Planta Med 2016; 82(S 01): S1-S381
DOI: 10.1055/s-0036-1596118
Abstracts
Georg Thieme Verlag KG Stuttgart · New York

Separating the old from the new; rapid differentiation of Catha edulis (Vahl. Endl.) using single point and imaging vibrational spectroscopy

S Combrinck
1   Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
2   SAMRC Herbal Drugs Unit, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
,
M Atlabachew
3   Department of Chemistry, Bahir Dar University, P.O. Box 79, Ethiopia
,
M Sandasi
1   Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
,
W Chen
1   Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
,
A Viljoen
1   Department of Pharmaceutical Sciences, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
2   SAMRC Herbal Drugs Unit, Tshwane University of Technology, Private Bag X680, Pretoria, 0001, South Africa
› Author Affiliations
Further Information

Publication History

Publication Date:
14 December 2016 (online)

 

The leaves of Catha edulis (Vahl. Endl.), known as Khat, are widely used as a "natural amphetamine" stimulant in Africa and in the Arabian Peninsula. The psychostimulatory effects of the leaves are attributed to the phenylpropylamino alkaloids i.e., cathinone, cathine and norephedrine [1]. The concentrations of these alkaloids depend on leaf maturity and the origin of the plant. Young leaves contain higher levels of the more potent stimulant, cathinone, than their mature counterparts [2], but the maturity level is impossible to determine by inspection once the material is dried and powdered. A rapid method to identify Khat, regardless of the maturity, would be beneficial to forensic environments. In this study, powdered young and mature leaves were differentiated using vibrational spectroscopy, which included mid-infrared (MIR) and near-infrared (NIR) spectroscopy, and hyperspectral imaging (HSI), as well as ultra performance liquid chromatography-mass spectrometry (UPLC-MS), in combination with chemometric data analysis. Powdered Khat samples were classified according to their geographical origin and maturity level by applying principal component analysis (PCA) and orthogonal projection to latent structures-discriminant analysis (OPLS-DA). The OPLS-DA model constructed from the MIR and UPLC-MS data could clearly differentiate young and mature leaves, as reflected by the excellent model statistics (R2Xcum and Q2 cum > 80% and R2Y above 90%) obtained. Similar results were obtained using NIR. Shortwave infrared HIS permitted Khat samples from two distinct geographical regions (Ethiopia and South Africa) to be distinguished with good model statistics (R2Xcum= 0.91 and Q2 cum= 0.92). It was also possible to differentiate the maturity levels (R2Xcum= 0.85 and Q2 cum= 0.80). These models could prove valuable as rapid techniques for identifying confiscated Khat in law enforcement environments.

Acknowledgements: The National Research Foundation and South African Medical Research Council are thanked for financial support.

Keywords: Catha edulis, Khat, hyperspectral imaging, chemometrics, mid-infrared, UPLC.

References:

[1] Geisshüsler S, Brenneisen R. The content of psychoactive phenylpropyl and phenylpentenyl khatamines in Catha edulis Forsk. of different origin. J Ethnopharmacol 1987; 19: 269 – 277

[2] Krikorian DA. Khat and its use: a historical perspective. J Ethnopharmacol 1984; 12: 115 – 178