Bioactive flavonoids from the leaves of Lawsonia alba (Henna).

Abstract: Three new flavonoids, lawsochrysin (1), lawsochrysinin (2), and lawsonaringenin (3) were isolated from the leaves of Lawsonia alba Lam. along with four flavonoids 3′,4′-dimethoxy flavone (4), 7-hydroxy flavone (5), 3,3′,4′,7-tetrahydroxy flavanone (6) and rhoifolin (7) hitherto unreported from this genus. Their structures were elucidated on the basis of spectroscopic evidences. Compounds (3) and (6) showed a good urease inhibition activity IC₅₀ =139.1±0.77 and 184.53±0.61μM respectively, (6) also showed a DPPH radical scavenging activity with IC₅₀ =33.83μM. [Copyright &y& Elsevier]