Total Flavonoid Distribution in the Different Parts of Lotus and Study on the Extraction Technology of Flavonoid in Lotus Leaf

OBJECTIVE To determine the total flavonoid distribution in the different parts of lotus and explore on the best extraction technology of flavonoid in lotus leaf. METHODSThe total flavonoids of lotus petal, lotus leaf, lotus stalk, lotus receptaculu mloti and lotus stamen were extracted by Soxhlet′s apparatus method, the NaNO2-Al (NO3)3-NaOH solution was adopted as development system and rutin as the standard sample, and the total flavonoids from the five parts of lotus were then determined through ultraviolet spectrophotometer and their distribution was calculated. The ultrasonic-assistant reflux extraction method was also used to extract the flavonoids of lotus leaf, and the optimum extraction condition was explored using orthogonal design. RESULTSThe total flavonoid distribution in the different parts of lotus is as follows: lotus receptaculu mloti > lotus leaf > lotus stamen > lotus petal > lotus stalk. The extraction technology of flavonoid in lotus leaf by using ultrasonic-assistant reflux extraction method was got to the optimum condition: 30 fold of 60% alcohol solution proportion to the lotus leaf materials, ultrasonic-assistant reflux extraction 90 min under the temperature 70℃,and ultrasonic time 20 min. CONCLUSIONThe content of total flavonoid varies in the different parts of lotus; the extraction efficiency of flavonoid of lotus leaf has been influenced to some extent under different experimental condition using ultrasonic-assistant reflux extraction.