Enzymatic modification of natural compounds with pharmacological properties.

Glycosides of various classes of natural products are widely distributed in nature, where they are often present esterified with aliphatic and aromatic acids at specific OH's of their sugar moieties. Many of these compounds are pharmacologically important molecules or possess other interesting properties. For instance, ginsenosides (e.g., 3) are therapeutic dammarane-type oligoglycosides isolated from the water-soluble portion of the dried roots and leaves of Panax ginseng C.A. Meyer (Aralianceae), a plant widely used in traditional Chinese medicine. In recent years, we have exploited the regioselectivity of lipases and proteases in organic solvents for the synthesis of specific esters of ginsenosides as well as the selectivity of the beta-1,4-galactosyltransferase from bovine colostrum to obtain new glycosyl derivatives of these compounds. The application of these two enzymatic methodologies has also been exemplified with other natural compounds with pharmacological properties: digitonin (5), colchicoside (6), and flavonoid glycosides.