ISO 5228:2023

INTERNATIONAL ISO
STANDARD 5228
First edition
2023-07
Traditional Chinese medicine —
Rheum palmatum, Rheum tanguticum
and Rheum officinale root and rhizome
Reference number
© ISO 2023
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
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Description . .2
5 Requirements . 4
5.1 General characteristics . 4
5.2 Morphological features . 4
5.3 Identification . 4
5.3.1 Microscopic identification . . 4
5.3.2 Thin-layer chromatography (TLC) identification . 5
5.4 Rhaponticin . 5
5.5 Moisture . 5
5.6 Total ash . 5
5.7 Acid-insoluble ash . 6
5.8 Extractives . 6
5.9 Heavy metals . 6
5.10 Pesticide residues . 6
5.11 Marker compounds . 6
6 Sampling . 6
7 Test methods . 6
7.1 Macroscopic identification . 6
7.2 Thin-layer chromatogram (TLC) identification . 6
7.3 Rhaponticin identification . 6
7.4 Determination of moisture . 6
7.5 Determination of total ash . 6
7.6 Determination of acid-insoluble ash . 6
7.7 Determination of extractives . 7
7.8 Determination of heavy metals . 7
7.9 Determination of pesticide residues . 7
7.10 Determination of marker compounds . 7
8 Test report . 7
9 Packaging, storage and transportation . 7
10 Marking and labelling . 7
Annex A (informative) Thin-layer chromatography (TLC) identification .9
Annex B (informative) Determination of marker compounds by HPLC-UV .10
Annex C (informative) National and regional requirements for Rheum root and rhizome .17
Annex D (informative) Differentiation of the three species .19
Bibliography .21
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 ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 249, Traditional Chinese medicine.
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
Rheum root and rhizome is the dry root and rhizome of Rheum palmatum Linne., Rheum tanguticum
Maxim. ex Balf. and Rheum officinale Baill. As one of the four traditional Chinese medicines in China,
Rheum root and rhizome is documented in Shennong materia medica. Rheum root and rhizome has
a wide range of clinical applications, high frequency of use and a long history of medicinal use. It is
recorded in traditional Chinese medicine books such as Yao pin hua yi, Yi xue zhong zhong can xi lu and
Su Wen.
Rheum root and rhizome has a complex chemical composition, including various compounds such as
anthraquinone, anthrone, tannin and polysaccharide. Modern pharmacological studies have shown that
sennoside and anthraquinone glucosides are the main components of Rheum root and rhizome that can
induce diarrhoea; free anthraquinones are antibacterial and antitumour active ingredients of Rheum
root and rhizome; n-butyrophenones have good anti-inflammatory and analgesic effects; gallic acid
glucosides and galloyl proanthocyanidins in the tannins have hypolipidemic effects; and d-catechin
and gallic acid have haemostatic effects. Moreover, Rheum root and rhizome also has the functions
of relieving phlegm, protecting the liver and gallbladder, and protecting against cardiovascular and
cerebrovascular diseases.
In global trade, taking Chinese customs data as an example, Rheum root and rhizome in China is mainly
exported to Japan, the Republic of Korea, the United States, Indonesia, Germany, Italy, Singapore,
France, Thailand, Vietnam and Malaysia. From 2012 to 2016, the average annual export trade volume
of Rheum root and rhizome in China was 7 128 400 US dollars, making it one of the main Chinese herbal
medicines exported by China.
There are 152 Chinese patent medicines containing Rheum root and rhizome in the Chinese
Pharmacopoeia (2015 Edition) and two preparations in Japanese Pharmacopoeia (17th Edition).
Rheum root and rhizome and its products have applications in a variety of medical fields, also involving
detoxification and beauty, lipid-lowering, weight-loss health products and food additives. Many
users believe that Chinese medicine is non-toxic and fail to take it strictly according to their doctor's
instructions, which can lead to excessive and chronic irregular use of Rheum root and rhizome and liver
and kidney damage.
As a globally used drug, Rheum root and rhizome is included in the pharmacopoeia of many countries
and regions, such as China, Japan, the Republic of Korea and Europe. At present, the quality control
of Rheum root and rhizome and its preparations is mostly based on the content of anthraquinones.
However, the medicinal ingredients of Rheum root and rhizome are not just anthraquinones. The
diversity of ingredients in traditional Chinese medicine determines that quality control should adopt a
multi-index quality evaluation model.
Furthermore, Rheum root and rhizome is ranked tenth in the priority list of single herbal medicines for
developing standards in ISO/TR 23975, which indicates its high priority. Therefore, it is necessary to
establish an International Standard of Rheum root and rhizome which unifies the quality and safety of
Rheum root and rhizome, ensures the safety and effectiveness of the medication and regulates trade in
the international market. The establishment of an International Standard for Rheum root and rhizome
is necessary to guarantee the clinical effectiveness, safety and controllability of this valuable medicine
in global commerce and trade.
As national implementation can differ, national standards bodies are invited to modify the values given
in 5.5, 5.6, 5.7 and 5.8 in their national standards. Examples of national and regional values are given in
Annex C.
v
INTERNATIONAL STANDARD ISO 5228:2023(E)
Traditional Chinese medicine — Rheum palmatum, Rheum
tanguticum and Rheum officinale root and rhizome
1 Scope
This document specifies the quality and safety requirements of Rheum root and rhizome (the dried root
and rhizome of Rheum palmatum Linne., Rheum tanguticum Maxim. ex Balf. and Rheum officinale Baill.).
