Lei Wang,Shiping Cao,Guoqing Guo,Yang Hu,Jie Li,Xianying Fang,Linguo Zhao
Deep eutectic solvents (DES) have received extensive attention in the extraction of natural products in the last few years. They are considered a substitute for conventional organic solvents because of their environmental advantages. To efficiently extract bioactive polyphenols and triterpenoids from the medicinal plant Celtis sinensis, fifteen DESs were prepared. The resulting DES1 (choline chloride-levulinic acid) showed the maximum extraction yield of total polyphenols, while DES9 (choline chloride-1,2-propylene glycol) had the maximum yield of total triterpenes. Further, the extraction conditions of DES1 and DES9 were methodically optimized. After optimizing the extraction conditions of DES1 and DES9, the extraction yield of total polyphenols was enhanced from 82.05 mg g−1 to 101.38 mg g−1 and that of total triterpenes from 57.87 mg g−1 to 72.72 mg g−1, both significantly superior to those of traditional water- and methanol-based extraction approaches. We designed a new DES by mixing DES1 and DES9 in the ratio of 7.25 : 2.75 to perform extraction of both polyphenols and triterpenes with high efficiency. The new DES solvent simultaneously increased the extraction yields of polyphenols and triterpenes to 118.46 mg g−1 and 88.51 mg g−1, respectively, after response surface methodology. More importantly, the extract obtained by the mixed solvent of DES1 and DES9 displayed significant antioxidant activity superior to those of extracts individually produced by DES1 and DES9. Our results indicate that a DES-based approach has promising potential in extracting bioactive substances from medicinal arbor species with high efficiency and eco-friendliness.
The present study was executed to analyze the functional phytochemicals of hulless barley grass grown under different intensities of ultraviolet stress. The wheat seedlings were imposed to 0.5, 1.0, 1.5, 2.0, and 2.5 h ultraviolet radiation and harvested in different times at vegetative stage. Specifically, the contents of total polyphenols, total flavonoids, total triterpenes, total polysaccharides, proanthocyanidins, and chlorophyll were determined and antioxidants capacity was evaluated by OH• and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging ability. A mathematical model (Technique for Order Preference by Similarity to Ideal Solution, TOPSIS) was also employed for the comprehensive evaluation of functional components of hulless barley grass at different growth stages. The results showed that the UV stress could efficiently improve/preserve the contents of total polyphenols, total flavonoids, total triterpenes, total polysaccharides, proanthocyanidins, chlorophyll a, chlorophyll b, and total chlorophyll, as well as the OH• and ABTS scavenging capacity. TOPSIS evaluation revealed that the highest phytochemical contents were yield on the 15th day under 1.0 h ultraviolet treatment.
危险品化学品经营许可证（带存储）