Figure 4

(a) Absorbance spectra of Congo Red of aggregated WtAS samples in the presence or absence of compounds 1, 3, 6 and 15. WtAS (210 µM) was co-incubated with equimolar concentration of compounds 1, 3, 6 and 15 for 30 days. The ability of these compounds to prevent aggregation was monitored by observing the peak shift from 490 nm to 540 nm. Samples were incubated with 50 µM Congo Red for 1 h at 37°C and Absorbance was scanned from 400 nm-600 nm using UV-Vis spectrophotometer. Results are mean of three independent experiments done in duplicate. (b) Dose response curves for determination of IC₅₀ values of compounds 1, 3, 6 and 15 against WtAS aggregation. WtAS (210 µM) was co-incubated with various concentrations (1–500 µM) of compound 1, 3, 6 and 15 for 30 days. The ability of these compounds to prevent aggregation was monitored by ThT assay. Aggregated samples were incubated with 50 µM of ThT for 30 min at 25°C. Samples were excited at 440 nm and emissions recorded at 480 nm. The percentage of aggregation was calculated by measuring corrected ThT fluorescence post 30 days of incubation and was plotted against log of compound concentration. The 3-parameter sigmoidal fit gives the best fit and IC₅₀ values were calculated from the graph. Results are mean of three independent experiments done in duplicate and the error bars show the standard deviation.