Antioxidant and Hypoglycemic Activity of Sequentially Extracted Fractions from Pingguoli Pear Fermentation Broth and Identification of Bioactive Compounds

Gamma Irradiation and Exogenous Proline Enhanced the Growth, 2AP Content, and Inhibitory Effects of Selected Bioactive Compounds against α-Glucosidase and α-Amylase in Thai Rice

Exogenous proline can improve the growth, aroma intensities, and bioactive compounds of rice. This study evaluated the effects of gamma irradiation under proline conditions on the 2-acetyl-1-pyrroline (2AP), phenolic, and flavonoid contents of rice. Moreover, the bioactive compounds of gamma-irradiated rice under proline conditions that inhibited α-glucosidase and α-amylase were evaluated by in silico study. A low gamma dose (40 Gy) induced the highest rice growth under 5 mM proline concentration. The highest 2AP content was stimulated at a gamma dose of 5－100 Gy under 10 mM proline concentration. At 500 and 1,000 Gy gamma dose, the highest flavonoid and phenolic contents of rice were stimulated. 1-(2-Hydroxy-5-methylphenyl)-ethanone, which had the highest binding affinity (-7.9 kcal/mol) against α-glucosidase, was obtained at 500 and 1,000 Gy gamma dose under 5 and 10 mM proline concentrations. Meanwhile, 6-amino-1,3,5-triazine-2,4(1H,3H)-dione, which had the highest binding affinity (-6.3 kcal/mol) against α-amylase, was obtained under 10 mM proline concentration in non-gamma-irradiated rice. The results indicate that using a combination of gamma irradiation and exogenous proline is suitable for producing new rice varieties. Moreover, the bioactive compounds that were obtained in new rice varieties exhibited health benefits, especially for diabetes mellitus treatment (inhibition of α-glucosidase and α-amylase).

Studies on the Changes of Fermentation Metabolites and the Protective Effect of Fermented Edible Grass on Stress Injury Induced by Acetaminophen in HepG2 Cells

In this study, gas chromatography-mass spectrometry (GC-MS) based untargeted metabolomics was used to describe the changes of metabolites in edible grass with Lactobacillus plantarum (Lp) fermentation durations of 0 and 7 days, and subsequently to investigate the protective effect of fermented edible grass on acetaminophen-induced stress injury in HepG2 cells. Results showed that 53 differential metabolites were identified, including 31 significantly increased and 22 significantly decreased metabolites in fermented edible grass. Fermented edible grass protected HepG2 cells against acetaminophen-induced stress injury, which profited from the reduction in lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels and the enhancement in superoxide dismutase (SOD) activity. Cell metabolomics analysis revealed that a total of 13 intracellular and 20 extracellular differential metabolites were detected. Fermented edible grass could regulate multiple cell metabolic pathways to exhibit protective effects on HepG2 cells. These findings provided theoretical guidance for the formation and regulation of bioactive metabolites in fermented edible grass and preliminarily confirmed the protective effects of fermented edible grass on drug-induced liver damage.

Influence of Particle Size and Extraction Methods on Phenolic Content and Biological Activities of Pear Pomace

The main goal of this research was to investigate how particle size influences the characteristics of pear (Pyrus Communis L.) pomace flour and to examine the impact of different pre-treatment methods on the phenolic content and associated bioactivities. Pear pomace flour was fractionated into different particle sizes, namely 1 mm, 710 µm, 180 µm, 75 µm and 53 µm. Then two extraction methods, namely maceration with methanol and two-step extraction with hexane via Soxhlet followed by ultrasound extraction with methanol, were tested. Total phenolic and total flavonoid contents ranged from 375.0 to 512.9 mg gallic acid/100 g DW and from 24.7 to 34.6 mg quercetin/100 g DW, respectively. Two-step extraction provided antioxidant activity up to 418.8 (in FRAP assay) and 340.0 mg Trolox/100 g DW (in DPPH assay). In order to explore various bioactive properties, this study assessed the inhibitory effects of enzymes, specifically α-amylase and β-glucosidase (associated with antidiabetic effects), as well as angiotensin-converting enzyme (linked to potential antihypertensive benefits). Additionally, the research investigated antibacterial potential against both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria, revealing significant results (p < 0.05), particularly in the case of the two-step extraction method. This investigation underscores the substantial value of certain food industry wastes, highlighting their potential as bioactive ingredients within the framework of a circular economy.