This document applies to Rheum root and rhizome that is sold and used as natural medicines in
international trade, including Chinese materia medica (whole medicinal materials) and decoction
pieces derived from these plants.
This document does not apply to the processing methods and processed products of Rheum root and
rhizome.
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 21371, Traditional Chinese medicine — Labelling requirements of products intended for oral or topical
use
ISO 22217:2020, Traditional Chinese medicine —Storage requirements for raw materials and decoction
pieces
ISO 22258, Traditional Chinese medicine — Determination of pesticide residues in natural products by gas
chromatography
ISO 23723:2021, Traditional Chinese medicine — General requirements for herbal raw material and
materia medica
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
Rheum root and rhizome
dried root and rhizome of Rheum palmatum Linne., Rheum tanguticum Maxim. ex Balf. and Rheum
officinale Baill
3.2
batch
samples collected from the same place at the same time, of no more than 5 000 kg
[SOURCE: ISO 22988:2020, 3.8]
4 Description
Rheum root and rhizome is the dried root and rhizome of Rheum palmatum Linne. (Figure 1 a), Rheum
tanguticum Maxim. ex Balf. (Figure 1 b) and Rheum officinale Baill. (Figure 1 c). The crude drug is
collected in late autumn when stem and leaves have withered or in spring just before budding. The
crude drug is removed from rootlet and the outer bark, cut into segments or sections and either hung in
line for drying or dried directly.
a) Rheum palmatum Linne.
b) Rheum tanguticum Maxim. ex Balf.
c) Rheum officinale Baill.
Key
1 inflorescence 5 leaf
2 flower 6 xylem, cambium and phloem
3 stem 7 pith
4 root and rhizome 8 abnormal vascular bundles
Figure 1 — Structure of Rheum root and rhizome
5 Requirements
5.1 General characteristics
The following requirements shall be met before sampling:
a) Rheum root and rhizome shall be clean and free from leaf and foreign matter.
b) The presence of living insects, mouldy fruit and external contaminants which are visible to the
naked eye shall not be permitted.
5.2 Morphological features
The medicinal materials of rheum root and rhizome are subcylindrical, conical, ovoid or irregular pieces,
3 cm to 17 cm long and 3 cm to 10 cm in diameter. Externally, they are yellowish-brown to reddish-
brown when peeled, sometimes with whitish reticulations and visible scattered star spots (abnormal
vascular bundles), occasionally with brownish-black patches of cork, mainly with a hole through which
the string is passed and coarse wrinkles. The texture of the medicinal parts is firm, sometimes loose
and soft in the centre, the facture pale reddish-brown or yellowish-brown and granular. The pith of the
rhizome is broad, with star spots arranged in a ring or irregularly scattered. The wood of the root is
well developed, lined radially, the cambium ring distinct and without star spots. The odour is delicately
aromatic, the taste bitter and slightly astringent. It is sticky and gritty to chew.
NOTE The hole and the string are for hanging Rheum root and rhizome when dry.
5.3 Identification
5.3.1 Microscopic identification
Transverse section of Rheum palmatum Linne. (Figure 2 a), Rheum tanguticum Maxim. ex Balf. (Figure 2 b)
and Rheum officinale Baill. (Figure 2 c): the cork and phelloderm of root are mostly removed. In phloem,
the sieve tube groups are distinct and the parenchyma is well developed. The cambium forms a ring.
Xylem rays are relatively dense, two to four rows of cells wide, containing brown masses. The vessels
are non-lignified, usually single or several grouped together and sparsely arranged. Parenchymatous
cells contain clusters of calcium oxalate and abundant starch granules.
The rhizome pith is broad, usually showing mucilage cavities and containing reddish-brown masses,
scattered with abnormal vascular bundles. The cambium forms a ring. Xylem is on the inside of the
cambium and phloem on the outside. Rays are stellate.
The powder is yellowish-brown. Clusters of calcium oxalate are 20 μm to 160 μm in diameter, sometimes
up to 190 μm in diameter. Bordered pitted vessels, reticulated vessels, spiral vessels and annular
vessels are non-lignified. Starch granules are abundant, single granules are spheroid or polygonal, 3 μm
to 45 μm in diameter, and hilum is stellate. The compound granules consist of two to eight components.
a) Rheum palmatum Linne. b) Rheum tanguticum Maxim. ex c) Rheum officinale Baill.
Balf.
Key
1 cork
2 cortex
3 phloem
4 cambium
5 xylem
6 pith
7 abnormal vascular bundles
a
Clusters of calcium oxalate.
b
Mucilage cavities.
Figure 2 — Transverse section of Rheum root and rhizome
5.3.2 Thin-layer chromatography (TLC) identification
Spots in the chromatogram obtained with the test solution should correspond in position and colour to
the spots in the chromatogram obtained from the reference drug solution or reference solution.
5.4 Rhaponticin
a) The bright-blue fluorescence spot in the chromatogram obtained with the test solution shall not
correspond in position and colour to the spot in the chromatogram obtained with the reference
solution TLC chromatogram.
b) When high-performance liquid chromatography (HPLC) is performed, the chromatographic peak of
the test solution shall not correspond at the retention time to the rhaponticin (C H O ) chemical
21 24 9
reference standard (CRS) of the HPLC chromatogram.
5.5 Moisture
The content of water should be a mass fraction of 15,0 %.
5.6 Total ash
The content of total ash should be a mass fraction of ≤ 13,0 %.
...