Atricephenols A and B, two phenolic compounds from Indigofera atriceps Hook.f. (Fabaceae).

The phytochemical investigation of a previously unstudied species of the genus Indigofera , I. atriceps Hook.f. was undertaken and two new phenolic compounds, atricephenols A ( 1 ) and B ( 2 ) were isolated, along with nine known secondary metabolites viz ., (-)-melilotocarpan D ( 3 ), genistein ( 4 ), melilotocarpan A ( 5 ), maackiain ( 6 ), p- hydroxybenzaldehyde ( 7 ), bornesitol ( 8 ), β -sitosterol ( 9 ), sitosterol-3- O -β-D-glucopyranoside ( 10 ) and stigmasterol-3- O -β-D-glucopyranoside ( 11 ). Their structures were elucidated by extensive NMR spectroscopic analyses and HRESIMS, and by comparing their data with those reported in the literature. Compounds 1 , 4 , 7 - 11 were tested for their antibacterial efficacies and for their potential to inhibit the enzyme urease. Compounds 7 and 9 showed significant antibacterial activity against Salmonella typhi (ZOIs of 13 and 15 mm, respectively), while the best urease inhibition was measured for compound 9 with an IC ₅₀ value of 18.6 µM, which is higher than that of the potent inhibitor, thiourea (IC ₅₀ = 21.5 µM).