Hyperspectral imaging and chemometric modeling of echinacea - a novel approach in the quality control of herbal medicines.

Maxleene Sandasi,Weiyang Chen,Iize Vermaak,Alvaro Viljoen

doi:10.3390/molecules190913104

Maxleene Sandasi, Weiyang Chen + Show 2 more

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https://doi.org/10.3390/molecules190913104

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Abstract

Echinacea species are popularly included in various formulations to treat upper respiratory tract infections. These products are of commercial importance, with a collective sales figure of $132 million in 2009. Due to their close taxonomic alliance it is difficult to distinguish between the three Echinacea species and incidences of incorrectly labeled commercial products have been reported. The potential of hyperspectral imaging as a rapid quality control method for raw material and products containing Echinacea species was investigated. Hyperspectral images of root and leaf material of authentic Echinacea species (E. angustifolia, E. pallida and E. purpurea) were acquired using a sisuChema shortwave infrared (SWIR) hyperspectral pushbroom imaging system with a spectral range of 920–2514 nm. Principal component analysis (PCA) plots showed a clear distinction between the root and leaf samples of the three Echinacea species and further differentiated the roots of different species. A classification model with a high coefficient of determination was constructed to predict the identity of the species included in commercial products. The majority of products (12 out of 20) were convincingly predicted as containing E. purpurea, E. angustifolia or both. The use of ultra performance liquid chromatography-mass spectrometry (UPLC-MS) in the differentiation of the species presented a challenge due to chemical similarities between the solvent extracts. The results show that hyperspectral imaging is an objective and non-destructive quality control method for authenticating raw material.

Highlights

Echinacea species have a long history of use as traditional medicine to treat various ailments, including infections such as syphilis and septic wounds, cough, sore throat and tonsillitis
Principal component analysis of the root and leaf image showed a clear separation of E. pallida from the other two species based on the colour amplitude, as observed in the PCA score image of the first
The results revealed that hyperspectral imaging in combination with multivariate data analysis could convincingly distinguish between the three Echinacea species

Summary

Introduction

Echinacea species have a long history of use as traditional medicine to treat various ailments, including infections such as syphilis and septic wounds, cough, sore throat and tonsillitis. The three species currently used medicinally and most commonly to treat the common cold, influenza-like illnesses and upper respiratory tract infections (URTIs) are Echinacea angustifolia DC., Echinacea pallida (Nutt.) Nutt. Pallida (Nutt.) Cronq but the three species (E. angustifolia, E. pallida and E. purpurea) are still separately indicated on commercial products and will be referred to as such in this study. Clinical trials to investigate the effectiveness of Echinacea preparations in the treatment of URTIs have reported effects superior to placebo, but the phytochemical diversity makes the interpretation of research findings difficult [1]. A structured review on clinical trials concluded that Echinacea use has no benefit in the treatment and prevention of colds [2]. In the United States of America, annual sales of all Echinacea products exceeded $200 million in 2000 and 2001 whereafter it steadily declined to about $129 million in

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