Isolation and characterization of two prenylated flavonoids from the stem bark of Artocarpus hirsutus Lam.

The genus Artocarpus (Moraceae) is a rich source of prenylated flavonoids with diverse pharmacological properties. Among its members, Artocarpus hirsutus—endemic to the Western Ghats of India—is traditionally used in folk medicine but remains underexplored phytochemically. This study reports the isolation and structural elucidation of two prenylated flavonoids from the acetone extract of the stem bark of A. hirsutus. The compounds, designated AHSB (1) and AHSB (2), were isolated by silica gel column chromatography and characterized using UV, IR, mass spectrometry, and advanced NMR techniques, including 1D and 2D experiments. Compound AHSB (1) was identified as Artonin J, and compound AHSB (2) was characterized as Artonin E. Both compounds possess flavonoid skeletons substituted with prenyl groups, and their structural features were confirmed through HMBC correlations. These findings expand the phytochemical profile of A. hirsutus and highlight its potential as a source of bioactive flavonoids for pharmacological applications.