I was doing some research on licorice and stumbled across this research paper.
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Isoliquiritigenin Selectively Inhibits H2 Histamine Receptor Signaling.
Dong-Chan Kim, Se-Young Choi, Sun-Hee Kim, Bong-Sik Yun, Ick-Dong Yoo,
Nanga. Ravi Prakash Reddy, Ho Sup Yoon, and Kyong-Tai Kim
accepted May 3, 2006
ABSTRACT
Isoliquiritigenin, one of the major constituents of Glycyrrhiza uralensis (licorice), is a natural pigment with a simple chalcone structure 4,2,4-trihydroxychalcone. In this study, isoliquiritigenin showed selective H2 histamine receptor (H2R) antagonistic effect and remarkably reduced several H2R-mediated physiological re- sponses. Preincubation of U937 and HL60 hematopoietic cells with isoliquiritigenin significantly inhibited H2R agonist-induced cAMP response in a concentration-dependent manner without affecting the viability of cells. Isoliquiritigenin also blocked the binding affinity of [3H]tiotidine to membrane receptors in HL-60 cells. Isoliquiritigenin did not affect the elevation of cAMP levels induced by cholera toxin, forskolin, or isoproterenol, indicatingthat the action site of isoliquiritigenin is not Gs protein, effector enzyme, adenylyl cyclase, or 2-adrenoceptor.
Isoliquiritigenin affected neither H1R- nor H3R-mediated signaling. In molecular docking studies, isoliquiritigenin exhibited more favorable interac- tions with H2R than histamine. Isoliquiritigenin prominently inhib- ited H2R selective agonist dimaprit-induced cAMP generation in MKN-45 gastric cancer cell. Moreover, isoliquiritigenin reduced gastric acid secretion and protected gastric mucosal lesion for- mation in pylorus-ligated rat model.
Taken together, the results demonstrate that isoliquiritigenin is an effective H2R antagonist and provides the basis for designing novel H2R antagonist.
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The entire Paper can be found here:
http://www.ncbi.nlm.nih.gov/pubmed/16675659