Chemical studies on some natural products from Myrothamnus flabellifolius

Abstract

Crude extracts from Myrothamnus flabellifolius were fractionated through variouschromatography techniques in order to achieve satisfactory separations. Two compounds, arbutin and lupeol, were isolated from the butanol and ethyl acetate extracts, respectively. Structural elucidation of the compounds was carried out on the basis of 1H and 13C NMR spectroscopy. It was the first time that lupeol had been isolated from M. flabellifolius.The water extract was found to contain heterogeneous pectic polysaccharides. Three polysaccharide fractions were separated from the water extract, namely; MPS, MPS-I and MPS-II. The predominant fraction was found to be MPS, with a molecular weight distribution of 2 X 105 Da. The polysaccharides were made up the following monosaccharides; arabinose, rhamnose, xylose, mannose, galactose and glucose. Monosaccharide composition was determined through acid hydrolysis at high temperatures, followed by GC analysis. The linkage analysis was carried out by GC-MS, following partial methylation of the polysaccharides. The use of human serum albumin (HSA) following its anchoring on magnetic nanoparticles, in order to isolate targeted saponins from Sutherlandia frutescens led to successful isolation of four saponins, namely; sutherlandiosides A-D. The saponins showed great affinity to bind to the HSA.