Comparative Chemical Characterization of Potato Powders Using 1H NMR Spectroscopy and Chemometrics.

This study presents the metabolic profiling of potato powders obtained through various processing procedures and commercially available potato powders. The metabolic fingerprinting was conducted using 1H NMR-based metabolomics coupled with machine learning projections. The results indicate hot air-dried potatoes have higher fumarate, glucose, malate, asparagine, choline, gamma aminobutyric acid (GABA), alanine, lactate, threonine, and fatty acids. In comparison, steam-cooked potatoes have higher levels of phenylalanine, sucrose, proline, citrate, glutamate, and valine. Moreover, the contents of metabolites in processed potatoes in this study were higher than those found in commercial potato powders, regardless of the drying or cooking methods used. The results indicate that a new processing technique may be developed to improve the nutritional value of potatoes.

Quantitative 1H NMR with global spectral deconvolution approach for the determination of gamma-aminobutyric acid in Chinese yam (Dioscorea polystachya Turczaninow).

We developed a quantitative proton nuclear magnetic resonance (qNMR) with global spectral deconvolution (GSD) method to determine the gamma-aminobutyric acid content in Chinese yam with the proton signal at δH 2.30. Trimethylsilyl-2,2,3,3-tetradeuteropropionic acid sodium salt was set as the internal standard. The method was validated and showed admissible stability, repeatability, and precision. Compared to the traditional high-performance liquid chromatography method, this method did not involve tedious pre-treatment and expensive standard. Compared to ordinary qNMR, GSD algorithm could effectively remove the effect of noise, baseline distortions and signal overlapping. Overall, qNMR with GSD method is a rapid, simple and reliable method to quantitatively determine functional metabolites even overlapped with other compounds in herbs or foods.

Synthesis and Biological Evaluation of Novel Allobetulon/Allobetulin-Nucleoside Conjugates as AntitumorAgents.

Allobetulin is structurally similar tobetulinic acid, inducing the apoptosis of cancer cells with low toxicity. However, both of them exhibited weak antiproliferation against several tumor cell lines. Therefore, the new series of allobetulon/allobetulin-nucleoside conjugates 9a-10i were designed and synthesized for potency improvement. Compounds 9b, 9e, 10a, and 10d showed promising antiproliferative activity toward six tested cell lines, compared to zidovudine, cisplatin, and oxaliplatin based on their antitumor activity results. Among them, compound 10d exhibited much more potent antiproliferative activity against SMMC-7721, HepG2, MNK-45, SW620, and A549 human cancer cell lines than cisplatin and oxaliplatin. In the preliminary study for the mechanism of action, compound 10d induced cell apoptosis and autophagy in SMMC cells, resulting in antiproliferation and G0/G1 cell cycle arrest by regulating protein expression levels of Bax, Bcl-2, and LC3. Consequently, the nucleoside-conjugated allobetulin (10d) evidenced that nucleoside substitution was a viable strategy to improve allobetulin/allobetulon's antitumor activity based on our present study.

Discovery of an effective processing method for edible rhizome to enhance the gamma-aminobutyric acid content.

This study aimed to discover a simple, rapid, effective, inexpensive, and natural method to enhance the GABA content in edible rhizomes. To achieve this aim, edible rhizome samples were treated with different processing methods. Drying with hot air increased the GABA content in Chinese yam (CY) eight-fold compared with untreated CY. Drying with sunshine or hot air increased it 13- and 28-fold in taro root, respectively. These processing methods also produced an apparent increase in the GABA contents in other edible rhizome, such as lotus rhizomes, potatoes, and sweet potatoes. However, lyophilization did not affect the GABA content. Further, HPLC data showed that while GABA levels increased, glutamate levels decreased, indicating that GABA is produced by the catalytic action of glutamate decarboxylase on glutamate under drought conditions. Drying with hot air or sunshine to enhance the GABA content was not indicated in the literature.

[Photodegradation of naproxen in aqueous systems by UV irradiation: mechanism and toxicity of photolysis products].

This paper studies the degradation mechanism, the reaction kinetics and the toxicity of photolysis products of naproxen in waters under UV irradiation (120 W mercury lamp) by quenching experiments of reactive oxygen species (ROS), oxygen concentration experiment and toxicity evaluation using Vibrio fischeri bacteria. The results demonstrated that NPX could be degraded effectively by UV irradiation and the photolysis pathways was the sum of the degradation by direct photolysis and self-sensitization via ROS, and the contribution rates of self-sensitized photodegradation were 0.1%, 80.2%, 35.7% via *OH, (1)O2, O2*-, respectively. The effect of oxygen concentration illustrated that dissolved oxygen had an inhibitory effect on the direct photodegradation of NPX, and the higher the oxygen content, the more obvious the inhibitory effect. The toxicity evaluation illustrated the formation of some intermediate products that were more toxic than NPX during the photodegradation of NPX. The process of NPX degradation in all cases could be fitted by the pseudo first-order kinetics model.