Qing-Sheng Zhao

Cannabinoids are very valuable natural products of industrial hemp. In this work, the high-pressure ultrasonic-assisted extraction (HUE) technique was employed for the first time to extract cannabinoids from industrial hemp leaves. A maximum extraction yield (60.02 ± 0.09 mg/g) was obtained through the single-factor experiments, which was much higher compared to ultrasonic-assisted extraction (UE, 42.88 ± 0.02 mg/g) and stirring extraction (SE, 35.35 ± 0.07 mg/g). The optimized HUE conditions were: extraction time was 40 min, EtOH concentration was 60%, extraction temperature was 60 °C, ultrasonic power was 400 W, RL/S was 20 mL/g, stirring rate was 400 rpm, and extraction pressure was 0.6 MPa. The total phenolic content (TPC, 244.36 ± 0.84 mg GAE/g extract) and the total flavonoids content (TFC, 0.27 ± 0.02 mg RE/g extract) of the HUE extract were also the highest. The HUE mechanism was revealed to some extent by several characterizations including surface morphology that HUE could deeply destroy the structure of leave particles. Furthermore, the in vitro antioxidant activity of HUE extract was the best among the three extracts. The EC50 values against DPPH and ABTS were 0.28 mg/mL and 0.25 mg/mL, respectively. In summary, this work confirmed that HUE was a suitable method for extracting cannabinoids and the obtained extract with a high content of cannabinoids had great application values.

Catechin (C) is a flavonoid natural polyphenol with various biological activities; however, it has poor solubility, stability and oral bioavailability, which greatly limit its application in the food and medical fields. Unlike ordinary cyclodextrins, hyperbranched cyclodextrin (CDP), as a hyperbranched polymer, exhibits several remarkable characteristics, such as a high degree of molecular branching, abundant active ends, and a macromolecular structure with multiple cavities. These features provide CDP with unique advantages in a variety of applications. In this study, catechin/hyperbranched cyclodextrin inclusion complex (catechin/CDP IC) and catechin/β-cyclodextrin inclusion complex (catechin/β-CD IC) were prepared using the freeze-drying method at a molar ratio of 1 : 1. The embedding efficiencies (CEs) of the two inclusion complexes were 83.85% and 64.85% respectively. Structural characterization was carried out via FT-IR, XRD, SEM, DSC and ¹H NMR analyses. Furthermore, the results for solubility, thermal stability, storage stability, sustained-release characteristics, cell viability, antioxidant capacity and antibacterial ability of catechin complexed with CDP were superior to those complexed with β-CD. This study provides potential application value for the further development of catechin-based functional foods and health products.

Procyanidins (PC) are formed by the polymerisation of flavan-3-ol monomers, which have excellent bioactivity and present great health benefits. However, the application range of the PC is greatly limited due to their poor stability. Therefore, in this study, starch aerogels were used as carriers to encapsulate PC. After screening, wheat starch aerogel (WSA) was finally chosen to encapsulate PC. Afterward, characterization (SEM, XRD, FT-IR, TGA and BET), stability testing, investigations on antioxidant activity, and in vitro tests simulating digestion were carried out. The results of relevant characterization showed that the micro surface structure of the procyanidin wheat starch aerogel (PC-WSA) presented a network structure, and PC were encapsulated in WSA. In addition, PC-WSA allows PC to be released in the final stage of simulated digestion. Meanwhile, the results of antioxidant experiments indicate that PC-WSA exhibits antioxidant activity after encapsulating PC. Moreover, the retention of PC in PC-WSA was still 53.63 ± 3.23% when stored at 70 °C for 20 days. After 6 days of light exposure, the retention of PC in PC-WSA under different light sources was all above 85%, which was higher than that of PC. In conclusion, the wheat starch aerogel could improve the stability of PC and has great potential for application.

Phillyrin has good biological activity, but it is insoluble in water, which restricts its use in various industries. In our work, we prepared phillyrin using a green and rapid method from Forsythia suspensa leaves, and its purity is greater than 93%. Then, phillyrin was made to interact with different kinds of cyclodextrins (CDs) as a way to improve the water solubility of phillyrin, and the interaction mechanism between CDs and phillyrin was speculated by various characterization methods. First, phase solubility experiments showed that the phase solubility curves of all three CD inclusion complexes were A_L-shaped, indicating that all three inclusion complexes were prepared using phillyrin with CDs in a 1 : 1 stoichiometric ratio. And based on this result, three cyclodextrin inclusion compounds, phillyrin/HP-β-CD (complexation efficiency (CE): 82.58%, the loading efficiency (LE): 22.27%), phillyrin/DM-β-CD IC (CE: 89.31%, LE: 24.83%) and phillyrin/β-CD IC (CE: 68.59%, LE: 23.67%), were prepared. Then, phillyrin was successfully encapsulated as determined by various characterization analyses, after which the conformations of the inclusion complex interactions were analyzed by NMR and molecular docking. The result also indicated that the water solubility of the phillyrin/HP-β-CD, phillyrin/DM-β-CD IC and phillyrin/β-CD IC has significantly improved, which was 30.02, 41.91 and 14.56 times higher than that of pure phillyrin. And the inclusion of CDs also considerably improved the antioxidant capacity of phillyrin, and the DPPH clearance rates of the three inclusion compounds were 4.34, 4.46 and 4.79 times higher than those of pure phillyrin, respectively, and the ABTS clearance rates were 1.35, 1.70 and 1.62 times higher than that of pure phillyrin. The prepared inclusion complexes can be applied in the functional food industry as active ingredients.