Fig. 8

Principal component analysis (PCA) of FTIR spectral ranges 3000–2800 cm^− 1 and 1800–950 cm^− 1 giving PCA score plot. The 2D PCA score plots showed the clustering separation spectra between 3T3-L1 non-differentiated cells, differentiated cells, simvastatin- and Oroxylum indicum extract-treated differentiated cells after 10 days (a). PCA loading plot (b). The biomarker differences over a spectral range of samples are identified by the PC1 and PC2 loading plots