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CHARACTERIZATION OF PHENOLIC COMPOUNDS FROM PECAN KERNELS AND THEIR BIOLOGICAL EFFECTS ON ADIPOGENESIS AND INFLAMMATION A Thesis by ANA GABRIELA ORTIZ QUEZADA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2010 Major Subject: Food Science and Technology Characterization of Phenolic Compounds from Pecan Kernels and Their Biological Effects on Adipogenesis and Inflammation Copyright 2010 Ana Gabriela Ortiz Quezada CHARACTERIZATION OF PHENOLIC COMPOUNDS FROM PECAN KERNELS AND THEIR BIOLOGICAL EFFECTS ON ADIPOGENESIS AND INFLAMMATION A Thesis by ANA GABRIELA ORTIZ QUEZADA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Co-Chairs of Committee, Luis Cisneros-Zevallos Leonardo Lombardini Committee Members, Joseph Awika Chaodong Wu Chair of Food Science and Technology Faculty, Jimmy T. Keeton August 2010 Major Subject: Food Science and Technology iii ABSTRACT Characterization of Phenolic Compounds from Pecan Kernels and Their Biological Effects on Adipogenesis and Inflammation. (August 2010) Ana Gabriela Ortiz Quezada, B. S., Instituto Tecnológico y de Estudios Superiores de Monterrey, Monterrey Campus Co-Chairs of Advisory Committee: Dr. Luis Cisneros-Zevallos Dr. Leonardo Lombardini Pecan [Carya illinoinensis (Wangenh.) K. Koch] kernels from four cultivars were screened for their phenolic content and antioxidant capacity. Ellagitannin content was quantified by HPLC after hydrolysis as free ellagic acid. Characterization of phenolic compounds present in defatted pecan was conducted by liquid chromatography- mass spectrometry. In addition, ellagic acid metabolites, urolithin A and urolithin B, were evaluated for their anti-adipogenic and anti-inflammatory effects in 3T3-L1 preadiadipocyte cells by protein and gene expression. Variations among cultivars were observed. „GraCross‟ and „Desirable‟ showed the highest total phenolic content; in the same way, „GraCross‟ had the highest values for condensed tannin content, antioxidant capacity using the 2, 2-diphenyl-1-picryl- hydrazyl (DPPH) assay and the oxygen radical absorbance capacity (ORAC). According to these results, the cultivar with the highest condensed tannin content had the highest antioxidant capacity using the DPPH and ORAC assays. „Desirable‟ and „Kiowa‟ had the highest ellagitannin content. Even though ellagitannins comprise a small percentage iv compared to condensed tannins, the latter have restricted bioavailability and up to trimers can be absorbed. Eleven ellagitannins were identified for the first time in pecans. Their masses ranged from 433 to 1207 m/z. Condensed tannins up to pentamers were detected. Other compounds included gallic acid, ellagic acid, and isorhamnetin in the glucoside, pentosyl and galloyl pentosyl forms. Ellagitannins are metabolized in vivo yielding urolithins which are absorbed by the gut. Urolithins are derivatives from ellagic acid. These compounds, urolithin A and urolithin B, were used to treat 3T3-L1 preadypocytes as an obesity model. Results of the adipocytes‟ protein expression immediately after differentiation indicated no inhibition of differentiation of the preadipocytes after treating cells with urolithins and ellagic acid. Results on the mature adipocytes indicated that treatments with 25 µM of urolithin A, urolithin B, and ellagic acid during differentiation did not significantly reduce their lipid content. Inflammatory effects in 3T3-L1 adipocytes were evaluated by the LPS model through protein and gene expression. Urolithin A and ellagic acid reduced p-NF-κB protein expression. Urolithin A and urolithin B reduced TNF-α mRNA basal expression, a protective effect in a non-inflammatory state. Interleukin-6 (IL-6) expression was increased by urolithins and lipopolysaccharide (LPS), probablly due to a synergistic inflammatory effect coming from different pathways. v DEDICATION To my parents, José Antonio and Socorro, for giving me life, love, support, and guidance. To my brothers Gustavo and Mauricio, who have walked next to me in life. To my boyfriend Rolando, for his love, support, endless patience, for making me laugh and enjoy life. And to God. vi ACKNOWLEDGEMENTS I would like to thank my committee co-chairs, Dr. Cisneros and Dr. Lombardini, for the opportunity given to me to do my degree, for trusting me and for their support. Thanks to my committee members, Dr. Awika, for his support and guidance and Dr. Wu, for letting me work in his lab, for helping me understand adypocytes and for his guidance, support and patience throughout the course of this research. Thanks to Dr. Morgan, who listened and guided me and to Dr. Sturino, for letting me work in his lab. My gratitude to my friends and colleagues from food science and horticulture: Gabriela Angel, Alex Puerta, Nenge Njongmeta, Congmei Cao, Judith Turlington. Special thanks to the biochemists, Freddy Ibañez and Paula Castillo, for their technical support, for giving me hope and for the good times in the lab. Thanks to colleagues from CEBAS in Murcia, Spain, Dr. Francisco Tomás-Barberán, for letting me work in his lab, and to Dr. Rocío González-Barrio, for her support no matter where we were. This project was supported thanks to the financial support of the Vegetable and Fruit Improvement Center (VFIC), Texas Pecan Board, and the Texas Pecan Growers Association. Thanks to my parents, for their continuous encouragement; my brothers, for being there for me, and to my beloved boyfriend, for his love. vii TABLE OF CONTENTS Page ABSTRACT .............................................................................................................. iii DEDICATION .......................................................................................................... v ACKNOWLEDGEMENTS ...................................................................................... vi TABLE OF CONTENTS .......................................................................................... vii LIST OF FIGURES ................................................................................................... ix LIST OF TABLES .................................................................................................... xii CHAPTER I INTRODUCTION AND LITERATURE REVIEW ............................ 1 Tannins ........................................................................................... 3 Tannins bioavailability ................................................................... 6 Health benefits ................................................................................ 7 Obesity overview ............................................................................ 8 Adipose tissue and gene expression ............................................... 10 Objectives ....................................................................................... 13 II PECAN CULTIVAR SCREENING FOR PHENOLICS, ANTIOXIDANT CAPACITY, AND POLYPHENOLIC CHARACTERIZATION BY LC-MS .................................................. 14 Summary ........................................................................................ 14 Introduction .................................................................................... 14 Materials and methods ................................................................... 16 Results and discussion .................................................................... 23 Conclusions .................................................................................... 51 viii CHAPTER Page III EFFECTS OF UROLITHINS A AND B AS METABOLITES FROM PECAN ELLAGITANNINS ON ADIPOGENESIS IN 3T3-L1 CELLS ............................................................................... 52 Summary .............................................................................................. 52 Introduction .......................................................................................... 53 Materials and methods ......................................................................... 55 Results and discussion .......................................................................... 59 Conclusions .......................................................................................... 74 IV EFFECTS OF UROLITHINS A AND B IN INFLAMMATION WITH 3T3-L1 CELLS ......................................................................... 75 Summary .............................................................................................. 75 Introduction .......................................................................................... 75 Materials and methods ......................................................................... 77 Results and discussion .......................................................................... 82 Conclusions .......................................................................................... 94 V CONCLUSIONS AND RECOMMENDATIONS FOR FURTHER RESEARCH ...................................................................... 95 REFERENCES .......................................................................................................... 97 VITA ......................................................................................................................... 120 ix LIST OF FIGURES Page Figure 1 Examples of a condensed (A) and a hydrolyzable (B) tannin ................... 5 Figure 2 Condensed