THE INHIBITORY EFFECT OF METHANOLIC AND AQUEOUS EXTRACTS OF TERMINALIA CHEBULA DRIED FRUITS ON METALLOBETALACTAMASES OF ACINETOBACTER BAUMANNII

Objective: toevaluate Metallo-betalactamase (MBL) inhibitory effect and antimicrobial activity against Acinetobacter baumannii of methanolic and aqueous extracts of Terminaliachebuladried fruits.Methods: effect of EDTA (Ethylenediaminetetraacetic acid), methanolic and aqueous extracts of dried fruits of T. chebula on Metallo-betalactamase activity was studied in vitroby using cephaloridin asasubstrate. The degree of inhibition was determined byIC50and the antimicrobial activities of both extracts against Acinetobacter baumannii were qualitatively and quantitatively assessed by the presence or absence of inhibition zones, MIC and MBC values.Results: EDTA, methanolic and aqueous extracts inhibit metallo-betalactamases activity withIC50(3.98 mM, 18.45 and 19.68µg/ml), respectively. Polyphenols in aqueousand methanolic extracts are 513.094±3.061 and 496±2.856 µg GAE/mg, respectively.Conclusion: These results indicate that both extracts of T. chebula are rich in polyphenols and have a strong inhibitory effect on metallo-betalactamases in a competitive manner compared to EDTA. In addition, both extracts of T. chebula were also screened for their remarkable antibacterial and bactericidal activity against Acinetobacter baumannii confirmed by low minimum inhibitory and bactericidal concentration (MIC and MBC).Â

Investigation of common chemical components and inhibitory effect on GES-type beta-lactamase (GES22) in methanolic extracts of Algerian seaweeds

HOUCHI, Selma/0000-0002-6922-709X; SANDALLI, Cemal/0000-0002-1298-3687WOS: 000458468100008PubMed: 30393116This 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 beta-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 +/- 0.65 and 2.66 +/- 1.33 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 (IC50 = 13.01 +/- 0.046 mu g/mL) more than clavulanate, sulbactam and tazobactam (classical beta-lactam inhibitors) (IC50 = 68.38 +/- 0.17 mu g/mL, 52.68 +/- 0.64 mu g/mL, and 29.94 +/- 0.01 mu g/mL, respectively). IC50 of the other ME of U.intestinalis, C.tomentostum, and H.scoparia were 16.87 +/- 0.10 mu g/mL, 16.54 +/- 0.048 mu g/mL, and 25.72 +/- 0.15 mu 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, alpha-linolenic acid (C18:3 omega 3), linoleic acid (C18:2 omega 6), oleic acid (C18:1 omega 9), the eicosanoid precursors "arachidonic acid" (C20:4 omega 6). 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 beta-lactamases. Besides that, they contain important components with potential health benefits