Antimicrobial Activities of Saponin-Rich Guar Meal Extract
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ANTIMICROBIAL ACTIVITIES OF SAPONIN-RICH GUAR MEAL EXTRACT A Dissertation by SHERIF MOHAMED HASSAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2008 Major Subject: Poultry Science ANTIMICROBIAL ACTIVITIES OF SAPONIN-RICH GUAR MEAL EXTRACT A Dissertation by SHERIF MOHAMED HASSAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved by: Chair of Committee, Aubrey L. Cartwright Committee Members, Christopher A. Bailey James A. Byrd Michael E. Hume Head of Department, John B. Carey May 2008 Major Subject: Poultry Science iii ABSTRACT Antimicrobial Activities of Saponin-Rich Guar Meal Extract. (May 2008) Sherif Mohamed Hassan, B.S.; M.S., Suez Canal University Chair of Advisory Committee: Dr. Aubrey Lee Cartwright Three saponin-rich extracts (20, 60, 100% methanol), four 100% methanol sub- fractions and seven independently acquired fractions (A-G) from guar meal, Cyamopsis tetragonoloba L. (syn. C. psoraloides), were evaluated for antimicrobial and hemolytic activities. These activities were compared against quillaja bark (Quillaja saponaria), yucca (Yucca schidigera), and soybean (Glycine max) saponins in 96-well plates using eight concentrations (0.01 to 1.0 and 0.1 to 12.5 mg extract/mL). Initial guar meal butanol extract was 4.8 ± 0.6% of the weight of original material dry matter (DM). Butanol extract was purified by preparative reverse-phase C-18 chromatography. Two fractions eluted with 20, and one each with 60, and 100% methanol with average yields of 1.72 ± 0.47, 0.88 ± 0.16, 0.91 ± 0.16 and 1.55 ± 0.15% of DM, respectively. Further purification of the 100% methanol fraction using normal-phase silica gel preparatory high pressure liquid chromatography eluted 4 peaks at 16, 39, 44 and 46 min. Only the 100% methanol fraction, its 16 min peak, F and G fractions, and quillaja saponin, exhibited both hemolytic and antibacterial activities against Staphylococcus aureus, Salmonella Typhimurium and E. coli, but 20 and 60% methanol fractions stimulated Lactobacillus spp. growth. Guar meal (0 or 5%) was added to diets fed to chicks from 1 iv to 21 days of age. Chicks fed both diets were unchallenged or challenged with 5 x 103 Eimeria tenella sporulated oocysts at 10 days. Guar meal diets reduced oocysts shed per gram of feces, body weight, and feed efficiency. Adding 2.5% guar meal, 1% guar gum, or 0.125% saponin-rich guar meal extract to diets fed to chicks to 21 days of age showed that guar meal increased the cfu concentrations of digesta more than controls following a challenge with 107 cfu of Clostridium perfringens at 14 days. Body weights of chicks fed guar meal and saponin-rich extract were significantly lower than control body weights at 21 days of age, whereas the weekly feed to gain ratio of chicks fed saponin-rich extract was higher than controls. Guar meal reduced severity of Eimeria tenella infection and guar saponin-rich extract exhibited antimicrobial activity against several common poultry pathogens. v DEDICATION My love and gratitude is expressed to my parents, my wife and my entire family for their continued encouragement, support, and sacrifices throughout my educational pursuits and daily life. vi ACKNOWLEDGEMENTS My sincere appreciation is expressed to: Dr. A. L. Cartwright and Dr. Christopher A. Bailey for their many hours of counsel, guidance, advice, support, endless encouragement, time and instruction throughout the course of this research. Their shared wisdom and insight concerning education and life are greatly appreciated. Gratitude and appreciation are extended to Dr. James A. Byrd, Dr. Michael E. Hume and Dr. Jack L. McReynolds for their assistance, suggestions and comments during experiments and the preparation of this dissertation. Thanks also go to my colleagues, department faculty and staff for making my time at Texas A&M University a great experience. I also want to extend my gratitude to Dr. Akram Haq for his help in isolation and purification and Dr. Mark Berhow for his help in the identification of the guar saponin. Special thanks and sincere appreciation are extended for the hard work and assistance of Mr. Omar Gutierrez, Mrs. Denise Caldwell and Mrs. Elizabeth M. Hirsschler and the entire staff of the Texas A&M Poultry Research Center. Their assistance, suggestions, and advice were indispensible. The friendships I made while at Texas A&M University are cherished. Most importantly, I express my love and gratitude to my parents, my wife, my children and the entire family for their patience, love, continual encouragement, support, sacrifices and prayers throughout my educational pursuits and daily life. vii TABLE OF