**Abstract**

*Citrus* species is a category of fruit that contains a variety of bioactive components throughout the plant. *Citrus* fruits (and items made from them) are among the most widely eaten fruits in the world, and their supply continues to increase. Oranges, pomelos, limes, tangelos, mandarins, lemons, kumquats, grapefruits, and other *Citrus* fruits are among them. They are frequently employed in the culinary, cosmetics, and pharmaceutical sectors due to their fragrance and taste. Vitamin C, pectin, limonene, phenolics, iso-limonene, flavanones, and nonanal are the main bioactive components present, and they provide a variety of health advantages. Pharmacological studies have shown that the fruit has numerous nutraceutical benefits, including a strong antioxidant, antidiabetic, anti-hypertensive, anticancerous, antibacterial, antifungal, antimicrobial, antihyperglycemic, and cardioprotective. It should also be highlighted that all *Citrus* fruits are an excellent source of minerals, which are required to maintain water and electrolyte balance. *Citrus* fruit-eating has been linked to a range of health advantages in recent research. This chapter presents an overview of the nutritional aspects of *Citrus* as well as its health benefits, which will be detailed.

**Keywords:** *Citrus*, nutrition, bioactive substance, healthy food, vitamin, antioxidant, phenolic compound

## **1. Introduction**

*Citrus* fruits are members of the *Rutaceae* family and are the most marketed natural product on earth. *Citrus*, also known by the Romance loanword agrumes (sour fruits), is one of the world's dominant cultivars, with a feature of the application and acceptance significantly to human food [1]. *Citrus,* which is commonly grown in subtropical and tropical regions, is one of the largest and most significant crops. Annually, over 150 million tons of *Citrus* natural products are filled in more than 140 nations. According to Food and Agriculture Organization (FAO), Italy, Spain, Argentina, the United States, and Greece are significant exporters of fresh *Citrus*, while the main exporters of organic *Citrus* juices are Brazil, Israel, Costa Rica, the United States, Italy, Mexico, and Cuba [2]. *Citrus* natural products have been appreciated by people since ancient times. *Citrus* fruits are an important part of today's diet since they are soft, easy to peel, and have juicy flesh with a distinct flavor. Many

*Citrus* species, such as grapefruits (*Citrus paradisi*), mandarins (*Citrus reticulata)*, lemons (*Citrus limon*), oranges (*Citrus sinensis)*, *Citrus clementina*, and *Citrus unshiu* are consumed as juice or used for the development of new products all over the planet [3]. *Citrus* is popular due to its distinct flavor, taste, and scent, as well as its increased level of phenolics, vitamin C, and other nutritional properties [4]. *Citrus* belongs to the *Citrinae* subtribe, tribe *Citreae*, and subfamily *Aurantioideae*. Furthermore, the continuing ordered study seems, by all accounts, to be confounded and disputed, as a result of sexual suitability among *Citrus* species and other taxa, a frequency range of bud modifications, and apomixis (e.g., adventitious embryonic) [5]. Swingle and Reece and Tanaka's taxonomy classifications for *Citrus,* which classified 16 and 162 species, respectively, are the most frequently accepted [6]. Fruit and vegetablerich cuisines have been significantly linked to multiple therapeutic benefits and a decreased probability of having illness [7]. *Citrus* is one of the world's most significant natural product crops, grown for both fresh juice production and food processing. *Citrus* fruits and commodities are quite common with significant economic and nutritional influence in both developing and developed nations due to inexpensive economic accessibility, and customer attitude toward the increasingly recognized potential health benefits [8].

Dietary choices have been related to a range of health outcomes, including high blood cholesterol, hyperglycemia, high blood pressure, and other major chronic degenerative conditions [9]. There is a huge necessity for nutritious meals that, in addition to providing nourishment, may improve the public overall health status. Fruits and vegetables are high in nutrients, anti-inflammatory compounds, and phytochemicals [10]. Aside from that, the demand for plant-based commodities is increasing in both emerging and developed countries [11]. Thus, we may employ specific fruits, such as citron (*C. medica*), in various formulations and benefit from their health capabilities in lowering the risk of numerous prevalent ailments. The World Health Organization (WHO) suggests, including 400 g of fruits, in your balanced meals. Consuming more *Citrus* fruits, vegetables, and whole grains has been associated with a decreased risk of numerous metabolic syndrome-related disorders, particularly malignancy, impaired glucose tolerance, coronary heart disease, and neurodegenerative diseases, according to deterministic, observational, and intervention studies [12]. These illnesses are essentially connected with serious and second-rate extensive irritation created by responsive oxygen species. The bioactive constituents included in whole grains, vegetables, and fruits protect cells against oxidative damage by neutralizing free radicals, hence lowering the prevalence of these disorders [13]. *Citrus* fruit species have been extensively researched for their bioactive content and medicinal properties. Oranges account for the majority of all *Citrus* production/exports, followed by lemons/limes (8%), grapefruit (7%), and tangerines/mandarins (one-third) [14]. *Citrus* fruits have gained popularity in recent years due to their health-promoting properties. A variety of active substances contained in *Citrus* natural products have been detached and portrayed, and their part in people's well-being has been extensively researched. *Citrus* fruits' significance in one's nutrition, as well as the abundance of key bioactive compounds, such as ascorbic acid (AsA), carotenoids, and flavonoids, in *Citrus* fruits, and their therapeutic properties are discussed in this chapter.
