Suhyeon Baek

This study evaluated hot-water infusion as a practical and sustainable extraction method for functional flower petal teas. Six edible flowers—Tagetes erecta, Lonicera japonica, Celosia argentea var. cristata, Centaurea cyanus, Hibiscus sabdariffa, and Malva sylvestris—were compared under hot-water and 80% ethanol extraction. Hot-water extraction was performed at 100 °C for 15 min. Hot-water extracts showed 1.3–4.0 times higher total phenolic content (TPC) and stronger antioxidant activities (ABTS, DPPH, and FRAP) than 80% ethanol extracts, reflecting efficient extraction of hydrophilic phenolic acids. UPLC-ESI-Q-TOF-MS and GC–MS analyses of hot-water extracts revealed chlorogenic acid, caffeic acid, coumaric acid derivatives, flavonoid glycosides, and aroma volatiles such as hexanal and α-pinene. These findings confirm that simple hot-water infusion effectively recovers both bioactive and aroma-active compounds, supporting its application in developing safe, natural, and functional flower teas.

The iminosugars 1-deoxynojirimycin (1-DNJ) and 1-deoxymannojirimycin (1-DMJ) were produced by recombinant Corynebacterium glutamicum (CgTYB) bearing the 1-DNJ-producing GabT1-Yktc1-GutB1 (TYB) gene cluster from Bacillus velezensis MBLB0692. The enhanced iminosugar biosynthesis in CgTYB cultures increased both α-mannosidase inhibition (AMI) and α-glucosidase inhibition (AGI) activity. Individual cultures harboring GabT1, Yktc1, and GutB1 genes were found to be able to produce both 1-DNJ and 1-DMJ in mixed cultures of one pot analysis. This suggests that the genes necessary for epimerization and reduction are intrinsic to the cells rather than close to the 1-DNJ-producing cluster. Glucose was the preferred carbon source and a provision of 10 g/L glucose increased AGI and AMI to 69.8% and 70.1%, respectively. The 1 mM IPTG produced 55.0% AGI and 72.1% AMI, and 20% ethanolic permeabilization produced 62.8% AGI and 74.2% AMI. Batch fermentation increased iminosugar yields from 18.7 to 229.9 mg/L 1-DNJ, and 41.8 to 63.7 mg/mL 1-DMJ.

Sargahydroquinoic acid (SHQA), a bioactive compound found in certain Sargassum species, exhibits significant health benefits. This study optimized the extraction of SHQA from Sargassum yezoense using response surface methodology (RSM) and evaluated its antioxidant effects through in vitro and in vivo assays. A Box–Behnken design (BBD) was effectively employed to investigate the effects of incubation temperature, time, and ethanol concentration on SHQA yield, achieving a high coefficient of determination (R² = 0.961). Analysis of variance (ANOVA) validated the model’s reliability (F = 13.86, p = 0.005) and highlighted ethanol concentration as a highly significant factor (p < 0.001). Optimal extraction conditions were identified as 52.8 °C, 8.3 h, and 74.1% ethanol. The SHQA-maximized extract (SME) contained 67.8 ± 0.6 mg SHQA/g and 25.00 ± 1.01 mg phloroglucinol equivalent/g. SME exhibited antioxidant capacity of 26.45 ± 0.66 mg and 28.74 ± 2.30 mg vitamin C equivalent/g in ABTS and DPPH assays, respectively, and 0.29 ± 0.02 mM FeSO₄ equivalent/g in the FRAP assay. Additionally, SME at 50 µg/mL and SHQA at 1 µg/mL inhibited reactive oxygen species (ROS) generation in an H₂O₂-induced zebrafish model. This study presents the first optimization of SHQA extraction using RSM and demonstrates SHQA’s ROS inhibition in a zebrafish model.

The anti-inflammatory effect of the ethanol extract of Sargassum yezoense and its fractions were investigated in this study. The ethanol extract exhibited a strong anti-inflammatory effect on lipopolysaccharide-stimulated RAW 264.7 macrophages and effectively suppressed the M1 polarization of murine bone-marrow-derived macrophages stimulated by lipopolysaccharides and IFN-γ (interferon-gamma). Through a liquid–liquid extraction process, five fractions (n-hexane, chloroform, ethyl acetate, butanol, and aqueous) were acquired. Among these fractions, the chloroform fraction (SYCF) was found to contain the highest concentration of phenolic compounds, along with two primary meroterpenoids, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), and exhibit significant antioxidant capacity. It also demonstrated a robust anti-inflammatory effect. A direct comparison was conducted to assess the relative contribution of SHQA and SCM to the anti-inflammatory properties of SYCF. The concentrations of SHQA and SCM tested were determined based on their relative abundance in SYCF. SHQA contributed to a significant portion of the anti-inflammatory property of SYCF, while SCM played a limited role. These findings not only highlight the potential of the chloroform–ethanol fractionation approach for concentrating meroterpenoids in S. yezoense but also demonstrate that SHQA and other bioactive compounds work additively or synergistically to produce the potent anti-inflammatory effect of SYCF.

