In this thesis four projects related to bioactive carbohydrates are described. The first project is about the extraction of iminosugars from Hyacinthoides non-scripta. This is the first time that extraction from English bluebell seeds has been described. Efficient extraction and isolation methods are reported. Another project discusses the development of a total synthetic carbohydrate conjugate vaccine candidate against Streptococcus pneumoniae type 14 using Gold nanoparticles as carrier. The synthetic pathway of the introduction of a linker for conjugation, and the deprotection of the tetrasaccharide corresponding to the repeating unit of the Streptococcus pneumoniae type 14 capsular polysaccharide is described. The biological results of the developed vaccine candidate are briefly discussed. In the third project, attempts to synthesise regioselectively sulfated disaccharides to be used in binding studies with FedF adhesin of E. coli are described. In this section, an improved high-yielding method based on the Heyns rearrangement for the synthesis of N-acetyl lactosamine (LacNAc) is also reported. In the fourth part, conjugation of the Lewis b hexasaccharide to be used for studies of Lewis b blood group antigen binding adhesin is reported.