RESUMEN
This study aimed to investigate the total phenolic content (TPC), the identification of the common compounds by HPLC-ESI-MS and HPLC-ESI-MS-TOF and the inhibitory effects against class A-type ß-lactamase (GES-22 variant, produced recombinantly) in methanolic extracts (MEs) of four Algerian seaweeds [Ulva intestinalis, Codium tomentosum, Dictyota dichotoma and Halopteris scoparia]. The TPC varied among the four species, ranging between 0.93⯱â¯0.65 and 2.66⯱â¯1.33â¯mg GAEs/g DW. C.tomentosum had higher total phenol content than other seaweeds while, all of them inhibited uncompetitively GES-22 activity in a dose-dependent manner. Nitrocefin was used as chromogenic substrate to evaluate the inhibitory effect on GES-22. The methanolic extract of D.dichotoma exhibited significant inhibitory effect on GES-22 (IC50â¯=â¯13.01⯱â¯0.046⯵g/mL) more than clavulanate, sulbactam and tazobactam (classical ß-lactam inhibitors) (IC50â¯=â¯68.38⯱â¯0.17⯵g/mL, 52.68⯱â¯0.64⯵g/mL, and 29.94⯱â¯0.01⯵g/mL, respectively). IC50 of the other ME of U.intestinalis, C.tomentosum, and H.scoparia were 16.87⯱â¯0.10⯵g/mL, 16.54⯱â¯0.048⯵g/mL, and 25.72⯱â¯0.15⯵g/mL, respectively. Except H. scoparia, other three seaweed extracts showed almost two times or more inhibition on GES-22. Furthermore, four common compounds in these MEs were identified, α-linolenic acid (C18:3ω3), linoleic acid (C18:2ω6), oleic acid (C18:1ω9), the eicosanoid precursors ''arachidonic acid'' (C20:4ω6). Baicalein (C15H10O5) was identified in U.intestinalis and D.dichotoma seaweeds. The fact that all seaweed extracts inhibited the GES-22 better than commercial samples makes these seaweeds candidate for discovering new inhibitors against ß-lactamases. Besides that, they contain important components with potential health benefits.