Background: Species of Echium trygorrhizum Pomel , are used traditionally in Algeria folk medicine for the treatment of Diabetes, Jaundice and Tonsillitis. To our knowledge, no previous study has been conducted out on the pharmacological activities of this species. Objective: The objective of the present research was to evaluate the content of polyphenols , flavonoids and condensed tannins compounds and to assess in vitro the antioxidant activity and the inhibitory effect of the hydroalcoholic extract of this plant, on α-amylase activity, an enzyme responsible for digestion of carbohydrate before the process of intestinal absorption. Methods: Polyphenols, flavonoids and condensed tannins were evaluated spectrophotometrically using Folin–Ciocalteu, the Aluminum chloride and vanillin methods respectively. The antioxidant activity using DPPH radical scavenging, ABTS, Ferric reducing antioxidant power and β- carotene bleaching tests and the assessment of in vitro α- amylase inhibitory potential by an Aspergillus oryzae α- amylase have been studied. Results: The hydroalcoholic crude extract was able to inhibit the α-amylase enzyme in vitro, with an IC50 of 0.56 ± 0.044 mg/ml, in addition the contents of polyphenols and flavonoids were found to be 157.403 ± 0.835 µg GAE/mg extract and 30.156±2.634µg Q E / mg extract, respectively, Whereas the amount of tannins was 65.293 ± 0.883µg Cat E/ mg of dry extract. Conclusion: The present study revealed that the extract is rich in phenolic compounds, which play a really important role in the scavenging of free radicals. It has been reported the inhibitory capacity of hydroalcoholic roots extract on Aspergillus oryzae α-amylase enzyme might be used as a natural agent within the management of diabetes mellitus.