Abstract: The non-linear relationships between the contents of ginsenoside Rg₁, Rb₁, Rd and Panax notoginseng saponins(PNS) in Panax notoginseng root herb and the near infrared(NIR) diffuse reflectance spectra of the herb were established by means of artificial neural networks(ANNs).Four three-layered perception feed-forward networks were trained with an error back-propagation algorithm.The significant principal components of the NIR spectral data matrix were utilized as the input of the networks.The networks architecture and parameters were selected so as to offer less prediction errors.Relative prediction errors for Rg₁, Rb₁, Rd and PNS obtained with the optimum ANN models were 8.99%, 6.54%, 8.29%, and 5.17%, respectively, which were superior to those obtained with PLSR methods.It is verified that ANN is a suitable approach to model this complex non-linearity.The developed method is fast, non-destructive and accurate and it provides a new efficient approach for determining the active components in the complex system of natural herbs.

Key words: Near infrared diffuse reflectance spectroscopy, Artificial neural network, PLSR, Non-linearity, Analysis of natural herb, Panax notoginseng