Since ancient times the therapeutic uses of traditional
medicines and phytomedicines have proved very popular for health maintenance by various means. During thelast century chemical and pharmacological studies have been performed on many plant extracts in order toinvestigate their chemical composition and conrm their therapeutic usefulness. Most of the bioactive constituentsof phytomedicines are water-soluble molecules (
e.g.
phenolics, glycosides, and avonoids). However, water-soluble phytoconstituents are limited in their effective-ness because they are poorly absorbed [1] when takenorally or when applied topically. Many approaches have been developed to improve the oral bioavailability, suchas inclusion of solubility and bioavailability enhancers,structural modication and entrapment with the lipophiliccarriers [2-4]. There are many factors which may contri-
.