Season and Ecotype Effects on Soluble Phenolic Compounds Content and Antioxidant Potential of Tamarindus indica and Mitragyna inermis

Tamarindus indica and Mitragyna inermis are widely used by herbalists to cure diabetes. However, the suitable areas and season for harvesting these plants remain unexplored. Moreover, the adaptation to stress is mostly affected by an environmental factor. Also, the ingredients responsible of bioactivity remain unknown. Season and ecology effect on phenolic compounds content was carried out with Folin-Ciocalteu Reagent and their antioxidant potentials was checked by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and Fe3+ chelation assays. Then, correlation between antioxidant activities and polyphenol contents of aqueous extract, phenolic-rich fractions, and flavonoid-rich fractions was established. For this purpose, sampling of stem, root barks, and leaves from three zones of Burkina Faso was done in the rainy season and the dry season. The results showed that antioxidant potential and properties vary from one area to another, from one plant to another and from one part to another for the same plant. Also, the dry season sounds favorable for the harvesting of these plants, as during this season plants produce high phenolic compounds with high anti-oxidant potential. The results obtained with these extracts suggest their plant collection and use as a basis for the research of improved traditional drugs following further investigations.