Integrating DNA Barcoding Within an Orthogonal Approach for Herbal Product Authentication: A Narrative Review

Abstract

Introduction: Existing methods for morphological, organoleptic, and chemical authentication may not adequately ensure the accurate identification of plant species or guarantee safety. Herbal raw material authentication remains a major challenge in herbal medicine. Over the past decade, DNA barcoding, combined with an orthogonal approach integrating various testing methods for quality assurance, has emerged as a new trend in plant authentication.

Objective: The review evaluates DNA barcoding and common alternative testing in plant-related sectors to enhance quality assurance and accurate authentication.

Method: Studies were selected based on their relevance to the identification, quality assurance, and safety of herbal products. Inclusion criteria were peer-reviewed articles, systematic reviews, and relevant case studies from the last two decades focused on DNA barcoding, identification methods, and their applications. Exclusion criteria involved studies lacking empirical data, those not peer-reviewed, or those unrelated to the main focus. This ensured the inclusion of high-quality, pertinent sources while excluding less relevant studies.

Results: An orthogonal approach refers to the use of multiple, independent methods that provide complementary information for more accurate plant identification and quality assurance. This reduces false positives or negatives by confirming results through different techniques, combining DNA barcoding with morphological analysis or chemical profiling. It enhances confidence in results, particularly in cases of potential adulteration or misidentification of plant materials.

Conclusion: This study highlights the persistent challenges in assuring the quality, purity, and safety of plant materials. Additionally, it stresses the importance of incorporating DNA-based authentication alongside traditional methods, to enhance plant material identification.

Keywords: DNA barcode; adulteration; authentication; chemical analysis; herbal products; metabarcoding; mini barcoding; orthogonal approach; quality assurance.

FIGURE 1

Overview of the authentication process in quality assurance.

FIGURE 2

Illustration of microscopic diagnostic features in Echinacea species, adapted from the British Pharmacopoeia monograph [55] (A) Narrow lignified fibers with black phyto‐melanin in E. angustifolia . (B) Spindle‐shaped fibers in E. purpurea . (C) Lignified fibers with black phyto‐melanin in E. pallida . (D) Vessels with reticulate bordered‐pitted thickenings in E. angustifolia . (E) Vessels with reticulate thickenings in E. pallida . (F, G) Sclereids with phyto‐melanin in E. angustifolia and E. pallida respectively. (H) Sclereids with no phyto‐melanin in E. purpurea . (I, L) Outer layers with squarish and rectangular cells with fine wall pitted parenchyma in E. angustifolia . (J, M) Squarish and rectangular cells of outer layers, pitted in E. purpurea . (K, N) Squarish to rectangular cells with abundant thin‐walled and pitted parenchyma in E. pallida .

FIGURE 3

An exemplary situation of whether and when an orthogonal approach is needed.

FIGURE 4

Complementary scenario where genetic (DNA) and chemical‐based interventions and methods help in an orthogonal approach of herbal medicinal plants and HMP authentication. (Conc. = concentration).