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.

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).

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.

Neuroprotective Fatty Acids from the Stem Bark of Sorbus commixta.

Phytochemical investigation of the bark from the stems of Sorbus commixta led to the isolation and characterization of a new fatty acid, sorcomic acid (1), along with nine known analogues (2-10). The structure of the new compound (1) was determined through NMR ((1)H and (13)C NMR, HSQC, HMBC, and NOESY), MS, and specific optical rotation. The known compounds (2-10) were identified by comparison of their spectroscopic data with those in the literature. The biological activities of all the isolated compounds (1-10) were evaluated: compounds 1, 5, and 7 potently induced NGF secretion from C6 glioma cells (233.40 ± 12.82, 194.40 ± 8.05, and 185.74 ± 10.25 %, respectively) and compound 10 reduced NO levels with an IC50 value of 71.25 µM in murine microglia BV2 cells stimulated by LPS.

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.

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.

Bioactive lignan constituents from the twigs of Lindera glauca.

A bioassay-guided fractionation and chemical investigation of the MeOH extract from the twigs of Lindera glauca (SIEB. et ZUCC.) BLUME resulted in the isolation and identification of six lignans (1-6) including three new lignan derivatives, named linderuca A (1), B (2), and C (3). The structures of the new compounds (1-3) were determined on the basis of spectroscopic analyses, including two dimensional NMR and circular dichroism (CD) spectroscopy studies. The cytotoxic activities of the isolates (1-6) were evaluated by determining their inhibitory effects on human tumor cell lines. Compounds 1-5 showed antiproliferative activities against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 7.79-29.42 µM. Based on the understanding that inflammation is a crucial cause of tumor progression, we also investigated the anti-inflammatory activities of the isolates (1-6) in the lipopolysaccharide-stimulated murine microglia BV-2 cell line by measuring nitric oxide (NO) levels. The new lignans (1-3) significantly inhibited NO production with IC50 values of 12.10, 9.48, and 9.87 µM, respectively, without cytotoxicity.