Studies On Extraction, Purification And Activity Of Flavonoids From Leaves Of Fagopyrum Tataricum (L.) Gaertn

The leaf which contained the hightest flavonoids among the materials, so the flavonoids from tartary buckwheat leaves were investigated on the character and quantity for the multi-utilization of tartary buckwheat resource in this paper. And tartary buckwheat leaves was selected to produce tartary buckwheat flavonoids powder (TBFP), and the extraction and purification procedure of TBFP was optimized. A method of extraction and purification of rutin from tartary buckwheat was estabilished. The results were as follow:1. The best technology of extracting flavonoids from tartary buckwheat leaves was as follow: the leaves(5g) was extracted with 150mL, pH=8, 60% ethanol under ultrasonic(20kHz) for 40 minutes, and reflux 120min in a water bath at 70℃.The extraction ratio of flavonoids was 95.26%.2. The column of DA-201 resin was applied in the purification of flavonoids extract, the best technology was as follows:First, condensing the extract to slurry, removing the oiliness by petroleum ether, extracting flavonoids from the slurry for 8h with acetone, filtrating in vacuum, and adapting the content of total flavonoids of extracted solution to 0.5mg/mL.Second, taking 150 mL sample solution (0.5mg/mL) to pass the column at the flow speed of 1.0mL/min.Third, eluting the flavonoids by 150 mL 80% ethanol-water solution at the velocity of 1.0 mL/min.3. Condensing and drying the eluted solution under the vacuum. Refined craft of the buckwheat leaf purification: The methyl alcohol heated the backset current is dissolved, filtrate and put coldly, crystallization. Mother liquor retrieve methyl alcohol, put coldly crystallization, filter, wet 40℃in the oven of rutin 2 times, 0.09MPa photophobic condition bakes most methyl alcohol, then dry to 90℃gradually, the step made rutins to heat and dissolve to about 70℃of then utilized n-butyl alcohol to dissolve, filter, filtrate it with 5mL deionized water, the cold crystallization puts, filter rutins wetly, put 90℃in 0.09MPa photophobic condition oven dry rutins purly. The contents of rutin and total flavonoids of tartary buckwheat flavonoids powder were 95.13%, 97.89%, separately4. The condition of HPLC was: column, Kromasil C18, 10μm, 4.6×250mm stainless steel; mobile phase, methanol—water—acetic acid(40: 60: 1); flow rate: 1.0 mL/ min; scanning wave-length 330 nm; temperature of column: room temperature(20℃). The absorbance peak of rutin is symmetry and seperated on the radical line. The conelation of content of rutin and area of peak was y = 806.16x + 297.45 R² = 0.999, the correlation was significant..5. The antioxidizing activity of the extract of shattered leaves was better in scavenging superoxide anion, hydroxyl radical and deoxidizing Fe³⁺. And the capacity of scavenging enhance with the raise of content of total flavonoids in extracting from tartary buckwheat leaves. But the capacity of scavenging of total flavonoids in extracting flavonoids from tartary buckwheat leaves was inferior to Vc. The capability of scavenging sodium nitrite by extract of extracting from tartary buckwheat leaves was 67.18%. The results showed that the extract has high capabilities of scavenging sodium nitrite.