Study of the marketplace variation in the chemical profile of Qi Ju Di Huang Wan (Lycium, Chrysanthemum and Rehmannia Formula)

Abstract

Current quality control (QC) of herbal medicines mainly focus on safety concerns"" there is mandatory testing for herbal identity, pesticides, heavy metals, bacterial contamination and toxic components if an herb has been known to contain it. There is no requirement to quantify putative active components unless the supplier makes a label claim. Therefore while there is no concern about safety, the consumer is mostly uninformed about herbal quality regarding the amount of putative active components. Quantifying the putative actives is a twostep process "" firstly the analytes that reflect herbal quality for the consumer have to be selected and secondly the analytical method has to be developed and validated. The complexity in quantifying the putative actives in a multi herb formulation increases with the number of herbs used. This study demonstrates how to estimate the quality of an eight herb formulation; Qi Ju Di Huang Wan (QJDHW) (Lycium, Chrysanthemum and Rehmannia Formula) described in the Chinese Pharmacopeia for the treatment of liver and kidney disorders. Nine analytes were systematically selected for monitoring by liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis. The MS/MS detector is particularly suitable for complex matrices because it is highly selective and the chances of peak misidentification is minimised. The developed analytical method was then applied to analyse a total of eleven samples of QJDHW to estimate variability of the medication in the marketplace. There was significant concentration variation of the analytes studied which ranged from 4.4 to 28.9 fold (average 12.6 fold). Due to the large analyte concentration variation observed, it was decided to study the concentration of putative actives of one herb, namely Lycium barbarum. This herb is also of interest because two species, L. barbarum and L. chinense are readily available in the marketplace and it is also consumed as a so called 'super food'. The two Lycium berries are similar physically and the question arose as to whether the two species have distinguishing chemical profiles. Seven analytes were quantified in the two Lycium species and the fold variation in concentration ranged from 1.8 to 7.8 (average 4.9) across twelve samples obtained from the marketplace. The extracts were also analysed by LC with photodiode array detection and gas chromatography with mass spectrometric detection. Our results indicate that the chemical compositions of the two Lycium species are not significantly different (eight L. barbarum and four L. chinense samples examined) and that the two should be interchangeable. In addition to targeted analysis where the selected analytes were quantified, untargeted analysis (where all detectable constituents are considered) was also carried out where the chromatographic profile of the test samples (QJDHW and Lycium) were compared and statistically analysed by hierarchical cluster analysis (HCA) and principal component analysis (PCA). The conclusions reached by statistical analysis are similar to those reached by targeted analysis "" that is, there is significant compositional variation in the QJDHW formulation with no obvious clustering of samples into similarity groups. With L. barbarum and L. chinense there is also no species clustering indicating that there is no compositional difference between the two species.

Date of Award	2014
Original language	English