Won Se Suh

A new monoacylglycerol from the fruiting bodies of Gymnopilus spectabilis

Bioassay-guided fractionation and chemical investigation of the MeOH extract of the wild mushroom Gymnopilus spectabilis resulted in the isolation of a new monoacylglycerol, together with five known compounds. The structure of the new compound (2′S) −1-O-(6,6-dimethoxyhexanol)-glycerol was elucidated on the basis of 1D and 2D NMR (1H and 13C NMR, 1H-1H COSY, HMQC and HMBC) spectroscopic data as well as chemical reactions. The known compounds were identified by comparison of their spectroscopic and physical data with the reported values. The metabolites were evaluated for their anti-proliferative activities against four human tumour cell lines (A549, SK-OV-3, SK-MEL-2 and HCT-15) and for their inhibitory effects on nitric oxide production in lipopolysaccharide (LPS)-activated murine microglial cells.

Bioactive lignan derivatives from the stems of Firmiana simplex

The CHCl3 soluble fraction of the 80% MeOH extract of the stems of Firmiana simplex strongly inhibited nitric oxide production in lipopolysaccharide-activated BV-2 cells. A bioactivity-guided column chromatographic separation yielded two new lignans, firmianols A and B (1-2) together with seventeen known lignans (3-19). The structural elucidation of the new compounds was determined by spectroscopic methods, including 1D, 2D NMR and HR-FAB-MS. All isolated lignans were evaluated for their antineuroinflammatory effects on nitric oxide (NO) production in lipopolysaccharides (LPS)-activated murine microglia BV2 cells. Among the isolated, compounds 14 and 15 showed potent inhibitory activity against NO production (IC50 1.05 and 0.929 μM, respectively) without cell toxicity in murine microglia BV-2 cells. Compounds 11-13 and 17 also exhibited strong inhibitory effects on NO production, with IC50 values ranging from 7.07 to 15.28 μM.

A biphenyl derivative from the twigs of Chaenomeles speciosa

In our continuing search for bioactive constituents of Korean medicinal sources, we investigated an 80% MeOH extract of the twigs of Chaenomeles speciosa. Column chromatographic purification of the CHCl3 fraction resulted in the isolation of a new biphenyl derivative (1), along with four known biphenyl compounds (2-5) and six triterpenes (6-11). The chemical structure of the new compound was determined on the basis of spectroscopic analyses including 1D and 2D NMR data. Among isolates, compound 3 exhibited potent cytotoxic activities against SK-OV-3, SK-MEL-2, and XF498 cell lines (IC50=5.91, 4.22, and 6.28μM, respectively). Also, Compounds 9 and 10 showed strong anti-neuroinflammatory activities (IC50 2.38, and 6.70μM, respectively).

Two new phenylpropane glycosides from Allium tuberosum Rottler

A phytochemical investigation of Allium tuberosum Rottler afforded two new phenylpropane glycosides, named tuberonoid A (1) and B (2), along with four known flavonoids, kaempferol 3-O-β-sophoroside (3), 3-O-β-d-(2-O-feruloyl)-glucosyl-7,4′-di-O-β-d-glucosylkaempferol (4), 3-O-β-sophorosyl-7-O-β-d-(2-O-feruloyl)glucosyl kaempferol (5), kaempferol 3,4′-di-O-β-d-glucoside (6). The identification and structural elucidation of the new compounds were carried out based on spectral data analyses (1H and 13C NMR, 1H–1H COSY, HMQC) and HR-MS.

A new phenolic glycoside from Spiraea prunifolia var. simpliciflora twigs

The phytochemical investigation of the methanol extract from the twigs of Spiraea prunifolia var. simpliciflora (Rosaceae) using column chromatography led to the isolation of a new phenol glycoside, 1-O-(E)-caffeoyl-2-O-p-(E)-coumaroyl-β-d-glucopyranose (1), together with 16 known phenolic compounds (2–17). The structure of this new compound was elucidated by analysis of spectroscopic data including 1D, 2D nuclear magnetic resonance and HR-FAB-MS data. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using the sulforhodamine B bioassay.

Anti-Neurodegenerative Biflavonoid Glycosides from Impatiens balsamina

Four biflavonoid glycosides, balsamisides A-D (1-4), and nine known compounds (5-13) were obtained from the white petals of Impatiens balsamina. The 2D structures of the purified phytochemicals were established using conventional NMR techniques in addition to the new long-range HSQMBC NMR experiment. Acid hydrolysis followed by experimental and quantum-mechanics-based ECD data analysis permitted full configurational assignment of the purified metabolites. Compounds 1-13 were assessed for their potential to impede the generation of nitric oxide in lipopolysaccharide-stimulated BV2 cells. They were also investigated for potential neuroprotective activity using C6 cells and cytotoxicity against some human tumor cell lines, but were inactive (IC50 > 10 μM) against all the cell lines.

