ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optimization of ultrasound-assisted extraction of phenolic compounds from Populus nigra as potential myeloperoxidase inhibitors

Sidali Zaidi, Nadjet Benaida-Debbache, Sara Oumenoune Tebbi, Radia Kadi, and Naima Saidene

Laboratoire de Biochimie Appliquée, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, Bejaia, Algérie

E-mail: sidali.zaidi@univ-bejaia.dz

Received: 29 August 2023  Accepted: 6 December 2023

Abstract:

Myeloperoxidase is a key enzyme that plays an important role in innate immune defense, while overexpression of this enzyme implies the development of inflammatory damage, making it an interesting target for the identification of new anti-inflammatory drugs of natural origin to limit the use of synthetic substances with toxic effects. To this end, our work focuses on the phytochemical compounds of P.nigra buds. In the present study, Box–Behnken design response surface methodology was introduced to optimize ultrasound-assisted extraction parameters of phenolic compounds followed by the evaluation of myeloperoxidase enzymatic activity in vitro as well as molecular docking to further elucidate macromolecular–ligand interactions. Optimization results by ultrasound-assisted extraction revealed a total phenolic content of around 42.87 ± 0.33 mg GAE/g dw obtained with a lactic acid percentage of 66.54% at a temperature of 35 °C for 20 min. In addition, evaluation of the enzymatic activity of the optimized extract in vitro revealed a strong inhibitory activity involving an IC₅₀ of 0.084%. Furthermore, molecular docking of the most abundant phytochemical compounds in the extract tested in interaction with the myeloperoxidase active site showed the formation of hydrogen bonds; Pi-alkyl and Pi-sigma with a high affinity equal to − 9.0 and − 10.1 kcal/mol attributed to esculoside and rhamnosyl-hexosyl-acyl-quercetin, respectively. Based on the data obtained, our results demonstrate the efficiency of phenolic compound extraction using ultrasound as an energy source and lactic acid as an alternative solvent. In addition, the selected compounds exhibit a strong anti-inflammatory activity and can serve as a core structure for the design of more potent inhibitors.

Keywords: Populus nigra L; Eco-extraction; Ultrasonic-assisted extraction; Lactic acid; Myeloperoxidase

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03275-4

Chemical Papers 78 (5) 2841–2854 (2024)