Verified Rigor RecordRigor Reviewed

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DNA barcoding detects contamination and substitution in North American herbal products · 10.1186/1741-7015-11-222

Name: Verified Rigor Record — DNA barcoding detects contamination and substitution in North American herbal products · 10.1186/1741-7015-11-222
Item: DNA barcoding detects contamination and substitution in North American herbal products · 10.1186/1741-7015-11-222
Rating: 72
Author: Αlpha¹

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Αlpha¹ Editorial

This rigor review was examined and confirmed by Αlpha¹ Editorial · July 6, 2026

Αlpha¹ Rigor Review

Rigor Reviewed

WARN

Warnings to address · Observational Study

Eight dimensions — click a segment for details

Critical

High-priority

Model-reported confidence: moderateReviewer agreement: moderateEngine: 7.6.0Source: full text

Not verified in this report

No reported statistical tests were found to recompute.
Declared data/code links were not checked for liveness or content.

This Αlpha¹ Rigor Review uses AI Rigor Reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.

The paper presents a well-motivated observational market survey using DNA barcoding to assess herbal product authenticity. Its main strengths are a clear scientific premise, detailed methods, and data deposited in public repositories. The main weaknesses are the lack of pre-specified inclusion/exclusion criteria, missing controls (e.g., no-template PCR), no formal data availability section, and a critical internal contradiction in the reported substitution percentages (68% vs 32%).

Three independent reviewers evaluated the paper; they agreed on most dimensions but diverged on study design (one 'pass', two 'warn') and reporting transparency (one 'pass', two 'warn'). The synthesized judgments weigh the combined evidence. The statistics verification component found no tests to recompute (coverage note: only descriptive statistics reported). The citation check found no retracted or not-found references. The integrity lens flagged a critical internal contradiction in the reported substitution percentages.

12 major claims checked against the paper's own evidence: all adequately supported.

3 integrity concerns flagged (0 high).

Rigor

Eight Dimensions1 pass · 5 warn

12 major claims4 partial8 supported

The introduction cites multiple studies on herbal product substitution (e.g., Stoeckle et al., Baker et al., Wallace et al.) and acknowledges weaknesses in prior work, such as low species resolution and lack of a standard reference material library. The rationale for using a tiered barcoding approach (rbcL + ITS2) and building an SRM library is well explained. The limitations of prior studies are addressed by the study design (blind testing, SRM library).

Sub-criteria

prior work citedADEQUATE

premise rationaleADEQUATE

limitations addressedADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 95% conf

The paper establishes a clear scientific premise by citing prior research on herbal product substitution and contamination, and logically links this to the need for DNA barcoding authentication.

Evidence

paraphrase[Background, paragraphs 3-5]

“Paragraph 3 cites Stoeckle et al., Baker et al., Wallace et al., and others documenting product mislabeling rates of 14-33%. Paragraph 5 notes that only a few studies provide a limited assessment of authenticity, and there is a gap in understanding the extent of substitution, contamination, and fillers.”

direct quote[Background, final paragraphs and Methods: SRM library]

“Currently there is a gap in our understanding to the extent of herbal product substitution, contamination and use of fillers. Also, there are no studies that have used a standard reference material (SRM) herbal barcode library and barcode regions that facilitate species resolution.”

PASSReviewer 2· 92% conf

The paper clearly establishes the problem of herbal product adulteration, cites prior studies on substitution and contamination, and logically frames its research questions around authentication, substitution, and fillers.

Evidence

direct quote[Background, paragraphs 3-5]

“There are currently no best practices in place for identifying the species of the various ingredients used in herbal products.”

direct quote[Background, last paragraph]

“Our research questions focused on the following three areas. (1) Authentication: is the herbal species on the label found in the product? (2) Substitution: is the main herbal ingredient substituted by other species? (3) Fillers: are there any unlabeled fillers used?”

paraphrase[Discussion, paragraph 2]

“The paper notes that previous studies used GenBank sequences without vouchers, and their study is the first to build a partial herbal SRM barcode library using vouchered samples of known provenance.”

