Echinacea Supplement Testing — Echinacea purpurea, E. angustifolia
Echinacea Supplement Testing — Echinacea purpurea, E. angustifolia
Echinacea testing is critical to determining the quality, identity and potency of an echinacea material. NaturPro Scientific offers testing consulting for echinacea supplements.
Echinacea analysis and testing is based mainly on the WHO monograph on Echinacea that is excerpted in part below, and the USP monograph.
Herba Echinaceae Purpureae
Definition
Herba Echinaceae Purpureae consists of the fresh or dried aerial parts of Echinacea purpurea (L.) Moench harvested in full bloom (Asteraceae) (1).
Synonyms
Brauneria purpurea (L.) Britt., Echinacea intermedia Lindl., E. purpurea (L.) Moench f., E. purpurea (L.) Moench var. arkansana Steyerm., E. speciosa Paxt., Rudbeckia purpurea L., R. hispida Hoffm., R. serotina Sweet (2, 3).
Asteraceae are also known as Compositae.
Selected vernacular names
Coneflower, purple coneflower herb, purpurfarbener Igelkopf, purpurfarbene Kegelblume, purpurfarbener Sonnenhut, red sunflower, roter Sonnenhut (4–8).
Description
A hardy, herbaceous perennial. Stems erect, stout, branched, hirsute or glabrous, 60–180 cm high; basal leaves ovate to ovate-lanceolate, acute, coarsely or sharply serrate, petioles up to 25 cm long, blades to 20 cm long and 15cm wide, blade abruptly narrowing to base, often cordate, decurrent on petiole, 3–5 veined; cauline leaves petiolate below, sessile above, 7–20 cm long, 1.5–8cm broad, coarsely serrate to entire, rough to the touch on both surfaces; phyllaries linear-lanceolate, attenuate, entire, pubescent on outer surface, ciliate, passing into the chaff; heads 1.5–3cm long and 5–10mm broad, purplish; pales 9– 13mm long, awn half as long as body; disc corollas 4.5–5.5mm long, lobes 1mm long; achene 4–4.5 mm long, pappus a low crown of equal teeth; pollen grains yellow, 19–21µm in diameter; haploid chromosome number n = 11 (2).
Plant material of interest: fresh or dried aerial parts
General appearance
The macroscopic characteristics of Herba Echinaceae Purpureae are as described above under Description. An abbreviated description is currently unavailable.
Organoleptic properties
Mild, aromatic odour; initially sweet taste that quickly becomes bitter.
Microscopic characteristics
A description of the microscopic characteristics of a cross-section of the aerial parts of the plant is currently unavailable.
Powdered plant material
A description of the powdered plant material is currently unavailable.
Geographical distribution
Echinacea purpurea is native to the Atlantic drainage area of the United States of America and Canada, but not Mexico. Its distribution centres are in Arkansas, Kansas, Missouri, and Oklahoma in the United States of America (2). Echinacea purpurea has been introduced as a cultivated medicinal plant in parts of north and eastern Africa and in Europe (9).
General identity tests
Macroscopic examination (2) and thin-layer chromatography and highperformance liquid chromatography (4, 10–13) of the lipophilic constituents and chicoric acid in methanol extracts.
Purity tests
Microbiology
The test for Salmonella spp. in Herba Echinaceae Purpureae should be negative. The maximum acceptable limits of other microorganisms are as follows (14– 16). For preparation of decoction: aerobic bacteria-not more than 107/g; fungi-not more than 105/g; Escherichia coli-not more than 102/g. Preparations for internal use: aerobic bacteria-not more than 105/g or ml; fungi-not more than 104/g or ml; enterobacteria and certain Gram-negative bacteria-not more than 103/g or ml; Escherichia coli-0/g or ml. Preparations for external use: aerobic bacteria-not more than 102/g or ml; fungi-not more than 102/g or ml; enterobacteria and certain Gram-negative bacteria-not more than 101/g or ml.
Pesticide residues
To be established in accordance with national requirements. Normally, the maximum residue limit of aldrin and dieldrin in Herba Echinaceae Purpureae is not more than 0.05 mg/kg (16). For other pesticides, see WHO guidelines on quality control methods for medicinal plants (14) and guidelines for predicting dietary intake of pesticide residues (17).
Heavy metals
Recommended lead and cadmium levels are no more than 10 and 0.3mg/kg, respectively, in the final dosage form of the plant material (14).
Radioactive residues
For analysis of strontium-90, iodine-131, caesium-134, caesium-137, and plutonium-239, see WHO guidelines on quality control methods for medicinal plants (14).
Other purity tests
Chemical tests and tests for acid-insoluble ash, dilute ethanol-soluble extractive, foreign organic matter, moisture, total ash, and water-soluble extractive to be established in accordance with national requirements.
Chemical assays
For essential oil (0.08–0.32%); chicoric acid (1.2–3.1%) (4). Quantitative analysis of echinacoside, chicoric acid, isobutylamides, and other constituents by high-performance liquid chromatography (4). Quantitative analysis of alkamides and caffeic acid derivatives by thin-layer chromatography and highperformance liquid chromatography (4, 12).
