PHYTOTHERAPY RESEARCH Phytother. Res. 17, 000 – 000 (2003) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ptr.1108 Copyright © 2003 John Wiley & Sons, Ltd. Received 1 October 2001 Revised 15 November 2001 Accepted 22 January 2002 UNCORRECTED PROOF 5 10 15 20 25 30 35 40 45 50 55 60 65 70 John Wiley & Sons, Ltd. In Vitro Susceptibility of Helicobacter pylori to Isoquinoline Alkaloids from Sanguinaria canadensis and Hydrastis canadensis In vitroSusceptibility of Helicobacter Pylori Gail B. Mahady, 1,2 Susan L. Pendland, 2 Adenia Stoia 1 and Lucas R. Chadwick 1 1 Program for Collaborative Research in the Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois 2 Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois Methanol extracts of the rhizomes of Sanguinaria canadensis, and the roots and rhizomes of Hydrastis canadensis, two plants used traditionally for the treatment of gastrointestinal ailments, were screened for in vitro antibacterial activity against 15 strains of Helicobacter pylori. The rhizome extracts, as well as a methanol extract of S. canadensis suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC 50 range of 12.5–50.0 μg/ml. Three isoquinoline alkaloids were identified in the active fraction. Sanguinarine and chelerythrine, two benzophenanthridine alkaloids, inhibited the growth of the bacterium, with an MIC 50 of 50.0 and 100.0 μg/ml, respectively. Protopine, a protopine alkaloid, also inhibited the growth of the bacterium, with a MIC 50 of 100 μg/ml. The crude methanol extract of H. canadensis rhizomes was very active, with an MIC 50 of 12.5 μg/ml. Two isoquinoline alkaloids, berberine and β β -hydrastine, were identified as the active constituents, and having an MIC 50 of 12.5 and 100.0 μg/ml, respectively. Copyright © 2003 John Wiley & Sons, Ltd. Keywords: Helicobacter pylori; Sanguinaria canadensis; Hydrastis canadensis; berberine; sanguinarine. INTRODUCTION The discovery of the bacterium Helicobacter pylori (HP) as the main etiologic organism of chronic gastritis, peptic ulcer disease, and gastric cancer was the most significant discovery in the field of gastroenterology of the twentieth century (Graham, 1989, 1994). Helicobacter pylori-induced gastritis is now associated with duodenal ulcer disease, peptic ulcer disease, gastric carcinoma, primary gastric B-cell lymphoma, ischemic heart disease and hyperemesis gravidarum (Goodwin, 1997; Kuipers and Appelmelk, 1997; Frigo et al., 1998; Markus and Mandal, 1998). Statistics from 1997 indicate that as much as one-half of the world’s population is infected with the bacterium (Breuer et al., 1997). Treatment of HP infections often consists of triple drug therapy, including a proton pump inhibitor or bismuth salts in combination with two antibiotics for 7–14 days (Sung et al., 1996; Salcedo and Al Kawas, 1998). While, triple and quadruple drug therapy is usually effective, anti- biotic resistant strains of H. pylori have emerged, and are becoming problematic throughout the world (Graham et al. , 1996; Fedorak et al. , 1997; Dore et al. , 1999). In view of the development of antibiotic resistance, HP is now viewed as a significant human pathogen in need of new chemotherapeutic agents for treatment and pre- vention (Doig and Trust, 1997). The discovery and development of botanical extracts for the treatment of HP infections is one such strategy. Plant-based medicines have been used throughout history, in traditional systems of medicine, to treat a variety of gastrointestinal ailments, including stomachache, gastritis, diarrhea, and peptic ulcers. Two such plants, Sanguinaria canadensis L. (bloodroot, Papaveraceae) and Hydrastis canadensis L. (goldenseal, Ranunculaceae), are herbaceous perennials native to eastern Canada and the United States (Der Marderosian, 1977; Mahady, 1993). Traditionally, the Native American Indians used hot water extracts of both plants for the treatment of a variety of ailments including dyspepsia, gastritis and indigestion (Anderson, 1885; Veninga and Zaricor, 1976; Mahady et al., 1993). The rhizomes of S. canadensis contain an acrid orange-red juice from which numerous isoquinoline alkaloids, including chelerythrine, protopine and sanguinarine (Fig. 1) have been isolated (Mahady et al., 1993). Experimental evidence has shown that aqueous and alcohol extracts of the rhizomes inhibit the growth of Staphylococcus aureus and Mycobacterium tubercu- losis in vitro, and the constituents responsible for this activity were two of the benzophenanthridine alka- loids, sanguinarine and chelerythrine (D’Amico, 1950; Gottshall et al., 1949). Similarly, the roots and rhizomes of H. canadensis produce a yellow-orange juice con- taining isoquinoline alkaloids, including berberine and β-hydrastine (Fig. 1) (Der Marderosian, 1977) Crude extracts of the rhizome, as well as berberine have been shown to inhibit the growth of Staphylococcus aureus and E. coli in vitro (D’Amico, 1950; Hocking, 1977). * Correspondence to: Dr G. B. Mahady, PCRPS, Room 310, College of Pharmacy, University of Illinois, 833 S. Wood St., MC 877, Chicago, Il 60612, USA. Tel: 312 996-1669. Fax: 312 413-5894. E-mail: mahady@uic.edu Contract/grant sponsor: National Center for Complementary and Altern- ative Medicine; Contract/grant number: At00413. Contract/grant sponsor: NIH. Contract/grant sponsor: Hans Valhteich Scholarship award. 1