ISO 21316:2026

• Abstract:

  This document specifies the minimum requirements and test methods for Isatis indigotica root derived from the plant Isatis indigotica Fort. It is applicable to Isatis indigotica roots that are sold as Chinese material medica (whole medicinal materials) and decoction pieces derived from this plant.

• Status: Published
• Publication Date: 09-Jul-2026
• ICS: 11.120.10 - Medicaments
• Technical Committee: ISO/TC 249 - Traditional Chinese medicine
• Drafting Committee: ISO/TC 249/WG 1 - Quality and safety of raw materials and traditional processing
• Current Stage: 6060 - International Standard published
• Start Date: 10-Jul-2026
• Due Date: 05-Aug-2026
• Completion Date: 10-Jul-2026

• Revises: ISO 21316:2019 - Traditional Chinese medicine — Isatis indigotica root
• Effective Date: 08-Feb-2025

ISO 21316:2026 is an International Standard from ISO for Isatis indigotica root, the dried root of Isatis indigotica Fort. It specifies minimum requirements and test methods for roots sold as Chinese material medica and for decoction pieces derived from this plant. It is written for producers, laboratories, traders, quality teams and buyers who need a common basis for identification, sampling, testing, packaging and labelling.

What does ISO 21316:2026 specify?

ISO 21316:2026 specifies the quality checks and test methods for Isatis indigotica root as used in traditional Chinese medicine. The document applies to whole medicinal materials and decoction pieces made from this root.

The document is organized into clauses 1 to 10 and four informative annexes.

Annex	What it covers
Annex A	Determination of ethanol-soluble extractives
Annex B	Thin-layer chromatogram (TLC) identification
Annex C	Determination of (R,S)-goitrin content
Annex D	National and regional limits for moisture, ash, (R,S)-goitrin and ethanol-soluble extractive contents

Clause 6 covers sampling, Clause 7 covers test methods, Clause 8 covers the test report, Clause 9 covers packaging, storage and transportation, and Clause 10 covers marking and labelling.

What are the key requirements of ISO 21316:2026?

ISO 21316:2026 focuses on appearance, identity, purity, chemical markers, contaminant control and sampling. In practice, it tells users what to inspect on arrival and which laboratory tests to run before release or trade.

Product condition and visual identity

• Clause 5.1 requires the material to be clean, free from leaves, stems and foreign matter, and free from living insects, mouldy fruit and visible external contaminants. This is the first acceptance check before any testing.
• Clause 5.2 describes the expected morphological features, including the shape, colour, size, stem residue, texture, fracture, odour and taste. This helps users distinguish genuine root from poor-quality material or adulterants.

Quality indicators and marker compounds

• Clauses 5.3 to 5.6 cover moisture, total ash, acid-insoluble ash and ethanol-soluble extractives. In this edition these are recommendations rather than mandatory requirements, so readers use them as quality indicators and align them with local rules where needed.
• Clause 5.7 requires TLC identification of a marker compound such as (R,S)-goitrin, with spots from the test and reference solutions in the same position and colour. This is the document’s main identity test.
• Clause 5.8 states that marker compound content, such as (R,S)-goitrin, should be determined. Annex C gives the assay approach, so users can measure a chemical marker linked to the plant’s quality.

Safety, sampling and handling

• Clauses 5.9 and 5.10 require determination of heavy metals and pesticide residues, naming arsenic, mercury, lead, cadmium and examples such as DDT, endrin, BHC, aldrin and dieldrin. This addresses contamination risk in raw material supply chains.
• Clause 6 sets the sampling approach, including how many containers to sample, how to combine and quarter samples, and how much final sample is needed for different tests. Good sampling matters because it determines whether the laboratory result represents the batch.
• Clause 7 links each test to a method: macroscopic identification, microscopic identification, moisture, ash, extractives, TLC, marker compound content, heavy metals and pesticide residues. That lets laboratories choose the right procedure quickly.

Packaging, storage and labelling

• Clause 9 requires packaging and transport that do not taint or damage the product, and it refers storage to ISO 22217. Clause 10, using ISO 21371, requires key quality features, mass, origin, dates and storage method to be marked on the package.

What terms does ISO 21316:2026 define?

• Isatis indigotica root - the dried root of Isatis indigotica Fort. (Fam. Brassicaceae), with Isatis tinctoria L. given as a synonym.
• Final sample - the sample prepared for the tests required in this document; it may be packed in different materials if those materials suit the test conditions.
• traditional Chinese medicine (TCM) - the medicinal system in which this herbal material is used, and the context for the document’s quality controls.
• thin-layer chromatogram (TLC) - the chromatographic identification approach used here to compare test and reference spots for marker verification.

Who uses ISO 21316:2026?

ISO 21316:2026 is used by laboratories that test herbal raw materials, by manufacturers and processors of Isatis indigotica root, and by quality assurance teams checking batch release. It is also useful for suppliers, purchasers and auditors who need to verify identity, contamination status, packaging conditions and label information for trade or compliance work.

What changed in ISO 21316:2026 from the previous edition?

ISO 21316:2026 is the second edition and cancels and replaces ISO 21316:2019. The stated changes are that Clauses 5.3 to 5.6 were changed from mandatory requirements to recommendations, and the document and Annex D were updated.

Which standards are used with ISO 21316:2026?

