Identification of herbal materials and extracts

Questions & answers

25 May 2004

The overarching principle for the identification of herbal starting materials is traceability to a primary source or certified herb.

Identification testing must discriminate between related species and/or potential adulterants/substitutes that are likely to be present.

The manufacturers specifications for identity testing using chromatographic methods should be consistent with the principles described in Australian Regulatory Guidelines for Complementary Medicines (ARGCM) Part III - Section 4.7.3 - Profile Chromatogram Interpretation.

A. Herbal materials 1 (excluding extracts)

1 Whole, fragmented or cut (including chopped), plants, parts of plants (including leaves, roots, flowers, seeds, bark etc), in an unprocessed state, usually in dried form. For the purposes of this guidance document, herbal powders (herbal materials that are dried and ground to powders) are also included in this definition.

1. What testing is required to identify these materials?

Identification tests should be specific for the herbal material and are usually a combination of three or more of the following:

  • macroscopic characters
  • microscopic characters
  • chromatographic procedures
  • chemical reactions.

Manufacturers should refer to the specific herbal material monographs in the current British Pharmacopoeia (BP) for the range of tests usually employed. More information on the range of tests required is also outlined in the ARGCM Appendix - Herbal Ingredients - Quality.

2. What do I compare my consignment of herbal material with?

Comparison must be made against:

  • the current scientific literature (see Questions 3 and 4); and/or
  • an authenticated reference specimen (see Questions 5 and 6).

3. What literature must I comply with?

Where there is a BP monograph, this must be followed. All identification tests in the monograph must be complied with. In this case an authenticated voucher specimen is not essential.

4. What if there is no BP monograph?

If there is no BP monograph, manufacturers should use the scientific literature (including current editions of other National Pharmacopoeias2) to choose an authoritative source3.

Having decided on an authoritative literature source3, it is then necessary to perform a comparative analysis between the consignment and the literature reference. All morphological testing must be done by a person suitably qualified in the field of botanical examination (who may or may not be independent of the manufacturer of the extract).

2 National Pharmacopoeias such as the European, United States (of America), Chinese, German, Indian and Japanese etc. The pharmacopoeias must be issued by or endorsed by the relevant government authority. (Note that the word 'pharmacopoeia' in the title of a text does not mean it is a government-endorsed text). Sponsors should contact the Office of Complementary Medicines (OCM) if they are unsure as to the suitability of a pharmacopoeia.

3 To be considered suitable as an authoritative literature source, the content must reflect the types and ranges of tests found in the current BP (including botanical examination and chromatographic profile). Such sources must clearly state that the identification tests were performed on an authenticated reference specimen. Any chemical identity testing not performed using BP / National Pharmacopoeia must be validated for specificity (see the Identification subsection for Herbal Materials in the ARGCM Appendix - Herbal Ingredients - Quality. Further information on the types of tests required is also contained in the EMEA guideline - Note for Guidance on Specifications: Test Procedures and Acceptance Criteria for Herbal Drugs, Herbal Drug Preparations and Herbal Medicinal Products (CPMP/QWP/2820/00).

5. What is an authenticated reference specimen?

This is a specimen that has been certified by a person suitably qualified in the field of botanical authentication. If the reference specimen is not the whole plant, it must contain the same part of the plant as that requiring identification, (eg. root compared to root and leaf compared to leaf).

6. Is a comparative botanical examination of my consignment versus the authenticated reference specimen sufficient for identification purposes?

No. The range of tests that are typically included in the monograph of the current BP for the herbal material, should be performed (eg. organoleptic, physical and chemical as well as morphological tests are usually required). See Question 1.

7. Do all consignments of herbal material require full testing?

Each consignment is required to be identified and the identity test(s) must be unambiguous. See Question 1. The usual rules regarding reduced/rotational testing for other parameters apply.

Note: Unless the supplier has been validated, the Code of GMP requires every container to be sampled and tested for identity.

B. Herbal extracts

8. What identification testing is necessary for herbal extracts?

There are three options available:

  • comparison with descriptions in the current scientific literature (see Questions 9, 10 and 11); or
  • chromatographic comparison against an authenticated reference specimen (see Question 12); or
  • chromatographic comparison against a reference extract (see Question 13).

9. What do I use as the reference for comparison?

Where there is a BP monograph, this must be followed. All identification tests in the monograph must be complied with.

10. What if there is no BP monograph?

Other National Pharmacopoeias2 may be used.

2 National Pharmacopoeias such as the European, United States (of America), Chinese, German, Indian and Japanese etc. The pharmacopoeias must be issued by or endorsed by the relevant government authority. (Note that the word 'pharmacopoeia' in the title of a text does not mean it is a government-endorsed text). Sponsors should contact the Office of Complementary Medicines (OCM) if they are unsure as to the suitability of a pharmacopoeia.

11. Can I use other literature sources?

Generally no, because there is no assurance that the correct species of herb has been used. However, a literature source would be considered acceptable if:

  • it describes the authenticated specimen; and
  • it clearly states that the identification tests in the literature source were performed on an authenticated specimen; and
  • the extraction process used to obtain the extract from the authenticated herb in the literature source matches that used to obtain the consignment extract.

12. Is it valid to compare the chromatographic profile of an extract to that of an authenticated reference specimen?

A laboratory extract prepared from an authenticated reference specimen may be used for a chromatographic comparison if the results of the comparison indicate that the extraction process applied to the reference herb has reproduced the manufacturing process used for the herbal extract consignment. Otherwise the chromatographic comparison may not provide unambiguous identification of the consignment extract.

