Abstract

The in vitro antioxidant activity of ten different parts of lotus (Nelumbo nucifera Gaertn.) was evaluated and compared. Among the ten lotus extracts, the receptacle did not only possessed the highest phenolic, flavonoid and proanthocyanidin contents, but its 2-picrylhydrazyl free (DPPH) and 2, 2'-Azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, reducing power as well as total antioxidant activity were also comparable to, if not better than those of the butylated hydroxytoluene (BHT)  control (p < 0.05). Compared with the BHT, all ten lotus extracts even exhibited significantly (p < 0.05) higher metal chelating activity. Nevertheless, the hydroxyl radical scavenging ability of all ten lotus extracts was significantly (p < 0.05) lower than that of the ascorbic acid control. In contrast to the metal chelating ability, phenolic compounds in the ten lotus extracts would likely be responsible for their DPPH and ABTS radical scavenging activities.

Key words: Louts (Nelumbo nucifera), total phenolic content, total flavonoid content, total proanthocyanidin content, antioxidant activity.