Original Research ARTICLE
Ginkgolic acid is a multi-target inhibitor of key enzymes in pro-inflammatory lipid mediator biosynthesis
- 1Friedrich Schiller University Jena, Germany
- 2Institut für Pharmazie und Biochemie, Universität Tübingen, Germany
- 3Abteilung für Pharmakognosie, Institut für Pharmazie, Universität Innsbruck, Austria
- 4University of Vienna, Austria
- 5University of Salzburg, Austria
Introduction: Lipid mediators (LM) comprise bioactive metabolites of polyunsaturated fatty acids, including pro-inflammatory prostaglandins (PG), thromboxanes (TX), and leukotrienes (LT) but also specialized pro-resolving mediators (SPM). They are essentially biosynthesized via cyclooxygenase (COX) and lipoxygenase (LO) pathways in complex networks and regulate the progression but also the resolution of inflammatory disorders including inflammation-triggered cancer. Ginkgolic acid (GA) is a phenolic acid contained in Ginkgo biloba L. with neuroprotective, antimicrobial and antitumoral properties. Although LM regulate microbial infections and tumor progression, whether GA affects LM biosynthesis is unknown and was investigated here in detail.
Methods: Pharmacophore-based virtual screening was performed along with docking simulations. Activity assays were conducted for isolated human recombinant 5-LO, cytosolic phospholipase (PLA)2α, COX-2, and ovine COX-1. The activity of human mPGES-1 and thromboxane A2 synthase (TXAS) was determined in crude cellular fractions. Cellular LM formation was studied using human monocytes, neutrophils, platelets and M1- and M2-like macrophages. LM were identified after (ultra)high-performance liquid chromatography by UV detection or ESI-tandem mass spectrometry.
Results: GA was identified as virtual hit in a mPGES-1 pharmacophore-based virtual screening. Cell-free assays revealed potent suppression of mPGES-1 activity (IC50 = 0.7 µM) that is fully reversible and essentially independent of the substrate concentration. Moreover, cell-free assays revealed COX-1 and TXAS as additional targets of GA with lower affinity (IC50 = 8.1 and 5.2 µM). Notably, 5-LO, the key enzyme in LT biosynthesis, was potently inhibited by GA (IC50 = 0.2 µM) in a reversible and substrate-independent manner. Docking simulations support the molecular interaction of GA with mPGES-1 and 5-LO and suggest concrete binding sites. Interestingly, interference of GA with mPGES-1, COX-1, TXAS and 5-LO was evident also in intact cells with IC50 values of 2.1 - 3.8 µM; no radical scavenging or cytotoxic properties were obvious. Analysis of LM profiles from bacteria-stimulated human M1- and M2-like macrophages confirmed the multi-target features of GA and revealed LM redirection towards the formation of 12-/15-LO products including SPM.
Conclusions: We reveal GA as potent multi-target inhibitor of key enzymes in the biosynthesis of pro-inflammatory LM that contribute to the complex pharmacological and toxicological properties of GA.
Keywords: Ginkgolic acid, microsomal prostaglandin E (PGE) synthase-1, 5-lipoxygenase, cyclooxygenase, Multi-target inhibitor, lipid mediator
Received: 08 Apr 2019;
Accepted: 20 Jun 2019.
Edited by:Roberta D'Emmanuele Di Villa Bianca, Department of Pharmacy, University of Naples Federico II, Italy
Reviewed by:Melania Dovizio, Università degli Studi G. d'Annunzio Chieti e Pescara, Italy
Sven-Christian Pawelzik, Karolinska Institute (KI), Sweden
Copyright: © 2019 Werz, Gerstmeier, Seegers, Witt, Waltenberger, Temml, Rollinger, Stuppner, Koeberle and Schuster. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Oliver Werz, Friedrich Schiller University Jena, Jena, Germany, firstname.lastname@example.org