Abstract
Immunomodulators can be either synthetic in origin or naturally obtained.
Natural plant-based compounds can influence the immune system by either affecting
antibody secretion to control the infection or affecting the functions of immune cells,
thus contributing to maintaining immune homeostasis. Phytochemicals in plants, such
as polysaccharides, lactones, flavonoids, alkaloids, diterpenoids and glycosides, have
been reported to possess immunomodulating properties. However, there are many
challenges limiting the clinical use of natural immunomodulators. In this chapter, we
have discussed in detail standardization, formulation development, route of
administration and regulatory concerns of natural immunomodulators. In order to
overcome these challenges and ensure that natural immunomodulators reach the target
site at therapeutic concentrations, different polymer and lipid-based nanocarrier
delivery systems have been developed. These nanocarriers by virtue of their size, can
easily penetrate and reach the target site and deliver the drugs. Many nanocarriers like
liposomes, niosomes, nanoparticles, microemulsions, phytosomes and other vesicular
systems designed for natural immunomodulators are discussed in this chapter.