Herbal Medicine quality and safety issues – a primer for health professionals

Dr Hans Wohlmuth PhD BSc

Southern Cross University Lismore NSW

EFFECTIVE

QUALITY

SAFE

Expectations of all medicines

Medicine

Plant Species

Chemotype

Plant part

Age

Environment Stability

Post-harvest

Harvest

Extraction

Formulation

After Booker A et al, J Ethnopharmacology 2012;140:624-33

The industry chain

Grower / Collector

Primary processor / Regional middlemen / Cooperative

Middlemen

Exporter

Consumer country importer / Secondary processor

Retailer / Practitioner

Patient / Consumer

Secondary processor / National retailer

Consumer / Patient

The challenge of herbal quality control

Chemical complexity Natural variability

CONSISTENT MEDICINE

vs

Analytical Chemistry 101 Advanced Analytical Chemistry

Aspects of quality of medicines

• Authenticity

– they are what they purport to be

• Consistency

– they have a consistent composition

• Purity

– they contain ONLY what they’re supposed to contain

Authenticity

Herbal authentication

Authentication

Taxonomy

Chemistry

Macroscopic morphology

Microscopic morphology

DNA analysis

TLC HPLC LC-MS GC-MS Reaction tests

Thyme from Morocco

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DAD1 A, Sig=210,8 Ref=off (040112X\CP030929.D)

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Comparative chemistry

Fluid extract

Authentic reference

HPTLC HPLC

There is something about Marigold…

Authentic reference

Extract

Calendula officinalis

Tagetes erecta

Don’t rely on common names!

Skullcap (Scutellaria lateriflora)

• Native to N America

– cultivated US, Chile, Mexico, Costa Rica, Australia

• Leaf rich in flavonoid glycosides

– baicalin (~5%), dihydrobaicalin, lateriflorin

• King’s Dispensatory 1898:

– ‘larger part of the drug sold… is derived from two other species…’

• AHP Monograph 2009:

– substituted with S. galericulata, S. alpina, S. incana, S. baicalensis, Teucrium spp.

HPTLC on silica gel 60 F254 plates Mobile phase: tetrahydrofuran:toluene: formic acid:water (16:8:2:1 v/v) Visualisation: Natural Products Reagent followed by polyethylene glycol 4000 Photographed under UV 366 nm

S. lateriflora (6 samples) S. lateriflora (left) Scutellaria sp. (4 samples)

Left to right: Scutellaria sp. S. baicalensis root S. galericulata Scutellaria ‘Bluebird’ S. baicalensis aerial

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iflora S2

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sima S3

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Scutellarin Baicalin Baicalein Chrysin

Looking for Teucrium spp.

• No Teucrium found in Scutellaria samples

• T. chamaedrys contained teucrioside – no verbascoside

– no flavonoids typical of Scutellaria

Minutes

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S. lateriflora T. chamaedrys

Saffron – the world’s most precious botanical commodity

• Styles and stigmas from Crocus sativus

• Retails for $10-30 per gram

• 100-150 flowers needed for 1 g

• Spice

• Anti-cancer, anti-depressant activity

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R1OOR2

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70% EtOH extracts from (l-r): Iran, Tasmania, Kashmir

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CHO

Safranal

Crocetin HOOC

COOH

Fake saffron

Authentic saffron

Variability

Natural variability

Sirvent et al. Economic Botany 2002

8 wild SJW population in Montana and N California

Passiflora incarnata

• Some material grown in Australia have atypical C-glycosyl flavone profiles

Six Australian samples (1-6) and two typical samples. (C=chlorogenic acid, H=hyperoside, R=rutin.) Wohlmuth et al. Biol Pharm Bull 2010

Passiflora incarnata chemotypes

• Much (but not all) material grown in Australia is of swertisin chemotype

• Typical material is of shaftoside/isovitexin chemotype

HPLC trace of four samples with the typical flavonoid profile.

