New flavonoids from the Saudi Arabian plant Retama raetam which stimulates secretion of insulin and inhibits α-glucosidase

Abstract

Retama raetam is a bush which is a member of the family Fabaceae. It is used traditionally in North Africa and Saudi Arabia for the treatment of diabetes. Several flavonoids and alkaloids were already known from this plant. Chromatographic fractionation and purification led to the isolation of three new derivatives of prenylated flavones, retamasin C-E and four new derivatives of prenylated isoflavones, retamasin F-I, in addition to two isoflavones which had not previously been reported in this plant. Particularly interesting structures included isoflavones containing 3,5-dihydro-2H-2,5-methanobenzo[e] [1,4]dioxepine and 3a,8b-dihydro-7-hydroxyfuro[3,2-b]benzo[2,1-d]furan units, both of which are new amongst natural product flavonoids. Five new examples (two flavones and three isoflavones) strongly enhanced the glucose-triggered release of insulin by murine pancreatic islets and one isoflavone was a potent inhibitor of α-glucosidase. This study may rationalise the traditional medicinal use of R. raetam and provides new leads for drug design in the treatment of diabetes.

A Neoclerodane Orthoester and Other New Neoclerodane Diterpenoids From Teucrium Yemense, Which Stimulate the Secretion of Insulin From Pancreatic Islets

“…Gács-Baitz et al 42 Compounds 1-12 were evaluated for their ability to enhance the glucose-triggered secretion of insulin by freshly isolated murine pancreatic islets, using our previous assay. 48 In negative-control islets, insulin secretion was 9.1 ± 0.3 ng islet − 1 h − 1 , triggered by glucose (16.7 mM) (…”

Synthesis and Transformation of 5-Acetyl-2-aryl-6-hydroxybenzofurans into Furanoflavanone Derivatives

“…35 In the context of the X-ray analyses, crystallographic numbering has been used in place of the systematic numbering. There is intramolecular hydrogen bonding between the oxygen acceptor (O1) and the - Very few examples of the naturally occurring furanoflavanoid derivatives substituted at the C-2 position of the benzofuran moiety with carbon-based substituent have been reported in the literature [36][37][38][39] and their synthesis remain surprisingly less explored. 4,18,39,40 The o-hydroxytrans-,-unsaturated carbonyl moiety represents suitable scaffold for possible cycloisomerization or oxidative cyclization to afford analogues of the naturally occurring furanoflavanones, furanoflavones, furanoisoflavones, and furanoflavonols.…”

Inhibición de la α-glucosidasa mediante flavonoides de origen natural como vía de control en el desarrollo de diabetes mellitus

“…Los compuestos fueronextraídos y aislados de las partes aéreas de Retama raetam junto con la elucidación de la estructura mediante técnicas espectroscopicas como RMN y ESI masas como lo presenta Ghani y colaboradores (9). Asimismo, se realizaron pruebas cinéticas de inhibición.…”

“…De esta manera, es de interés la identificación de los constituyentes de flavonoides de Retama raetam, se ha llevado al descubrimiento de la luteolina 4′-neohespiridosida, atalantoflavona, saponarina, retamasina A y B, licoflavona C, genisteína 8-C-glucósido y efedroidina (8,9). Los flavonoides son metabolitos secundarios polifenólicos presentes en plantas, frutas y vegetales, se consideran una clase importante de compuestos en varios productos farmacéuticos, medicinales y nutracéuticos debido a sus efectos terapéuticos que incluyen propiedades antiinflamatorias, actividad anticancerígena y antioxidante.…”