Phenolic compounds and antioxidant properties of bulb extracts of Lilium leucanthum (Baker) Baker native to China

Lilium leucanthum is popularly used as one of the ornamental lily plant and medicinal bulbs in its local distribution areas with a long history in China. The aim of this study was to provide sufficient experimental evidence for further utilisation of wild L. leucanthum as a source of natural antioxidants. Total phenolic content and antioxidant activity of three ecotypes of L. leucanthum from Zhenping, Zhouqu and Liuba County of China P. R. were determined using the method of Folin-Ciocalteau and 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, cupric-reducing antioxidant capacity, hydroxyl radical scavenging activity, superoxide radical scavenging activity and lipid peroxidation inhibition. Ten antioxidant standards were used in high-performance liquid chromatography (HPLC) with diode array detection for phenolic compounds. The results showed that the tested samples from wild Zhenping ecotype had the highest phenolic content and the strongest antioxidant capacity among all three ecotypes, except for superoxide radical scavenging activity. HPLC analysis revealed that myricetin was the most abundant phenolic and the chlorogenic acid was the major phenolic acid in all bulb extracts tested. According to the linear correlation analysis, the total phenolic content was the major contributor to the total antioxidant capacity in lily bulb except for superoxide radical scavenging activity. The results suggest the wild Zhenping ecotype of the selected L. leucanthum would have a promising application as a potential source of food and medicinal herb by virtue of its valuable properties for human health.