The lotus seed embryos could be promising sources with antioxidant activity and used as dietary supplements for health promotion.
Lotus (Nelumbo nucifera) is a perennial aquatic plant widely distributed throughout Asia, Australia, and North America (Kredy and others 2010). Almost all parts of lotus, including the seed embryos, have long been used as functional foods. The seed embryos have mainly been used for the treatment of nervous disorders, insomnia, and cardiovascular diseases such as hypertension and arrhythmia (National Commission of Chinese Pharmacopoeia 2010). More recently, their anti-ischemic, antioxidant, antiinflammatory, antiarrhythmic, and anti-HIV activities have been revealed (Mukherjee and others 2009). Besides being used as functional food, lotus seed embryos have also been used as Chinese traditional herbal medicines more than 2000 y in Eastern Asia (Mukherjee and others 2009). Increasing attention have been paid on analyzing bioactive components from lotus seed embryos (Zhu and others 2016). Apart from alkaloids that have been well reported from lotus seed embryos, flavonoids have attracted enough attention due to their health benefits in treating some diseases, including neurodegenerative diseases, type II diabetes, and cardiovascular diseases (Perveen and others 2015). However, systematic studies on flavonoids composition of the lotus seed embryos are scarce, unlike for their leaves, flowers fruits, and other tissues, which have been reported to be rich in flavonoid O-glycosides (Chen and others 2012). Li and others (2014) 1st identified flavonoid C-glycosides in lotus seed embryos by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS2), and the flavonoid C-glycosides were also identified for the 1st time in lotus. Flavonoid C-glycosides received less attention as secondary plant metabolites compared with their well-understood O-glycosyl cousins (Courts and Williamson 2015). The C-glucosyl bond between the flavonoid carbon skeleton and the saccharide moiety are stable to hydrolytic effect of acidic and enzymatic treatments. This leads to big differences in the bioactivity and pharmacokinetics of these flavonoid C-glycosides (Courts and Williamson 2015; Xiao and others 2016). Flavonoid C-glycosides have multiple pharmacological benefits including antioxidant, hepatoprotective, antiviral, antiinflammatory, and anticancer activities (Courts and Williamson 2015). Further research into the flavonoid C-glycosides of lotus could explore more important applications in functional food industry. In addition, lotus has been widely cultivated throughout Asia and northern Australia, especially in China. It is estimated that annual harvest of dry lotus seeds in China has reached 15000 tons (Guo 2009). To explore other essential applications of lotus seed embryos in food and pharmaceutical industries, it is necessary to thoroughly investigate the constituents and activity of lotus seed embryos. Zhao and others (2014) measured the concentration of some flavonoids and alkaloids in lotus seed rhizomes from Korea, China, Vietnam, and Thailand, and evaluated the antioxidant activities of these lotus seed rhizomes. However, only 4 flavonoids in lotus seed rhizomes were measured. It is necessary to profile the flavonoids in louts seed rhizomes, especially including flavonoid C-glycosides.Consequently, the total flavonoids from lotus seed embryos were fractionated by macroporous resin chromatography, and then subjected to chemical analysis with HPLC-ultraviolet detection (HPLC-UV) and HPLC-MS2, followed by a subsequent antioxidant activity assay to explore the correlations between chemical components of lotus seed embryos and their nutritional or pharmaceutical activities.
References:
Zhu, M., Liu, T., Zhang, C., & Guo, M. (2017). Flavonoids of Lotus (Nelumbo nucifera) Seed Embryos and Their Antioxidant Potential. Journal of Food Science, 82(8), 1834–1841. https://doi.org/10.1111/1750-3841.13784
