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 [1] 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 [2]. 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), 53^rd 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.