Phytochemical Investigations on the Leaves of Bafodeya benna using LC-SPE-NMR

Bafodeya benna (Scott-Elliot) Prance ex F.White or Parinari benna Scott-Elliot (Chrysobalanaceae) is a tree that only grows in the savanna of Mali, Guinea-Conakry and Sierra Leone. Since it is used in traditional medicine against infectious diseases such as malaria, phytochemical investigations were started in order to identify potentially active constituents using LC-SPE-NMR and LC-MS. A crude extract was prepared from the leaves using 80% methanol, and 4 subfractions of different polarity (petroleum ether, 90% methanol, chloroform and water). The tannins were removed from the aqueous fraction, and this fraction was submitted to LC-SPE-NMR analysis. Five major constituents were observed in the HPLC chromatogram and they were identified as neoastilbin (1), astilbin (2), neoisoastilbin (3), isoastilbin (4), and quercetin-3-O-α-L-rhamnoside.

Moderate antiplasmodial activity has already been reported for taxifolin, however not for astilbin ((2R,3R)-taxifolin-3-O-alpha-L-rhamnoside). It is possible that the glycosides are hydrolysed first in the gastro-intestinal tract. It was concluded that these flavonoid glycosides contribute, at least in part, to the traditional use against malaria.