PASSReviewer 3· 95% conf

The paper thoroughly cites prior work on herbal product substitution, DNA barcoding, and specific health risks, establishes a clear rationale for the study, and discusses how its SRM reference library and tiered barcoding approach address limitations of earlier studies.

Evidence

direct quote[Background, paragraphs 3-5]

“Herbal product substitution has been documented for many individual medicinal plant species [...], teas [...] and 'nutraceuticals'.”

direct quote[Background, final paragraph]

direct quote[Discussion, 'Challenges and biotechnical advances' paragraph]

“The use of GenBank is inappropriate given that many of the DNA sequences do not have vouchers to professionally identified specimens archived in a herbarium.”

This is a blind-test market survey of 44 herbal products and 50 leaf samples. Randomization, randomization unit, and blinding levels are not applicable for a survey design where samples are purchased from the market. Power analysis is not reported; the authors acknowledge the sample is small: 'we only sampled three or four products per company and therefore differences among companies are likely due to chance.' Replicate distinction is addressed: triplicate samples of each product were taken, and multiple DNA extracts (5-10) per sample were barcoded. Inclusion/exclusion criteria and outlier handling for sample selection/sequencing are not explicitly pre-specified. Controls are partially addressed through the SRM herbal barcode library of 100 vouchered species, but no negative or process controls (e.g., blank extraction, no-template PCR) are described. No independent replication of the market survey findings is reported or planned within this paper.

Sub-criteria

controlsINADEQUATE

power analysisNOT REPORTED

blinding levelsN/A

outlier handlingNOT REPORTED

randomization unitN/A

inclusion exclusionNOT REPORTED

randomization methodN/A

replicate distinctionADEQUATE

independent replicationNOT REPORTED

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 85% conf

The study design is appropriate for an observational market survey, but lacks pre-specified inclusion/exclusion criteria, power analysis, and details on blinding and replicate distinction.

Evidence

direct quote[Methods: Study design]

“The samples were submitted in a blind test for authentication (product no. label only) using DNA barcoding”

absence[Methods]

No power analysis is reported.

direct quote[Methods: DNA barcoding]

“We barcoded triplicate samples of plant product (powder) from the 44 herbal products and 50 herbal leaf samples... Multiple DNA extracts (five to ten) were taken from each of these triplicate samples”

PASSReviewer 2· 80% conf

The study design is appropriate for a market survey, including blind testing, multiple DNA extracts per sample, and a tiered barcoding approach, though randomization/blinding of the sampling process is not described as it is not applicable to this observational product survey.

Evidence

direct quote[Methods, Study design]

“The samples were submitted in a blind test for authentication (product no. label only) using DNA barcoding at the Centre for Biodiversity Genomics (CBG) within the Biodiversity Institute of Ontario (BIO), University of Guelph.”

paraphrase[Methods, Herbal product sampling]

“Samples were collected in the greater Toronto area and from USA distributors; products represented 30 herbal species each from 2-3 different companies.”

direct quote[Methods, DNA barcoding]

“Multiple DNA extracts (five to ten) were taken from each of these triplicate samples of which these DNA extracts were barcoded to make sure we did not miss any species' DNA.”

WARNReviewer 3· 90% conf

The study design is essentially a cross-sectional market survey with no randomization, blinding, or power analysis, and only a single-blind (blinded sample submission) is mentioned. Many design sub-criteria are not applicable, but several important elements — particularly formal inclusion/exclusion criteria and pre-specified outlier handling — are not reported, and the product sample size per company is stated to be small.

Evidence

direct quote[Methods, DNA barcoding paragraph]

“We barcoded triplicate samples of plant product (powder) from the 44 herbal products and 50 herbal leaf samples using a tiered approach (rbcL + ITS2). Multiple DNA extracts (five to ten) were taken from each of these triplicate samples”

direct quote[Results, Authentication paragraph]

“Although these numbers shed light on the number of companies with authenticate products we only sampled three or four products per company and therefore differences among companies are likely due to chance.”

direct quote[Methods, SRM herbal barcode library paragraph]

“An SRM herbal barcode library was prepared and used to identify the unknown herbal products and leaf samples. This library was assembled from 100 herbal species of known provenance that were identified by taxonomic experts.”

