Phenolic Profiling, Antioxidant, and Antibacterial Activities of Selected Medicinal Plants from Tunisia.

Phytochemical screening of aqueous extract from six medicinal wild plants growing in South-eastern of Tunisia were evaluated. Both decoction and ultrasound assisted extraction were used. Antioxidant, antibacterial proprieties, and phenolic profiling, using LC-ESI-MS method, were assessed. Total polyphenols, flavonoids, and condensed tannins contents ranged from 7.47±0.19 to 22.25±0.49 mg GAE/g Dw, 5.47±0.06 to 7.55±0.07 mg RE/g Dw, and 0.33±0.02 to 19.43±0.64 mg TAE/g Dw, respectively. Moreover, the reducing power and DPPH tests showed that P. equisetiforme (EC50: 12.50±0.50 µg/ml; DPPH.+: 213.49±4.24 mg TEAC/g DW), T. polium (EC50: 25.00±1.00 µg/ml; DPPH.+: 181.39±9.47 mg TEAC/g DW) as well as H. tuberculatum (EC50: 56.25±0.25 µg/ml; DPPH.+: 177.83±5.85 mg TEAC/g DW) extracts were the most effective natural antioxidants. The ultrasonic extract of H. tuberculatum showed the highest activity against both P. aeruginosa (13.50 ± 0.71 mm) and S. aureus (13.00 ± 0.00 mm) at 10 mg/ml. Furthermore 24 phenolic compounds were identified, with predominance of quinic acid, gallic acid, protocatchuic acid, syringic acid, p-coumaric acid, trans-ferulic acid, catechin (+), trans-cinnamic and silymarin. These results were further consolidated by to heatmap clustering with P. equisetiforme, H. tuberculatum, T. polium as the main antioxidant and antibacterial sources which supports their domestication and industrial use.