Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Nov 6, 2015; 6(4): 223-237
Published online Nov 6, 2015. doi: 10.4292/wjgpt.v6.i4.223
Orally administered extract from Prunella vulgaris attenuates spontaneous colitis in mdr1a-/- mice
Kelley MK Haarberg, Meghan J Wymore Brand, Anne-Marie C Overstreet, Catherine C Hauck, Patricia A Murphy, Jesse M Hostetter, Amanda E Ramer-Tait, Michael J Wannemuehler
Kelley MK Haarberg, Meghan J Wymore Brand, Anne-Marie C Overstreet, Michael J Wannemuehler, Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
Catherine C Hauck, Patricia A Murphy, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, United States
Jesse M Hostetter, Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
Amanda E Ramer-Tait, Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68583, United States
Author contributions: Haarberg KMK, Wymore Brand MJ, Ramer-Tait AE, and Wannemuehler MJ designed the research; Haarberg KMK, Wymore Brand MJ, and Overstreet AMC performed the research; Hauck CC and Murphy PA prepared the extract; Hostetter JM provided histopathological analysis, Haarberg KMK and Wymore Brand MJ analyzed the data, Haarberg KMK, Wymore Brand MJ, Ramer-Tait AE, and Wannemuehler MJ prepared the manuscript, figures, and data analysis.
Supported by The award from NIH (9P50 AT004155-06).
Institutional review board statement: There were no human subjects involved in this work and, therefore, approval from the Iowa State University Institutional Review Board was not required.
Institutional animal care and use committee statement: All studies involving were live vertebrate animals were approved by the Iowa State University IACUC prior to use.
Conflict-of-interest statement: There are no conflicts of interest to declare for any of the authors of this manuscript.
Data sharing statement: Based on the types of data collected and included in this manuscript, there is no data sharing (e.g., gene sequences) required for this project.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Michael J Wannemuehler, Professor, Chair, Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, 2178 Vet Med, Ames, IA 50011, United States. mjwannem@iastate.edu
Telephone: +1-515-2943534 Fax: +1-515-2943839
Received: June 30, 2015
Peer-review started: July 5, 2015
First decision: July 31, 2015
Revised: August 31, 2015
Accepted: September 29, 2015
Article in press: September 30, 2015
Published online: November 6, 2015
Processing time: 135 Days and 17.5 Hours
Abstract

AIM: To investigate the ability of a Prunella vulgaris (P. vulgaris) ethanolic extract to attenuate spontaneous typhlocolitis in mdr1a-/- mice.

METHODS: Vehicle (5% ethanol) or P. vulgaris ethanolic extract (2.4 mg/d) were administered daily by oral gavage to mdr1a-/- or wild type FVBWT mice from 6 wk of age up to 20 wk of age. Clinical signs of disease were noted by monitoring weight loss. Mice experiencing weight loss in excess of 15% were removed from the study. At the time mice were removed from the study, blood and colon tissue were collected for analyses that included histological evaluation of lesions, inflammatory cytokine levels, and myeloperoxidase activity.

RESULTS: Administration of P. vulgaris extracts to mdr1a-/- mice delayed onset of colitis and reduced severity of mucosal inflammation when compared to vehicle-treated mdr1a-/- mice. Oral administration of the P. vulgaris extract resulted in reduced (P < 0.05) serum levels of IL-10 (4.6 ± 2 vs 19.4 ± 4), CXCL9 (1319.0 ± 277 vs 3901.0 ± 858), and TNFα (9.9 ± 3 vs 14.8 ± 1) as well as reduced gene expression by more than two-fold for Ccl2, Ccl20, Cxcl1, Cxcl9, IL-1α, Mmp10, VCAM-1, ICAM, IL-2, and TNFα in the colonic mucosa of mdr1a-/- mice compared to vehicle-treated mdr1a-/- mice. Histologically, several microscopic parameters were reduced (P < 0.05) in P. vulgaris-treated mdr1a-/- mice, as was myeloperoxidase activity in the colon (2.49 ± 0.16 vs 3.36 ± 0.06, P < 0.05). The numbers of CD4+ T cells (2031.9 ± 412.1 vs 5054.5 ± 809.5) and germinal center B cells (2749.6 ± 473.7 vs 4934.0 ± 645.9) observed in the cecal tonsils of P. vulgaris-treated mdr1a-/- were significantly reduced (P < 0.05) from vehicle-treated mdr1a-/- mice. Vehicle-treated mdr1a-/- mice were found to produce serum antibodies to antigens derived from members of the intestinal microbiota, indicative of severe colitis and a loss of adaptive tolerance to the members of the microbiota. These serum antibodies were greatly reduced or absent in P. vulgaris-treated mdr1a-/- mice.

CONCLUSION: The anti-inflammatory activity of P. vulgaris ethanolic extract effectively attenuated the severity of intestinal inflammation in mdr1a-/- mice.

Keywords: Prunella vulgaris; Spontaneous colitis; Inflammatory bowel disease; Mdr1a; Botanical extract; Mucosal inflammation; Nutraceutical

Core tip: Extracts of Prunella vulgaris (P. vulgaris) contain multiple anti-inflammatory phenolics and flavonoids and we report that oral administration of an ethanolic extract of P. vulgaris ameliorated the severity of spontaneous colitis in 20 wk old mdr1a-/- mice. Because these mice are genetically prone to develop colitis by 10 wk of age, daily oral treatments were initiated at 6 wk of age. This treatment regimen resulted in the inhibition of multiple parameters of inflammation that collectively contributed to ameliorate the severity of mucosal inflammation suggesting that botanical extracts may be used as effective complementary intervention strategies for the treatment of colitis.