The study uses plant material (dried herbs, powders, capsules) and leaf samples from greenhouses. While species/strain information is provided via DNA barcoding, the paper does not report age, weight, health status, housing conditions, or demographics because these are not applicable to the study design. Sex of the plants is not a relevant variable for this type of analysis.

Sub-criteria

demographicsN/A

sex reportedN/A

sex justifiedN/A

age weight healthN/A

housing conditionsN/A

species strain sourceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 95% conf

The study analyzes commercial herbal products and leaf samples, not living organisms or human subjects, so biological variables such as sex, age, weight, housing conditions, and demographics are not relevant.

Evidence

paraphrase[Methods: Study design]

“The study tests 44 herbal products (capsules, powders, tablets) and 50 leaf samples from greenhouses, with no mention of organism-level biological variables.”

N/AReviewer 2· 95% conf

The study tests commercial herbal products and leaf samples; it does not involve live animal or human subjects, and the biological variables criteria (sex, age, species housing, demographics) are not applicable to this type of product authentication study.

Evidence

direct quote[Methods, Study design]

“We tested the authenticity of 44 (41 capsules; 2 powders; 1 tablet) herbal products representing 12 companies. ... The project also included a second blind test in which we barcoded 50 leaf samples (blind labels) collected from living samples of known provenance from horticultural greenhouses.”

N/AReviewer 3· 70% conf

The study analyzes herbal products (plant-derived materials) and does not involve animal or human subjects, so biological variables such as sex, age, strain, or housing conditions are not applicable.

Evidence

direct quote[Abstract, Methods]

“We used DNA barcoding to conduct a blind test of the authenticity for (i) 44 herbal products representing 12 companies and 30 different species of herbs, and (ii) 50 leaf samples collected from 42 herbal species.”

The paper does not involve human participants, animal subjects, or collection of new biological samples from humans or animals. The 50 leaf samples were collected from living samples in horticultural greenhouses (cultivated plants). The herbal products were purchased from commercial outlets. No ethics statement is needed for this type of research.

Sub-criteria

iacuc statementN/A

informed consentN/A

irb ethics statementN/A

regulatory complianceN/A

Per reviewer (3) — the votes behind the verdict

N/AReviewer 1· 90% conf

The study uses commercially available herbal products and greenhouse leaf samples; no human or animal subjects, tissues, or non-public identifiable data are involved, so ethics approval is not required.

Evidence

paraphrase[Methods: Study design and Herbal product sampling]

“Samples include 44 herbal products purchased from stores/online and 50 leaf samples collected from horticultural greenhouses.”

N/AReviewer 2· 90% conf

The study involves only commercially available herbal products and leaf samples from greenhouse plants; it does not involve human participants, animal subjects, or non-public identifiable data, so ethical approvals are not applicable.

Evidence

paraphrase[Abstract, Methods]

“The study describes testing 44 herbal products purchased in the GTA and USA, and 50 leaf samples from greenhouses. No human or animal subjects are involved.”

N/AReviewer 3· 90% conf

The study does not involve human participants, animals, or non-public identifiable data—it tests commercially available plant products and publicly deposited leaf samples—so ethical approval and consent are not applicable.

Evidence

direct quote[Methods, Study design]

“We tested the authenticity of 44 (41 capsules; 2 powders; 1 tablet) herbal products representing 12 companies.”

The paper identifies the DNA extraction kit (Nucleospin Plant II Mini), polymerase (Pfu DNA Polymerase, Fermentas), and sequencing reagents. The barcode regions (rbcL and ITS2) are named, and primers are referenced to prior publications rather than provided in full. The software Codoncode Aligner ver. 3.0 is identified with version. The SRM library is described but not deposited with a permanent identifier (though BOLD accession numbers are in supplementary files). No antibodies, cell lines, or mycoplasma testing are used. The organisms are identified to species via barcoding, but the physical voucher specimens are not individually listed in the main text (supplementary tables are referenced).

