Abstract
Picrorhiza kurroa is an important medicinal plant in the Ayurvedic system of medicine. The root and
rhizome of this plant are used for the treatment of various liver and inflammatory
conditions. In the present study, we sought to investigate the anti-inflammatory activity
of P. kurroa rhizome extract against carrageenan-induced paw edema and cotton pellet implantation-induced
granuloma formation in rats. In addition, its immunomodulatory activity was evaluated
in Complete Freundʼs Adjuvant-induced stimulation of a peritoneal macrophage model
and lipopolysaccharide-stimulated RAW 264.7 murine macrophages. Pretreatment with
P. kurroa rhizome extract inhibited carrageenan-induced paw edema and cotton pellet-induced
granuloma formation in a dose-dependent manner. This was associated with reduced levels
of inflammatory cytokines (TNF-α, IL-1β, IL-6) accompanied with increased anti-inflammatory cytokine (IL-10) in the serum
and peritoneal macrophages. Additionally, P. kurroa rhizome extract inhibited inflammatory TNF-receptor 1 and cyclooxygenase-2 in Complete
Freundʼs Adjuvant-induced activated peritoneal macrophages. Furthermore, P. kurroa rhizome extract treatment significantly inhibited iNOS and suppressed the activation
of NF-κB through inhibition of its phosphorylation and by blocking the activation of IκB kinase alpha in lipopolysaccharide-stimulated RAW264.7 macrophages. Taken together,
these results suggest that P. kurroa has anti-inflammatory activity that is mediated through the suppression of macrophage-derived
cytokine and mediators via suppression of NF-κB signaling.
Key words
Picrorhiza kurroa
- Scrophulariaceae - inflammation - proinflammatory cytokines - macrophages
