Combined Liquid Chromatography-mass Spectrometry and Next-generation DNA Sequencing Detection of Adulterants and Contaminants in Analgesic and Anti-inflammatory Herbal Medicines

Abstract

Introduction: Methods for assessing the quality of herbal medicine preparations have advanced significantly in recent years in conjunction with increases in herbal medicine use and reports of adulteration and contamination.

Objective: This study examined the quality of analgesic and anti-inflammatory herbal medicine preparations available on the Australian market by detecting the presence of listed ingredients, adulterants and contaminants.

Methods: Forty-nine analgesic and anti-inflammatory herbal medicine preparations were randomly sourced from Australian capital cities. They were audited using a dual approach of liquid chromatography-mass spectrometry (LC-MS) combined with next-generation DNA sequencing. Once screened, a comparison of listed ingredients with verified ingredients was conducted to determine the accuracy of labelling, and the extent of adulteration and contamination.

Results: Twenty-six of 49 (53%) herbal medicines were adulterated or contaminated with undeclared ingredients. LC-MS revealed the presence of pharmaceutical adulterants including atropine and ephedrine. DNA sequencing uncovered concerning levels of herbal substitution, adulteration and contamination, including the use of fillers (alfalfa, wheat and soy), as well as pharmacologically relevant species (Centella asiatica, Panax ginseng, Bupleurum and Passiflora). Pig/boar and bird DNA was found in some preparations, inferring substandard manufacturing practices. Of the 26 contaminated samples, 19 (73%) were manufactured in Australia, and 7 (27%) were imported from other countries (6 from China, 1 from New Zealand). In 23 of 49 (47%) herbal medicine samples, no biological ingredients were detected at all. These were predominantly pain and anti-inflammatory preparations such as glucosamine and eicosapentaenoic and docosahexaenoic acids found in krill and fish oils, so DNA would not be expected to survive the manufacturing process.

Conclusion: The high level of contamination and substitution of herbal medicine preparations sourced from Australian dispensaries supports the need for more stringent pharmacovigilance measures in Australia and abroad.