Phenolic compounds from cultivated Glycyrrhiza uralensis and their PD-1/PD-L1 inhibitory activities

One new compound (1) and fifteen known phenolic compounds (2–16) were isolated and identified from the roots and rhizomes of Glycyrrhiza uralensis, including ten flavonoids, four coumarins, and two benzofurans compounds. Their structures were identified by NMR and MS analysis. Most of these compounds showed weak PD-1/PD-L1 inhibitory activities with the inhibition ratios from 30 to 65% at 100 uM. To our knowledge, it is the first time that their PD-1/PD-L1 inhibition activities were reported.