Role of phytochemicals as immunomodulatory agents: A review

Abstract

A strong, well-functioning immune system is the cornerstone of good health. Immunity is the balanced state of having adequate biological defenses to fight infection, disease, or other unwanted biological invasion while having tolerance to avoid allergy and autoimmune diseases. Immune responses are the result of an effective interaction between innate (natural and non-specific) and acquired (adaptive and specific) components of the immune system. Over the last three decades, there has been remarkable interest in the immune system as a potential target of toxicity following exposure to drugs, chemicals or environmental pollutants. Immunodeficiencies occur when one or more of the components of the immune system are inactive. Many factors play a significant role in altering the immunocompetence such as age, sex, genetic variability, stress, alcohol/drug abuse, malnutrition, environmental pollution, lifestyle. Immunomodulation is a very broad term which refers to any changes in the immune response and may involve induction, expression, amplification or inhibition of any part or phase in the immune response. In clinical perspective immunomodulators can be classified into the following three categories: Immunoadjuvants, immunostimulants, and immunosuppresants. A diverse array of synthetic, natural and recombinant compounds is available with both merits and demerits. Phytochemicals are naturally occurring compound with bioactive potentials, which have potential immunostimulating activity. The present review focused on the immune-modulating activity of various phytochemicals such as alkaloids, polysaccharides, lectins, glycosides, phenolic compounds, flavonoids, anthocyanins, tannins, saponins, terpenoids, sterols and also explains the role of antioxidants as immune-modulators.