Profiling the chemical differences of diterpenoid alkaloids in different processed products of Aconiti Lateralis Radix Praeparata by UHPLC-LTQ-Orbitrap mass spectrometry combined with untargeted metabolomics and mass spectrometry imaging

Aconiti Lateralis Radix Praeparata (“Fuzi”) is a famous traditional Chinese medicine possessing both significant pharmacological activities and toxicity. Different processing methods are often conducted to reduce the toxicity of raw Fuzi by influencing the toxic and effective components, which are mainly diterpenoid alkaloids. To have a comprehensive understanding of the chemical differences between different products of Fuzi, UHPLC-LTQ-Orbitrap mass spectrometry was applied for systematic characterization of “Shengfuzi”, “Heishunpian” and “Baifupian”. A total of 249 diterpenoid alkaloids were finally characterized, all of which were existed in “Shengfuzi”, but only 111 and 61 could be detected in “Heishunpian” and “Baifupian” respectively, showing great differences of these products. To further compare their chemical differences, an untargeted metabolomics method combined with multivariate statistical analysis was conducted to discover 42 potential chemical markers. Then 52 batches of commercial “Heishunpian” and “Baifupian” samples were further introduced for validation of these markers, and 8 robust markers were finally selected to distinguish these two products, including AC1-propanoic acid-3OH, HE-glucoside, HE-hydroxyvaleric acid-2OH, dihydrosphingosine, N-dodecoxycarbonylvaline and three unknown compounds. Furthermore, to explore the effects of different processing procedures on the chemical differences between “Heishunpian” and “Baifupian”, mass spectrometry imaging (MSI) technique was utilized to visualize the spatial distribution of chemical constituents in raw Fuzi. The results showed that the distribution features of different subtypes of diterpenoid alkaloids could partly explain the chemical differences of different products. This study provided valuable references from the material basis for future investigation about different products of Fuzi.