PTP1B and α-glucosidase inhibitory activities of the chemical constituents from Hedera rhombea fruits: Kinetic analysis and molecular docking simulation.

In this study, we present the first investigation of Hedera rhombea Bean fruit, which led to the isolation of six undescribed compounds including two megastigmane glucosides, two rare 1,4-dioxane neolignanes, and two quinic acid derivatives, together with 26 known compounds. Their structures and absolute configurations were elucidated by extensive analysis of NMR spectroscopic data, HRMS, and ECD calculations. This is the first report on the isolation of methyl 3-O-caffeoyl-5-O-p-coumaroylquinate from a natural source. Among the isolated compounds, falcarindiol and caffeoyltryptophan showed significant PTP1B inhibition with IC50 values of 7.32 and 16.99 µM, respectively, compared to those of the positive controls [sodium orthovanadate (IC50 = 17.96 µM) and ursolic acid (IC50 = 4.53 µM)]. These two compounds along with several other compounds displayed significant α-glucosidase inhibitions with IC50 values ranging from 12.88 to 91.89 µM, stronger than that of the positive control (acarbose, IC50 = 298.07 µM). Enzyme kinetic analysis indicated that caffeoyltryptophan and falcarindiol displayed competitive and mixed-type PTP1B inhibition, respectively, whereas the α-glucosidase inhibition type was mixed-type for caffeoyltryptophan and uncompetitive (rarely reported for a-glucosidase inhibitors) for falcarindiol. In addition, molecular docking results showed that these active compounds exhibited good binding affinities toward both PTP1B and α-glucosidase with negative binding energies. The results of the present study demonstrate that these active compounds might be beneficial in the treatment of type 2 diabetes.

Glycosylated constituents isolated from the trunk of Abies holophylla and their anti-inflammatory and neurotrophic activity.

Eleven previously undescribed glycosylated compounds with phenolic (abeoside A-F), monoterpenyl (abeoside G and H), or 2-heptanyl (abeoside I-K) aglycone, and twenty one reported compounds were isolated from the trunk of Abies holophylla. The structures of the previously undescribed compounds were elucidated on the basis of the conventional NMR and HRMS data analysis, and the absolute configuration of sugar units were assigned by chiral derivatization and LC-MS analysis. All the isolated compounds were evaluated for their anti-neuroinflammatory and neurotrophic activities. Among the evaluated compounds, twelve compounds including abeoside A, B, E, G, H, J, and K exhibited strong anti-neuroinflammatory activities with IC50 values of 4.6-18.2 µM by inhibiting production of LPS-induced NO levels, and abeoside C and 1-O-[(S)-oleuropeyl]-ß-D-glucoside showed powerful effects on the stimulation of NGF secretion levels with 157.09 ± 8.53% and 154.74 ± 1.24%, respectively.

New bis-thioglycosyl-1,1'-disulfides from Nasturtium officinale R. Br. and their anti-neuroinflammatory effect.

As a part of our continuing search for bioactive constituents from Brassicaceae family, three new bis-thioglycosides (1-3) were isolated from the 80% MeOH extract of Nasturtium officinale, together with 13 known compounds (4-16). The chemical structures of three new bis-thioglycosides (1-3) were elucidated using NMR techniques (1H and 13C NMR, 1H-1H COSY, HSQC, and HMBC), HRESIMS, and a chemical method. All the compounds were evaluated for their inhibitory effects on nitric oxide (NO) levels in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Among the isolates, compound 5 exhibited a strong inhibitory effect on NO production, and compounds 4 and 15 showed moderate inhibitory activities, suggesting the neuroprotective and anti-neuroinflammatory effects of bis-thioglycosides from N. officinale.

Phenolic Glycosides from Capsella bursa-pastoris (L.) Medik and Their Anti-Inflammatory Activity.

A new sesquilignan glycoside 1, together with seven known phenolic glycosides 2-8 were isolated from the aerial parts of Capsella bursa-pastoris. The chemical structure of the new compound 1 was elucidated by extensive nuclear magnetic resonance (NMR) data (¹H- and 13C-NMR, ¹H-¹H correlation spectroscopy (¹H-¹H COSY), heteronuclear single-quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), and nuclear overhauser effect spectroscopy (NOESY)) and HR-FABMS analysis. The anti-inflammatory effects of 1-8 were evaluated in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Compounds 4 and 7 exhibited moderate inhibitory effects on nitric oxide production in LPS-activated BV-2 cells, with IC50 values of 17.80 and 27.91 µM, respectively.