Modification of Quorum Quenching Analogs from Schinus terebinthifolia Fruit Extract Open Access

Abstract

       With the rise of antibiotic resistance, antivirulence strategies such as quorum quenching have been investigated as an alternative approach to treat bacterial skin infections. From a medicinal plant used to treat wounds in the Brazilian pharmacopeia, Schinus terebinthifolia fruit extract “430D-F5” has been reported to attenuate quorum sensing and dermanecrosis in skin infection caused by Staphylococcus aureus. With the three bioactive triterpenoids from the extract as precursors, 430F-F5 was modified by ammonolysis, bromination, and epoxidation to investigate the effect on the quorum quenching activity. After monitoring the reaction with high performance liquid chromatography (HPLC), the ammonolyzed products were confirmed by one-dimensional nuclear magnetic resonance (NMR), and the brominated and epoxidated products were detected by liquid chromatography-mass spectrometry (LC-MS). While the ammonolyzed 430F-F5 decreased the quorum quenching activity in accessory gene regulator system (agr) I and III of S. aureus, the brominated and epoxidated 430F-F5 showed statistically significant increase in the inhibition of agr I and III, respectively. However, the fractions of the epoxidated 430F-F5 isolated by the preparative HPLC resulted in a decreased inhibition of agr I and III. In this study, semisynthetic quorum quenching analogs generated by ammonolysis, bromination and epoxidation of 430F-F5 were tested on agr I and III in S. aureus to optimize the antivirulence activity.

Table of Contents

Chapter 1: Introduction 1

Chapter 2: Literature Review 5

Chapter 3: Experimental Procedures 10

Chapter 4: Results and Discussion 19

Chapter 5: Conclusion 39

References 40

Supporting Information 44

About this Honors Thesis

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School	Emory College
Department	Chemistry
Degree	B.S.
Submission	Honors Thesis
Language	English
Research Field	Chemistry, Analytical Biology, Microbiology Chemistry, Organic
Keyword	natural products quorum sensing antivirulence Schinus terebinthifolia
Committee Chair / Thesis Advisor	Dr. Cassandra Quave, Emory University
Committee Members	Dr. Frank McDonald, Emory University Dr. Dennis Liotta, Emory University

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