Analgesic and Anti-inflammatory Activities of the Aqueous Extract of Plantago major L.

This study aimed to validate the pharmacological effects of Plantago major L., a medicinal plant used to decrease pain and inflammation. The aqueous extract (AE) was prepared from the dried ground leaves. Pretreatment with AE (1 g/kg, p.o.) decreased writhing induced by acetic acid in mice, but it did not change the tail flick responses to heat nociceptive stimuli. In rats, AE (1 g/kg, p.o.) reduced the paw edema and pleurisy induced by carrageenin, but it did not alter the paw edema induced by dextran. The effect of AE on the carrageenin inflammatory responses was more intense than that obtained on the ear edema induced by croton oil in mice. In addition, daily treatment with AE (1 g/kg/day during 8 days, p.o.) inhibited the exudative process induced by croton oil injected into the air pouch of rats. The results indicate that the aqueous extract of Plantago major is endowed with effective antiinflammatory and analgesic activities.