Soluble sugars, malic acid, and ascorbic acid in 17 apple cultivars (Malus domestica Borkh.) and three wild forms (M. pumila ‘Saiwaihong’, M. prunifolia (Willd.) Borkh. and M. micromalus Makino) from three major apple cultivation regions in China were quantified using gas chromatography equipped with flame ionization detector (GC-FID). Fructose was the most abundant sugar, followed by sucrose, glucose, and sorbitol. Wild apples contain more sorbitol and less sucrose and were significantly more acidic than cultivated fruits. The total sugar content varied from 110 to 160 mg/g fresh fruits, total acid content from 2 to 6 mg/g, with a strong influence of genetic background and growth location. Overall, ‘Gala’, ‘Xiali’, ‘Liuyuehong’, ‘Lihong’, ‘Starking Delicious’, and ‘Starkrimson’ were characterized by higher sugar/acid ratio indicating sweeter taste compared to other cultivars. The wild apples had the highest content of ascorbic acid (0.6–0.96 mg/g). Compared to other cultivars, ‘Zhongqiuwang’, ‘Qinguan’, and ‘Nagafu No. 2′ were richer in ascorbic acid. The ascorbic acid content in the commercial cultivars was highly dependent on growth location. The content of malic acid and sucrose positively correlated to altitude, and that of glucose negatively. Malic acid positively correlated with ascorbic acid and sucrose, glucose content with ascorbic acid.

As a valuable traditional Chinese herbal medicine, Radix Astragali has attracted much attention due to its extensive pharmacological activities. In this study, density functional theory (DFT) was used thermodynamically and kinetically in detail to predict the antioxidant activity and reaction mechanisms involved in the free radical scavenging reactions of three representative isoflavonoids (formononetin, calycosin, and calycosin-7-glucoside) extracted from Radix Astragali. Three main mechanisms, including hydrogen atom transfer (HAT), proton transfer after electron transfer (SET-PT), and sequential proton loss electron transfer (SPLET) were examined by calculating the thermodynamic parameters. It was found that HAT is the predominant mechanism in the gas phase, while SPLET is supported in the solvent environment. The isoflavonoids’ order of antioxidant activity was estimated as: calycosin > calycosin-7-glucoside > formononetin. For the calycosin compound, the result revealed the feasibility of double HAT mechanisms, which involve the formation of stable benzodioxazole with significantly reduced energy in the second H⁺/e⁻ reaction. In addition, the potential energy profiles and kinetic calculations show that the reaction of ^•OH into the 3′-OH site of calycosin has a lower energy barrier (7.2 kcal/mol) and higher rate constant (4.55 × 10⁹ M⁻¹ s⁻¹) compared with other reactions in the gas phase.

Thiamethoxam and its metabolite clothianidin residues pose a potential threat to human health. This study aims to investigate the residue behavior and acute dietary risk assessment of thiamethoxam and clothianidin on spinach. Thiamethoxam and clothianidin were extracted using a quick, easy, cheap, effective, rugged, safe (QuEChERS) method and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). At spike levels from 0.01 to 5 mg kg⁻¹, the average recoveries of both analytes were in the range of 94.5–105.5%, with relative standard deviations (RSDs) of 3.8–10.9%. The dissipation behavior of thiamethoxam followed first-order kinetics, with half-lives of ≤1.6 days. Clothianidin appeared readily as a plant metabolite with highest level exhibited during 3 to 5 days after application. Temperature and light may be two main factors for degradation of thiamethoxam. Besides, acute risk assessment of thiamethoxam and clothianidin was evaluated with risk quotients (RQs) <100%, which suggested a low health risk for all consumer groups of Chinese residents.

Anthocyanins, typical polyphenol compounds in grape skin, have attracted increasing interest due to their health-promoting properties. In this body of work, five representative anthocyanins (Cy-3-O-glc, Dp-3-O-glc, Pn-3-O-glc, Mv-3-O-glc, and Pt-3-O-glc) were studied using the density functional theory (DFT) to elucidate structure–radical scavenging activity in the relationship and the reaction path underlying the radical-trapping process. Based on thermodynamic parameters involved in HAT, SET-PT, and SPLET mechanisms, along with the structural attributes, it was found that the C4′ hydroxyl group mainly contributes to the radical scavenging activities of the investigated compounds. Pt-3-O-glc exhibits a good antioxidant capacity among the five compounds. The preferred radical scavenging mechanisms vary in different phases. For the Pt-3-O-glc compound, the calculations indicate the thermodynamically favoured product is benzodioxole, rather than o-quinone, displaying considerably reduced energy in double HAT mechanisms. Additionally, the thermodynamic and kinetic calculations indicate that the reaction of ^•OH into the 4′-OH site of Pt-3-O-glc has a lower energy barrier (7.6 kcal/mol), a higher rate constant (5.72 × 10⁹ M⁻¹ s⁻¹), and exhibits potent ^•OH radical scavenging properties. Molecular docking results have shown the strong affinity of the studied anthocyanins with the pro-oxidant enzyme xanthine oxidase, displaying their significant role in inhibiting ROS formation.