Byung Sun Min's research while affiliated with Catholic University of Daegu and other places

Historically, Astragalus membranaceus Bunge has been used as a beneficial medicinal plant, particularly in the Asian traditional medical systems, for the treatment of various human diseases such as stomach ulcers, diarrhea, and respiratory issues associated with phlegm. In this study, a phytochemical characterization of the aerial parts of A. membranaceus led to the isolation of 29 oleanane-type triterpenoid saponins, including 11 new compounds named astraoleanosides E–P (6–9, 13, 14, 18–22), as well as 18 known ones. The structures of these compounds were elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Among them, astraoleanoside H (9) and cloversaponin III (15) demonstrated the most potent β-glucuronidase inhibitory activities, with IC50 values of 21.20 ± 0.75 and 9.05 ± 0.47 µM, respectively, compared to the positive control d-saccharic acid 1,4-lactone (IC50 = 20.62 ± 1.61 µM). Enzyme kinetics studies were then conducted to investigate the type of inhibition exhibited by these active compounds. In addition, the binding mechanism, key interactions, binding stability, and dynamic behavior of protein–ligand complexes were investigated through in silico approaches, such as molecular docking and molecular dynamics simulations. These findings highlight the promising potential of triterpenoid saponins from A. membranaceus as lead compounds for β-glucuronidase inhibitors, offering new possibilities for the development of therapeutic agents targeting various diseases where β-glucuronidase plays a crucial role.

Diabetes, characterized by elevated blood glucose levels, has a significant impact on cardiovascular, neural, and vascular systems. α-Glucosidase inhibitors have emerged as potential therapeutic agents for type 2 diabetes, as they slow carbohydrate digestion and reduce postprandial blood sugar levels. In this study, we investigated the phytochemical and pharmacological properties of Celastrus orbiculatus Thunb., renowned for its diverse phytochemical constituents and potential medicinal applications. Through the application of chromatographic and spectroscopic techniques, we successfully isolated and structurally elucidated 16 compounds from the stems of C. orbiculatus. The in vitro α-glucosidase inhibitory activity of these compounds was evaluated. Notably, celaphanol A (1) and (+) lariciresinol (7) exhibited strong α-glucosidase inhibition, with IC50 values of 8.06 ± 0.30 and 48.02 ± 0.47 µM, respectively. Enzyme kinetics analysis revealed that the most active compound 1 acted as a non-competitive inhibitor against α-glucosidase, with a Ki value of 7.77 ± 0.16 µM. These findings underscore C. orbiculatus as a valuable source for discovering and developing new α-glucosidase inhibitors. Furthermore, compound 1 shows promise as a candidate for natural herbal therapy targeting α-glucosidase inhibition. This suggests the potential for further investigation into its effectiveness through in silico or in vivo studies using a diabetes model.

Salvia miltiorrhiza is a traditional medicinal plant used in Asian medicine for various therapeutic purposes. This plant contains numerous bioactive secondary metabolites, particularly abietane-type diterpenoids. In this study, 16 abietane-type diterpenoids were isolated from S. miltiorrhiza root extracts and structurally identified through advanced spectroscopic techniques. Among them, tanshinone IIA (6) and 15,16-dihydrotanshinone I (11) exhibited potent α-glucosidase inhibition, with IC50 values of 48.38 ± 0.57 and 48.02 ± 0.47 µM, respectively. Enzyme kinetic studies revealed that these compounds served as non-competitive inhibitors of α-glucosidase. Our findings indicate that natural compounds from S. miltiorrhiza show promise as safe and effective α-glucosidase inhibitors, providing an alternative approach to diabetes treatment. This study contributes to the growing interest in utilizing natural sources for α-glucosidase inhibition and their potential application in healthcare and disease management.

Cinnamomum cassia L., commonly known as cinnamon, is a widely used aromatic spice and medicinal plant with a rich history of culinary and therapeutic applications. In this study, a new phenylpropanoid, named di(1,3-dioxane)cassin A (4), and 13 known compounds (1‒3, 5‒14), were isolated from the bark of C. cassia. Their structures were successfully elucidated using modern spectroscopic techniques, such as nuclear magnetic resonance, high-resolution mass spectrometry, and circular dichroism spectroscopy. In addition, isolated compounds were evaluated for their inhibitory effects on soluble epoxide hydrolase (sEH). Compound 4 exhibited sEH inhibition with an IC50 value of 28.80 µM. Enzyme kinetics experiment indicated that compound 4 acted as a competitive sEH inhibitor. In silico methods, including molecular docking and molecular dynamics simulations, were employed to determine and understand the binding mechanism and dynamics behavior of this active compound with sEH.

Two new neolignans, myrifralignans F–G (14 and 18), four new diarylnonanoid derivatives, myrifragranones A–D (21–24), and 18 known compounds were isolated and structurally elucidated from nutmeg (Myristica fragrans Houtt.) seeds. The absolute configurations of these secondary metabolites were determined using the electronic circular dichroism technique. The inhibitory potential of these isolated compounds on soluble epoxide hydrolase (sEH) was investigated for the first time. Among them, malabaricones B and C (19 and 20) and four new compounds 21–24 displayed inhibitory activities against sEH, with IC50 values ranging from 14.24 to 46.35 µM. Additionally, the binding mechanism, key binding interactions, stability, and dynamic behaviour of the active compounds with the sEH enzyme were analysed using in silico molecular docking and dynamics simulations. Our findings suggest that nutmeg could become a promising natural source for discovering and developing new sEH inhibitors.