title: What the devil is in your phytomedicine? Exploring species substitution in Harpagophytum through chemometric modeling of 1H-NMR and UHPLC-MS datasets.
abstract: Harpagophytum procumbens (Pedaliaceae) and its close taxonomical ally Harpagophytum zeyheri, indigenous to southern Africa, are being harvested for exportation to Europe where phytomedicines are developed to treat inflammation-related disorders. The phytochemical variation within and between natural populations of H. procumbens (n=241) and H. zeyheri (n=107) was explored using proton nuclear magnetic resonance ((1)H-NMR) and ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) in combination with multivariate data analysis methods. The UHPLC-MS results revealed significant variation in the harpagoside content: H. procumbens (0.17-4.37%); H. zeyheri (0.00-3.07%). Only 41% of the H. procumbens samples and 17% of the H. zeyheri samples met the pharmacopoeial specification of ⩾1.2%. Both principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) indicated separation based on species (UHPLC-MS data OPLS-DA model statistics: R(2)X=0.258, R(2)Y (cum)=0.957 and Q(2)(cum)=0.934; (1)H-NMR data OPLS-DA model statistics: R(2)X=0.830, R(2)Y=0.865 (cum) and Q(2)(cum)=0.829). It was concluded that two species are not chemically equivalent and should not be used interchangeably.
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.
authors.forename: Nontobeko P
authors.initials: NP
authors.lastname: Mncwangi
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa; Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Electronic address: viljoenam@tut.ac.za.
authors.forename: Alvaro M
authors.initials: AM
authors.lastname: Viljoen
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, MS 38677, USA.
authors.forename: Jianping
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.
authors.forename: Ilze
authors.initials: I
authors.lastname: Vermaak
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South Africa.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy, The University of Mississippi, MS 38677, USA; Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, MS 38677, USA.
authors.forename: Ikhlas
authors.initials: I
authors.lastname: Khan
mesh_terms: D015415:Biomarkers / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D006027:Glycosides / Q000737:chemistry*; D031684:Harpagophytum / Q000737:chemistry* / Q000145:classification; D013058:Mass Spectrometry; D008956:Models, Chemical; D010936:Plant Extracts / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry* / Q000145:classification; D066244:Proton Magnetic Resonance Spectroscopy; D011714:Pyrans / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D006027:Glycosides; D010936:Plant Extracts; D011714:Pyrans; C033249:harpagoside
keywords: Chemometrics; Devil’s Claw; Harpagophytum procumbens; Harpagophytum zeyheri; Harpagoside; Iridoid glycosides; Nuclear magnetic resonance; Pedaliaceae; Ultra-high performance liquid chromatography-mass spectrometry