Isovitexin

Vitexin

Schaftoside/isoschaftoside Isovitexin-2-O- β-glucopyranose

Wohlmuth et al. Biol Pharm Bull 2010

Vitexin

Isovitexin Swertisin

Isovitexin-2-O- β-glucopyranose

HPLC trace of six samples of swertisin chemotype

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Percentage ethanol

Rosmarinic acid from Melissa - extraction efficiency of different solvents

Extraction solvent matters!

Non-alcoholic liquid extract

60% EtOH

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Sorbate: E200 Sorbic acid E201 Sodium sorbate E202 Potassium sorbate

Alkylamides in Echinacea preparations

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Purity

Assay aglycones before and after hydrolysis:

A(glycosides) = A(post) — A(pre)

Ginkgo biloba adulteration

• USP, EP/BP – 22-27% flavonoids, expressed as flavonol glycosides, but

quantified after hydrolysis

– specified aglycone ratios:

• kaempferol : quercetin 0.8-1.2

• isorhamnetin : quercetin ≥0.1

• Does not allow for detection of adulteration with aglycones!

• Ginkgo leaf (5) contained no free aglycones

• 8 ginkgo products tested

Ginkgo biloba adulteration

Ginkgo biloba adulteration

• Current USP method overestimated flavonoid glycoside content by 29-41%.

Genistein

Ginkgo biloba adulterant?

• Styphnolobium japonicum

– genistein

– quercetin and kaempferol glycosides

– previously reported as a suspected adulterant of ginkgo extracts

He K, Roller M (2011) In Formulating, Packaging and Marketing of Natural Cosmetic Products, ed. N Dayan & L Kromidas, Wiley, pp. 361-85. Qi Y et al. (2007) J Chromatogr A 1140:219-24.

Heavy metal contamination

• Heavy metals may be intentionally added to Indian and Chinese remedies

• Some plants accumulate heavy metals from the soil (e.g. Hypericum, Salix – cadmium)

(Wenzig & Bauer, in Houghton & Mukherjee, Evaluation of Herbal Medicinal Products 2009)

• 3.5% of 317 batches of dried herbs delivered to German TCM hospital had heavy metal content exceeding legal limits

(Melchart, Alt Ther Health Med 2001)

Pharmaceuticals in traditional Chinese medicines

In Taiwan, 24% of 2600 TCM preparations contained at least one drug compound

(Huang, J Clin Pharmacol 1997)

In the US, 10% of 500+ Chinese patent

medicines contained undeclared drugs and/or toxic levels of heavy metals

(Au, Bull Env Contam Toxicol 2000)

Herbal Viagra products…

Herbal Viagra – indeed!

Tea tree oil Oil of Melaleuca, terpinen-4-ol type

ISO 4730 , Australian Standard 2782: α-pinene 1-6%

sabinene tr-3.5% α-terpinene 5-13% limonene 0.5-1.5% p-cymene 0.5-8% 1,8-cineole tr-15% γ-terpinene 10-28% terpinolene 1.5-5% terpinen-4-ol 30-48% α-terpineol 1.5-8% + 4 others

Tea tree oil – adulteration issues

• Terpinen-4-ol content >40% attracts premium

• Adulteration with t-4-ol from other sources: – pine bark – marjoram – synthetic

• T-4-ol chiral ratio (+/-) should be ~2.1 • Synthetic oil

– lacks sesquiterpenes – short-chain hydrocarbons

Tea tree oil – safety concerns

• Methyl eugenol – <0.01-0.06% (mean 0.02%)

– 106 times lower than carcinogenic dose in rats

• Contact allergy

• Sensitising potential linked to oxidation products – increased p-cymene – peroxides, endoperoxides

and epoxides – protect from oxygen,

light, heat

Southwell et al. Flavour & Fragrance 2011

Conclusions

• Quality assurance of natural products presents unique challenges

• Rigorous quality assurance must be maintained to ensure the quality, safety and effectiveness of herbal medicines

Acknowledgments

Ashley Dowell, SCU

Peter Mouatt, SCU

Roy Upton, American Herbal Pharmacopoeia

Dr Reg Lehmann, Integria Healthcare

Rose Cornelissen, Integria Healthcare