Effect of the association of other plants on the antioxidant activity of Cochlospermum tinctorium

Résumé

Cochlospermum tinctorium is a medicinal plant recognized for the treatment of various diseases. In Benin, C. tinctorium (wild or cultivated form) alone or its combination with Chromolaena odorata or Combretum micranthum, used in the treatment of liver diseases. The present study aimed to evaluate the association of Chromoleana odorata  or Combretum micranthum to C. tinctorium on its phenolic composition and antioxidant activity. The aqueous, ethanolic and hydroethanolic extracts of Cochlospermum tinctorium preparations were prepared. The antioxidant activity of the extracts was explored by the DPPH radical scavenging test. Their polyphenol and total flavonoid contents were determined by the spectrophotometric method. Results showed that there was no difference in phenolic composition and antioxidant activity between wild and cultivated forms of C. tinctorium. However, recipes combining Cochlospermum tinctorium with Chromolaena odorata or Combretum micranthum enhance the antioxidant activity of the aqueous extracts but do not influence the antioxidant activity of the hydroethanolic and ethanolic extracts of the plant. Similarly, the polyphenol and flavonoid contents did not vary with the combination. Hydroethanolic extracts presented the best antioxidant activities and the highest polyphenols contents. This study showed that the cultivation of C. tinctorium does not alter its phenolic composition and antioxidant activity. The combination of Chromolaena odorata or Combretum micranthum does not significantly enhance the antioxidant activity of Cochlospermum tinctorium.