Enzyme-Site Blocking Combined with Optimization of Molecular Docking for Efficient Discovery of Potential Tyrosinase Specific Inhibitors from Puerariae lobatae Radix

Abstract

Enzyme inhibitors from natural products are becoming an attractive target for drug discovery and development; however, separating enzyme inhibitors from natural-product extracts is highly complex. In this study, we developed a strategy based on tyrosinase-site blocking ultrafiltration integrated with HPLC-QTOF-MS/MS and optimized molecular docking to screen tyrosinase inhibitors from Puerariae lobatae Radix extract. Under optimized ultrafiltration parameters, we previously used kojic acid, a known tyrosinase inhibitor, to block the tyrosinase active site in order to eliminate false-positive results. Using this strategy, puerarin, mirificin, daidzin and genistinc were successfully identified as potential ligands, and after systematic evaluation by several docking programs, the rank of the identified compounds predicted by computational docking was puerarin > mirificin > kojic acid > daidzin ≈ genistin, which agreed with the results of tyrosinase-inhibition assays. Structure-activity relationships indicated that C-glycosides showed better tyrosinase inhibition as compared with O-glycosides, with reduced inhibition achieved through the addition of glycosyl, which provides ideas about the screen of leading compounds and structural modification.

Evaluation of Anti-Melanogenesis Activity of Enriched Pueraria lobata Stem Extracts and Characterization of Its Phytochemical Components Using HPLC–PDA–ESI–MS/MS

“…The docking affinity scores of the 12 compounds found in the enriched PLS extracts to human tyrosinase are illustrated in Figure 3 . Puerarin and daidzin showed strong docking abilities, which are consistent with the results of previous reports [ 26 ]. Discovery studio was used to decipher the hydrogen bond pocket view of the interactions between the active compounds (puerarin, daidzin, and kojic acid (positive control)) and human tyrosinase ( Figure 5 a–c).…”

“…Based on previous literature and the use of authenticated standards, we identified the phytochemical constituents of the enriched PLS extracts. Among them, puerarin was the most abundant compound that exerted a good tyrosinase inhibitory effect with an IC 50 value of 478.5 μM [ 26 ]. Puerarin has long been recognized for its beneficial effects on cardiovascular, hyperglycemic, and neurological disorders.…”

Recent advance in the discovery of tyrosinase inhibitors from natural sources via separation methods

“…UF-HPLC-QTOF-MS/MS strategy was applied by Liu et al. 15 to screen TYR inhibitors from Puerariae lobatae Radix, kojic acid was used to blocking the TYR-site to eliminate false positives. The activity results predicted by molecular docking are consistent with that obtained from in vitro activity.…”

“… 11 and Liu et al. 15 also discovered the importance of hydrogen bonding and π-cation interaction for binding. The more hydrogen bonds that can be formed, the stronger the biological or activity is.…”

“…Liu et al. 15 Ranked the inhibitory activities of discovered hit compounds, which were as follows: puerarin > mirificin > Kojic acid > daidzin≈genistin, the molecular-docking analysis indicated that the addition of glycosyl reduced TYR inhibition due to steric hindrance and changes in polarity.…”