A combined approach of DNA metabarcoding collectively enhances the detection efficiency of medicinal plants in single and polyherbal formulations

DNA metabarcoding unveils authenticity and adulteration in commercial Chinese polyherbal preparations: Renshen Jianpi Wan as a critical case study

Objectives

Ensuring quality and authenticity of traditional medicines is crucial, particularly for multi-ingredient formulations like commercial Chinese polyherbal preparations (CCPPs). This study aims to authenticate Renshen Jianpi Wan (RSJPW), a classical CCPP composed of 11 prescribed botanical drugs, using DNA metabarcoding to overcome challenges in species-level identification of processed biological ingredients.

Methods

We analyzed 56 commercial RSJPW products from different manufacturers and production batches, alongside eight laboratory-prepared reference samples serving as authentic controls. A dual-marker protocol combining ITS2 and psbA-trnH regions was employed, with optimized DNA extraction and PCR protocols to mitigate degradation issues.

Results

Detection rates varied across samples, with the highest detection being 10 out of 11 prescribed ingredients in a single sample. The key fungal ingredient Poria cocos () was consistently undetectable, likely due to DNA degradation during processing and challenges in extracting fungal DNA from complex matrices. Multiple high-abundance non-prescribed species from Fabaceae, Apiaceae, Brassicaceae, and other families were frequently detected as potential contaminants.

Conclusions

This study establishes a systematic framework for molecular authentication of complex herbal formulations, providing technical support for reliable identification of botanical drugs. While DNA metabarcoding offers valuable insights into CCPP composition, authentication of heavily processed ingredients remains a significant technical limitation. The integration with complementary analytical methods such as metabolomics could provide more comprehensive quality assessment in future studies, demonstrating the necessity of multi-analytical approaches in ensuring the authenticity of traditional medicine.

Identification of toxic Gelsemium elegans in processed food and honey based on real-time PCR analysis

Gelsemium elegans (GE) is a widely distributed hypertoxic plant that has caused many food poisoning incidents. Its pollen can also be collected by bees to produce toxic honey, posing a great threat to the health and safety of consumers. However, for the complex matrices such as cooked food and honey, it is challenging to perform composition analysis. It is necessary to establish more effective strategies for investigating GE contamination. In this study, the real-time PCR (qPCR) analysis combined with DNA barcode matK was proposed for the identification and detection of GE. Fifteen honey samples along with twenty-eight individuals of GE and the common confusable objects Lonicera japonica, Ficus hirta, Stellera chamaejasme and Chelidonium majus were gathered. Additionally, the food mixtures treated with 20-min boiling and 30-min digestion were prepared. Specific primers were designed, and the detection capability and sensitivity of qPCR in honey and boiled and digested food matrices were tested. The results demonstrated that the matK sequence with sufficient mutation sites was an effective molecular marker for species differentiation. GE and the confusable species could be clearly classified by the fluorescence signal of qPCR assay with a high sensitivity of 0.001 ng/μl. In addition, this method was successfully employed for the detection of deeply processed food materials and honey containing GE plants which even accounted for only 0.1 %. The sequencing-free qPCR approach undoubtedly can serve as a robust support for the quality supervision of honey industry and the prevention and diagnosis of food poisoning.

Comprehensive analysis using DNA metabarcoding, SCAR marker based PCR assay, and HPLC unveils the adulteration in Brahmi herbal products

BACKGROUND

Brahmi is one of the important nootropic botanicals, widely sold in the market, with the name "Brahmi'' being used to describe both Bacopa monnieri and Centella asiatica species. The Brahmi herbal products market is expanding; hence, economically motivated adulteration is highly prevalent.

METHODS AND RESULTS

This study aimed to develop DNA-based methods, including SCAR marker-based PCR and metabarcoding, to authenticate Brahmi herbal products and compare these methods with HPLC. These methods have been validated using mock controls (in-house blended formulations). All targeted plant species in mock controls were detected successfully with all three methods, whereas, in market samples, only 22.2%, 55.6%, and 50.0% were found positive for Brahmi by PCR assay, DNA metabarcoding, and HPLC, respectively. Metabarcoding can detect the presence of non-labeled plants together with targeted species, which is an advantage over PCR assay or HPLC.

CONCLUSION

SCAR marker-based PCR is a rapid and cost-effective method for detecting the presence of B. monnieri and C. asiatica. However, in this study, the success rate of PCR amplification was relatively low because the primers targeted either RAPD or ITS-based SCAR markers. HPLC assay, although an alternative, was unable to detect the presence of other botanicals, just like the SCAR marker-based PCR assay. On the other hand, metabarcoding can be utilized to identify the target plants, even in very small quantities, while also providing simulated identification of other botanicals. This study successfully addressed the need for quality control of Brahmi herbal products and provided the first-time report of DNA metabarcoding for such products.