Identification of Genistein and Biochanin A by THz (far-infrared) vibrational spectra

The temperature dependent vibrational spectra of Genistein and Biochanin A, major components in Mongolian medicines Agi, in the range of 0.5–4.5 THz (16.7–150 cm−1) are presented for the first time. Over the temperature range from 295 to 77 K, 12 highly resolved spectral features for the Genistein and 13 features for Biochanin A were measured by THz-TDS and display strong linewidth narrowing and frequency blue-shift with cooling. Such narrow-line THz fingerprint spectra provide a rapid, nondestructive and reliable method for the identification of these Chinese traditional medicines.