Ethanol/water extracts from halophyte species Arthrocnemum macrostachyum and Tetraena qatarensis

Microwave-assisted extraction using various concentrations of ethanol in water (25%, 50%, 75% v/v) was carried out using biomass from halophytes; Arthrocnemum macrostachyum and Tetraena qatarensis. Total phenolic content (TPC; expressed as mg Gallic acid equivalent; GAE) and antioxidant activity using half-maximal inhibitory concentration of DPPH-free radical (IC50; expressed as µg/mL) was highest in extracts from 75% ethanol in both plant species; TPC = 45.6 ± 1.0 and 54.4 ± 0.8 mg GAE/g extract; IC50 = 62.7 ± 0.4 and 67.9 ± 4.8 µg/mL for A. macrostachyum and T. qatarensis, respectively. UV-VIS spectral analysis and metabolome profile analysis obtained using UHPLC-Q-ToF-MS suggest the 50% and 75% ethanol extracts are similar in A. macrostachyum, whereas the 25% and 50% ethanol extracts are similar in T. qatarensis. Increasing the concentration of ethanol results in phytoextracts with greater chemical complexity.