Extraction, purification of saponins components from Xanthoceras sorbifolium Bunge leaves: potential additives in the food industry

Xanthoceras sorbifolium Bunge leaves (XLs) are the agricultural by-products of Xanthoceras sorbifolium Bunge, which are widely cultivated in the north of China. For recycling XLs, in this study, the extraction optimization, construction of purification models, identification of saponins components and the antimicrobial and antioxidant activities were firstly investigated. Ultrasonic-assisted extraction of saponins from XLs using Box-Behnken design (BBD) method of response surface methodology (RSM) was investigated. The optimum conditions were as follows: the temperature 60.79 degrees C, ethanol concentration 71.56%, liquid/solid ratio 30.67 (v/m). Under these conditions, the optimization of the extraction with maximize yield of 7.36 +/- 0.078% was obtained. Corresponding adsorption models were established to analyze the maximum yield of saponins during the adsorption process, and AB-8 resin was used for the purification of saponins using static adsorption/desorption with final purity was 38.48 +/- 2.51%. Then, ten saponins, including ginsenoside-Rg1, ginsenoside-F, ginsenoside-Rg2, alpha-hederin, hederagenin, licoricesaponin G2, betulinic acid, ursolic acid, betulonic acid, and dehydro (11,12) ursolic acid lactone, were identified using ultra performance liquid chromatography-mass spectrometry (UPLC-MS). Biological evaluations showed that XLs saponins possessed good scavenging activity on DPPH and ABTS, and exerted obvious inhibitory effect on E. coli (Gram-negative bacteria) and S. areus (Gram-positive bacteria). Results indicated that the saponins extracted from XLs can be used as a natural antimicrobial and antioxidant agent to the food products. This study provided a theoretical basis for the development and utilization of the by-product saponins from the bio-products resources XLs.

Automated summary

In this study, the extraction, purification, identification, and biological activities of saponins from Xanthoceras sorbifolium Bunge leaves were investigated. The results showed that the saponins possessed good scavenging activity on DPPH and ABTS, and exhibited inhibitory effects on E. coli and S. aureus. This study provides a theoretical basis for the development and utilization of the by-products from Xanthoceras sorbifolium Bunge leaves.