Seasonal and solvent extraction influence on phenolic contents, antioxidant activity and antidiabetic capacity of three selected herbs from Chenopodiaceae family

The aim of this research was to study seasonal influence on antioxidantactivity, antidiabetic activity and phenolic content of three endemic plantsbelonging to Chenopodiaceae family: Caroxylonimbricatum (Forssk.) Akhani & Roalson, Caroxylon vermiculatum (L.) Akhani & Roalson and Agatophora alopecuroides (Delile) Bunge. The totalphenolic content ranged from 15.98 to 0.61 mg gallic acid equivalents/g ofdry weight where spring was found to be the best harvest season. The antioxidantactivity of the butanolic fraction of A.alopecuroides (collected in October and May) measured by the DPPH andCUPRAC assays displayed the highest antioxidant activity(EC₅₀ = 0.032 mg/mL and0.016 mg/mL respectively).The ethyl acetate fraction of C. imbricatum (collected in October) displayed thehighest iron chelating activity(EC₅₀ = 0.141 mg/mL). All extractsinhibit α-amylase and α-glucosidase activities with different levelsof inhibition more or less significant (3.39–91.01%). In order to havegood inhibition of α-amylase and α-glucosidase tests, the best harvestseason of A. alopecuroides was in May and inOctober for C. vermiculatum. For C. imbricatum the adequate harvest season forα-amylase test was in May and June for α-glucosidase test. Thisfinding opens door to better use these natural plants in pharmacologicalproducts.