Background: Immunomodulators could alter the activity of the immune system. Most of the
synthetic chemotherapeutic agents are immune suppressants and produce side effects.
Immunomodulators derived from plants are used as general adaptogens and immune strengtheners
without undesired effects.
Methods: Present study established the mode of immunostimulatory action of punarnavine alkaloid
(PA) isolated from Boerhaavia diffusa Linn. root by examining various parameters. PA was separated
from B. diffusa and its acute toxicity was studied by up-down regulation method. Immunomodulatory
activity of PA was determined in Albino mice by observing its effect on organ weight (liver, spleen,
thymus and kidney), expression of cytokines, bone marrow cellularity and alpha-esterase positive cells.
Plaque Forming Assay (PFA), Delayed Type Hypersensitivity (DTH), and phagocytosis activity were
also carried out to support the effect of PA. PA did not exhibit any toxic effect in mice.
Results: In DTH study, the foot pad thickness due to influx of mononuclear cells at the site of inoculation
was distinctly increased in PA treated mice. PA enhanced the phagocytic activity of the polymorphonuclear
cells by increasing the engulfment of the Candida cells thereby stimulating a non-specific
immune response. PFA confirmed that PA treatment could elevate the humoral immune response due to
the synthesis of antibody which in turn is responsible for the enhancement of macrophages and Blymphocyte
subsets. The significant increase in the number of α-esterase positive cells and bone marrow
cellularity due to immunomodulatory effect indicated the proliferation of stem cells. Different organ
weight was also markedly improved by PA treatment compared to SRBC sensitized group. Further, in
real time PCR studies treatment of PA significantly increased IL- 7, IL- 10, IL-12a and IL-12b mRNA
Conclusion: From the above findings it can be concluded that PA could be developed as a potent immunomodulatory