Investigating antioxidant extraction from Receptaculum Nelumbinis

Abstract

Receptaculum Nelumbinis, also known as Lotus receptacle, is a byproduct of the seed-harvesting process of Nelumbo nucifera. It is dried and used as fuel, aesthetic decoration or for cooking drinking water. Extracts from Lotus receptacle contain several active compounds such as alkaloids, polyphenols, flavonoids, glycosides, tannins, steroids, and saponins. Among these, polyphenols are a compound of strong antioxidant activity. In this study, the extraction method and solvent were investigated to increase the polyphenol content. The polyphenol and flavonoid contents and the antioxidant activity of the Lotus receptacle extract were also evaluated. The results showed that the highest yield of the extract (34,06%) was obtained using the reflux method with 70% ethanol as the solvent, a 90-minute extraction time, and a temperature of 70^oC. The chemical composition of the Lotus receptacle extract included polyphenols, alkaloids, flavonoids, terpenoids, tannins, and coumarins. The extract’s flavonoid and polyphenol contents were determined to be 361,86 ± 11,16 mg QE/g and 585,12 ± 6,01 mg GAE/g, respectively. The Lotus receptacle extract also exhibited strong antioxidant activity, as demonstrated by its ability to scavenge DPPH and ABTS^•+ free radicals and its reducing power (RP), with corresponding EC50 values of 11,10 ± 0,14 μg/mL, 6,78 ± 0,52 μg/mL and 56,05 ± 0,73 μg/mL, respectively. These results suggest that the Lotus receptacle is a potential source of antioxidant phytochemicals.