Antinociceptive and anti-inflammatory activities of extract and two isolated flavonoids of Carthamus tinctorius L.

ETHNOPHARMACOLOGICAL RELEVANCE: Safflower (Carthamus tinctorius L.) has been long used both in the traditional system and folk medicine as an analgesic anti-inflammatory agent in China. The aim of the study was to evaluate the antinociceptive and anti-inflammatory activities of hydroalcoholic extract (HE) and two isolated kaempferol glycosides of Carthamus tinctorius L. to provide experimental evidence for its traditional use.

MATERIALS AND METHODS: Antinociceptive effects of HE, kaempferol 3-O-rutinoside (K-3-R) and kaempferol 3-O-glucoside (K-3-G) were assessed in mice using the acetic acid-induced writhing test, formalin test and cinnamaldehyde test. The anti-inflammatory effects of HE, K-3-R and K-3-G were determined in two animal models: carrageenan-induced paw edema and xylene-induced ear edema.

RESULTS: The HPLC analysis showed the presence of K-3-R and K-3-G in Carthamus tinctorius L. HE (500 and 1000mg/kg) as well as K-3-R and K-3-G (150, 300 and 600mg/kg) produced significant inhibition on nociception induced by acetic acid and formalin. Oral treatment of HE, K-3-R and K-3-G at all doses significantly reduced both the nociceptive response and cinnamaldehyde-induced paw edema, effect that was superior to aspirin. In anti-inflammatory tests, HE and K-3-G significantly inhibited the paw edema during the both phases of carrageenan-induced inflammation while K-3-G suppressed the late phase inflammation only. HE (400 and 800mg/kg) and K-3-G (200, 400, 800mg/kg) produced significant dose-dependent inhibition of xylene-induced ear edema development. K-3-R only suppressed ear edema formation at a high dose (800mg/kg).

CONCLUSIONS: These results demonstrate that Carthamus tinctorius L. extract possess remarkable antinociceptive and anti-inflammatory activities which may be due to K-3-R and K-3-G at least in part, supporting the folkloric usage of the plant to treat various inflammatory and pain diseases.