## 1 Introduction  
Black rice (BR) (_Oryza sativa_ L) is a distinctive rice variety primarily cultivated in Asia and is often referred to as \"forbidden rice\" due to its historical association with Chinese royalty [1]. BR has long been used as a medicinal food in China because of its health benefits. BR comprises an outermost layer, referred to as black rice bran (BRB), and an inner layer, referred to as milled black rice (MBR). The rice seeds are purple-black because of the rich anthocyanin pigment in the BRB layer [2, 3]. Studies have shown that BR is popular not only for its unique color and flavor but also for its various health benefits [4].  
BR is rich in dietary fiber, anthocyanins, phenolic compounds, flavonoids, \(\gamma\)-oryzanol, \(\beta\)-glucan, and other nutrients and bioactive substances [5]. These bioactive compounds are associated with various physiological activities that impart the BR with antioxidant, anti-inflammatory, and anti-obesity properties, thereby enhancing its reputation as a healthy food [6]. The antioxidant activity of BR has been extensively studied, with findings indicating that it possesses significantly higher antioxidant activity than other rice varieties, primarily due to the abundance of certain bioactive compounds such as anthocyanins, phenolic acids, and flavonoids [7, 8]. Recent studies have suggested that BR can effectively scavenge free radicals, thereby reducing oxidative stress and having a positive impact on health [9].  
In addition, BR has shown good application prospects and health benefits in various physiological activity studies, which are attributable to its high fiber content and multiple bioactive compounds that are closely associated with its anti-inflammatory, anti-cancer, anti-obesity, and anti-diabetic effects [3]. According to previous studies, BR is rich in antioxidant compounds and can be used to make products such as bread, cakes, and cookies, offering a healthier alternative to traditional baked goods. In addition, mead made from BR has higher antioxidant activity and provides more health benefits than mead made from ordinary grains [4]. Research has shown that BRB not only serves as a high-quality source of dietary fiber but also has multiple health benefits, such as anti-inflammatory and hypoglyemic effects, which render it a promising raw material for developing functional foods [10; 11].  
Although a large number of studies have focused on the individual bioactive compounds or physiological activities of BR, comprehensive analyses and comparative studies of \(\gamma\)-oryzanol, \(\beta\)-glucan, total phenolic, and total flavonoid contents in BR and its components (i.e., BRB and MBR), as well as their antioxidant, anti-obesity, anti-obeseogenic, and anti-muscle atrophy effects, are relatively limited. Therefore, this study aimed to comprehensively compare and evaluate the bioactive compound contents and physiological activities of BR, BRB, and MBR in water and 80% ethanol (EtOH) extracts to identify the most potent fractions of BR, explore their application prospects, and promote their use as healthy functional food materials. For example, they can be used in the development of dietary supplements and nutritional products to prevent diseases such as obesity, obesogenic effects, and muscle atrophy, thereby providing a deeper understanding of the application value of BR.