To investigate the anti-diabetic properties of chebulic acid (CA) associated with the prevention of methyl glyoxal (MG)-induced mitochondrial dysfunction in INS-1 pancreatic β-cells, INS-1 cells were pre-treated with CA (0.5, 1.0, and 2.0 μM) for 48 h and then treated with 2 mM MG for 8 h. The effects of CA and MG on INS-1 cells were evaluated using the following: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; glyoxalase 1 (Glo-1) expression via Western blot and enzyme activity assays; Nrf-2, nuclear factor erythroid 2-related factor 2 protein expression via Western blot assay; reactive oxygen species (ROS) production assay; mRNA expression of mitochondrial dysfunction related components (UCP2, uncoupling protein 2; VDAC1, voltage-dependent anion-selective channel-1; cyt c, cytochrome c via quantitative reverse transcriptase-PCR; mitochondrial membrane potential (MMP); adenosine triphosphate (ATP) synthesis; glucose-stimulated insulin secretion (GSIS) assay. The viability of INS-1 cells was maintained upon pre-treating with CA before exposure to MG. CA upregulated Glo-1 protein expression and enzyme activity in INS-1 cells and prevented MG-induced ROS production. Mitochondrial dysfunction was alleviated by CA pretreatment; this occurred via the downregulation of UCP2, VDAC1, and cyt c mRNA expression and the increase of MMP and ATP synthesis. Further, CA pre-treatment promoted the recovery from MG-induced decrease in GSIS. These results indicated that CA could be employed as a therapeutic agent in diabetes due to its ability to prevent MG-induced development of insulin sensitivity and oxidative stress-induced dysfunction of β-cells.

Background: Various Schisandra chinensis (SC) varieties grow in diverse regions in Korea. However, there is no valid scientific evidence of these varieties. This study aimed to select the excellent resources in terms of the growth characteristics, antioxidant activities, and analysis of the active compounds of the SC collection. Method and Results: In total, 154 resources of SC were collected from various regions of Korea. The growth characteristics were measured by the number of fruit bunches, fruit number, and weight of 100 fruits. The antioxidant activities were investigated by analyzing the total flavonoid and total polyphenol contents and the radical scavenging activity of DPPH and ABTS. Schizandrin A, schizandrin c, gomisin a, and gomisin N were analyzed by HPLC. Each resource showed different growth characteristics. Among the antioxidative effects, the highest 20 resources showed high antioxidant activities in selected 29 resources. Analysis of the SC lignan index showed that all resources contained more than 1.16% of active compounds. Conclusions: All of the selected 29 SC resources were shown to have excellent growth characteristics, antioxidant activities, and bioactive compound richness. Especially, SC-004, SC-007, and SC-154 showed the best growth characteristics, and SC-22, SC-40, and SC-45 showed the best antioxidant activities and bioactive compound richness.

Background: There have been no studies to date on rhizome development and optimal harvest timing for Rehmannia glutinosa. We therefore, undertook this investigation. Methods and Results: R. glutinosa ‘Jihwang 1’ was sown in early May and harvested in early November. Growth investigations were carried out at intervals of 10 days between 90 and 180 days after sowing (DAS). Leaf length, leaf width, and number of leaves increased until 150 DAS but decreased after 160 DAS. Rhizome length increased until 120 DAS subsequently, rhizome diameter increased rapidly between 130 and 150 DAS. Thus, the key period for rhizome enlargement in R. glutinosa is thought to be 130 to 150 DAS. Fresh root yield increased sharply from 916 ㎏/10a to 1,914 ㎏/10a between 4 and 5 months after sowing (MAS). Dry matter ratio increased gradually from 19.2% at 4 MAS to 24.4% at 6 MAS. Finally, the level of catalpol, a key active ingredient, increased sharply from 0.41% to 4.21% between 5 and 6 MAS. Given the dry matter ratio, catalpol content and yield measured, we suggest that optimal R. glutinosa harvest time is 6 MAS. Conclusions: Based on our results, the key period for rhizome enlargement is 130 to 150 DAS and optimal harvest timing is 6 MAS. We anticipate that these and other results of this study can be used to inform cultivation of R. glutinosa.