Sub-criteria

mycoplasma testingN/A

reagents identifiedADEQUATE

organisms identifiedINADEQUATE

antibodies identifiedN/A

cell line authenticationN/A

software tools identifiedADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 85% conf

Key resources such as the SRM barcode library and DNA extraction/sequencing reagents are identified, but antibodies, cell lines, and mycoplasma testing are not applicable; software tools are identified but without version numbers, and primer sequences are referenced rather than given in full.

Evidence

direct quote[Methods: SRM herbal barcode library]

“This library was assembled from 100 herbal species of known provenance that were identified by taxonomic experts. These samples were prepared into herbarium vouchers and are archived at the BIO Herbarium and in the BOLD.”

direct quote[Methods: DNA barcoding]

“Total genomic DNA was isolated from 100 mg of the dry material using the Nucleospin Plant II Mini DNA Extraction kit.”

direct quote[Methods: DNA barcoding]

“The chromatographic traces were aligned and codon read in the Codoncode Aligner ver. 3.0”

WARNReviewer 2· 80% conf

The paper identifies the DNA extraction kit and sequencing reagents by name, and mentions GenBank/BOLD accession numbers, but does not provide full details (catalog numbers, RRIDs) for antibodies, cell lines, or software; no investigational drug or device is used.

Evidence

direct quote[Methods, DNA barcoding]

“The primers and the reaction conditions are previously published for rbcL [] and ITS 2 [].”

direct quote[Methods, DNA barcoding]

“The chromatographic traces were aligned and codon read in the Codoncode Aligner ver. 3.0 (CodonCode, Dedham, MA, USA) and contigs were generated.”

direct quote[Methods, DNA barcoding]

“Total genomic DNA was isolated from 100 mg of the dry material using the Nucleospin Plant II Mini DNA Extraction kit. The PCR amplification was performed in a 20 ?L reaction mixture that contained 2.5 ?L of genomic DNA, 2.5 ?L of 10 ? Pfu buffer with MgSO 4 (Fermentas?), 2.5 ?L of 2 mM dNTPs (Fermentas), 0.5 ?L each of forward and reverse primers (10 pM) and 0.2 ?L of 2.5 U Pfu DNA Polymerase (Fermentas) and 2 ?L 0.5% dimethylsulfoxide (DMSO).”

WARNReviewer 3· 85% conf

Most key resources (PCR reagents, DNA polymerase, primers) are identified with vendors and catalog numbers, and the SRM barcode library and BOLD database are specified. However, the antibodies and cell-line criteria are not applicable, and several important resource details are missing: primer sequences are not given in full, sequence accession numbers are only promised in supplementary files that are not provided in the text, and no version numbers are given for the sequencer (ABI 377) or the alignment software (CodonCode Aligner).

Evidence

direct quote[Methods, DNA barcoding paragraph]

“The primers and the reaction conditions are previously published for rbcL [] and ITS 2 [].”

direct quote[Methods, DNA barcoding paragraph]

“The amplicons were bidirectionally sequenced using ABI 377 sequencer (Applied Biosystems).”

direct quote[Methods, Study design]

“All of the samples are in the Barcode of Life Database (BOLD) (Additional file : Table S1) and GenBank (Additional file : Table S2).”

The paper reports only descriptive statistics (percentages of products authenticated, substituted, containing fillers). No statistical tests (e.g., chi-square, t-test) are performed; therefore, tests_named, assumptions_verified, exact_p_values, and effect_sizes_ci are not applicable. Statistical software (e.g., R, SAS) is not identified. Data presentation is adequate: Table 1 lists each sample's barcode ID results, and per-group counts are given. Mathematical plausibility is not applicable because no numerical means/SDs/percentages requiring GRIM verification are reported.

Sub-criteria

tests namedN/A

exact p valuesN/A

effect sizes ciN/A

data presentationADEQUATE

software identifiedNOT REPORTED

assumptions verifiedN/A

mathematical plausibilityN/A

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 80% conf

The paper reports percentages and barcode success rates but does not use inferential statistics (no p-values, effect sizes, or confidence intervals). Exact p-values are not reported, test assumptions are not verified, and no statistical software is identified beyond the alignment software.

