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

Overview

ISO 21316:2026 - Traditional Chinese medicine - Isatis indigotica root establishes international requirements and test methods for Isatis indigotica root, a key herbal ingredient in traditional Chinese medicine (TCM). The standard applies to roots derived from Isatis indigotica Fort. (commonly known as Banlangen) that are sold both as whole medicinal raw materials and as decoction pieces. By specifying clear quality criteria, sampling methods, and safety guidelines, this ISO standard aims to support consistency, efficacy, and safety in the global trade and application of Isatis indigotica root.

Key Topics

• Material Requirements:

  • Only clean, whole roots with no leaves, stems, or foreign matter are permitted.
  • Strict exclusion of visible external contaminants, insects, or mould.
  • Roots must exhibit specific morphological characteristics, such as color, size, texture, and odour criteria.

• Chemical and Physical Testing:

  • Measurement of moisture content, total ash, acid-insoluble ash, and ethanol-soluble extractives.
  • Verification of marker compound, such as (R,S)-goitrin, using thin-layer chromatogram (TLC) and high-performance liquid chromatography (HPLC).
  • Determination of heavy metals (arsenic, mercury, lead, cadmium) and pesticide residues (e.g., DDT, BHC).

• Sampling and Test Methods:

  • Defined procedures for how to collect representative samples from different batch sizes.
  • Verification by both macroscopic and microscopic examination methods.
  • Detailed instructions for laboratory methods, including sample preparation and appropriate analytical procedures.

• Packaging, Storage, and Labelling:

  • Requirements to prevent contamination, exposure to moisture, and preserve product quality during storage and transport.
  • Clear and accurate labelling in compliance with ISO 21371, detailing quality parameters, origin, production and expiry dates, and storage instructions.

Applications

ISO 21316:2026 is highly relevant for stakeholders in the supply chain of traditional Chinese medicine, including:

• Manufacturers and Traders:
  Ensures compliance with recognized international quality standards, reducing the risk of rejection in domestic or export markets.

• Pharmacists and Healthcare Providers:
  Facilitates the sourcing of high-quality, standardized Banlangen root for use in clinical preparations and prescriptions.

• Regulatory Authorities:
  Provides a harmonized benchmark for the inspection, quality assessment, and approval of Isatis indigotica products in markets worldwide.

• Testing Laboratories:
  Offers standardized protocols for quality assessment, supporting consistent and reliable results across regions.

By implementing ISO 21316:2026, entities help reduce risks of adulteration, support patient safety, and foster the global credibility of TCM herbal products.

Related Standards

• ISO 18664: Determination of heavy metals in herbal medicines used in Traditional Chinese Medicine.
• ISO/TS 21310: Microscopic examination of medicinal herbs.
• ISO 21371: Labelling requirements for products intended for oral or topical use.
• ISO 22217: Storage requirements for raw materials and decoction pieces.
• ISO 22258: Determination of pesticide residues in natural products by gas chromatography.
• ISO 23723:2021: General requirements for herbal raw material and materia medica.

Together, these standards form a comprehensive framework for ensuring the quality, safety, and traceability of herbal medicine materials, supporting both regulatory compliance and international trade of Isatis indigotica root.

Keywords:
Isatis indigotica root, Banlangen, traditional Chinese medicine standard, ISO 21316, herbal medicine quality requirements, TCM test methods, Isatis indigotica safety, decoction pieces, marker compound (R,S)-goitrin, herbal product labelling, heavy metal testing, pesticide residue limits.

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
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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
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
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
...