Rapid Identification of Dendrobium officinale from Other Species Using 3D Front-Face Fluorescence Technique

Dendrobium officinale is a rare and endangered perennial herb in China, which have been used in preparing Chinese tonic medicine for hundreds of years. The severe shortage of this herb and high price have caused that many similar plants were processed as an adulterant and it became difficult to distinguish genuine D. officinale by traditional authentication methods. A sensitive, convenient, and specific method for rapid identification of D. officinale is urgently needed. In the present study, 3D front-face fluorescence technique merged with Independent Component Analysis was used to get the "pure" independent fluorescence signals. The overall 3D-FFF spectra were decomposed into seven independent components (IC). To distinguish D. officinale from other species, IC1 and IC4 were chosen as fluorescence markers and the fluorescence intensity (FI) value at 340 nm/ 442 nm (excitation /emission wavelength) of IC1and 315 nm/ 468 nm of IC4 were used to build a linear model for identifying D. officinale successfully. Compared with other Dendrobium species, D. officinale showed much higher FI1 and FI4 value which is a direct criterion for identification. Meanwhile, even though the FI values of D. officinale may fluctuate due to the difference of growing conditions, the relation between FI1 and FI4 amazingly always fit the linear model constructed (FI4 = 9.9046 + 0.6119FI1, R² = 0.9811). The linear model is an important finding and specific for D. officinale. Based on the FI value and the goodness of fit in the linear model, D. officinale can be identified quickly.