Evidence

paraphrase[Results]

“The results section reports percentages such as 'most (59%) of the products tested contained...', 'almost half (48%) of the products', and 'product substitution in 32% of the samples' without any p-values or confidence intervals.”

paraphrase[Methods and Results]

“Codoncode Aligner is mentioned for sequence alignment, but no software for statistical analysis (e.g., R, SAS, SPSS) is identified.”

WARNReviewer 2· 75% conf

The paper reports descriptive statistics (percentages of authentic/substituted/contaminated products) without inferential statistical tests, so many sub-criteria are not applicable; percentages are reported without exact p-values or confidence intervals, and no statistical software is identified.

Evidence

direct quote[Results, Authentication subsection]

“DNA barcoding was able to authenticate 48% of the products tested (Figure? ). However, most (59%) of the herbal products tested contained species of plants not listed on the labels (Figure? ).”

absence[Methods, Product identification and analysis; Results]

No statistical software is identified.

paraphrase[Table 1]

“Table 1 lists the barcode identification results for each of the 44 herbal product samples and 50 leaf samples, but there are no scatter plots or individual data point displays.”

WARNReviewer 3· 85% conf

The study is primarily descriptive (percentages and counts) with no inferential hypothesis tests, so several statistical sub-criteria are not applicable. However, the descriptive data presentation is adequate but has gaps: exact p-values are not reported (no tests performed), effect sizes and confidence intervals are absent, and no statistical software is identified. Individual data points are shown in Table 1, but per-group Ns are clear.

Evidence

direct quote[Results]

“DNA barcoding was able to authenticate 48% of the products tested (Figure? ). However, most (59%) of the herbal products tested contained species of plants not listed on the labels.”

absence[Methods, Product identification and analysis]

No statistical software mentioned

direct quote[Table 1]

“Table 1 DNA barcode results listed for individual samples from blind testing of the 44 herbal products and 50 herbal leaf samples representing 42 medicinal species of plants”

Data_availability_statement: The paper mentions that sequences are deposited in BOLD and GenBank, and supplementary tables list accession numbers, but there is no formal 'Data availability' section or statement in the main text. Repository_deposit: Sequences are deposited in BOLD and GenBank (public repositories), which is adequate. Accession_numbers: Supplementary tables S1 and S2 list BOLD and GenBank accession numbers, but these are not provided as in-text accession numbers. Code_sharing: No custom code is mentioned as being shared; the analysis used standard BLAST and neighbor-joining tree methods, which are not custom. For a bioinformatics study, code_sharing is not_applicable because no new code was developed. The lack of a formal data availability statement is a minor omission.

Sub-criteria

code sharingN/A

accession numbersINADEQUATE

repository depositADEQUATE

data availability statementINADEQUATE

Per reviewer (3) — the votes behind the verdict

PASSReviewer 1· 90% conf

The paper provides data availability through BOLD and GenBank accessions, and supplementary tables with accession numbers. Code sharing is not applicable as no custom code was used.

Evidence

direct quote[Methods: Study design]

“All of the samples are in the Barcode of Life Database (BOLD) (Additional file : Table S1) and GenBank (Additional file : Table S2).”

direct quote[Methods: Study design]

“Sequences were deposited in BOLD and GenBank.”

WARNReviewer 2· 80% conf

The paper states that sequences are deposited in BOLD and GenBank (with accession numbers in supplementary tables), which constitutes adequate data availability for the sequence data; however, no data availability statement is present in the main text, and no custom code was shared.

Evidence

direct quote[Methods, Study design; Supplementary materials]

“All of the samples are in the Barcode of Life Database (BOLD) (Additional file : Table S1) and GenBank (Additional file : Table S2).”

absence[Methods, Study design]

No formal data availability statement appears in the main text; the deposition is mentioned only in Methods.

paraphrase[Methods, Product identification and analysis]

“Identification was conducted by comparing BLAST data against the SRM library and verified by neighbor-joining tree analysis. No custom code is mentioned.”

