In order to provide novel polymeric biomaterials for chemotherapeutic purposes, in this paper we described the synthesis and the characterization of the physicochemical properties of a betulin-based polyanhydride exhibiting anti-cancer effects.

The synthesis and evaluation of the anticancer activity of new acylated oximes derivatives of oleanolic acid with 4-thiazolidinone-3(5)-carboxylic acid moieties were described. Newly synthesized compounds were elucidated on the basis of elemental analyses and spectral data (IR, 1 H, and 13 C NMR). Anticancer activity of the tested compounds has been evaluated in vitro at National Cancer Institute (NCI) in which some structure activity relationships (SARs) were discussed. Among the tested compounds, 3-[(2,4-thiazolidinedione-5-ylidene)-carboxyimino] olean-12-en-28-oic acid methyl ester (IVm) was superior to other related compounds with mean values of pGI 50 = 5.51/5.57, pTGI = 5.09/5.13, and pLC 50 = 4.62/4.64, low toxicity and moderate activity level in vivo hollow fiber assay.

Oleanolic acid ketones, oximes, lactams and nitriles were obtained. Complete spectral characterizations (IR, (1)H NMR, (13)C NMR, DEPT and MS) of the synthesized compounds are presented. The derivatives had oxo, hydroxyimino, lactam or nitrile functions at the C-3 position, an esterified or unmodified carboxyl group at the C- 17 location and, in some cases, an additional oxo function at the C-11 position. The new compounds were tested for cytotoxic activity on the HeLa, KB, MCF-7 and Hep-G2 cancer cell lines with the application of MTT [3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test. Among the tested compounds, some oximes and all lactams proved to be the most active cytotoxic agents. These triterpenes significantly inhibited the growth of the HeLa, KB, MCF-7 and Hep-G2 cancer cell lines at micromolar concentrations.

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