ether lipids (e.g., PAF) or synthetic derivatives that were developed to study their biological properties. The synthesis of neutral or charged ether lipids are reported with the aim to assemble in this review the most frequently used methodologies to prepare this specific class of compounds.

Halimanes and cancer: ent-halimic acid as a starting material for the synthesis of antitumor drugs

The development of new anti-cancer agents is an urgent necessity nowadays, as it is one of the major causes of mortality worldwide. Many drugs currently used are derived from natural products. Halimanes are a class of bicyclic diterpenoids present in various plants and microorganisms. Many of them exhibit biological activities such as antitumor, antimicrobial, or anti-inflammatory. Among them, ent-halimic acid is an easily accessible compound, in large quantities, from the ethyl acetate extract of the plant Halimium viscosum, and it has been used as a starting material in a number of bioactive molecules. In this work, we review all the natural halimanes with antitumor and related activities until date as well as the synthesis of antitumor compounds using ent-halimic acid as a starting material.

The Methylene-Cycloalkylacetate (MCA) Scaffold in Terpenyl Compounds with Potential Pharmacological Activities

Recently, the methylene-cycloakylacetate (MCA) scaffold has been reported as a potential pharmacophore for neurite outgrowth activity. In this work, natural diterpenes that embed MCA fragments are reviewed, as they are major components of Halimium viscosum: ent-halimic acid, the prototype for these bioactive compounds. Herein, structures, sources, and activities for the natural diterpenes, as well as their synthetic derivatives of interest, are reviewed.

Halimane diterpenoids: sources, structures, nomenclature and biological activities

Diterpenes with a halimane skeleton constitute a small group of natural products that can be biogenetically considered as being between labdane and clerodane diterpenoids.