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

Phytochemical screening of aqueous extract from six medicinal wild plants grown in South-eastern of Tunisia: Atriplex halimus, Teucrium polium, Moricandia arvensis, Deverra tortuoa, Haplophyllum tuberculatum and Polygonum equisetiforme 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 mu g/ml; DPPH*+: 213.49 +/- 4.24 mg TEAC/g DW), T. polium (EC50: 25.00 +/- 1.00 mu g/ ml; DPPH*+: 181.39 +/- 9.47 mg TEAC/g DW) as well as H. tuber- culatum (EC50: 56.25 +/- 0.25 mu g/ml; DPPH*+: 177.83 +/- 5.85 mg TEAC/g DW) extracts were the most effective natural antioxidants. For anti-bacterial activity, 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, protocatechuic 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.

Automated summary

Phytochemical screening of aqueous extract from six medicinal wild plants grown in South-eastern of Tunisia, including Atriplex halimus, Teucrium polium, Moricandia arvensis, Deverra tortuoa, Haplophyllum tuberculatum and Polygonum equisetiforme, was conducted using decoction and ultrasound assisted extraction methods. The antioxidant, antibacterial properties, and phenolic profiling were assessed, and the extracts of P. equisetiforme, T. polium, and H. tuberculatum showed the highest effectiveness as natural antioxidants. The ultrasonic extract of H. tuberculatum exhibited the highest antibacterial activity against P. aeruginosa and S. aureus. Additionally, 24 phenolic compounds were identified, with quinic acid, gallic acid, and protocatechuic acid being the predominant components.