13. Can I use a reference extract solely to identify my consignment of extract?

Yes, as long as there is documentation available which traces the reference extract back to an authenticated reference specimen.

14. How do I know that the extract manufacturer used the correct herb to prepare the consignment extract?

The manufacturer of the extract must perform the identification of the herbal material, consistent with the criteria described in Question 1. It is necessary to hold the documentation (see the Complementary Medicines Australia Code of Practice for Ensuring Raw Material Quality & Safety for guidance on appropriate documentation) that supports the traceability of the consignment extract back to an authenticated herb.

15. Can I use chemical markers in the extract to confirm the identity of the herb that was used to prepare the extract?

Generally No. This is generally only a partial identification and is prone to giving misleading information unless the chemical markers are unique to the herbal species and plant part under investigation (eg. the ginkgolides and bilobalide present in Ginkgo biloba). Accordingly, the use of caffeine as a marker for Paullinia cupana is not, by itself, suitable to unambiguously identify this species.

16. Is it necessary to identify the herb used in an extract containing standardised quantities of a component(s)?

Yes. Quantifying the standardised ingredient by itself, is not sufficient.

17. Is it acceptable to compare a consignment of extract to a previous consignment of the extract?

No. All consignments must be identified in accordance with this guidance document. The potential for increasing variability as each extract is further distanced from the original comparator may lead to mis-identification.

Flow chart: Identification of Herbal Materials1 (excluding extracts)

(this does not replace the need to comply with relevant statutory requirements)

What identification testing is needed for herbal materials1 prior to use in production?
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Is there an applicable BP monograph?
YES
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NO
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Compliance with all identification tests in the relevant BP monograph (including, where relevant, organoleptic, chemical and morphological tests), is required. Options available
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Comparison against an authoritative literature source2 Comparison against an authenticated reference specimen3
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Use the scientific literature (including current editions of other National Pharmacopoeias5) to choose an authoritative literature source2.

The comparison must include three or more of the following:

  • macroscopical characters
  • microscopical characters
  • chromatographic procedures
  • chemical reactions.

A suitably qualified person4 must perform a comparative analysis between the consignment and the authenticated reference specimen.

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A suitably qualified person4 must perform a comparative analysis between the consignment and the literature reference.

1 Whole, fragmented or cut (including chopped), plants, parts of plants (including leaves, roots, flowers, seeds, bark etc), in an unprocessed state, usually in dried form. For the purposes of this flow chart, herbal powders (herbal material that is dried and ground to a powder) are also included in this definition.

2 To be considered suitable as an authoritative literature source, the content must reflect the types and ranges of tests found in the current BP (including botanical examination and chromatographic profile) and clearly state that the identification tests in the literature source were performed on an authenticated specimen. Any chemical identity testing not performed using BP / National Pharmacopoeia must be validated for specificity (see the Identification subsection for Herbal Materials in the ARGCM Appendix - Herbal Ingredients - Quality).

3 A herb evaluated and certified by a qualified person (see footnote 4).

4 A person suitably qualified in the field of botanical authentication is necessary for the morphological examination of samples. The qualified person may or may not be independent of the manufacturer.

5 National Pharmacopoeias include European, United States (of America), Chinese, German, Indian, Japanese etc. The pharmacopoeias must be issued by or endorsed by the relevant government authority. (Note that the word 'pharmacopoeia' in the title of a text does not mean it is a government-endorsed text). Sponsors should contact the Office of Complementary Medicines (OCM) if they are unsure as to the suitability of a pharmacopoeia.

Flow Chart: Identification of Herbal Extracts1

(this does not replace the need to comply with relevant statutory requirements)

What identification testing needs to be performed on a herbal extract1 prior to production?
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Is there an applicable BP monograph for the extract?
YES
arrow down
NO
arrow down
Compliance with all identification tests in the relevant BP monograph (including, where relevant, organoleptic, chemical and physical tests) is required. Options available
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Comparison against a non-BP literature source. Chromatographic comparison against an authenticated reference specimen3.   Chromatographic comparison against a reference extract.
  arrow down arrow down   arrow down
Options available

An authenticated herb may be used for a chromatographic comparison if the results of the comparison indicate that the extraction process applied to the reference herb has reproduced the manufacturing process used on the consignment of extract.

NB. An extract identified in this way can be designated as a in-house reference extract for identification purposes.

  There must be documentation tracing the reference extract back to an authenticated reference specimen3.
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Comparison against a (current edition of a) National Pharmacopoeia2 which contains a monograph for the extract.

The National Pharmacopoeia2 must also contain a monograph for the herbal raw material.

Compliance with all identification tests in the relevant monograph (including, where relevant, organoleptic, chemical and physical tests) is required.

 

Comparison against a another literature source would be acceptable if:

  • the source described the authenticated specimen; and
  • it clearly states that the identification tests in the literature source were performed on an authenticated specimen; and
  • the extraction process used to obtain the extract from the authenticated herb in the literature source matches that used to obtain the consignment extract.

1 For the purposes of this flow chart, tinctures, expressed juices and exudates are also included in this definition.

2 National Pharmacopoeias include the European, United States (of America), Chinese, German, Indian, Japanese etc. The pharmacopoeias must be issued by or endorsed by the relevant government authority. (Note that the word 'pharmacopoeia' in the title of a text does not mean it is a government-endorsed text). Sponsors should contact the Office of Complementary Medicines (OCM) if they are unsure as to the suitability of a pharmacopoeia.

3 A herb evaluated and certified by a suitably qualified person. NB. The morphological examination must be performed by a person qualified in the field of botanical authentication. Qualified persons may or may not be independent of the manufacturer.