In vitro Antioxidant, α-amylase and Horseradish Peroxidase Inhibitory Potential of Phenolics Extracts from Chamomilla pubescens, Pulicaria crispa and Rhanterium adpressum Growing in Algeria

Background: Plants are the main source of drugs for the therapy of a large number of diseases. Objective: The aim of the present work is to evaluate the in vitro antioxidant and anti-α-amylase and anti- peroxidases (HPR) potentials of phenolic extracts obtained from three spontaneous plants growing in the South of Algeria, namely Chamomilla pubescens, Pulicaria crispa, and Rhanterium adpressum. This is the first report on the study of α-amylase and horseradish peroxidase (HRP) inhibitory activity for phenolic extracts from the Chamomilla pubescens and Pulicaria crispa plants. Methods: The antioxidant activity was evaluated in vitro using four tests: DPPH, CUPRAC, FRAP, and ABTS. The phenolic, flavonoid, and tannin compounds of the three selected Algerian plants were quantified. Also, the inhibition of α-amylase and HRP was evaluated. Results: The quantification of the total phenolic contents revealed that they are variable and widely dependent on extraction solvents. The highest content was recorded by the ethyl acetate extract of Chamomilla pubescens (flowers) 774.93±60.14mg/100 g of dry matter. In all the antioxidant tests, ethyl acetate extracts showed the most effective activity, of which the best was (VCEAC = 65.62 ±0.50 μM/g dry matter) of Pulicaria crispa for the DPPH test. Furthermore, the results of α-amylase and peroxidase inhibitory effects indicated that all plants extracts have inhibitory effects on the two enzymes, with AEIC values ranging from 76.55±3.54 to 149.54±6.68 μM/g of dry matter for the α-amylase and CEIC values ranging from 8.89±2.22 to 9668.31±254.42 μM/g of dry matter for the peroxidase (HRP). Conclusion: The present study results suggest that the three Algerian spontaneous plant species (Rhanterium adpressum, Pulicaria crispa and Chamomilla pubescens) inhibit peroxidase and α-amylase and exhibit a high antioxidant activity which can be related to the treatment of diabetes and thyroid diseases.