Synthesis and cytotoxic activity of 4-O-β-D-galactopyranosyl derivatives of phenolic acids esters.

The glycosylation of naturally occurring phenolic acids has a significant impact on their solubility, stability and physiochemical properties. D-Galactose residue was found to form a part of glycoconjugates in several tissues and involved in a variety of physiological process. To the best of our knowledge, we have noticed a little information about the glycosylation of the phenolic acids with galactose residue. In this work, we describe the glycosylation of methyl vanillate and methyl ferulate with peracetylated-β-D-galactopyranose in the presence of BF3·OEt2. The coupling reaction yielded efficiently and selectively only the acetylated β-D-galactopyranosides 3 and 6. Removal of the acetyl groups using sodium methoxide afforded the corresponding β-D-galactopyranosides 4 and 7 in good yields. Anticancer activity in vitro was evaluated against two human cancer cell lines (MCF-7 breast cancer cell lines and PC-3 prostate cancer cell lines). β-D-galactopyranosides 4 and 7 demonstrated improved cytotoxic activity compared to the parental esters.