Background: The human body has natural defenses against viruses. During the virus infection, as a
self-protective mechanism, immune cells and other cells will secrete amount of antiviral cytokines to promote the
host to clear virus and microorganism, with multiple mechanisms such as alteration of major histocompatibility
complex (MHC) molecules, activation of cellular antiviral responses involving natural killer cells (NK cells) and
cytotoxic lymphocytes (CTLs), production of antiviral proteins and antibodies. Natural products as traditional
pharmaceutical sources for the curability of various illnesses in the form of medicines possess immunostimulatory
properties to enhance the immune system and eventually combat the disease or infection. In the past 20 years, numerous
natural products have been subjected to investigation for their antiviral effects and many of them such as
polyphenols, flavonoids, saponins and polysaccharides exhibit significant antiviral effects via regulation of these
cytokines, specifically interferons (IFNs), tumor necrosis factor α (TNF-α) and interleukins (ILs).
Objective: The purpose of this review is to provide an overview of antiviral cytokines and regulation functions of
natural products on antiviral cytokines, demonstrating natural products as a promising source for discovery of antiviral
agents for the prevention and treatment of virus infection via regulating endogenous antiviral cytokines.