Immuno-enhancing effects of the herbal extract from Himalayan rhubarb Rheum emodi Wall. ex Meissn

► The immune-enhancing activity of Rheum emodi ethyl acetate rhizome extract studied on the cell lines. ► Effects on signal transduction parameters studied providing a plausible mechanism of action of the plant extract. ► Activation of various cytokines on RAW 264.7 cell lines studied in the presence and absence of the ethyl acetate extract. ► A dose dependant increase in the release of nitric oxide (NO) and cytokine TNF-α, IL-12 and a decrease in IL-10 by RAW 264.7 in macrophage cell lines in the presence of extract alone was observed. ► Cytokine level is concomitantly increased in the presence of stimulant as well as extract.