Macrophages play an important role in managing the onset and progression of chronic inflammatory diseases. The primary objective of this study is to explore the antioxidant potential and anti-inflammatory properties of Sargassum hemiphyllum ethanol extract (SHE) and its fraction. SHE and its five constituent fractions were assessed for overall antioxidant capabilities and inhibitory effects on LPS-induced inflammation by modulating macrophages polarization in both RAW 264.7 macrophages and bone-marrow-derived macrophages (BMDM). Among the organic solvent fractions of SHE, the ethyl acetate fraction displayed the highest total phenolic content and total antioxidant capacity. Notably, the n-hexane (Hex) fraction showed the most substantial suppression of LPS-induced tumor necrosis factor α secretion in BMDM among the five fractions of SHE. The SHE and Hex fraction significantly reduced the heightened expression of pro-inflammatory cytokines and inflammation-inducible enzymes induced by LPS in RAW 264.7 macrophages. In particular, the SHE and Hex fraction inhibited M1 macrophage polarization by reducing the mRNA expression of M1 macrophage markers in macrophages that were polarized toward the M1 phenotype. Furthermore, the SHE and Hex fraction attenuated the induction in nuclear factor E2-related factor 2 and its target genes, which was accompanied by an alteration in antioxidant gene expression in M1-polarized BMDM. The findings suggest that both SHE and its Hex fraction exhibit inhibitory effects on LPS-triggered inflammation and oxidative stress by modulating the polarization of M1 macrophages within macrophage populations.

Bangladeshi medicinal plants (BMP) have been used as traditional medicinal plants to treat chronic inflammatory diseases, but the antioxidant and anti-inflammatory effects of the bark of BMP are not yet known. The objective of this study was to determine antioxidant and anti-inflammatory activities using methanolic extracts of bark obtained from 15 medicinal spices of Bangladesh plants. The bark methanol extracts of BMP evaluated the total antioxidant activity and anti-inflammatory effect of lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. Among the 15 bark extracts of BMP, Albizia odoratissima (A. odoratissima), Engelhardia spicata (E. spicata), and Shorea robusta (S. robusta) showed the highest total phenolic contents and total antioxidant capacity by reducing free radicals scavenging activity. In particular, the three bark extracts significantly reduced the mRNA expression of LPS-induced inflammatory cytokines and inflammation-inducible enzymes in macrophages. Also, the mRNA expression of NADPH oxidase 2 was significantly suppressed by three bark extracts in LPS-induced RAW 264.7 macrophages. The results suggest that among the 15 bark extracts obtained from medicinal plant in Bangladesh, three bark extracts of A. odoratissima, E. spicata, and S. robusta exert total antioxidant capacity by reducing free radicals scavenging activity and inhibitory effects on LPS-stimulated inflammation in macrophages.

The brown alga Saccharina japonica is widely consumed in Asian countries, and post-harvest drying methods such as sun drying and oven drying are commonly used to extend the shelf life of S. japonica. Thus, the present study analyzed the ethanol extract and organic solvent fractions of S. japonica to examine the effects of UVA and heating on certain bioactive compounds (fucoxanthin, phlorotannin compounds, and total antioxidants) during the drying process. The fucoxanthin contents in the ethanol extract and different solvent fractions significantly decreased in response to UVA. However, fucoxanthin in the ethanol extract and other fractions showed resistance to thermal treatment. It is noteworthy that the total phlorotannin content (TPC) in the ethanol extract and all fractions showed an approximately 2.5-fold increase upon UVA radiation. The TPC also increased in all samples exposed to high temperatures, except for those in the chloroform fraction. The total antioxidant capacity (TAC) also exhibited significant increases in a pattern similar to the TPC. The findings demonstrate that UVA exposure and heating stimulated the degradation of fucoxanthin while it increased the TPC and TAC in the extract and fractions of S. japonica.