Eco-Friendly Extraction of Chlorogenic Acid and its Biological Activity Evaluation in Vitro

Abstract:

The chlorogenic acid was a natural bioactive ingredient which was usually hindered in the dense structure of plant fibers and difficult to be extracted. An enzymatic cell wall-breaking process was thus developed using the combination of cellulase and ligninase to reduce transfer resistance during extraction and to improve the extraction efficiency of chlorogenic acid from Lonicera japonica leaves. The antioxidant activity in vitro of chlorogenic acid was evaluated by DPPH free radical scavenging method and ferricyanide reduction analysis. The product of enzymatic hydrolysis by the dual-enzyme complex was characterized by SEM. The complex was confirmed to effectively destruct the plant fiber structure and help to form the internal loose structure. The effect of various metal ions on the enzyme activity were weakened in the order of Mg2+，Na+，Ca2+，K+，and Cu2+. The optimized extraction condition was determined using 3∶2 of cellulase to ligninase ratio （U/U） with 50 U/g of enzymes/substrate and Mg2+ at 45 ℃ and pH 4.0 for 11 h. Under the optimal condition，the extraction rate of chlorogenic acid could reach as high as 94.68%，which was 19.60% higher than that of ultrasound-assisted ethanol extraction. The anti-oxidative of reductive activities of chlorogenic acid were improved. This study provides a theoretical foundation to the comprehensive utilization of Lonicera japonica leaves and industrialization of chlorogenic acid.