CONTENTS Page ABSTRACT .............................................................................................................. iii DEDICATION .......................................................................................................... v ACKNOWLEDGEMENTS ...................................................................................... vi TABLE OF CONTENTS .......................................................................................... vii LIST OF FIGURES ................................................................................................... ix LIST OF TABLES .................................................................................................... x CHAPTER I INTRODUCTION ............................................................................... 1 II LITERATURE REVIEW ..................................................................... 4 Pathogenic Bacterial and Coccidial Diseases ................................. 4 Antibiotic Resistance Is a Growing Problem ................................. 15 Saponin as an Antibiotic Alternative ............................................. 19 Guar Meal Is a Saponin-Rich Legume ........................................... 43 Research Description ...................................................................... 50 III ANTIMICROBIAL AND HEMOLYTIC ACTIVITIES OF SAPONIN- RICH EXTRACTS FROM GUAR MEAL .......................................... 53 Introduction .................................................................................... 53 Materials and Methods ................................................................... 55 Results and Discussion ................................................................... 64 Summary and Conclusions ............................................................. 82 IV ANTIMICROBIAL AND HEMOLYTIC ACTIVITIES DIFFER AMONG SAPONIN-RICH EXTRACTS FROM GUAR, QUILLAJA, YUCCA AND SOYBEAN .................................................................. 84 Introduction .................................................................................... 84 viii CHAPTER Page Materials and Methods ................................................................... 86 Results and Discussion ................................................................... 88 Summary and Conclusions ............................................................. 100 V GUAR MEAL AMELIORATES EFFECTS OF EIMERIA TENELLA CHALLENGE IN BROILER CHICKS ............................................... 101 Introduction .................................................................................... 101 Materials and Methods ................................................................... 103 Results and Discussion ................................................................... 106 Summary and Conclusions ............................................................. 114 VI ANTIBACTERIAL ACTIVITIES OF GUAR MEAL, GUAR GUM AND SAPONIN-RICH GUAR MEAL EXTRACTS AGAINST CLOSTRIDIUM PERFRINGENS IN CHICKENS .............................. 115 Introduction .................................................................................... 115 Materials and Methods ................................................................... 118 Results and Discussion ................................................................... 123 Summary and Conclusions ............................................................. 132 IV SUMMARY AND CONCLUSIONS ................................................... 134 REFERENCES .......................................................................................................... 137 VITA ......................................................................................................................... 179 ix LIST OF FIGURES FIGURE Page 1 Skeletal types of aglycone found in the three principal classes of saponin 20 2 Steroid saponins differ in sugar side chain structure and position (R1 and R2) on the aglycone nucleus .......................................................... 27 3 Triterpenoid saponins differ in sugar side chain structure and position (R1 to R5) on the aglycone nucleus ............................................................. 28 4 Example elution profile of reverse-phase C-18 flash chromatography of saponin-rich guar meal n-butanol extract. Fractions eluted at 20%, 60% and 100% methanol, respectively ............................................................... 57 5 Example analytical HPLC chromatography of guar fraction (F) from Dr. Mark Berhow .............................................................................................. 71 x LIST OF TABLES TABLE Page 1 Hemolytic activity of saponin-rich