Methenamine, a urinary antiseptic with antimicrobial properties, decomposes into toxic formaldehyde under acidic conditions. Its use is prohibited in dairy cattle in Korea to prevent harmful residues in milk. This study was designed to develop and validate a sensitive and reliable LC–MS/MS method for determining methenamine in raw milk and bovine muscle in compliance with the Positive List System (PLS) regulations. Samples were extracted with acetonitrile (ACN)–methanol (MeOH) (7:3, v/v) containing ammonia water, followed by defatting with n-hexane and purification with primary secondary amine (PSA). Chromatographic separation was performed on a hydrophilic interaction liquid chromatography (HILIC) column, and quantification was conducted using matrix-matched calibration to minimize matrix effects. The method showed excellent linearity (R² > 0.999), low limits of quantification (LOQ) (0.49 μg/kg for raw milk; 0.64 μg/kg for bovine muscle), and acceptable recoveries (78.1–102.8%) with precision (CV ≤ 8.75%), meeting Codex CAC/GL 71-2009 criteria. Stability studies demonstrated that methenamine remained stable in stock solutions, working standards and processed extracts under the storage and handling conditions used. Application to incurred samples resulted in the detection of methenamine in 2 of 32 raw milk samples (0.65 and 1.14 μg/kg) but in none of the 25 bovine muscle samples, with all detected levels below the Korean PLS limit. These findings confirm that the developed method is accurate, sensitive, and applicable for routine surveillance of methenamine residues to ensure consumer safety.

Background: This study was conducted to compare the physicochemical properties of 12 different cultivars of Rehmannia glutinosa, a plant used in Korean traditional herbal medicine. Method and Results: We investigated the following 12 cultivars of R. glutinosa; Jihwang1, Goryeo, Daegyung, Gogang, Togang, Dagang, Wongang, Yeongang, Hwanggang, Dahwang, Segang and Chunggang. We measured water content, chromaticity, hardness, active components levels, and antioxidant activity. Our results showed that Togang has the lowest water content and the highest yield. The catalpol content was the highest in Togang (40.50 ㎎/g) and the lowest in Chunggang (22.17 ㎎/g). The aucubin content was the highest in Hwanggang (0.28 ㎎/g). Chunggang had the lowest aucubin content, but the highest level of verbascoside. Total flavonoid and total polyphenol were the highest in Daegyung and Chunggang, respectively. There was a strong correlation between the total flavonoid and total polyphenol (r = 0.89) content. Conclusions: There were significant differences in physicochemical properties among 12 cultivars. These properties will affect suitability for processing and final product quality. We therefore suggest the selection of appropriate cultivars for different uses.

This study evaluated the fitness for purpose of official Korean Food Code LC-MS/MS methods for five prohibited veterinary drugs and one major metabolite—pyrimethamine, dapsone, monoacetyldapsone, roxarsone, chloramphenicol, and vancomycin—in bovine, porcine, and chicken muscle and applied the evaluated methods to nationwide monitoring of production-stage samples. In 2024, dapsone, monoacetyldapsone, pyrimethamine, and roxarsone were analyzed in 202 muscle samples, whereas in 2025, chloramphenicol and vancomycin were analyzed in 300 muscle samples (total n = 502). Analytical performance was assessed for selectivity, linearity, limits of detection (LOD) and quantification (LOQ), recovery, repeatability, inter-day precision, and between-analyst performance; all analyte–matrix combinations met the predefined acceptance criteria. For chloramphenicol, an LOQ of 0.15 μg/kg was achieved in all three matrices, equal to the European Union reference point for action. An external proficiency test for chloramphenicol in bovine muscle yielded a satisfactory z-score of −0.30. No sample met the regulatory reporting criterion for any target analyte included in the respective annual survey. These findings support the fitness for purpose of the evaluated official methods and provide baseline analytical and occurrence data for surveillance of selected prohibited substances in production-stage meat in Korea.