Chemical and Pharmaceutical Studies on Medicinal Plants in Paraguay. I. Isolation and Identification of Lens Aldose Reductase Inhibitor from “Tapecué, ” Acanthospermum australe O.K.

Abstract
The EtOH extract of "Tapecue", Acanthospermum australe, was found to have a potent inhibitory activity towards rat lens aldose reductase (AR). From the active fraction of the extract, 5,7,4''-trihydroxy-3,6-dimethoxyflavone was isolated. It was found to have higher activity (IC50 = 1 .times. 10-7 M) than quercitrin, which is a known inhibitor of AR (IC50 = 1.8 .times. 10-6 M in our bioassay).