Chapter 9 - Harpagophytum procumbens

Abstract

Harpagophytum procumbens (Burch.) DC. ex Meisn. is an important traditional medicine that grows in the Kalahari region of southern Africa, where it is taken as a general health tonic and anti-inflammatory to treat arthritis, rheumatism, pain, sprains, fever, ulcers and boils. Iridoid glycosides and phenyl derivatives have been the focus of phytochemical investigations, and the biological activity has been ascribed to iridoid glycosides, which are common in nature and are known to have anti-inflammatory activity. Additionally, H. procumbens has been shown to have analgesic, anti-oxidant, antidiabetic, anti-epileptic, antimicrobial and antimalarial activities. The main exporter of this highly commercialised plant is Namibia. The high demand for health products based on this plant has led to overharvesting, raising concerns about sustainability, as the secondary root tubers are utilised commercially, and the whole plant is often destroyed during harvesting. Methods are being assessed to promote sustainable harvesting and propagation of the species. Harpagophytum procumbens is commonly adulterated by its close taxonomic ally H. zeyheri, and this affects the quality of the raw material. Methods such as semi-automated high-performance thin-layer chromatography (HPTLC), ultra-performance liquid chromatography coupled to mass spectrometry (UPLC–MS), and mid-infrared (MIR) spectroscopy have been investigated as quality control methods to profile the non-volatile constituents in H. procumbens raw material. The marker compound harpagoside in the non-volatile fraction was detected in both HPTLC and UPLC–MS analyses.