Fraxinellone is isolated from the root bark of the Rutaceae plant, Dictamnus dasycarpus. Fraxinellone is a PD-L1 inhibitor and inhibits HIF-1α protein synthesis without affecting HIF-1α protein degradation. Fraxinellone has the potential to be a valuable candidate for cancer treatment by targeting PD-L1^[1]. In Vitro: Fraxinellone (0-100 μM；12 hours) decreases the percent of PD-L1 positive cells from 20.4% to 11.4% in A549 cells^[1].
In Vivo: Fraxinellone (oral gavage; 30 and 100 mg/kg; every three days; 30 days) significantly suppresses tumor growth, reduces HIF-1α, pTyr705 STAT3, PD-L1 and VEGF staining compared with the control group in female athymic BALB/c nude mice^[1].