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Proanthocyanidins from the herb of Myrothamnus flabellifolia Welw
Myrothamnus flabellifolia Welw. (Myrothamnaceae), a species growing in arid areas of Southeastern Africa, has the ability to survive regular periods of extreme dehydration to an air-dry-state (resurrection plant). In continuation of our previous results  we investigate the proanthocyanidin pattern from an aqueous acetone extract in more detail. Chemical investigation of the ethylacetate soluble fraction has led to the isolation and characterization of epicatechin, epigallocatechin, epicatechin-3-O-gallate and epigallocatechin-3-O-gallate as flavan-3-ol precursors. The dimeric proanthocyanidin fraction consists exclusively of procyanidins, partly substituted with gallic acid or p-hydroxybenzoic acid. A range of ten different procyanidins were identified by extensive 2D NMR studies of the peracetylated derivatives beside the known 3,4,5-tri-O-galloylquinic acid . In addition, the more abundant polymeric proanthocyanidin fraction was also isolated and its chemical constitution characterized by 13C NMR and optical rotation. The results are discussed briefly.
Acknowledgement: Myro AG, CH-8606 Greifensee, switzerland, for financial support.
References: 1. Deters, A. et al. (2005), 53rd Annual Congress of the Society for Medicinal Plant Research, Florence, P 130 (poster abstract). 2. Moore, J. et al. (2005), Biochem. J. 385: 301–308.