[Discrimination of seven species of Agrimonia pilosa Ledeb and its extracts by FTIR and 2D-IR].

The objective of the present study is to discriminate seven species of Agrimonia pilosa Ledeb herbs and their total tannin extracts by Fourier transform infrared spectroscopy (FTIR), second derivative infrared spectroscopy, and two-dimensional correlation infrared spectroscopy (2D-IR) under thermal perturbation. The structural information of the samples indicated that Agrimonia pilosa Ledeb and their extract residues contain a large amount of starch and calcium oxalate, since some characteristic absorption peaks of the starch, such as 1 151, 1 101, 1 032 and 988 cm(-1) can be observed; and some characteristic absorption peaks of the calcium oxalate, such as 1 618, 1 318 and 780 cm(-1), can be observed. Further more, the characteristic absorption peaks of the sulfate which arouse at 1 711 and 1 447 cm(-1) in the IR spectra of Agrimonia pilosa Ledeb acetone extracts can be found. The macroscopical fingerprint characters of FTIR and 2D-IR spectra can not only provide the information of main chemical constituents in medicinal materials and their different extracts, but also compare the components differences among the similar samples. In conclusion, the multi-steps IR macro-fingerprint method is rapid, effective, visual and accurate for pharmaceutical research.