Study on extraction technology and antioxidant activity of total flavonoids from Larix kaempferi litter needles

Abstract:

In order to promote the reuse of Larix kaempferi waste resources， this study used the litter needles of Larix kaempferi as raw materials to optimize the extraction process of total flavonoids by ultrasonic-assisted extraction method, and studied the antioxidant activity of flavonoids. By three-factor three-level response surface analysis, the best extraction process for total flavonoids from Larix kaempferi litter needles was: the ethanol concentration is 60%, the liquid-to-material ratio is 33:1 mL/g, the extraction temperature is 80 ℃, the ultrasonic power is 270 W, the ultrasonic frequency is 40 kHz, and the extraction time is 58 min. Studies on the antioxidant activity of different extraction phases in vitro showed that the antioxidant activity was n-butanol phase>water residue phase>ethyl acetate phase>petroleum ether phase from large to small. The semi-inhibitory rate of n-butanol on DPPH free radical was 7.438 μg/mL, which is slightly weaker than that of vitamin C (7.259 μg/mL); the IC50 value of ABTS radical scavenging was 6.425 μg/mL, showing a higher scavenging capacity than vitamin C. These results showed that the extraction process was stable and feasible, with a high yield of total flavonoids and good antioxidant activity. The research results show that Larix kaempferi waste has the potential to develop into plant-derived natural antioxidants.