Purification, Identification, and Inhibitory Mechanisms of a Novel ACE Inhibitory Peptide from Torreya grandis.

Torreya grandis meal has a high protein content and an appropriate amino acid ratio, making it an excellent protein source for producing ACE inhibitory peptides. To promote its application in food, medicine, and other fields, an alkaline protease hydrolysate of Torreya grandis was used in this study to isolate and identify a novel angiotensin-converting enzyme inhibitory peptide, VNDYLNW (VW-7), using ultrafiltration, gel chromatography purification, LC-MS/MS, and in silico prediction. The results show that the IC50 value of VW-7 was 205.98 µM. The Lineweaver-Burk plot showed that VW-7 had a mixed-type inhibitory effect on ACE. Meanwhile, according to the results of molecular docking, VW-7 demonstrated a strong affinity for ACE (binding energy -10 kcal/mol). VW-7 was bound to ACE through multiple binding sites. In addition, VW-7 could remain active during gastrointestinal digestion in vitro. Nitric oxide (NO) generation in human endothelial cells could rise after receiving a pretreatment with VW-7. These results indicated that Torreya grandis meal protein can be developed into products with antihypertensive function, and VW-7 has broad application prospects in the field of antihypertensive.

Purification of d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) by a temperature-modulated silica gel column chromatography: use of Taguchi method to optimize purification conditions.

The demand for high purity d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) is increasing with the exploitation of TPGS-related products. Previously, we synthesized a TPGS mixture by esterifying vitamin E succinate with polyethyleneglycol 1000. In this study, a temperature-modulated silica gel chromatographic column was used to purify the synthesized TPGS. Taguchi method was used to optimize purification conditions associated with column temperature, loading amount, feedstock concentration and flow rate of mobile phases. Purification efficacy under the Taguchi optimized conditions was predicted theoretically and the predicted results were verified experimentally. High-performance liquid chromatography was used to quantify the unpurified and purified TPGS. The Taguchi-based analysis separately produced an optimum combination of purification conditions for TPGS purity and recovery. Under the optimized conditions, both the theoretical prediction and the confirmatory experiment yielded TPGS purity and recovery approximating to 98% each. Impressively, the study also found that column temperature had a considerable effect on purification efficacy, in particular on TPGS purity, although it was a less influential factor compared to loading amount and feedstock concentration.