Kyeong Wan Woo

Flavonoid glycosides from the leaves of Allium victorialis var. platyphyllum and their anti-neuroinflammatory effects

Eight new flavonoid glycosides, named allivictoside A-H (1-8), together with twelve known flavonoids (9-20) were isolated from the leaves of Allium victorialis var. platyphyllum. The structures of 1-8 were determined by chemical and spectroscopic methods, including 1D, 2D NMR analyses and HR-MS. To evaluate the anti-neuroinflammatory activities of all isolates, we measured the secreted nitric oxide levels in murine microglia BV-2 cells stimulated by lipopolysaccharide. In this study, compounds 2, 6, 10, and 18 significantly inhibited nitric oxide production (IC(50) values of 20.67, 20.42, 21.48 and 19.80 μM, respectively) without cell toxicity. Therefore, we suggest that allivictoside B (2) and F (6), 3-O-β-D-glucosyl-7-O-β-D-(2-O-feruloyl)glucosylkaempferol (10) and quercetin 3-O-β-d-glucopyranoside (18) may be considered as candidates for the treatment of diseases associated with neuroinflammation.

A new lignan glycoside from Juniperus rigida

A new lignan glycoside, named juniperigiside (1) was isolated from the CHCl3 soluble fraction of the MeOH extract of stems and leaves of Juniperus rigida S.et Z. Compound 1 was identified by 1D- and 2D-NMR spectroscopy as well as CD analysis as (2R,3S)-2,3-dihydro-7-methoxy-2-(4′-hydroxy-3′-methoxyphenyl)-3-hydroxymethyl-5-benzofuranpropanol 4′-O-(3-O-methyl)-α-L-rhamnopyranoside. Five known lignans, icariside E4 (2), desoxypodophyllotoxin (3), savinin (4), thujastandin (5), and (−)-nortrachelogenin (6) in addition to five known labdane diterpenes including trans-communic acid (7), 13-epi-torulosal (8), 13-epi-cupressic acid (9), imbricatoric acid (10), and isocupressic acid (11) were also isolated and their structures were characterized by comparing their spectroscopic data with those in the literature. All compounds were isolated for the first time from this plant, and 5 and 6 were first reported from the genus Juniperus. The isolated compounds were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay. Compounds 3, 4, 7, and 8 showed considerable cytotoxicity against four human cancer cell lines in vitro.

Phenolic derivatives from the rhizomes of Dioscorea nipponica and their anti-neuroinflammatory and neuroprotective activities.

ETHNOPHARMACOLOGICAL RELEVANCE Dioscorea nipponica (Dioscoreaceae) have been used as traditional medicines for diabetes, inflammatory and neurodegenerative diseases in Korea. The aim of the study was to isolate the bioactive components from the rhizomes of Dioscorea nipponica and to evaluate their anti-neuroinfalmmatory and neuroprotective activities. MATERIAL AND METHODS The phytochemical investigation of 50% EtOH extract of Dioscorea nipponica using successive column chromatography over silica gel, Sephadex LH-20, and preparative high performance liquid chromatography (HPLC) resulted in the isolation and identification of 17 phenolic derivatives, including four new phenolic compounds (1-4). The structural elucidation of these compounds was based on spectroscopic methods, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy techniques, mass spectrometry, and optical rotation. All isolated compounds were evaluated for their effects on nerve growth factor (NGF) secretion in a C6 rat glioma cell line and nitric oxide (NO) production in lipopolysaccharide (LPS)-activated BV2 cells. The neurite outgrowth of compound 16 was further evaluated by using mouse neuroblastoma N2a cell lines. RESULTS Three new stilbene derivatives, diosniponol C (1), D (2) and diosniposide A (3) and one new phenanthrene glycoside, diosniposide B (4), together with 13 known compounds were isolated from the rhizomes of Dioscorea nipponica. Of the tested compounds (1-17), phenanthrene, 3,7-dihydroxy-2,4,6-trimethoxy-phenanthrene (16) was the most potent NGF inducer, with 162.35±16.18% stimulation, and strongly reduced NO levels with an IC50 value of 19.56 μM in BV2 microglial cells. Also, it significantly increased neurite outgrowth in N2a cells. CONCLUSIONS This study supports the ethnopharmacological use of Dioscorea nipponica rhizomes as traditional medicine.

Identification of antitumor lignans from the seeds of morning glory (Pharbitis nil).

In the search for antitumor compounds from Korean natural resources, activity-guided fractionation and purification processes were used on seeds of morning glory (Pharbitis nil). Air-dried P. nil seeds were extracted with ethanol and separated into n-hexane, chloroform, ethyl acetate, and n-butanol. Four new lignans, pharbilignans A-D (1-4) were isolated from the most active ethyl acetate fraction of the ethanol extract. Their structures were characterized on the basis of spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance (NMR) techniques, high resolution mass spectrometry (HRMS), and circular dichroism (CD) spectroscopy. The cytotoxic activities of the isolates (1-4) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) using a sulforhodamine B (SRB) bioassay. Pharbilignan C (3) showed potent cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 1.42, 0.16, 0.20, and 0.14 μM, respectively. On the basis of the expanded understanding that inflammation is a crucial cause in tumor progress, we also evaluated anti-inflammatory activity of the isolates (1-4). Pharbilignan C (3) strongly inhibited nitric oxide (NO) production in the lipopolysaccharide (LPS)-activated BV-2 microglia cell line with an IC50 value of 12.8 μM.

