Fig. 5

Interaction of Baicalein with soluble Tau. a The aggregation of Tau was monitored by ThS fluorescence. The positive control (heparin) showed an increase in intensity with respect to time as opposed to heparin negative control. The Baicalein treated soluble protein did not show any increase in fluorescence as compared to positive control suggesting that Baicalein does not lead to Tau fibrillization in absence of heparin. b The hydrophobicity imparted by Baicalein alone without heparin was monitored by ANS fluorescence. The intensity did not increase significantly as compared to the positive control. c The SDS-PAGE analysis revealed a time dependent increase in higher molecular aggregates in the positive control from 24 h of incubation (lane 2). No higher molecular weight aggregates were observed in negative control as well as sample treated with 25 μM of Baicalein (lanes 3, 4 respectively) but faint bands of higher order oligomers were observed in 100 μM treated sample from 72 h onwards (lane 5), suggesting formation of oligomers. d Quantification for SDS-PAGE for soluble Tau with Baicalein. e Conformational analysis of soluble Tau with Baicalein. The CD analysis showed normal spectra for negative control and Baicalein treated soluble Tau but a slight shift in the positive control (aggregated) Tau. f The electron micrographs at different time points reveal presence of amorphous aggregates at the initial time points and clumps of oligomers at the end point. (The statistical analysis was carried out by Student’s unpaired t test with respect to Baicalein untreated control. ***p ≤ 0.001, **p ≤ 0.01, *p ≤ 0.05. ns non-significant p value). Further, post hoc analysis was carried by one-way ANOVA and Tukey’s criterion was determined for honestly significant difference (HSD). The data was considered significant if |X–X′|> Tukey’s criterion