Phytochemical screening, phenolic compound content and antiradical activity of leaves, petioles, pulp and roasted kernels of Tamarindus indica L.

Abstract

Tropical plants constitute a very important natural wealth whose food valorization requires a perfect knowledge of their physicochemical compositions. The double objective of the study was -i- to identify the chemical groups of leaves, petioles, pulp and roasted kernels of Tamarindus indica L. from Benin by differential reactions and -ii- to evaluate the content of phenolic compounds in their hydroethanol extracts. Total polyphenols were determined by the Folin-Ciocalteu reagent. Aluminium trichloride method was used to quantify total flavonoids while condensed tannins content was determined by Butanol-HCl (9:1) method. Phytochemical screening revealed the presence of anthraquinones, anthocyanins, coumarin, reducing compounds, flavonoids, leucoanthocyanins, steroids and terpenoids in leaves, petioles and pulp of Tamarindus indica L. Its roasted kernels contained alkaloids while its leaves contained tannins. The spectrophotometric assay showed that the hydroethanol extract of the leaves had the highest contents of total polyphenols and total flavonoids respectively 0.82 ± 0.00 mg EAG/g DM and 26.82 ± 0.03 mg EQ/ g DM. It was followed by hydroethanol extract of petioles with 0.68± 0.00 mg EAG/g DM and 14.70 ± 0.01 mg EQ/ g DM. The highest content of condensed tannins with (32.57 ± 0.036) mg EQ/g was recorded by the hydroethanolic extract of petioles of Tamarindus indica L. These results thus translate a strong functional potential of Tamarindus indica L. for the populations of Bénin Republik and deserve a particular interest in the agroalimentary industries for the development of new products.