Alkaloids and Flavonoids of Erithrina Melanacantha
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Date
1994-06
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Addis Ababa Universty
Abstract
The tropical genus Erythril1a, which belongs to the family Leguminosae (sub-family
Papilionoideae), locally known as "Korch" (Amharic) and "Wolensu" (Oromo) has folk
medicinal uses such as in the treatment of stomach pain and female infertility. The seeds
of this plant have been investigated before, whereas no previous phytochemical work has
been reported from the stem bark of E. melanacantha.
The isolation and characterization of alkaloids and flavonoids from the seeds and
stem bark, respectively, of this species constitute the subject of this study. As a result, the
seeds and stem bark of E. melanacantha afforded eleven compounds, of which two are new
natural prodUCts. From the seeds three known alkaloids, namely, erythraline (11),
erymelanthine (50) and erysovine (3) have been identified. Chemical investigation of the
stem bark resulted in the isolation of two new compounds characterized on the basis of
spectroscopic data as 5-hydroxy-7 ,8-(hydroxyisopropyl dihydrofurano)flavanone (152) and
a biflavanone (159). In addition, from the stem bark of this plant, five known flavonoids,
namely, glabranin (153), obovatin (155), 7-hydroxy-8-prenylflavanone (156) 3'-0-
methylorobol (157), 3'-methoxydaidzein (158) and a known cinnamate ester,
erythrinasinate (160) have been isolated. Search in the chemical literature indicated that
compounds 153, 155, 156 and 158 have not been reported before from the genus
Erythril1a.
Glabranin (153) is proposed as the biosynthetic precursor of the three compounds
152, 155 and 156, while compounds 152 and 153 serve as building blocks of the dimer
159.
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Alkaloids and Flavonoids