Activités antioxydantes, antibactériennes et anti-α-amylases de divers extraits d'Anvillea radiata récoltés dans la région de Ghardaïa

Abstract

Current research is focused on molecules endowed with biological activities of natural origin. The objective of this study is to evaluate the antioxidant activity, the antibacterial and anti-α-amylase activities of various extracts of Anvillea radiata aerial part the (Asteraceae) from the region of Ghardaia, which is widely used in traditional medicine in Algeria. The extraction of the active ingredients of Anvillea radiata aerial part was carried out by cold maceration using three solvents of different polarities (methanol, ethyl acetate and petroleum ether). Phytochemical analysis of the various extracts is performed by phytochemical screening and quantification of some phenolic compounds classes. Several biological activities were evaluated namely the antioxidant activity using three tests (ABTS, FRAP and bleaching of β-carotene), the antibacterial activity by diffusion on agar medium and by microdilution method and the antidiabetic activity by the measurement of α-amylase inhibition. The obtained results showed the richness of the studied species in phenolic compounds (tannins, flavonoids, coumarines ... etc.) and terpene (saponosides and steroids). The highest contents of total polyphenols, flavonoids, phenolic acids and condensed tannins are obtained with the methanolic extract which are in the order of 81.38 ± 19.16 mg EAG / g, 16.37 ± 0 , 89 mg ER / g, 4542.00 ± 8.49 μg EAC / g and 33.97 ± 1.06 mg EC / g respectively. The methanolic extract of Anvillea radiata has the best inhibitory capacity of the ABTS •+ radical cation , iron reducing power and β-carotene bleaching inhibitory effect with IC50 equal to 153.48±10.02 μg/ml, 95.88±9.13 μg/ml and 172.94±14.88 μg/ml respectively comparable to those of the standard antioxidants used. As regard to the antibacterial activity, the ethyl acetate extract has the potential capacity to inhibit bacterial growth. on both strains tested (S. aureus and E. coli) with MIC equal to 0.33 mg/ml. The best inhibitory activity of α- amylase was recorded with the methanolic extract where the IC50 value of 76.31±5.60 μg/ml, which is lower than that of acarbose. In conclusion, the obtained results may justify the traditional use of this species to treat inflammatory problems, infectious diseases and diabetes.