Semi-synthesis and antiproliferative evaluation of PEGylated pentacyclic triterpenes.

Several PEGylated derivatives of oleanolic and maslinic acids have been semi-synthesized, attaching one acid-PEG reagent to the hydroxyl group/s at C-2 or C-2/C-3 of the A rings of these natural triterpenes, and also to their corresponding C-28 benzyl derivatives. Several monomeric and dimeric PEGylated compounds have also been produced by linking one diamine-PEG reagent to the carboxyl group at C-28 of the same natural triterpenes and also to their corresponding C-2 or C-2/C-3 acetylated derivatives. The cytotoxic effects of 12 triterpenic PEGylated derivatives in three cancer-cell lines (B16F10, HT29, and Hep G2) have been assayed.

Solid-phase library synthesis of bi-functional derivatives of oleanolic and maslinic acids and their cytotoxicity on three cancer cell lines.

A wide set of 264 compounds has been semisynthesized with high yields and purities. These compounds have been obtained through easy synthetic processes based on a solid-phase combinatorial methodology. All the members of this library have one central core of a natural pentacyclic triterpene (oleanolic or maslinic acid) and differ by 6 amino acids, coupled with the carboxyl group at C-28 of the triterpenoid skeleton, and by 10 different acyl groups attached to the hydroxyl groups of the A-ring of these molecules.

Semi-synthesis of acylated triterpenes from olive-oil industry wastes for the development of anticancer and anti-HIV agents.

A broad set of potential bioactive conjugate compounds has been semi-synthesized through solution- and solid-phase organic procedures, coupling two natural pentacyclic triterpene acids, oleanolic (OA) and maslinic acids (MA), at the hydroxyl groups of the A-ring of the triterpene skeleton, with 10 different acyl groups. These acyl OA and MA derivatives have been tested for their anti-proliferative (against the b16f10 murine melanoma cancer cells) and antiviral (as inhibitors of the HIV-1-protease) effects. Several derivatives have shown high levels of early and total apoptosis (up to 90%).

Maslinic acid derivatives induce significant apoptosis in b16f10 murine melanoma cells.

Maslinic acid (2α,3β-dihydroxyolean-12-en-28-oic acid), a natural dihydroxylated pentacyclic triterpene acid isolated from olive-pressing residues, has been investigated together with some of its derivatives regarding the induction of apoptosis in B16F10 melanoma cells. Some of the compounds tested are described in this work, but others come from previous studies. Ten of these derivatives induce over 80% of apoptosis, clearly promoting cell death in B16F10 melanoma.