Bioactive flavonoids from Populus ciliata: In vitro and In silico evaluation of antimicrobial, antioxidant and anti-inflammatory activities

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Inglés. The stem bark of Populus ciliata is recognized as a valuable source of medicinal and therapeutic compounds. The study focused on extracting bioactive compounds from the ethyl acetate fraction of P. ciliata stem bark. Four flavonoids were isolated for the first time from the plant: EF01 [3,5-dihydroxy-2-(4-hydroxyphenyl)-7-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-4-one], EF02 [5,7-dihydroxy-2-(4-hydroxyphenyl)-4H-chromen-4-one], EF03 [2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one] and EF04 [(2S)-5-hydroxy-2- (4- hydroxyphenyl)- 4-oxo- 3,4- dihydro-2H-chromen- 7-yl-2-O-(6-deoxy-α-L-mannopyranosyl)-?-D- glucopyranoside]. These compounds were characterized and evaluated for various biological activities using in vitro and in silico techniques. The findings revealed that EF01 (a flavonol glycoside) and EF04 (a flavanone glycoside) were isolated for the first time from the Populus genus. Among the compounds, EF03 exhibited the strongest biological activities, including antioxidant (IC50: 6.36±1.43 ?g/mL; 14.74±1.49 ?g/mL), antibacterial (MIC: 6.25-12.50 ?g/mL), antifungal (Fusarium oxysporum-6.25 ?g/mL; Candida glabrata-15.62 ?g/mL), and anti-inflammatory (IC50: 9.39±0.81 ?g/mL) activities. Additionally, EF04 demonstrated promising effects against Candida auris (MIC: 31.25 ?g/mL). In molecular docking, dynamics stimulations and molecular mechanics-generalized born surface area studies, EF03 showed notable binding affinity (surpassing the positive controls) and stable complexes with human cyclooxygenase-2, human peroxiredoxin 5, N-myristoyl transferase and penicillin-binding protein, reinforcing its potential antioxidant, antimicrobial, and anti-inflammatory properties. In conclusion, the flavonoids extracted from P. ciliata exhibit significant biological activity, which may contribute to its medicinal properties. Further research is warranted to identify additional bioactive phytochemicals from P. ciliata with potential applications in various fields.