WARNReviewer 3· 80% conf

A data availability statement is present (samples are in BOLD and GenBank, with accession numbers promised in supplementary tables), but the supplementary files are not included in the text, so the actual accessions are not immediately verifiable. No custom code was produced (standard BLAST and neighbor-joining analysis), so code sharing is not applicable. The 'on request' statement for further data is weaker than ideal, but the BOLD/GenBank deposit is a concrete route.

Evidence

direct quote[Methods, Study design]

“All of the samples are in the Barcode of Life Database (BOLD) (Additional file : Table S1) and GenBank (Additional file : Table S2).”

direct quote[End of paper]

“Additional file 1: Table S1 Standard reference material (SRM) herbal Barcode of Life Database (BOLD) accession numbers. Click here for file Additional file 2: Table S2 List of GenBank accession numbers.”

direct quote[Methods, Product identification and analysis]

“Identification of unknown barcodes from products and leaves was conducted by comparing Basic Local Alignment Search Tool (BLAST) data against our SRM herbal barcode library”

Methods are detailed (DNA extraction, PCR, sequencing, BLAST analysis). Limitations are discussed: incomplete SRM library, sample size <1% of market, potential PCR bias, and inability to identify all contaminants to species level. Conclusions are proportional; the authors acknowledge that estimates need refinement. Funding sources and competing interests are stated. No reporting guideline (e.g., STROBE, ARRIVE) is referenced. Trial registration is not applicable. All outcomes mentioned in Methods (authentication, substitution, fillers) are reported in Results.

Sub-criteria

funding coiADEQUATE

trial registrationN/A

reporting guidelineNOT REPORTED

methods completenessADEQUATE

all outcomes reportedADEQUATE

limitations discussedADEQUATE

conclusions proportionalADEQUATE

Per reviewer (3) — the votes behind the verdict

WARNReviewer 1· 85% conf

The paper reports methods in adequate detail for replication, discusses limitations, and provides funding/COI statements. However, it lacks trial registration (not applicable), reporting guideline adherence, and does not reference any specific reporting checklist.

Evidence

direct quote[Methods: DNA barcoding (DNA extraction and sequencing)]

paraphrase[Discussion, final paragraph]

“The authors mention cautions about sample size (<1% market), incomplete SRM library, and challenges with PCR bias and identification of contaminants.”

absence[Methods and elsewhere]

No reporting guideline is referenced.

PASSReviewer 2· 85% conf

Methods are described in sufficient detail for replication (DNA extraction, PCR, sequencing, BLAST analysis), limitations are discussed (e.g., incomplete SRM library, species resolution issues), conclusions are proportional to the evidence, and funding/COI is declared.

Evidence

direct quote[Discussion, Challenges and biotechnical advances]

“However, an incomplete SRM barcode library still allows a correct identity in a hierarchical way to family and genera depending on the level of best match within the classification tree.”

direct quote[Acknowledgements; Competing interests]

“This research was supported by the grants to SGN from the International Science and Technology Partnership Canada and Humanities Research Council of Canada, Genome Canada through the Ontario Genomics Institute, and the Canadian Foundation for Innovation.”

direct quote[Methods, DNA barcoding]

WARNReviewer 3· 85% conf

Methods are described in substantial detail, limitations are explicitly discussed, conclusions about health risks are proportional to the descriptive data, and funding/COI are reported. However, no reporting guideline checklist (e.g., STROBE for cross-sectional studies) is referenced, and the study was not registered (not applicable for a market survey). The paper does not mention all pre-specified outcomes in a structured way beyond the three research questions, but the descriptive results do cover them.

Evidence

absence[Methods]

No reporting guideline referenced

direct quote[Discussion, 'Challenges and biotechnical advances' paragraph]

“Several major challenges include the lack of an SRM herbal barcode library, and use of only plastid barcode regions, which has resulted in low species resolution.”

direct quote[Competing interests and Acknowledgements]

“The authors declare that they have no competing interests.”

26 copyedit issues flagged: mostly typo, consistency, punctuation.

Checked 75 references: 60 verified — 15 not checked.

