Formation of Nitrogen-Containing Metabolites from the Main Iridoids of Harpagophytum procumbens and H. zeyheri by Human Intestinal Bacteria

Abstract

The study of the metabolism of iridoid glycosides from Horpogophytum procumbens and Horpagophytum zeyheri by human intestinal bacteria, was realized in order to elucidate compounds responsible for the pharmacological activities of Harpagophytum. Harpagide, harpagoside and 8-O-p-coumaroyl-harpagide were transformed into the pyridine monoterpene alkaloid aucubinine B by human fecal flora and by bacteria isolated from this flora. Aucubinine B was also prepared from har-pagide, harpagoside and 8-O-p-coumaroylharpagide, by β-glucosidase in the presence of NH₄ ⁺.