Anti-arthritic activity of root bark of Oroxylum indicum (L.) vent against adjuvant-induced arthritis

Oroxylum indicum (Bignoniaceae) also known as Sonapatha is an indigenous medicinal plant widely used in Ayurvedic medicine for over thousands of years. It is an active ingredient of well-known Ayurvedic formulations such as Chyawanprash and Dasamula. Root bark of this plant has tonic and astringent properties and it is also used in rheumatism.

The present investigation was carried out to evaluate the anti-arthritic activity of different extracts of root bark of Oroxylum indicum against adjuvant - induced arthritis in rats.

Male Wistar rats were used in this study. Arthritis was induced by injecting 0.1 ml Freund's complete adjuvant intra-dermally into the left hind paw of the rats. The paw volume, hematological, biochemical, radiographic and histopathological aspects were evaluated.

The relative percentage inhibition potential of paw volume in rats treated with various extracts of Oroxylum indicum was found to be ethyl acetate extract (67.69%) >chloroform extract (64.61%) >n-butanol extract (58.46%) respectively. The hematological parameters like RBC count, hemoglobin content showed significant increase while there was a significant decrease in total WBC count and ESR in all the groups of animals pretreated with root bark extracts. The biochemical parameters such as catalase, glutathione contents showed a significant increase while the lipid peroxide and Cathepsin-D content decreased significantly only in case of ethyl acetate pretreated rats when compared to others.

The present study suggests that the chloroform, ethyl acetate and n-butanol extracts of root bark of Oroxylum indicum exhibit anti-arthritic activity. The order of activity of extracts was found to be ethyl acetate >chloroform >n-butanol respectively.