Synthesis, biological activities and mechanistic studies of C20-ketone pachysandra alkaloids as anti-hepatocellular carcinoma agents.

The pachysandra alkaloids found in Sarcococca ruscifolia demonstrate notable anti-hepatocellular carcinoma activity. Despite their efficacy, the structural diversity of these compounds remains limited, and their precise antitumor mechanism is still unclear. In pursuit of identifying novel lead compounds with high efficacy and low toxicity for combating hepatocellular carcinoma, twenty-three compounds of C₂₀-ketone pachysandra alkaloid derivatives were designed and synthesized by using 3-dimethylamine pachysandra alkaloids as scaffolds. Subsequent in vitro anticancer activity experiments showed that synthetic pachysandra alkaloids had a stronger effect on HepG2 cells than did their natural counterparts, with low toxicity and high selectivity. The most potent derivative, 6k, had an IC₅₀ value of 0.75 μM, demonstrating 25.7-fold greater anticancer activity than sarcovagine D against HepG2 cells. Through network pharmacology and molecular docking analysis, it was revealed that synthetic pachysandra alkaloids may exert their effects by inhibiting the JAK2/STAT3 pathway, thereby preventing the proliferation of liver cancer cells. Further research through scratch tests, immunofluorescence experiments, and Western blot analysis revealed that compound 6k effectively inhibited the migration of HepG2 cells and induced mitochondria-mediated intrinsic apoptosis of HepG2 cells by regulating the JAK2/STAT3 signaling pathway. The aforementioned results indicate that compound 6k could be developed as a potential candidate for the treatment of hepatocellular carcinoma.