Microwave-assisted extraction of flavonoids from Cajanus cajan leaves / 中草药

ABSTRACT

Objective: To select the proper method for extracting flavonoids from Cajanus cajan leaves and optimize the extraction parameters. Methods: Taking the extracting rate of orientoside, luteolin, and total flavonoids from C. cajan leaves and anti-oxidative activity as indexes, microwave-assisted method was compared with heat reflux extraction, ultrasound-assisted extraction, and maceration extraction. Central composite design was used for optimization of parameters affecting the extraction of orientoside and luteolin using microwave-assisted method. Results: The results showed that microwave-assisted extraction was the best method and the optimal conditions were 50 mesh particle size, 80% ethanol aqueous, 1 20 material/ethanol aqueous, temperature 60°C, 4 times cycle, 10 min extraction time, 500 W extraction power. The extraction yields of orientoside and luteolin were (4.42 ± 0.01) and (0.10 ± 0.01) mg/g from dry C. cajan leaves, respectively. Conclusion: The microwave-assisted method is feasible with less time, higher extraction yield, and better anti-oxidative activity.