ABSTRACT

Obesity is a chronic disease that increases the risk of suffering from a variety of life-threatening diseases including diabetes, hypertension, cardiovascular diseases, and also certain cancers. It is the result of a chronic imbalance between energy intake and energy expenditure, and it is characterized by an increase in both the size and number of adipocytes. The only obesity treatment medication currently available, Orlistat, has serious side effects that include increased blood pressure, dry mouth, constipation, headache, and insomnia (Yun 2010). Sibutramine, a previously prescribed weight loss medication, was withdrawn by the U.S. Food and Drug Administration in 2010 due to patients suffering an increased risk of cardiovascular adverse events. Therefore, in recent years, natural alternatives that exhibit antiobesity potential have been widely investigated. For instance, natural products such as crude extracts or isolated compounds found in edible plants, more specifically, fruits and vegetables, have been shown to reduce body weight and subsequently prevent diet-induced obesity (Han et al. 2005; Lopes et al. 2005; Moro and Basile 2000). The possible benefits found in dietary plants are due largely to the functional ingredients

10.1 Introduction .................................................................................................. 325 10.2 Citrus Flavonoids and Their Chemical Properties ....................................... 326

10.2.1 Introduction to Flavonoids ................................................................ 326 10.2.2 Biosynthesis of Flavonoids ............................................................... 327 10.2.3 Major Flavonoids in Citrus and Their Structural and Chemical

Properties .......................................................................................... 328 10.2.4 General Benefits of Flavonoids and Their Possible Applications ..... 331

10.3 Citrus Flavonoids and Their Antiobesity Activities ..................................... 331 10.3.1 Citrus Flavonoids as Regulators of Energy Intake ........................... 332 10.3.2 Citrus Flavonoids as Regulators of Energy Expenditure .................. 335 10.3.3 Citrus Flavonoids as Regulators of Lipid Metabolism ..................... 335 10.3.4 Citrus Flavonoids as Regulators of Adipose Tissue ......................... 337 10.3.5 Citrus Flavonoids as Regulators in Other Mechanisms ................... 339

10.4 Summary ......................................................................................................340 References ..............................................................................................................340