Kyung-Chul Shin

This study investigated nutritional composition and bioactive properties of thinned Shinanogold apples to evaluate their potential as functional food and cosmetic ingredients. Thinned Shinanobold apples exhibited markedly higher vitamin C (16.22 mg/100 g), total phenolics (886.27 mg GAE/100g), and total flavonoids (31.54 mg QE/g) levels than mature apples. The antioxidant capacity, assessed using DPPH and ABTS radical scavenging assays, was significantly higher in thinned apples (74% and 72%, respectively) than in mature apples (48% and 52%, respectively). The tyrosinase inhibitory activity, which is important for melanin reduction, and α-glucosidase inhibitory activity, which play a role in delaying glucose absorption, were higher in thinned apples (67% and 70%, respectively) than in mature apples (X and X, respectively), suggesting potential use of thinned apples as skin-whitening and antidiabetic agents. Furthermore, lipoxygenase inhibitory activity was higher in thinned apples (52%) than in mature apples (42%), suggesting potential use of thinned apples as an anti-inflammatory agent. These findings demonstrate that thinned Shinanobold apples contain bioactive constituents with superior activities compared with mature fruits. In addition, these results highlight the potential use of thinned apples as functional food ingredients and cosmetic agents.

Sophora japonica L., a medicinal herb used in East Asia, contains bioactive flavonoids such as sophoricoside and sophorabioside. Sophoricoside, a more bioavailable and therapeutically potent form, is known for its pharmacological properties, including anti-inflammatory, -cancer, and -osteoporotic effects. However, conversion of sophorabioside into sophoricoside has not been extensively studied. In this study, we aimed for the enzymatic conversion of sophorabioside, abundant in the S. japonica fruits and small branches, into sophoricoside using α-L-rhamnosidase from Chloroflexus aurantiacus. Optimal reaction conditions for this biotransformation were established, with maximal enzymatic activity observed at pH 6.0 and 55°C. Substrate specificity analysis revealed high selectivity of the enzyme for neohesperidose-containing flavonoids, including sophorabioside. Sophoricoside was efficiently produced from S. japonica fruit and branch extracts, enhanced by 2.5% methanol. The biotransformed extracts demonstrated significant lipoxygenase inhibitory activity, suggesting enhanced anti-inflammatory potential, highlighting the potential of S. japonica-derived sophoricoside-enriched products as functional food supplements with improved therapeutic properties.

Isoquercitrin, a monoglucoside form of quercetin, exhibits superior antioxidant, anti-inflammatory, and cardiovascular protective effects in comparison to its precursor, rutin. However, its natural abundance is limited. This study aimed to increase the functional value of Diospyros lotus leaf extract through enzymatic conversion of rutin to isoquercitrin using α-l-rhamnosidase and to evaluate the changes in biological activities after conversion. A sugar-free D. lotus leaf extract was prepared and subjected to enzymatic hydrolysis with α-l-rhamnosidase under optimized conditions (pH 5.5, 55 °C, and 0.6 U/mL). Isoquercitrin production was monitored via high-performance liquid chromatography. Antioxidant and anti-inflammatory activities were assessed using the 2,2-diphenyl-1-picrylhydrazyl radical scavenging and lipoxygenase (LOX) inhibition assays, respectively. The enzymatic reaction resulted in complete conversion of 30 mM rutin into isoquercitrin within 180 min, increasing isoquercitrin content from 9.8 to 39.8 mM. The enzyme-converted extract exhibited significantly enhanced antioxidant activity, with a 48% improvement in IC₅₀ value compared with the untreated extract. Similarly, LOX inhibition increased from 39.2% to 48.3% after enzymatic conversion. Both extracts showed higher inhibition than isoquercitrin alone, indicating synergistic effects of other phytochemicals present in the extract. This study is the first to demonstrate that α-l-rhamnosidase-mediated conversion of rutin to isoquercitrin in D. lotus leaf extract significantly improves its antioxidant and anti-inflammatory activities. The enzymatically enhanced extract shows potential as a functional food or therapeutic ingredient.

Perilla (P. frutescens L.) is widely cultivated across East Asia, and its seeds are highly regarded for their nutritional and functional properties. Seed size reportedly affects seed germination and growth; however, current research comparing the bioactive compounds and physiological activities across different seed sizes remains limited. We investigated the effect of seed size on the chemical composition and the antioxidant and anti-inflammatory activities of Perilla frutescens L. seeds. Seeds were categorized into small (average 1.26 mm), medium (average 1.66mm), and large (average 2.18 mm) categories. Larger seeds showed a higher content of fats, with a total fatty acid content of 48.3% compared to 38.4% in smaller seeds. Notably, α-linolenic acid, a key omega-3 fatty acid, was present at 69.55% in large seeds, whereas small seeds contained 62.25%. Total phenolic content and antioxidant activities, assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays, were significantly higher in larger seeds. The total phenolic content was 147.5 GAE μg/g for large seeds, 118.7 GAE μg/g for medium seeds, and 96.1 GAE μg/g for small seeds. For antioxidant activities, DPPH radical scavenging activity (IC50) was 79.5 μg/g in large seeds, 91.2 μg/g in medium seeds, and 121.8 μg/g in small seeds, while ABTS radical scavenging activity (IC50) was 54.3 μg/g in large seeds, 84.1 μg/g in medium seeds, and 105.8 μg/g in small seeds. Additionally, the anti-inflammatory activity, measured using the lipoxygenase (LOX) inhibitory assay, was also more pronounced in larger seeds, with LOX inhibition values of 28.2% for large seeds, 35.5% for medium seeds, and 43.7% for small seeds. These findings suggest that seed size significantly influences the nutritional and functional properties of Perilla frutescens seeds.

