The authenticity and quality of Rhodiola rosea products
Abstract
Background
Rhodiola rosea
L. Crassulaceae, root (Golden Root, Arctic Root) is a high-value herbal
medicinal product, registered in the UK for the treatment of
stress-induced fatigue, exhaustion and anxiety based on traditional use
and used throughout Europe as a herbal medicinal product for similar
indications. Numerous unregistered supplements are also available. There
are several Chinese species used in traditional Chinese medicine (TCM),
including Rhodiola crenulata (Hook.f. & Thomoson) that is believed to be a common adulterant in the R. rosea value chain.
Aims
The project is embedded in a larger study aiming to investigate the diverse value chains that lead to the production of R. rosea
as an herbal medicinal product or supplement. Here we focus on a
comparison of the quality of the finished products and assess any
phytochemical variation between products registered under the
Traditional Herbal Medicine Products Directive (THMPD) and products
obtained from the market without any registration (i.e. generally
unlicensed supplements). Our key aim is to establish the extent of the
problem in terms of adulteration of consumer products claiming to
contain R. rosea (or R. crenulata).
Methods
Approximately
40 commercial products (granulated powders and extracts) were sourced
from different suppliers. We analysed these samples using high
performance thin layer chromatography (HPTLC), mass spectrometry (MS)
and 1H NMR spectroscopy coupled with multi-variate analysis
software following a method previously developed by our group for the
analysis of turmeric products.
Results
We investigate the phytochemistry of the different species and assess the potential of R. crenulata as an adulterant at the end of the R. rosea
value chains. The consistency of the products varies significantly.
Approximately one fifth of commercial products that claimed to be R. rosea did not contain rosavin (the key reference markers used to distinguish R. rosea from related species). Moreover some products appeared not to contain salidroside, another marker compound found in other Rhodiola
species. Approximately 80% of the remaining commercial products were
lower in rosavin content than the registered products and appeared to be
adulterated with other Rhodiola species.
Conclusions
The
variation in phytochemical constituents present in Rhodiola products
available to European buyers via the internet and other sources is a
major cause for concern. Adulteration with different species, and other
sometimes unknown adulterants, appears to be commonplace. Good quality
systems and manufacturing practices, including those required under the
THMPD, enable consumers to have confidence that products are authentic
and meet a high specification for quality and safety.
Graphical abstract
Keywords
- Rhodiola;
- Quality;
- Adulteration;
- Metabolomics;
- Herbal medicinal products
Abbreviations
- GACP, Good agricultural and collection practice;
- GMP, Good manufacturing practice;
- HMP, Herbal medicinal product;
- HPTLC, High performance thin layer chromatography;
- HTP, Hydroxytryptophan;
- MS, Mass spectrometry;
- NMR, Nuclear magnetic resonance;
- PCA, Principal component analysis;
- PL, Product licence;
- TCM, Traditional Chinese medicine;
- THR, Traditional herbal registration;
- THMPD, Traditional Herbal Medicinal Products Directive
