Untargeted metabolomics and in-house database analysis reveal differences between Elephantopus scaber L. and Elephantopus tomentosus L.

In China, Elephantopus scaber L. and Elephantopus tomentosus L., two traditional Chinese medicinal herbs commonly known as "Ku-di-dan", are widely used. Moreover, they have demonstrated anti-hepatoma effects and hepatoprotective properties in experimental studies. Nonetheless, according to existing literature, E. scaber and E. tomentosus encompass compounds with similar but notably different chemical structures. Therefore, investigating the differences in secondary metabolites between E. scaber and E. tomentosus and elucidating their distinct anti-hepatocellular carcinoma activities is of great importance. This study employed an integrated approach combining untargeted metabolomics with bioactivity assays to effectively differentiate between the congeneric plant species E. scaber and E. tomentosus. To improve the accuracy of characterizing and identifying key metabolites, an in-house database and data screening methods were employed. The research findings revealed that thirty major secondary metabolites were detected in E. tomentosus and E. scaber extracts through untargeted metabolomics and data screening. Subsequently, eight significant differential metabolites were identified through multivariate statistical analyses. Thereafter, twelve compounds were isolated from these two plants and evaluated for their anti-hepatocellular activity, revealing that compounds 5-8 exhibited significant inhibitory effects on HepG2 and Hep3B cells. Consistent results were also observed in the tests conducted on the crude extracts of both E. scaber and E. tomentosus. This study demonstrates that E. scaber and E. tomentosus exhibit distinct secondary metabolite profiles and differential anti-hepatocellular carcinoma activities.