Bioactive lignan constituents from the twigs of Sambucus williamsii.

As part of our ongoing search for bioactive constituents of natural Korean medicinal plants, three new lignan derivatives, sambucasinol A-C (1-3), together with 7 known compounds (4-10) were isolated from the twigs of Sambucus williamsii. The structures of these new compounds were determined by a combination of 1D and 2D NMR spectroscopic data analysis, as well as circular dichroism (CD) spectroscopy studies. Here, we evaluated the anti-inflammatory effects of 1-10 in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Compounds 1-3 exhibited significant inhibitory effects on nitric oxide production in LPS-activated BV-2 cells, with IC50 values of 6.82, 7.04, and 14.70 μM, respectively. Additionally, we evaluated the effects of compounds 1-10 on NGF induction in a C6 rat glioma cell line. Compounds 1-3 upregulated NGF secretion to 183.95 ± 2.63%, 153.99 ± 5.15%, and 155.96 ± 5.15%, respectively, without any significant cell toxicity. Moreover, all isolates were evaluated for their cytotoxicity against A549, SK-OV-3, SK-MEL-2, and XF498 cell lines. Compounds 1-3 showed consistent cytotoxicity against the four human cell lines, with IC50 values in the range of 11.07-19.62 μM.

Allimacrosides A–E, new steroidal glycosides from Allium macrostemon Bunge

HIGHLIGHTSNine steroidal compounds including five new compounds were isolated from Allium macrostemon.Their chemical structures were determined based on spectroscopic methods.The isolateds were tested for cytotoxicity against four human tumor cell lines in vitro. ABSTRACT A new pregnane‐type steroidal glycoside (1), two new spirostane‐type steroidal glycosides (2, 3), and two new furostane‐type steroidal glycosides (4, 5), named allimacrosides A–E, together with four known compounds (6–9) were isolated from a 80% MeOH extract of Allium macrostemon Bunge. The identification and structural elucidation of these compounds were based on their 1D‐ and 2D‐NMR spectra, and HR‐FAB‐MS data analysis. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using the sulforhodamine B bioassay.

Iridoid Glycosides from the Twigs of Sambucus williamsii var. coreana and Their Biological Activities

Six new iridoid glycosides, sambucusides A-F (1-6), and two known derivatives (7 and 8) were isolated from a methanol extract of the twigs of Sambucus williamsii var. coreana. Their chemical structures were elucidated by spectroscopic methods, including NMR (1H and 13C NMR, 1H-1H COSY, HMQC, HMBC, and NOESY) and HRMS. All isolated compounds (1-8) were evaluated for their antiproliferative activities against four human cancer cell lines (A549, SK-OV-3, SK-MEL-2, and Bt549). Their effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV-2 cells and their neuroprotective effects through induction of nerve growth factor (NGF) in C6 glioma cells were also examined. Compounds 2, 3, and 5 showed cytotoxic effects (IC50 1.3-8.7 μM) against the SK-MEL-2 and Bt549 cell lines and inhibitory effects on NO production (IC50 of 0.9, 1.3, and 1.2 μM, respectively). Compounds 2, 4, and 8 exhibited NGF-releasing effects (147.0 ± 5.8%, 158.7 ± 5.2%, and 152.6 ± 7.3%, respectively).

Secoiridoid Glucosides from the Twigs of Syringa oblata var. dilatata and Their Neuroprotective and Cytotoxic Activities

Phytochemical investigation of the twigs of Syringa oblata var. diatata led to the isolation of two new secoiridoid glucosides, dilatioside A-B (1-2), along with thirteen known ones (3-15). The structures were determined by spectroscopic methods including one and two dimensional (1- and 2D-) NMR techniques, high resolution (HR)-FAB-MS, and chemical methods. The isolated compounds (1-15) were tested for the induction of nerve growth factor (NGF) secretion in a C6 rat glioma cell line and their cytotoxicity against four human cancer cell lines (A549, SK-OV-3, SK-MEL-2, HCT15) in vitro using a sulforhodamine B bioassay. Compounds 5, 7, 8, 10, and 14 were found to induce upregulation of NGF secretion without causing significant cell toxicity.