Major chemical constituents
A number of chemical entities have been identified, including alkamides, polyalkenes, polyalkynes, caffeic acid derivatives, and polysaccharides (3, 5–9).
The volatile oil contains, among other compounds, borneol, bornyl acetate, pentadeca-8-(Z)-en-2-one, germacrene D, caryophyllene, and caryophyllene epoxide.
Isobutylamides of C11–C16 straight-chain fatty acids with olefinic or acetylenic bonds (or both) are found in the aerial parts of Herba Echinaceae Purpureae, with the isomeric dodeca-(2E,4E,8Z,10E/Z)-tetraenoic acid isobutylamides.
The caffeic acid ester derivative chicoric acid is the major active compound of this class found in the aerial parts of Echinacea purpurea, with a concentration range of 1.2–3.1%. Chicoric acid methyl ester and other derivatives are also present.
Polysaccharide constituents from Herba Echinaceae Purpureae are of two types: a heteroxylan of average relative molecular mass about 35 000 (e.g. PS-I), and an arabinorhamnogalactan of average relative molecular mass about 45000 (e.g. PS-II).
Other constituents include trace amounts of pyrrolizidine alkaloids (tussilagine (0.006%) and isotussilagine). At these concentrations, the alkaloids are considered to be non-toxic (8). Furthermore, because these alkaloids lack the 1,2-unsaturated necine ring of alkaloids such as senecionine (structure in box) from Senecio species, they are considered to be non-hepatotoxic (3).
Dosage forms
Powdered aerial part, pressed juice and galenic preparations thereof for internal and external use (1, 3).
Medicinal uses
Uses supported by clinical data
Herba Echinaceae Purpureae is administered orally in supportive therapy for colds and infections of the respiratory and urinary tract (1, 3, 5, 7, 8, 18). Beneficial effects in the treatment of these infections are generally thought to be brought about by stimulation of the immune response (3, 5, 7). External uses include promotion of wound healing and treatment of inflammatory skin conditions (1, 3, 5, 7, 8, 9, 19).
Uses described in pharmacopoeias and in traditional systems of medicine
None.
Uses described in folk medicine, not supported by experimental or clinical data
Other medical uses claimed for Herba Echinaceae Purpureae include treatment of yeast infections, side-effects of radiation therapy, rheumatoid arthritis, blood poisoning, and food poisoning (1, 5, 7, 9).
The following summarizes some current methods for identifying from a published review on echinacea:
“Alkamides, caffeic acid derivatives, and polysaccharides have been considered important constituents of the plant. A number of studies revealed that alkamides are involved in the immunomodulatory properties of Echinacea extracts in vitroand in vivo.[4,5] Additionally, caffeic acid is found in some species of Echinacea and could be applied toward authentication and quality control of the plant extracts. The polysaccharides play an important role in the anti-inflammatory effect of Echinacea preparations.[6] Taxonomic, chemical, pharmacological, and clinical characteristics of some species of the Echinacea genus including E. angustifolia, E. pallida, and E. purpurea were reviewed in previous papers.[1,7] Medicinal properties of the plant were also considered in a review paper, which suggested that more research is required for more definitive medicinal recommendations.[8] This paper is a review about E. purpurea: Its phytochemical contents and its pharmacological and biological activities, along with common methods of plant extract analysis. In addition, the psychoactive and mosquitocidal effects of the plant are mentioned in this paper….
Alkamides have been analyzed with reverse-phase HPLC coupled with different detectors including UV spectrophotometric, coulometric electrochemical, and electrospray ionization mass spectrometric.[83,84] Furthermore, caffeic acid derivatives have been determined using reverse-phase HPLC or capillary electrophoresis (CE) with photodiode array (FDA) UV spectrophotometric detection.[85,86,87] Phenolic acids were analyzed by micellar benzoic acid electrokinetic chromatography (MEKC), both charged and uncharged analytes, based on the use of sodium deoxycholate (SDC), a surfactant in borate buffer (pH 9.2), as well as in the E. purpurea extract.[88] However, determination methods for both caffeic acid derivatives and alkamides have been developed in single analysis. Although it is a difficult process to separate these diverse constituents in one analysis, methods for the concurrent determination of caffeic acid derivatives and alkamides have the advantages of reduced time and sample size needed for the analysis.[85] Gradient elution on reverse-phase HPLC has been employed for concurrent analysis of caffeic acid derivatives and alkamides from E. purpurea using various detectors such as FDA UV spectrophotometric and electrospray ionization mass spectrometry (EIMS).[79,85] Simultaneous analysis of both mentioned derivatives has also been performed by electrophoresis with FDA UV spectrophotometric detector, together with sodium dodecyl sulfate and hydroxypropyl-β-cyclodextrin in Britton Robinson buffer (10 mM, pH 8.0).[89]”
Source: Pharmacogn Rev. 2015 Jan-Jun; 9(17): 63–72 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4441164/)
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