Alteration of Neutrophil Reactive Oxygen Species Production by Extracts of Devil’s Claw (Harpagophytum)

Abstract

Harpagophytum, Devil’s Claw, is a genus of tuberiferous xerophytic plants native to southern Africa. Some of the taxa are appreciated for their medicinal effects and have been traditionally used to relieve symptoms of inflammation. The objectives of this pilot study were to investigate the antioxidant capacity and the content of total phenols, verbascoside, isoverbascoside, and selected iridoids, as well as to investigate the capacity of variousHarpagophytumtaxa in suppressing respiratory burst in terms of reactive oxygen species produced by human neutrophils challenged with phorbol myristate acetate (PMA), opsonisedStaphylococcus aureus,andFusobacterium nucleatum.Harpagophytumplants were classified into different taxa according to morphology, and DNA analysis was used to confirm the classification. A putative new variety ofH. procumbensshowed the highest degree of antioxidative capacity. Using PMA, threeHarpagophytumtaxa showed anti-inflammatory effects with regard to the PBS control. A putative hybrid betweenH. procumbensandH. zeyheriin contrast showed proinflammatory effect on the response of neutrophils toF. nucleatumin comparison with treatment with vehicle control.Harpagophytumtaxa were biochemically very variable and the response in suppressing respiratory burst differed. Further studies with larger number of subjects are needed to corroborate anti-inflammatory effects of different taxa ofHarpagophytum.