Quality control of botanicals and botanical health products: Screening for adulterants and metabolomic investigations

Abstract

The overall objective of this study is to develop analytical methods and platform to investigate the quality of botanicals and botanical health products. The specific objectives of this research are: 1) to develop a high performance liquid chromatography-diode array detection (HPLC-DAD) method for the simultaneous detection and determination of phosphodiesterase Type 5 enzyme (PDE-5) inhibitors and their analogues; 2) to develop and optimize a pressurized liquid extraction (PLE) method and a liquid chromatography- linear ion trap-Orbitrap XL fourier transform mass spectrometric (LC-LTQ-Orbitrap XL FT MS) method for the extraction and metabolite profiling of adaptogenic botanicals as well as raw and steamed P. notoginseng; 3) to investigate the quality of five commonly used adaptogenic botanicals and P. notoginseng in Singapore and China using the developed LC-LTQ-Orbitrap XL FT MS method coupled with multivariate data analysis.

A simple HPLC-DAD method was developed, optimized and validated to simultaneously detect the presence of 19 PDE-5 inhibitors and their analogues in botanical health products used for sexual performance enhancement. This method has been successfully applied to screen these synthetic adulterants in 271 botanical health products purchased on-line. Three new synthetic adulterants (hydroxythiohomosildenafil, descarbonsildenafil and dapoxetine) were detected and isolated from three botanical health products used for sexual performance enhancement in the course of this work. Besides botanical health products, a metabolomic investigation platform was developed to assess the quality of five adaptogenic botanicals and P. notoginseng in Singapore and China. The PLE extract of each sample was profiled using the LC-LTQ-Orbitrap XL FT MS method developed in this study. Different PLS-DA models were developed, cross-validated and applied to analyze raw and steamed P. notoginseng as well as the five adaptogenic botanicals. The developed PLS-DA models were also applied to ten commercial botanical products. The metabolomic investigation platform developed in this study is shown to be a useful tool for the quality assessment of botanicals.

In conclusion, the work presented in this thesis has provided a new screening method for adulterants and a new metabolomic platform for evaluating the quality of botanicals and botanical health products. The methodologies developed and applied are important to ensure the quality of health products and hence the safety of consumers.