In vitro assay on physiological activities of flower and leaf extracts of red lotus.

This study was conducted to determine physiological activities of flower and leaf extracts of red lotus (Nelumbo nucifera). Flowers and leaves of red lotus grown at a field in Donggang-Myun, Naju-City, Jeonnam, was harvested on August 14, 2007. The flower and leaf samples were extracted with either hot water or ethanol, and were examined for their physiological activities. Content of total phenolics was the greatest (92.2 ㎎ㆍl⁻¹) in the ethanol extract of red lotus leaves. The α, α-diphenyl-β-picryl-hydrazyl (DPPH) radical scavenging activity of ethanol extracts of flowers and leaves at 500 ㎎ㆍl⁻¹ was 94.1% and 83.5%, respectively. However, the activity of hot-water extracts of flowers and leaves was 30.2% and 18.5%, respectively, showing higher activity in the ethanol than hot-water extracts. Contents of total flavonoid in the ethanol extracts of leaves and flowers were 90.2 ㎎ㆍl⁻¹ and 46.2 ㎎ㆍl⁻¹, respectively. Nitrite scavenging activity (% of the control) of the ethanol extracts at 500 ㎎ㆍl⁻¹ from flowers and leaves was 80.7% and 49.7%, respectively. Difference in mushroom tyrosinase inhibition activity (% of the control) of flower and leaf extracts between two extraction methods was not significantly different. Leaf and flower extracts of red lotus at 500 ㎎ㆍl⁻¹ showed highly significant anti-microbial activity against six gram positive and three gram negative microbial strains, regardless of plant parts and extraction methods used.