Biomarker-Based Determination of Equiseti herba Contamination by Equisetum palustre Using HPLC-MS/MS

Abstract

Equiseti herba has been traditionally indicated in bacterial diseases of the efferent urinary tract or bad healing wounds in many regions worldwide. Most of the plant material used for medical purposes comes from collections of wild growing plants. The European Pharmacopoeia requires that Equiseti herba should consist of a minimum of 95% Equisetum arvense and a maximum of 5% foreign ingredients. This includes Equisetum palustre, which is known for its potentially toxic alkaloid palustrine. However, both Equisetum species are quite common, look morphologically very similar, and share similar habitats, hence, are therefore often confused. Recently, several structurally related Equisetum alkaloids have been identified in E. palustre but not in E. arvense. We have established a hydrophilic interaction liquid chromatography HPLC-ESI-MS/MS method for the detection of these E. palustre-specific Equisetum alkaloids in order to quantify the contamination of Equiseti herba (E. arvense) by E. palustre plant material. In a second, independent approach, the results of the HPLC-MS/MS analysis were confirmed by scanning electron microscopy, looking for the species-specific characteristics of the stoma apparatus of E. palustre. Thirty-four Equiseti herba products obtained from different pharmacies, drug stores, supermarkets, and web stores were analyzed. The majority of the products (26 out of 34) were Equisetum alkaloid positive, with contents ranging from 0.29 – 21.7 mg of Equisetum alkaloids/kg (d. w.). In addition, the transfer of Equisetum alkaloids into tea infusions was investigated, demonstrating a 42 to 60% transfer rate for cold and hot water extraction of Equisetum alkaloid-contaminated Equiseti herba, respectively.

Key words

Equisetaceae - Equisetum alkaloids - Equisetum arvense - Equisetum palustre - food supplements - HPLC-ESI-MS/MS - herbal tea

