Effect of Cinnamomum Verum Extract on the Amyloid Formation of Hen Egg-white Lysozyme and Study of its Possible Role in Alzheimer’s Disease

introduction: diagnosing and treating diseases associated with amyloid fibers remain a greatchallenge despite of intensive research carried out. one important approach in the developmentof therapeutics is the use of herbal extracts which are rich in aromatic small molecules.cinnamomum verum extract (ce) contains proanthocyanidin and cinnamaldehyde, which havebeen suggested to be capable of directly inhibiting amyloid fibril formation in vitro. this studyis aimed at characterizing the inhibitory activity of ce against the fibrillation of hen egg whitelysozyme (hewl). methods: acidic ph and high temperatures were used to drive the protein towards amyloidformation. lysozyme was dissolved at 2 mg/ml in 50mm glycine buffer (ph 2.5), and thenincubated at 57 °c for the specified durations while stirred gently by teflon magnetic bars.various techniques including thioflavin t, fluorescence, congo red absorbance assay and afmmicrography were used to characterize the hewl fibrillation processes. results: in the absence of ce typical amyloid fibrils (like amyloids formed in alzheimer disease)became evident after 48 h of incubation. upon incubation with various extract concentrations inthe range of 0.1-1 mg/ml, formation of fibrillar assemblies were significantly inhibited (p<0.05).afm analysis and mtt assay also confirmed the role of the extract in amyloid inhibition. ourstudies showed that the presence of ce did not have any effect on protein stabilization and thusdirectly interact with amyloid structure and inhibit formation of these structures. furthermore, adocking experiment showed that a pi-pi interaction may occur between the aromatic componentof cinnamaldehyde and w62. interestingly, w62 is one of the principal aromatic residues thatinteract with glycine amide, which is an aggregation suppressor of hewl. discussion: these observations suggest that aromatic small molecules of ce may directly insertinto amyloidogenic core of early aggregates and inhibit amyloid fibril formation by disruptingthe pi-pi interactions.