Flavonoids are a class of poly-phenyl compounds, which are plant secondary metabolites. They have the
advantages of anti-inflammatory, antibacterial, hypolipemic, scavenging hydroxyl free radicals and cancer
prevent.
In the alkaline nitrite solution, the flavonoid and the aluminum ion can form a red complex with a
characteristic absorption peak at 470 nm. The sample flavonoid content can be calculated by measuring the
absorbance of the sample extract at 470 nm.
Reagents and Equipment Required but Not Provided:
Spectrophotometer, balance, oven, sieve, comminution apparatus, sonic breaker, centrifuge, 1mL glass
cuvette, 60% ethanol, distilled water.
Sample preparation:
The sample is dried to constant weight, pulverized, and after passing through a 40 mesh sieve, about 0.1 g
is weighed, 1 mL of the Extract is added, and extraction is performed by ultrasonic extraction for 30min
(ultrasonic power is 300 W, crushed for 5 s, intermittently 8 s, 60℃, total time 30 min). Centrifuge at
12000 rpm and 25℃ for 10 min, take the supernatant, and dilute to 1 mL with the extract.