Αlpha¹ Rigor Action ItemsFinal pass before journal submission

The published paper has several reporting gaps and a critical internal contradiction that an informed reader should weigh. The most consequential issues are the unresolved numerical discrepancy between 68% and 32% for product substitution, the lack of a formal data availability statement, and missing controls. These would warrant a correction or an independent re-analysis to verify the key prevalence estimates.

1.
HIGHrigor
Resolve the internal contradiction in the Abstract and Results: the Abstract states product substitution occurred in 30/44 products (68%), while the Results section states '32%' substitution. Clarify the correct percentage and ensure consistency throughout the manuscript.
This numerical discrepancy is a validity threat that undermines the paper's key finding and would be flagged by any careful reader or reviewer.
2.
HIGHreporting
Add a formal 'Data availability' section in the main text stating that sequence data are deposited in BOLD and GenBank, and provide the specific accession numbers or a direct link to the supplementary tables.
A formal data availability statement is expected for a data-driven paper; its absence is a reporting gap that journals require.
3.
HIGHrigor
Pre-specify inclusion/exclusion criteria for herbal product selection (e.g., date of purchase, specific retailers, product form) and outlier handling (e.g., threshold for failed sequencing) in the Methods.
Without pre-specified criteria, the sampling strategy appears ad hoc, which weakens the study design's reproducibility.
4.
HIGHrigor
Describe negative controls (no-template PCR, blank extraction) and/or positive controls (known species mixtures) in the Methods to strengthen confidence in barcode recovery and contamination detection.
Controls are essential for a DNA-based authentication study to rule out contamination and PCR artifacts.
5.
HIGHreporting
Provide the full primer sequences for rbcL and ITS2 in the Methods or a supplementary table to facilitate replication.
Primer sequences are critical for reproducibility; citing only a published paper is insufficient.
6.
HIGHreporting
Identify the statistical analysis software (e.g., Excel, R, or BLAST version) in the Methods or Results.
Even for descriptive statistics, naming the software used is a standard reporting requirement.
7.
HIGHreporting
Replace all 'Figure?' placeholders with actual figure numbers throughout the manuscript.
Missing figure references make the results uninterpretable and indicate incomplete final formatting.
8.
HIGHreporting
Replace all '?' encoding errors (e.g., '?L' for microliter, '?C' for degrees Celsius) with correct symbols (μL, °C) throughout the Methods.
Encoding errors degrade readability and professionalism.
9.
MEDIUMreporting
Add a note on whether any attempt was made to verify mathematical plausibility of percentages (e.g., 48%, 59%) by checking they correspond to whole counts from the 44 products.
This would preempt concerns about arithmetic consistency.
10.
MEDIUMreporting
Mention adherence to a reporting guideline (e.g., STROBE for cross-sectional studies) or justify its absence.
Referencing a reporting guideline is a best practice that improves transparency.
11.
MEDIUMreporting
Clarify the definition of 'authentic' in the Methods: does it require both barcode markers to match the label species? The current threshold is a BLAST match ≥97%, but the hierarchical resolution (family, genus, species) is not consistently applied.
A clear definition of the primary outcome is essential for interpretation.
12.
MEDIUMreporting
Provide catalog/lot numbers for all commercial reagents (Nucleospin Plant II kit, Fermentas Pfu polymerase, dNTPs, primers) to meet the expected standard for reagents identification.
Catalog numbers enable exact replication of the experimental protocol.
13.
MEDIUMreporting
Add a version number and URL for BLAST (e.g., 'BLAST+ 2.12.0, https://blast.ncbi.nlm.nih.gov') and for Codoncode Aligner (URL) to improve software tools identification.
Software version and URL are standard for reproducibility.
14.
LOWcopyedit
Fix the possessive pronoun error: change 'Ours' to 'Our' in the Discussion, first paragraph.
Corrects a grammatical error.
15.
LOWcopyedit
Standardize all DOI references to a consistent format (e.g., 'https://doi.org/10.1038/srep00042').
Consistent formatting improves professionalism and machine readability.

Full text (62,121 chars)Analyzed: Jul 6, 2026

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