Extraction and Determination by UV Spectrophotometry of Flavonoids from Ginkgo biloba

This study discussed organic solvent extraction and ultrasonic extraction method.The extraction ratio of ultrasonic method was higher than the organic solvent extraction method when it was used for extraction of flavonoids.Single factor experiments were done with different extraction conditions including the ratio of Ginkgo biloba and ethanol,ultrasonic time and the volume fractions of ethanol.The optimum extraction conditions of flavonoids from Ginkgo biloba were investigated by using orthogonal design.The results showed that 1g:30 mL,70% ethanol and extraction for 30 min was the optimal condition.Quantitative analysis of flavonoids was achieved by ultraviolet spectrophotometry and do not need add colour-display reagent,determined at 258 nm directly as maximum absorption wavelength.The results indicated that the average content of flavonoids in Ginkgo biloba was 2.77% under the optimal conditions,the relative standard deviation in precision test was 0.302%,and the average recovery rate was 100.3%.This study suggested that this method was simple,accurate,and also suitable for the extraction and quantitative analysis of flavonoids in Ginkgo biloba.