Riboflavin, similar to other
vitamins of the B complex, presents anti-inflammatory activity but its full characterization has not yet been carried out. Therefore, we aimed to investigate the effect of this
vitamin in different models of nociception,
edema,
fever and formation of fibrovascular tissue.
Riboflavin (25, 50 or 100 mg/kg, i.p.) did not alter the motor activity of mice in the rota-rod or the open field models. The second phase of the nociceptive response induced by
formalin in mice was inhibited by
riboflavin (50 or 100 mg/kg). The first phase of this response and the nociceptive behavior in the hot-plate model were inhibited only by the highest dose of this
vitamin.
Riboflavin (25, 50 or 100 mg/kg, i.p.), administered immediately and 2 h after the injection of
carrageenan, induced antiedema and antinociceptive effects. The antinociceptive effect was not inhibited by the pretreatment with
cadmium sulfate (1 mg/kg), an inhibitor of
flavokinase.
Riboflavin (50 or 100 mg/kg, i.p., 0 and 2 h) also inhibited the
fever induced by
lipopolysaccharide (LPS) in rats. Moreover, the formation of fibrovascular tissue induced by s.c. implant of a cotton pellet was inhibited by
riboflavin (50 or 100 mg/kg, i.p., twice a day for one week).
Riboflavin (10 or 25 mg/kg, i.p.) also exacerbated the effect of
morphine (2, 4 or 8 mg/kg, i.p.) in the mouse
formalin test. In conclusion, the study demonstrates the antinociceptive and anti-inflammatory activities of
riboflavin in different experimental models. These results, associated with the fact that
riboflavin is a safe drug, is approved for clinical use and exacerbates the antinociceptive effect of
morphine, may warrant clinical trials to assess its potential in the treatment of different painful or inflammatory conditions.