Derivatives of grindelic acid: from a non-active natural diterpene to synthetic antitumor derivatives.

Using several reactions that include homologations and asymmetric epoxidations as well as Ugi and Huisgen couplings, we generated a small focused library of new derivatives from the labdane-type diterpene grindelic acid. These compounds were evaluated as cytotoxic agents against a panel of five human solid tumor cell lines (HBL-100, HeLa, SW1573, T-47D, and WiDr). The presence of the diamide functionalizations enhanced the cytotoxic effect. N-Benzyl-N-(1-(benzylamino)-2-methyl-1-oxopropan-2-yl)grindelicamide, proved to be the most active product in all cell lines tested, with values of 0.95 (±0.38) µM against HBL-100 cells.

Cytotoxic bioactivity of some phenylpropanoic acid derivatives.

In this study, we synthesized a series of phenylpropanoic acid derivatives based on modifications at four selected points of the molecular scaffold. The in vitro antiproliferative activities of the compounds were examined in representative human solid tumor cell lines. A SAR was established pointing out the relevance of the substituents. The best activity profiles were obtained for the derivatives bearing more lipophilic esters (GI50 3.1-21 microM).

Antiproliferative activity of synthetic naphthoquinones related to lapachol. First synthesis of 5-hydroxylapachol.

A series of 5-hydroxy-1,4-naphthoquinones analogues was synthesized from juglone (6) and their antiproliferative activity against a representative panel of six human solid tumor cell lines has been investigated. The 2,5-dihydroxy-3-(3-methylbut-2-enyl)naphthalene-1,4-dione (4) and 2,3-dihydro-5-hydroxy-2-(prop-1-en-2-yl)naphtho[2,3-b]furan-4,9-dione (27) were the most potent antiproliferative agents with GI(50) values of 0.42-8.1 and 0.80-2.2microM, respectively. The results provide insight into the correlation between some structural properties of 5-hydroxynaphthoquinones and their antiproliferative activity.

Abietane diterpenoids from Salvia pachyphylla and S. clevelandii with cytotoxic activity against human cancer cell lines.

A phytochemical study has been carried out on the aerial parts of Salvia pachyphylla and S. clevelandii. From S. pachyphylla, the known diterpenes carnosol (2), rosmanol, 20-deoxocarnosol (3), carnosic acid, isorosmanol (4), 7-methoxyrosmanol, 5,6-didehydro-O-methylsugiol (5), 8beta-hydroxy-9(11),13-abietadien-12-one (6), 11,12-dioxoabieta-8,13-diene, and 11,12-dihydroxy-20-norabieta-5(10),8,11,13-tetraen-1-one were isolated, together with the new diterpene pachyphyllone (1). From S. clevelandii, the known diterpenes rosmadial (7), 16-hydroxycarnosol (8), abieta-8,11,13-triene, and taxodone were obtained, together with carnosol (2), rosmanol, and carnosic acid. The structure of the new compound (1) was identified on the basis of spectroscopic data analysis. Several of these compounds (1-8) were evaluated against a small panel of human cancer cell lines.