Antinociceptive and antioxidant effects of Onosma platyphyllum riedl extract

Pain is an unpleasant and annoying sensation caused by tissue damage and inflammatory stimuli. Due to the side effects of the conventional drugs, the present study was conducted to investigate the antinociceptive effects of Onosma platyphyllum (OP) and its antioxidant activity.

The OP hydroethanolic extract was evaluated by gas chromatography–mass spectrometry (GC-MS) analysis. The phenolic and flavonoid content respectively were determined by Folin-Ciocalteu and aluminum chloride assays. The antioxidant activity of the extract was evaluated by FRAP and DPPH methods. Formalin test was also used to evaluate the herbal antinociceptive effects on various doses (50, 100, 150 and 200mg/kg).

The content of β-phenylethyl butyrate, 2-pentanone,4-hydroxy-4-methyl, 3’-acetyllycopsamine and indolizine analysed by GC-MS were 25.9%, 8.86%, 8.5% and 5.52% of the extract respectively. The phenolic and flavonoid content of the extract were 45.20±2.75 µgGAE/mg and 184.40±26.23 µgQE/mg. The monovalent reducing activity was 382.35±34.83 μMFe2+. The radical scavenging activity of the extract in the dose of 500µg/mL was also 13.71±3.67. The acute and chronic pain score was significantly reduced in treatment with OP extract. The chronic antinociceptive effects of the extract were higher than acute effects. The highest antinociceptive effect was related to 200mg/kg concentration of the extract.

OP is effective in pain relieving, especially in the chronic phase probably by improving the oxidative stress. It’s side effects and hepatotoxicity should be evaluated.