Table 1 Major spectral peaks identified in different treatment groups and their functional group assignments17,49,50.

From: Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy: An analytical technique to understand therapeutic responses at the molecular level

Level of PC

Loadings Wavelength (cm−1)

PC-1 (+)

   1092 -PO2− group of DNA/RNA and phospholipids backbone

   1242- β-sheet of amide III bond

   1622- Antiparallel β-sheet, V(C = O) of carboxylate and V(C = C) of aromatic compounds of amide I bond

   1738- V(C = O) bond of esters group from fatty acids and lipid triglycerides

   2847- Vs(C–H) bond of methylene (–CH2) of lipids

   2929- Vas(C–H) bond of methylene (–CH2) of lipids

PC-1 (−)

   1758- V(C = O) bond of esters group from fatty acids and lipid triglycerides

   1649- V(C = C) of di substituted cis-olefins and α-helix of amide I

   1388- δs(CH3) and ds(CH2) of lipids and proteins

PC-2 (+)

   1377- δs(CH3) from cholesterol and fatty acid radicals

   1441- V(C–N) of the pyridine ring

   1526- Parallel mode of the α-helix of amide II

   1625- Antiparallel b-sheet of amide I, V(C = O) of carboxylate and V(C = C) of aromatic compounds

   2851- Vs(C–H) from methylene (–CH2) groups of lipids

   2937- Vas(C–H) from methylene (–CH2) groups of lipids

PC-2 (−)

   1675- β-turn of amide I

   1150- Vas(CO–O–C) group of glycogen and nucleic acids (DNA and RNA)

PC-3 (+)

   982- γ( = CH) of trans isomers and conjugated trans, vibration involving OH group of ribose rings in RNA

   1029- V(C–C) coupled with δ(CH2) of αCH2 in –CH2OH groups of polysaccharides

   1109- Vs(C–O) at the 2′-OH group of ribose rings in RNA

   1249- β-sheet of amide III

   1342- γwag(CH2) of αCH2 groups in polyethylene chains

   1416-δrock(CH2) of di-substituted cis-olefins

   1468-δscissor(CH2) from methylene (–CH2) groups in acyl chains of lipid bilayers in orthorhombic packing

   1555- α-helix and antiparallel β-sheet of amide II

   1675- β –turn of amide I

   2888- Vs (C–H) from methyl (–CH3) groups of lipids

   2948- Vas(C–H) from methylene (–CH2) groups of lipids

PC-3 (−)

   1649- V(C = C) of di-substituted cis-olefins and α-helix of amide I

   1529- Parallel mode of the α-helix in amide II

   1056- Vs (R–O–P–O–R) from ring vibrations of carbohydrates

   1229- -(PO2−) PO2− group of DNA/RNA and phospholipids backbone

  1. Abbreviations: V-Stretching Vibration; Vs–Symmetric Stretching Vibration; Vas-Asymmetric Stretching Vibration, δ- in plane bending vibration.
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