Litchi ( Litchi chinensis Sonn.) is a tropical to subtropical fruit that is widely cultivated in more than 20 countries worldwide. It is normally consumed as fresh or processed and has become one of the most popular fruits because it has a delicious flavor, attractive color, and high nutritive value. Whole litchi fruits have been used not only as a food source but also for medicinal purposes. As a traditional Chinese medicine, litchi has been used for centuries to treat stomach ulcers, diabetes, cough, diarrhea, and dyspepsia, as well as to kill intestinal worms. Both in vit ro and in vivo studies have indicated that whole litchi fruits exhibit antioxidant, hypoglycemic, hepatoprotective, hypolipidemic, and antiobesity activities and show anticancer, antiatherosclerotic, hypotensive, neuroprotective, and immunomodulatory activities. The health benefits of litchi have been attributed to its wide range of nutritional components, among which polysaccharides and polyphenols have been proven to possess various beneficial properties. The diversity and composition of litchi polysaccharides and polyphenols have vital influences on their biological activities. In addition, consuming fresh litchi and its products could lead to some adverse reactions for some people such as pruritus, urticaria, swelling of the lips, swelling of the throat, dyspnea, or diarrhea. These safety problems are probably caused by the soluble protein in litchi that could cause anaphylactic and inflammatory reactions. To achieve reasonable applications of litchi in the food, medical and cosmetics industries, this review focuses on recent findings related to the nutrient components, health benefits, and safety of litchi.

Non-extractable phenolic compounds (NEPs), or bound phenolic compounds, represent a crucial component of polyphenols. They are an essential fraction that remains in the residual matrix after the extraction of extractable phenolic compounds (EPs), making them a valuable resource for numerous applications. These compounds encompass a diverse range of phenolic compounds, ranging from low molecular weight phenolic to high polymeric polyphenols attached to other macro molecules, e.g., cell walls and proteins. Their status as natural, green antioxidants have been well established, with numerous studies showcasing their anti-inflammatory, anti-aging, anti-cancer, and hypoglycemic activities. These properties make them a highly desirable alternative to synthetic antioxidants. Fruit and vegetable (F&Veg) wastes, e.g., peels, pomace, and seeds, generated during the harvest, transport, and processing of F&Vegs, are abundant in NEPs and EPs. This review delves into the various types, contents, structures, and antioxidant activities of NEPs and EPs in F&Veg wastes. The relationship between the structure of these compounds and their antioxidant activity is explored in detail, highlighting the importance of structure-activity relationships in the field of natural antioxidants. Their potential applications ranging from functional food and beverage products to nutraceutical and cosmetic products. A glimpse into their bright future as a valuable resource for a greener, healthier, and more sustainable future, and calling for researchers, industrialists, and policymakers to explore their full potential, are elaborated.