The research activity of Professor De Castro is in carbohydrate structural chemistry, and her training in this subject started during her bachelor thesis, which focused on plant polysaccharides. Since then, even though Professor De Castro continued her work on carbohydrate structural chemistry, she shifted her interests and dedicated her activity to the analysis of the bacterial membrane carbohydrate components, paying attention, but not limiting the work, to Gram-negative bacteria and lipopolysaccharides (LPSs). This work has resulted in the development of state-of-the-art chemical and spectroscopical approaches that have been later applied with success to different kinds of carbohydrates, such as those from the bacteria of the gut microbiota or those from the giant viruses. This last topic is Professor De Castro's major field of research.
Professor De Castro is the author/co-author of about 130 peer-reviewed publications, an associated Editor for the journal Carbohydrate Polymers, and a member of the editorial board of Carbohydrate Research, Glycobiology, and Polysaccharides. She fruitfully collaborates with different research institutions, such as the Department of Plant Pathology (University of Nebraska Lincoln, NE, USA) and the Structural and Genomics Information Laboratory in Marseille (France).