Anti-Inflammatory Effect of Charantadiol A, Isolated from Wild Bitter Melon Leaf, on Heat-Inactivated Porphyromonas gingivalis-Stimulated THP-1 Monocytes and a Periodontitis Mouse Model.

Tzung-Hsun Tsai,Yueh-Hsiung Kuo,Lu-Te Chuang,Hsiang Chang,Jong-Ho Chyuan,Po-Jung Tsai,Chi-I Chang,Ya-Ling Hung,Wen-Cheng Huang

doi:10.3390/molecules26185651

Abstract

Porphyromonas gingivalis has been identified as one of the major periodontal pathogens. Activity-directed fractionation and purification processes were employed to identify bioactive compounds from bitter melon leaf. Ethanolic extract of bitter melon leaf was separated into five subfractions by open column chromatography. Subfraction-5-3 significantly inhibited P. gingivalis-induced interleukin (IL)-8 and IL-6 productions in human monocytic THP-1 cells and then was subjected to separation and purification by using different chromatographic methods. Consequently, 5β,19-epoxycucurbita-6,23(E),25(26)-triene-3β,19(R)-diol (charantadiol A) was identified and isolated from the subfraction-5-3. Charantadiol A effectively reduced P. gingivalis-induced IL-6 and IL-8 productions and triggered receptors expressed on myeloid cells (TREM)-1 mRNA level of THP-1 cells. In a separate study, charantadiol A significantly suppressed P. gingivalis-stimulated IL-6 and tumor necrosis factor-α mRNA levels in gingival tissues of mice, confirming the inhibitory effect against P. gingivalis-induced periodontal inflammation. Thus, charantadiol A is a potential anti-inflammatory agent for modulating P. gingivalis-induced inflammation.

Highlights

Periodontal diseases are complex, multifactorial diseases characterized by chronic inflammation of periodontal tissues, including gingival inflammation and alveolar bone resorption, and eventually tooth loss
Previous studies indicated that P. gingivalis can elicit high levels of IL-6 and IL-8 production in a variety of cell types comprising human oral epithelial cells, periodontal ligament cells and monocytes [13,14,15]
We previously demonstrated that sub-fractions, the fraction 5 (Fra. 5) and Fra. 5-2, isolated from crude Wild bitter melon (WBM) leaf extract inhibited P. gingivalis-stimulated IL-8 production by THP-1 cells [13]

Summary

Introduction

Periodontal diseases are complex, multifactorial diseases characterized by chronic inflammation of periodontal tissues, including gingival inflammation and alveolar bone resorption, and eventually tooth loss. Exposure to P. gingivalis causes innate responses through toll-like receptor (TLR)-2 and TLR-4 on the host cell surface and can trigger the production and release of pro-inflammatory mediators, such as interleukin (IL)-8 and IL-6, IL-1β, and tumor necrosis factor (TNF)-α These pro-inflammatory cytokines play a significant role in the development of periodontitis [3]. Natural products from the herbal remedy, medicinal plants, functional foods, and their constituent have been considered to be effective in the prevention and treatment of periodontal diseases [6,7,8] These studies did not purify specific compounds that have a meaningful anti-inflammatory effect on periodontitis from the crude extracts. We isolated 5β,19-epoxycucurbita-6,23-diene-3β,19,25-triol (kuguacin R) and 3β,7β,25-trihydroxycucurbita-5,23-dien-19-al (TCD) from WBM leaf extract and demonstrated that both compounds suppressed P. gingivalis-induced inflammatory responses with human THP-1 monocytic cell model and prevented periodontal disease progression in a mouse model of experimental periodontitis [13]. As part of our continuing efforts directed toward the discovery of bioactive compounds in WBM, 5β,19-epoxycucurbita6,23(E),25-triene-3β,19(R)-diol (charantadiol A) was isolated from WBM leaf extract and its possible anti-inflammatory activity against P. gingivalis was evaluated in this study

Results and Discussion

Effect of Charantadiol A

Isolation and Determination of Charantadiol A

Cell Culture

Conclusions