A Comparative Evaluation of Total Polyphenolic Content and Antioxidant Potential of Thirty Medicinal Halophytes from the Mediterranean Region

In the last decades, an increasing interest has been granted to halophytes due to their high phenolic content, which have therapeutic potential in the treatment and/or management of human health. Therefore, it is important to measure the halophyte total polyphenol content correctly and to valorize their antioxidant capacity. Ethanol extracts from thirty halophytes were analyzed to evaluate the Total Phenol Content (TPC). We employed three testing methods to prove their antioxidant potentialities, including DPPH• (1-DiPhenyl-2-PicrylHydrazyl), ABTS•+ (2,20-Azino-Bis-3-ethylbenzoThiazoline-6-Sulfonic acid) and IRP (Iron Reducing Power) assays. Results showed that plants exhibited different TPC, which varied significantly from 411.5 mg GAE g-1 DW in Cynomorium coccineum to 6.02 mg GAE g-1 DW in Ammophila arenaria. Concerning antioxidant activities, data revealed that Cynomorium coccineum (IC50= 3.82 µg ml-1 versus ABTS•+) and Euphorbia paralias had the highest antiradical capacity (IC50= 0.12 µg ml-1 against DPPH•) and exhibited the best efficient concentration with an EC50 value= 9.57 µg mL-1 for the IRP. Considering correlation between phenols and antioxidant tests, three groups were distinguished with a higher correlation coefficient between 0.78 and 0.98 for the first group. These data suggest the promising potentialities of the Mediterranean medicinal halophytes as valuable source of powerful antioxidants of industries, especially for Cynomorium coccineum, Carpobrotus edulis, Reaumuria vermiculata, Tamarix gallica, and Euphorbia paralias regarding their strong phenol content.