Anti-neuroinflammatory diarylheptanoids from the rhizomes of Dioscorea nipponica

In a continuing search for bioactive constituents from Dioscoreaceae medicinal plants, two new cyclic diarylheptanoids, diosniponol A (1) and B (2), together with 10 known compounds (3-12) were isolated from the rhizomes of Dioscorea nipponica. The structures of these new compounds were determined by spectroscopic analyses, including extensive two-dimensional nuclear magnetic resonance, high-resolution mass spectrometry, and optical rotation. All isolated compounds 1-12 were evaluated for their effects on nitric oxide (NO) production in murine microglia cell line BV-2. Compounds 8 and 11 showed potent inhibitory activities on NO production (IC50 13.36 and 14.36 μM, respectively) without cell toxicity in lipopolysaccharide-activated BV-2 cells.

Inhibition of Proinflammatory Cytokine Generation in Lung Inflammation by the Leaves of Perilla frutescens and Its Constituents.

This study was designed to find some potential natural products and/or constituents inhibiting proinflammatory cytokine generation in lung inflammation, since cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) are pivotal for provoking airway inflammation. In our preliminary screening procedure, the 70% ethanol extract of the leaves of Perilla frutescens (PFE) was found to clearly inhibit TNF-α production in the lung at 100 mg/kg, after intranasal lipopolysaccharide treatment of mice. Based on this result, ten constituents including phenylpropanoids (allyltetramethoxybenzene, caffeic acid, dillapiole, elemicin, myristicin, nothoapiole, rosmarinic acid methyl ester, rosmarinic acid) and monoterpenes (perilla aldehyde and perilla ketone) were successfully isolated from the extract. Among them, elemicin and myristicin were found for the first time to concentration-dependently inhibit IL-1β-treated IL-6 production from lung alveolar epithelial cells (A549) at concentrations of 10-100 μM. These findings suggest that the phenylpropanoids including elemicin and myristicin have the potential to be new inhibitory agents against lung inflammation and they may contribute, at least in part, to the inhibitory activity of PFE on the lung inflammatory response.

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.

Ursane Saponins from the Stems of Firmiana simplex and their Cytotoxic Activity

Three new ursane triterpene saponins, together with twelve known ursane triterpenes were isolated from the stems of Firmiana simplex. The structures of the saponines were elucidated on the basis of spectroscopic and chemical methods. The cytotoxic activity of all compounds was evaluated in vitro against lung adenocarcinoma (A549), ovarian cancer (SK-OV-3), skin melanoma (SK-MEL-2), and colon cancer (HCT-15) human cell lines, using a sulforhodamine (SRB) assay. 23-Hydroxyursolic acid showed cytotoxicity against the tested cell lines with IC50 values ranging from 11.96 to 14.11 µM.

Pulchellamin G, an amino acid-sesquiterpene lactone, from Saussurea pulchella suppresses lipopolysaccharide-induced inflammatory responses via heme oxygenase-1 expression in murine peritoneal macrophages

Saussurea pulchella (Asteraceae) is widely distributed in Korea and has been used in Korean folk medicine for the treatment of inflammation, hypertension, hepatitis, and arthritis. Pulchellamin G is an amino acid-sesquiterpene lactone conjugate isolated from S. pulchella. In the present study, we focused on the anti-inflammatory effect of pulchellamin G, which acts by inducing the expression of heme oxygenase (HO)-1. HO-1 plays important roles in cytoprotection since it has antioxidant, anti-inflammatory, antiproliferative, and antiapoptotic properties. Pulchellamin G inhibited the mRNA and protein expression of inducible nitric oxide synthase (iNOS), iNOS-derived nitric oxide (NO), and cyclooxygenase (COX)-2 and COX-derived prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-stimulated murine peritoneal macrophages. The compound also reduced tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) production and suppressed the phosphorylation and degradation of IκB-α and nuclear translocation of p65 in murine peritoneal macrophages in response to LPS stimulus. The inhibitory effects of pulchellamin G on nuclear factor kappa B (NF-κB) translocation was impaired by co-treatment of the cells with HO activity inhibitor tin protoporphyrin (SnPP). By using SnPP, we verified that the inhibitory effects of pulchellamin G on the pro-inflammatory mediators NO, PGE2, TNF-α, and IL-1β are associated with induction of HO-1 expression. Our data suggest that pulchellamin G might have potent therapeutic effects and it should be considered in the development of treatments for various inflammatory diseases.

Lignan glucosides from Sinomenium acutum rhizomes.

The new lignan glucoside, acutumoside (1), was isolated from Sinomenium acutum rhizomes together with nine known compounds (2–10). The structure of 1 was elucidated on the basis of extensive spectroscopic analyses, including two-dimensional nuclear magnetic resonance and chemical reactions. Compounds 2, 7, 8, and 10 displayed potential antiproliferative activity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines, while compound 1 showed weak activity against these human tumor cells.