Isolation of phenanthrenes and identification of phorbol ester derivatives as potential anti-CHIKV agents using FBMN and NAP from Sagotia racemosa

In an effort to identify inhibitors of Chikungunya virus (CHIKV) replication, a systematic study of 594 extracts of plant species originating from the French Guiana plateau region was performed in a virus-cell-based assay for CHIKV assay. The extract obtained from the stem bark of Sagotia racemosa was selected for its potent antiviral activity. Using a classical bioassay-guided procedure, three undescribed degraded diterpenoids, i.e. trigohowilols C and D and trigoflavidol D, as well as trigoxyphin K, stictic acid, hyperhomosekikaic acid and five known flavonoids were isolated. The structures of these compounds were elucidated by extensive NMR spectroscopic data analysis. Although trigohowilols C and D were isolated from the most active fraction they didn't show any antiviral activity. By using the Feature-Based Molecular Networking (FBMN) and Network Annotation Propagation (NAP) workflows, it has been shown that the strong anti-CHIKV activity found for this fraction might be due to the presence of analogues of 12-O-tetradecanoylphorbol-13-acetate (TPA), one of the most potent inhibitors of CHIKV replication identified to date.