Publication History

Received: 02 November 2020

Accepted after revision: 31 May 2021

Article published online:
22 July 2021

• References

• 1 Steward WN, Rothwell GW. Paleobotany and the Evolution of Plants. Cambridge: Cambridge University Press; 1993
• 2 Taylor TN, Taylor EL, Krings M. Paleobotany: The Biology and Evolution of Fossil Plants. Burlington, MA (USA): Elsevier; 2009
• 3 Knowlton A. Quick guide Equisetum . Curr Bio 2012; 10: R388-R390
• 4 Saslis-Lagoudakis CH, Bruun-Lund S, Iwanycki NE, Seberg O, Petersen G, Jäger AK, Rønsted N. Identification of common horsetail (Equisetum arvense L.; Equisetaceae) using Thin Layer Chromatography versus DNA barcoding. Sci Rep 2015; 5: 11942
• 5 Christenhusz MJM, Bangiolo L, Chase MW, Fay MF, Husby C, Witkus M, Viruel J. Phylogenetics, classification and typification of extant horsetails (Equisetum, Equisetaceae). Bot J Linn Soc 2019; 189: 311-352
• 6 Hauke RL. A taxonomic monograph of the genus Equisetum subgenus Hippochaete. Beih. Nova Hedwigia 1963; 8: 1-123
• 7 Hauke RL. The natural history of Equisetum in Costa Rica. Rev Biol Trop 1969; 15: 269-281
• 8 Husby CE. Ecophysiology and biomechanics of Equisetum giganteum in South America [Dissertation]. Miami: Florida International University; 2009
• 9 Houghton PJ, Manby J. Medicinal plants of the Mapuche. J Ethnopharmacol 1985; 13: 89-103
• 10 Lemus I, Garcia R, Erazo S, Peña R, Parada M, Fuenzalida M. Diuretic activity of an Equisetum bogotense tea (Platero herb): evaluation in healthy volunteers. J Ethnopharmacol 1996; 54: 55-58
• 11 Andrade-Cetto A, Heinrich M. Mexican plants with hypoglycemic effect used in the treatment of diabetes. J Ethnopharmacol 2005; 99: 325-348
• 12 Leal DP, Isla MI, Vattuone MA, Sampietro AR. A hysteretic invertase from Equisetum giganteum L. Phytochemistry 1999; 52: 1009-1016
• 13 Revilla MC, Andrade-Cetto A, Islas S, Wiedenfeld H. Hypoglycemic effect of Equisetum myriochaetum aerial parts on type 2 diabetic patients. J Ethnopharmacol 2002; 81: 117-120
• 14 Kanchanapoom T, Otsuka H, Ruchirawat S. Megastigmane glucosides from Equisetum debile and E. diffusum . Chem Pharm Bull 2007; 55: 1277-1280
• 15 dos Santos Alves CF, Bonez PC, de Souza Ebling M, Casagrande C, Freitas L, Dolwitsch C, Pires F, Rorato MR, de Brum GF, de Campos MMA, Santos RCV. Antimicrobial, cyto and genotoxic activities of Equisetum hyemale . Pharmacogn J 2019; 11 (Suppl.) 1563-1571
• 16 Gürbüz I, Yesilada E. In vivo anti-ulcerogenic activity of Equisetum telmateia Ehrh. extracts used in Turkish folk medicine. Turk J Biol 2008; 32: 259-263
• 17 Yesilada E, Honda G, Sezik E, Tabata M, Fujita T, Tanaka T, Takeda Y, Takaishi Y. Traditional medicine in Turkey. V. Folk medicine in the inner Taurus Mountains. J Ethnopharmacol 1995; 46: 133-152
• 18 Yesilada E, Gürbüz I. Evaluation of the antiulcerogenic activity profile of a flavonol diglucoside from Equisetum palustre L. J Ethnopharmacol 2010; 131: 17-21
• 19 Pharmacopoea Europaea, German Edition, Vol. 9. Eschborn: Govi Verlag; 2017: 2266-2268
• 20 Wichtl M. Equiseti herba – Schachtelhalmkraut. In: Blaschek W. ed. Teedrogen und Phytopharmaka. Stuttgart: Wissenschaftliche Verlagsgesellschaft mbH; 2009: 244-248
• 21 Sandhu NS, Kaur S, Chopra D. Equietum arvense: pharmacology and phytochemistry – a review. Asian J Pharm Clin Res 2010; 3: 146-150
• 22 Asgarpanah J, Roohi E. Phytochemistry and pharmacological properties of Equisetum arvense L. J Med Plants Res 2012; 6: 3689-3693
• 23 Saleh NAM, Majak W, Towers GHN. Flavonoids of Equisetum species. Phytochemistry 1972; 11: 1095-1109
• 24 Veit M, Becker C, Höhn C, Bauer K, Geiger H. Interspecific and intraspecific variation of phenolics in the genus Equisetum subgenus Equisetum . Phytochemistry 1995; 38: 881-891
• 25 Tipke I, Bücker L, Middelstaedt J, Winterhalter P, Lubienski M, Beuerle T. HILIC HPLC-ESI-MS/MS identification and quantification of the alkaloids from the genus Equisetum . Phytochem Anal 2019; 30: 669-678
• 26 Cramer L, Ernst L, Lubienski M, Papke U, Schiebel HM, Jerz G, Beuerle T. Structural and quantitative analysis of Equisetum alkaloids. Phytochemistry 2015; 116: 269-282
• 27 Karrer P, Eugster CH. Über ein Alkaloid aus Equisetum palustre . Helv Chim Acta 1948; 31: 1062-1066
• 28 European Medicines Agency. HMPC/278089/2015, 2016, Committee on Herbal Medicinal Products (HMPC), Assessment report on Equisetum arvense L., herba. Accessed March 18, 2021 at: https://www.ema.europa.eu/documents/herbal-report/final-assessment-report-equisetum-arvense-l-herba_en.pdf
• 29 Lubienski M, Dörken VM. Morphological studies on Equisetum × rothmaleri (E. arvense × E. palustre, Equisetaceae, Equisetopsida) in Finland. Fern Gaz 2013; 19: 117-134