Ja. Hasrat et al., ADENOSINE-1 ACTIVE LIGANDS - CIRSIMARIN, A FLAVONE GLYCOSIDE FROM MICROTEA-DEBILIS, Journal of natural products, 60(6), 1997, pp. 638-641
Several plants collected through different approaches were screened on
distinct receptors using ligand-binding studies as bioassay. Extracts
of Microtea debilis showed high activity on adenosine A(1) receptors.
Bioassay-guided fractionation using ligand-binding studies resulted i
n the isolation of an adenosine A(1) active ligand, cirsimarin (cirsim
aritin 4'-O-glucoside). GTP did not influence the radioligand inhibiti
on curve of cirsimarin, indicating that this compound is acting as an
antagonist at the adenosine-A(1) receptors. The use of this plant agai
nst ''proteinuria'' in traditional medicine in Suriname (South America
) may be explained by the adenosine A(1) antagonistic action of cirsim
arin. A series of flavonoids was tested in the same assay, but they we
re less active. No structure-activity relationship could be observed.