Figure 2

PCA-LDA scores plot of ATR-FTIR spectra with regards to LD1: Pre- vs Post-treatment (a) together with absorbance per wavenumber (b). The paired samples pre- and post-treatment were significantly different along LD1 (Mean/SD (a): 0.004/0.10 for ‘A’; −0.12/0.08 for ‘B’; p < 0.0001, 95% CI = −0.17 to −0.08). Absorbance associated with lipids, glycomaterials and proteins was shown to have a significant positive rate of change for the pre-treatment group compared with the post-treatment group, indicating their higher bioavailability. Similarly, absorbance associated Amide I and Amide II was shown to have a significant positive rate of change for the post-treatment group compared within the pre-treatment group. Absorbance associated with glycogen, collagen and symmetric phosphate of DNA was shown to have a significant negative rate of change for the pre-treatment group compared with the post-treatment group, suggesting lower bioavailability. Similarly, absorbance associated asymmetric phosphate for DNA was shown to have a significant negative rate of change for the post-treatment group compared with the pre-treatment group (b). ATR-FTIR: Attenuated total reflection Fourier-transform Infrared; CI: Confidence interval; LD1: Linear Discriminant 1; PCA-LDA: Principal Component Analysis coupled to Linear Discriminant Analysis; SD: Standard deviation.