Structurally diverse diterpenoid alkaloids from the lateral roots of Aconitum carmichaelii Debx. and their anti-tumor activities based on in vitro systematic evaluation and network pharmacology analysis

Abstract

Thirty-seven diterpenoid alkaloids (DAs) with diverse structures were isolated and identified from the lateral roots of Aconitum carmichaelii Debx., comprising eight C₂₀-DAs and twenty-nine C₁₉-DAs. Besides the 31 known DAs identified by comparing the ¹H NMR and ¹³C NMR data with those reported in the literature, the structures of four new compounds (1, 14, 17, and 25), and two other compounds (26 and 37) which were reported to be synthesized previously, were also elucidated based on the comprehensive analysis of their HR-ESI-MS, 1D and 2D NMR spectra, including ¹H–¹H COSY, HSQC and HMBC and NOESY/ROESY. Among them, compound 1 represents the first example of a C₂₀-DA glucoside. Besides, the anti-tumor activities of all the isolated compounds against human non-small-cell lung cancer A549 and H460 cells were systematically evaluated by MTT methods. The results revealed that all of the C₁₉-DAs possessed moderate activities against both of the two cell lines with IC₅₀ values ranging from 7.97 to 28.42 μM, and their structure–activity relationships indicated the active sites of C-8, C-10, and C-14 positions and the nitrogen atom in the C₁₉-DA skeleton. In addition, all of the isolated DAs, with chemical structures confirmed, were further applied for network pharmacology analysis, in order to give an insight into the possible mechanisms of their anti-tumor activities. As a result, 173 potential targets and three most important pathways related to non-small-cell lung carcinoma were finally unearthed.