Acute lung injury (ALI) is a severe inflammatory condition characterized by excessive immune responses and oxidative stress, leading to significant tissue damage. Given the need for novel therapeutic agents, this study aimed to explore the anti-inflammatory activity and mechanisms of biotransformed Platycodon grandiflorum root extracts (BT-PGR), which were enzymatically processed using rapidsase PL Classic from Aspergillus niger. The goal was to assess the potential of BT-PGR as a natural treatment for ALI. BT-PGR effectively inhibited the production of NO, iNOS, IL-1β, IL-6, and TNF-α induced by LPS in NR8383 cells. BT-PGR inhibited the phosphorylation of ERK1/2, p38, JNK and p65 in LPS-stimulated NR8383 cells. In addition, BT-PGR suppressed LPS-mediated activation of NF-κB luciferase activity. BT-PGR increased the levels of HO-1 and the inhibition of HO-1 by ZnPP attenuated BT-PGR-mediated inhibition of NO production. In addition, the inhibition of PI3K by LY294002 blocked the BT-PGR-mediated increase of HO-1 level. BT-PGR increased nuclear Nrf2 level and the knockdown of Nrf2 by siRNA inhibited BT-PGR-mediated increase of HO-1 level. In addition, inhibition of PI3K by LY294002 suppressed the increase of nuclear Nrf2 level. Based on these results, it can be inferred that BT-PGR exhibits anti-inflammatory activity in rat alveolar macrophages, suggesting its potential as a natural candidate for the improvement of ALI.

Protectins, 10,17-dihydroxydocosahexaenoic acids (10,17-DiHDHAs), are belonged to specialized pro-resolving mediators (SPMs). Protectins are generated by polymorphonuclear leukocytes in humans and resolve inflammation and infection in trace amounts. However, the quantitative production of protectin DX 10-epimer (10-epi-PDX, 10R,17S-4Z,7Z,11E,13Z,15E,19Z-DiHDHA) has been not attempted to date. In this study, 10-epi-PDX was quantitatively produced from docosahexaenoic acid (DHA) by serial whole-cell biotransformation of Escherichia coli expressing arachidonate (ARA) 8R-lipoxygenase (8R-LOX) from the coral Plexaura homomalla and E. coli expressing ARA 15S-LOX from the bacterium Archangium violaceum. The optimal bioconversion conditions to produce 10R-hydroxydocosahexaenoic acid (10R-HDHA) and 10-epi-PDX were pH 8.0, 30 °C, 2.0 mM DHA, and 4.0 g/L cells; and pH 8.5, 20 °C, 1.4 mM 10R-HDHA, and 1.0 g/L cells, respectively. Under these optimized conditions, 2.0 mM (657 mg/L) DHA was converted into 1.2 mM (433 mg/L) 10-epi-PDX via 1.4 mM (482 mg/L) 10R-HDHA by the serial whole-cell biotransformation within 90 min, with a molar conversion of 60% and volumetric productivity of 0.8 mM/h (288 mg/L/h). To the best of our knowledge, this is the first quantitative production of 10-epi-PDX. Our results contribute to the efficient biocatalytic synthesis of SPMs.

A lipoxygenase from Pleurotus sajor‐caju (PsLOX) was cloned, expressed in Escherichia coli, and purified as a soluble protein with a specific activity of 629 μmol/min/mg for arachidonic acid (AA). The native PsLOX exhibited a molecular mass of 146 kDa, including a 73‐kDa homodimer, as estimated by gel‐filtration chromatography. The major products converted from polyunsaturated fatty acids (PUFAs), including AA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), were identified as trioxilins (TrXs), namely 13,14,15‐TrXB₃, 13,14,15‐TrXB₄, and 15,16,17‐TrXB₅, respectively, through high‐performance liquid chromatography (HPLC) and liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) analyses. The enzyme displayed its maximum activity at pH 8.0 and 20 °C. Under these conditions, the specific activity and catalytic efficiency of PsLOX for PUFAs exhibited the following order: AA>EPA>DHA. Based on HPLC analysis and substrate specificity, PsLOX was identified as an arachidonate 15‐LOX. PsLOX efficiently converted 10 mM of AA, EPA, and DHA to 8.7 mM of 13,14,15‐TrXB₃ (conversion rate: 87 %), 7.9 mM of 13,14,15‐TrXB₄ (79 %), and 7.2 mM of 15,16,17‐TrXB₅ (72 %) in 15, 20, and 20 min, respectively, marking the highest conversion rates reported to date. Collectively, our results demonstrate that PsLOX is an efficient TrXs‐producing enzyme.

An isolated bacterium from soil that highly hydrolyzes cellulose was identified as Paenibacillus peoriae and named P. peoriae MK1. The cellulase from P. peoriae MK1 was cloned and expressed in Escherichia coli. The purified recombinant cellulase, a soluble protein with 13.2-fold purification and 19% final yield, displayed a specific activity of 77 U/mg for CM-cellulose and existed as a metal-independent monomer of 65 kDa. The enzyme exhibited maximum activity at pH 5.0 and 40 °C with a half-life of 9.5 h in the presence of Ca²⁺ ion. The highest activity was observed toward CM-cellulose as an amorphous substrate, followed by swollen cellulose, and sigmacell cellulose and α-cellulose as crystalline substrates. The enzyme and substrate concentrations for the hydrolysis of CM-cellulose were optimized to 133 U/mL and 20 g/L CM-cellulose, respectively. Under these conditions, CM-cellulose was hydrolyzed to reducing sugars composed mostly of oligosaccharides by cellulase from P. peoriae MK1 as an endo-type cellulase with a productivity of 11.1 g/L/h for 10 min. Our findings will contribute to the industrial usability of cellulase and the research for securing cellulase sources.