Advanced Methodologies for the Quality Control of Herbal Supplements and Regulatory Considerations

Herbal supplements and OTC herbal drugs enjoy wide popularity with consumers but their quality has been questioned by genomic methods of testing. Due to complex regulatory environments in Europe and North America, the quality assurance of herbal preparations depends on protocols, which can significantly differ between the respective national and supranational drug control agencies. Modern methods of analysis combine genetic testing (DNA barcoding) with advanced chromatographic techniques as well as traditional microscopic and macroscopic tests to detect adulterants and undesirable constituents of herbs, including alkylphenols, aristolochic acids, and pyrrolizidine alkaloids.

This review will give an account of current trends in herbal drug analysis and explain the shortcomings of existing methodologies. The article will also discuss regulatory protocols, compendial methods and differentiate between dietary supplement testing regimens and the requirements for approved herbal drugs. The purpose of this review is to document current trends in genetic testing and reveal future developments in drug analysis to reduce the possibility of adulterations and assure the authenticity of herbal products.

Chemometric methods and orthogonal approaches aid in the deconvolution of chromatographic and spectral data while expanding databases for nucleotide sequences and mineable spectra support method development in herbal analysis.

Genetic testing of herbal products has further increased the capabilities to detect minute adulterations, but such assays are only meaningful in combination with chromatographic and spectroscopic analysis. Despite the advancement of genomic testing, chemometrics, UHPLC and mass spectrometry, cost-effective quality control techniques such as HPTLC in conjunction with microscopic and macroscopic examination remain important particularly in regulated environments.