Ingkaninan K, IJzerman A P, Verpoorte R
Division of Pharmacognosy and Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
J Nat Prod. 2000 Mar;63(3):315-7. doi: 10.1021/np9904152.
Activity-guided fractionation led to the isolation of luteolin (1) from the leaves of Senna siamea (syn. Cassia siamea). This compound was found to be an antagonist at the adenosine A(1) receptor with a K(i) value in the low micromolar range. Four additional nonactive compounds (2-5) were also isolated, and their structures were elucidated. One compound was identified as cassia chromone (5-acetonyl-7-hydroxy-2-methylchromone) (2). Three other compounds are new, and they were identified as 5-acetonyl-7-hydroxy-2-hydroxymethyl-chromone (3), 4-(trans)-acetyl-3,6,8-trihydroxy-3-methyldihydronaphthalenone (4), and 4-(cis)-acetyl-3,6,8-trihydroxy-3-methyldihydronaphthalenone (5).
