Table 2: Transmittance bands correlated to the corresponding wave numbers representing the functional organic groups present in the SC-CO2 extracts of Orthosiphon stamineus.

Vibrational frequency (cm−1)SamplesCorresponding organic groups

3600–3200 (broad)A3, B3, and C3O–H stretching
2950–2800All nine samplesC–H stretching
1780–1720 (sharp)All nine samplesC=O stretching
1660–1650 (weak)C1, C2, B3 and C3C=C stretching
1610–1600 (Sharp)C1, A2, C2, A3, B3 and C3NO2– stretching
1480–1460All nine samplesC–H bending (deformation)
1385–1370All nine samplesC–C, C–H, O–H and C–O bending
1240–1160All nine samples except B2C–C, C–O, C–N stretching
1100–1090All nine samples except B2C–C, C–O, C–N stretching
1050–1045All nine samples except A1C–C, C–O, C–N stretching
960–900All nine samplesC–H bending
710–725All nine samplesC–H bending