Abstract:

Objective: To investigate the anti-nociceptive effect of total flavonoids from Gnaphalium affine D. Don and the
involved mechanism. Methods: Employing the mouse model of pain induced by heat and intraperitoneal injection of acetic
acid, the analgesic activity of oral administration of the total flavonoids was assessed. Moreover, the production of cytokines
in mouse plasma, including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) was determined.
The gene expression levels of TNF-α, IL-6 and inducible nitric oxide synthase (iNOS) in peritoneal macrophages were also
examined. Results: The total flavonoids significantly increased the withdrawal latency in hot plate tests and inhibited the
writhing response in mice. In addition, the total flavonoids blocked the production of TNF-α, IL-6, and NO in plasma and
reduced the expression levels of TNF-α, IL-6, and iNOS in the peritoneal macrophages. Conclusions: The total flavonoids
from Gnaphalium affine D. Don exert analgesic effects in mice, which is associated with the inhibition of the production of
cytokines in plasma and macrophage-mediated inflammation.

Key words: Gnaphalium affine D. Don, total flavonoids, analgesic effect, pro-inflammatory mediator