• ISO 18664 - provides the method used for determining heavy metals in herbal medicines used in traditional Chinese medicine.
• ISO/TS 21310 - provides the microscopic examination method used in Clause 7.2.
• ISO 21371 - provides the labelling requirements used in Clause 10.
• ISO 22217 - provides storage requirements for raw materials and decoction pieces, which Clause 9 refers to.
• ISO 22258 - provides the gas chromatography method for pesticide residue determination.
• ISO 23723:2021 - provides general requirements for herbal raw material and materia medica, and the sampling and related determination method referenced in Clauses 6, 7.3, 7.4 and 7.5.

What does the ISO 21316:2026 document contain?

The document includes a plant-and-root figure in Clause 4 to show the structure of Isatis indigotica Fort. It gives a full sampling procedure in Clause 6 and Table 1, including how to build pooled, average and final samples. Annex A gives a worked procedure and formula for ethanol-soluble extractives, while Annex B gives the TLC preparation, mobile phase and comparison scheme for marker identification. Annex C gives the HPLC conditions and calculation formula for (R,S)-goitrin content, and Annex D compares national and regional limits used by different authorities.

International
Standard
ISO 21316
Second edition
Traditional Chinese medicine —
2026-07
Isatis indigotica root
Médecine traditionnelle chinoise — Racine d'Isatis indigotica
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
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or ISO’s member body in the country of the requester.
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Descriptions . 2
5 Requirements and recommendations . 4
5.1 General .4
5.2 Morphological features .4
5.2.1 Appearance .4
5.2.2 Colour .4
5.2.3 Dimension .4
5.2.4 Stem residue .4
5.2.5 Texture .4
5.2.6 Fracture .4
5.2.7 Odour .4
5.3 Moisture .4
5.4 Total ash .4
5.5 Acid-insoluble ash .4
5.6 Ethanol-soluble extractives .5
5.7 Identification of marker compound .5
5.8 Marker compound(s) .5
5.9 Heavy metals .5
5.10 Pesticide residues .5
6 Sampling . 5
7 Test methods . 6
7.1 Macroscopic identification .6
7.2 Microscopic identification .6
7.3 Determination of moisture content .6
7.4 Determination of total ash content .6
7.5 Determination of acid-insoluble ash content .6
7.6 Determination of ethanol-extractives content .6
7.7 Thin-layer chromatogram (TLC) identification .6
7.8 Determination of marker compound(s).6
7.9 Determination of heavy metals contents .6
7.10 Determination of pesticide residues contents.6
8 Test report . 6
9 Packaging, storage and transportation . 7
10 Marking and labelling . 7
Annex A (informative) Determination of ethanol-soluble extractives . 8
Annex B (informative) Thin-layer chromatogram (TLC) identification . 9
Annex C (informative) Determination of (R,S)-goitrin content .11
Annex D (informative) National and regional limits of moisture, total ash, acid-insoluble ash,
(R,S)-goitrin and ethanol-soluble extractive contents in Isatis indigotica root .13
Bibliography . 14

iii
Foreword
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https://www.iso.org/foreword-supplementary-information.html.
This document was prepared by Technical Committee ISO/TC 249, Traditional medicine, Subcommittee SC1,
Traditional Chinese medicine.
This second edition cancels and replaces the first edition (ISO 21316:2019) which has been technically
revised.
The main changes are as follows:
— 5.3 to 5.6: change of mandatory requirements to recommendations;
— information updates in the document and Annex D.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Isatis indigotica root (Banlangen in Chinese pinyin; 板蓝根 in Chinese), dried root of Isatis indigotica Fort.
(Fam. Brassicaceae), is one of the most commonly used herbs in traditional Chinese medicine (TCM). It has
a long history of use in East Asian countries to remove heat and toxins, cool the blood and clear the throat.
Clinically, Isatis indigotica root is recognized as an important traditional Chinese herb for the prevention
and treatment of colds and malignant infectious diseases, especially SARS and H1N1. At present, Isatis
indigotica root and its processed products occupy a huge share of the international market. However, many
problems, such as different quality requirements among different countries and regions, adulteration with
Baphicacanthis root derived from the dried root and rhizome of Baphicacanthus cusia (Nees) Bremek (Fam.
Acanthaceae), and different packaging, transportation and storage conditions, can affect the quality of Isatis
indigotica root.
Therefore, the establishment of an international standard is necessary to establish the quality requirements
of Isatis indigotica root to support its clinical effectiveness and safety. This document consists of a
morphology observation of macroscopic characteristics, phytochemical indexes, and standardized physical
and chemical tests (moisture, total ash and acid-insoluble ash). Glucosinolates with multi-bioactivities are
specific compositions of the plant in the Brassicaceae family. Among them, (R,S)-goitrin with high specificity
reflects bioactivities relevant to the effects of Isatis indigotica root. Using (R,S)-goitrin as the marker, TLC
identification and HPLC assay methods are established in this document.
As national implementation may differ, examples of national and regional values are given in Annex D.

v
International Standard ISO 21316:2026(en)
Traditional Chinese medicine — Isatis indigotica root
1 Scope
This document specifies the minimum requirements and test methods for Isatis indigotica root derived from
the plant Isatis indigotica Fort.
It is applicable to Isatis indigotica roots that are sold as Chinese material medica (whole medicinal materials)
and decoction pieces derived from this plant.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 18664, Traditional Chinese Medicine — Determination of heavy metals in herbal medicines used in
Traditional Chinese Medicine
ISO/TS 21310, Traditional Chinese medicine — Microscopic examination of medicinal herbs
ISO 21371, Traditional Chinese medicine — Labelling requirements of products intended for oral
...