ARS | Publication request: Determination of naphthopyrone and anthraquinone glycosides from Sicklepod (Senna obtusifolia) seeds by HPLC-ESI-CID-MSn with potential medical utilization

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 10, 2007
Publication Date: October 10, 2007
Citation: Harry O Kuru, R.E., Payne Wahl, K.L., Busman, M., Berhow, M.A. 2007. Determination of naphthopyrone and anthraquinone glycosides from Sicklepod (Senna obtusifolia) seeds by HPLC-ESI-CID-MSn with potential medical utilization [abstract]. Association for the Advancement of Industrial Crops Conference. p. GC11.

Technical Abstract: Sicklepod (Senna/Cassia obtusifolia L) is a tropical leguminous plant chemically armoured to protect itself from herbivores. In the subtropical Southeastern United States, sicklepod has been a problem weed, especially in soybean fields, since its seeds contaminate soybean harvest and lowers the latter’s quality. Sicklepod seed contains water-soluble galactomannans and proteins sought after for use as a hydrocolloid in some food applications. Serendipitously, several of the chemical components in its seed are being discovered as medicinally useful compounds to man. This study was aimed at a simple method of separating and isolating the anthraquinone glycosides from defatted sicklepod seed meal using water as the extraction medium and to spectroscopically characterize the solute mixture of the extract. The defatted seed meal was vacuum-dried at 20 deg C and extracted with deionized water and centrifuged. Water-soluble proteins in the extract were precipitated by heating to 92-93 deg C for 40 minutes, allowed to cool to room temperature and vacuum filtered. Portions of the filtrate were applied to a preconditioned column of Amberlite XAD-4 (styrene-divinylbenzene non-ionic macroreticular resin) with particle size 20-60 mesh wet and 40 angstroms mean pore size and then washed with deionized water to remove the polysaccharides and free sugars. The anthraquinones and other phenolic constituents retained on the column were eluted with ethanol, followed by 0.1 M ammonium hydroxide in ethanol until the pink color was removed from the column. The combined ethanol eluant was concentrated to a red solid under reduced pressure with rotary evaporation at 40 deg C. The Fourier Transform InfraRed (FTIR) spectrum of the red solid gave absorbances in the range: 3411 vs, 2926 w-m, 1627 m-s, 1413 m, 1262 w, 1076 s cm-1 indicating a mixture of anthraquinones and their glycosides. In an earlier study, it was noticed from High Pressure Liquid Chromatography (HPLC) analysis that partitioning the aqueous extract with diethyl ether separated the aglycones, whereas dichloromethane exclusively isolated the anthraquinone glycosides. Analysis of this red solid extract by HPLC-ESI-CID-MSn techniques in acetonitrile/water revealed the presence of anthraquinone and naphthoquinone glycosides of potential medicinal value.