Poor chemical and microbiological quality of the commercial milk thistle-based dietary supplements may account for their reported unsatisfactory and non-reproducible clinical outcomes.

Herbal-based dietary supplements have become increasingly popular. The extract from milk thistle (Silybum marianum), is often used for the treatment of liver diseases. However, serious concerns exist regarding the efficacy, composition, as well as the safety of these over-the-counter preparations. Therefore, the aim of the present study was to investigate the composition as well as chemical and biological safety of 26 milk thistle-based dietary supplements purchased from both the U.S. and Czech markets between 2016 and 2017. The study was focused on a determination of the composition of active ingredients, as well as analyses of possible contaminants including: mycotoxins, plant alkaloids, and pesticide residues, as well as the microbial purity. High-throughput analyses were performed using advanced U-HPLC-HRMS techniques. Large differences in the silymarin content were observed among individual milk thistle preparations, often in contrast with the information provided by the manufacturers. In addition, substantial inter-batch differences in silymarin content were also demonstrated. In all milk thistle preparations tested, large numbers and high concentrations of mycotoxins and several pesticides, as well as the substantial presence of microbiological contamination were detected, pointing to serious safety issues. In conclusion, our results strongly indicate the need for strict controls of the composition, chemical contaminants, as well as the microbiological purity of commercial milk thistle extracts used for the treatment of liver diseases. Poor definition of these preparations together with contamination by biologically active substances may not only account for the inconsistency of clinical observations, but also be responsible for possible herbal-based dietary supplements-induced liver injury.

Analysis of phosphodiesterase type 5 inhibitors as possible adulterants of botanical-based dietary supplements: extensive survey of preparations available at the Czech market.

Popularity of natural-based preparations supporting the sexual potency significantly increased in recent years, which also led to the increase of illegal use of phosphodiesterase type 5 inhibitor (PDE-5) in sexual performance enhancement products. In this study, a rapid U-HPLC‒HRMS/MS method has been developed to simultaneously determine 59 PDE-5 inhibitors and their analogues. Within the development of sensitive method for analysis of 59 PDE-5 inhibitors and their analogues, both sample preparation procedure, as well as separation / detection conditions have been optimized. Extraction efficiency of particular extraction solvents, influence of different mobile phase additives on target analytes separation, as well as impact of various settings of mass analyzer on sensitivity of detection were examined. Data were collected in the 'full MS/data dependent MS/MS' acquisition mode (full MS-dd-MS/MS). Before the U-HPLC‒HRMS/MS method was used for analysis of real samples, proper validation had been conducted. The precision of the method expressed as the relative standard deviation (RSD) was ≤4.2% and ≤5.2% at spiking concentrations 5 µg/g and 0.25 µg/g, respectively. The limits of quantification were in the range 0.25 - 0.05 µg/g and the recovery ranged between 71 and 90%. The optimized method was successfully applied for analysis of 64 real samples, and 10 of them were proved to contain both registered or unregistered synthetic PDE-5 inhibitors. Additionally, the acquired U-HPLC‒HRMS/MS fingerprints were demonstrated to serve as an efficient tool for revealing of other type of possible fraud in products labeling. Retrospective mining of markers of herbs declared on dietary supplements packaging allowed to assess the trueness / untruth in the declaration of medical herbs composition.

Mycotoxins in Plant-Based Dietary Supplements: Hidden Health Risk for Consumers.

Mycotoxin contamination of dietary supplements represents a possible risk for human health, especially in the case of products intended for people suffering from certain health conditions. The aim of this study was to assess the extent of this problem based on analyses of a wide set of herbal-based dietary supplements intended for various purposes: (i) treatment of liver diseases (milk thistle); (ii) reduction of menopause effects (red clover, flax seed, and soy); and (iii) preparations for general health support (green barley, nettle, goji berries, yucca, etc.) The analytical method including 57 mycotoxins was based on a QuEChERS-like (quick, easy, cheap, effective, rugged, safe) approach and ultrahigh performance liquid chromatography coupled with tandem mass spectrometry. The main mycotoxins determined were Fusarium trichothecenes, zearalenone and enniatins, and Alternaria mycotoxins. Co-occurrence of enniatins, HT-2/T-2 toxins, and Alternaria toxins was observed in many cases. The highest mycotoxin concentrations were found in milk thistle-based supplements (up to 37 mg/kg in the sum).