Galactomannan of Delonix regia seeds reduces nociception and morphological damage in the rat model of osteoarthritis induced by sodium monoiodoacetate

This study investigated the effects of the protein-free galactomannan obtained fromDelonix regiaseeds (GM-DR) in an experimental osteoarthritis (OA) model. GM-DR was obtained from water-homogenized endosperms by collection of the supernatant and precipitation with ethanol. The remaining proteins in the galactomannan were removed by alkaline hydrolysis. Weight average molar mass (M-w) of the galactomannan was estimated in 5.8 x 10(5)g mol(-1), presenting mannose:galactose ratio of 2.39:1. Rats received sodium monoiodoacetate (OA groups, 1 mg/25 mu L) or saline (sham group) in the right tibio-tarsal joint. GM-DR (30-300 mu g) was administered by intra-articular route at days 14 and 21 after OA induction. Hypernociception was evaluated daily by the measurement of the mechanical threshold required to cause joint flexion and paw withdrawal reflex. The 56-day animal groups were euthanized for joint histopahological analysis using the OARSI score system. Lower doses of GM-DR (30 and 100 mu g) promoted antinociception from day 15 until the endpoint at day 56. Joint damage was reduced by GM-DR administration (100 mu g) in OA-subjected animals, compared to the vehicle-treated OA group (5.9 +/- 1.8 vs 19.0 +/- 1.8, respectively,p< 0.05). Conclusion: Both antinociception and damage reduction suggest thatDelonix regiagalactomannan is a promising approach for osteoarthritis therapy.

Automated summary

This study found that the protein-free galactomannan obtained from Delonix regia seeds has antinociceptive effects and can reduce joint damage in an experimental osteoarthritis model.