A review on extraction, composition, structure, and biological activities of polysaccharides from different parts of Nelumbo nucifera

Nelumbo nucifera (lotus plant) is an important member of the Nelumbonaceae family. This review summarizes the studies conducted on it since the past 15 years to provide an understanding on future areas of focus. Different parts of this plant, that is, leaves, roots, and seeds, have been used as food and for the treatment of various diseases. Polysaccharides have been extracted from different parts using different methods. The manuscript reviews the methods of extraction of polysaccharides used for leaves, roots, and seeds, along with their yield. Some methods can provide better yield while some provide better biological activity with low yield. The composition and structure of extracted polysaccharides have been determined in some studies. Although monosaccharide composition has been determined in various studies, too little information about the structure of polysaccharides from N. nucifera is available in the current literature. Different useful biological activities have been explored using in vivo and in vitro methods, which include antioxidant, antidiabetic, antitumor, anti‐osteoporotic, immunomodulatory, and prebiotic activities. Antitumor activity from polysaccharides of lotus leaves is yet to be explored, besides lotus root has been underexplored as compared to other parts (leaves and seeds) according to our literature survey. Studies dedicated to the successful use of combination of extraction methods can be conducted in future. The plant provides a therapeutic as well as nutraceutical potential; however, antimicrobial activity and synergistic relationships of polysaccharides from different parts of the plant need further exploration. Nelumbo nucifera is an important plant that has been used for therapeutic purposes and is an important part of human food. Leaves, roots, and seeds of this plant have been explored for extracting polysaccharides using different techniques and, in some studies, monosaccharide composition and structure have been determined. Several useful biological activities have been explored that have been discussed separately for each part of the plant in this review. These show a significant potential for this plant to be used for pharmaceutical as well as nutraceutical purposes. Antimicrobial potential has not been explored yet to the best of our knowledge from polysaccharides of this plant. Synergistic relationship of polysaccharides of this plant for therapeutic purposes remains to be studied, besides the determination of stru