Two New Phenolic Glycosides from Sorbus commixta.

From the stem bark of Sorbus commixta, two new phenolic glycosides, sorcomisides A and B (1 and 2), were isolated along with 10 known compounds. The structures of the isolates were determined by analysis of one-dimensional and two-dimensional NMR (1D- and 2D-NMR) data and high resolution (HR)-MS, chemical reaction, and computational methods. All the isolated compounds (1-12) were tested for their neuroprotective, anti-inflammatory, and cytotoxic activities.

Lignan Glycosides and Flavonoid Glycosides from the Aerial Portion of Lespedeza cuneata and Their Biological Evaluations.

Lespedeza cuneata (Fabaceae), known as Chinese bushclover, has been used in traditional medicines for the treatment of diseases including diabetes, hematuria, and insomnia. As part of a continuing search for bioactive constituents from Korean medicinal plant sources, phytochemical analysis of the aerial portion of L. cuneata led to the isolation of two new lignan glycosides (1,2) along with three known lignan glycosides (3⁻7) and nine known flavonoid glycosides (8⁻14). Numerous analysis techniques, including 1D and 2D NMR spectroscopy, CD spectroscopy, HR-MS, and chemical reactions, were utilized for structural elucidation of the new compounds (1,2). The isolated compounds were evaluated for their applicability in medicinal use using cell-based assays. Compounds 1 and 4⁻6 exhibited weak cytotoxicity against four human breast cancer cell lines (Bt549, MCF7, MDA-MB-231, and HCC70) (IC50 < 30.0 µM). However, none of the isolated compounds showed significant antiviral activity against PR8, HRV1B, or CVB3. In addition, compound 10 produced fewer lipid droplets in Oil Red O staining of mouse mesenchymal stem cells compared to the untreated negative control without altering the amount of alkaline phosphatase staining.

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.

Holophyllane A: A Triterpenoid Possessing an Unprecedented B-nor-3,4-seco-17,14-friedo-lanostane Architecture from Abies holophylla.

A novel triterpenoid, holophyllane A (1), featuring a B-nor-3,4-seco-17,14-friedo-lanostane, along with its putative precursor, compound 2 were isolated from the methanol extract of the trunks of Abies holophylla. The 2D structure and relative configuration of 1 were initially determined via analysis of 1D and 2D NMR spectroscopic data and the assignment was confirmed by quantum mechanics-based NMR chemical shift calculations. The absolute configuration was established by comparison of the experimental and simulated ECD data generated at different theory levels. Compounds 1 and 2 exhibited moderate to weak cytotoxicity and significant inhibitory activity against nitric oxide (NO) production.

A new rearranged eudesmane sesquiterpene and bioactive sesquiterpenes from the twigs of Lindera glauca (Sieb. et Zucc.) Blume.

A new rearranged eudesmane sesquiterpene, named eudeglaucone (1), and five known sesquiterpenes including (+)-faurinone (2) and four eudesmane-type sesquiterpenes (3-6), were isolated from the twigs of Lindera glauca (Sieb. et Zucc.) Blume. The structure of 1 was elucidated by a combination of extensive spectroscopic analyses, including extensive 2D NMR (1H-1H COSY, HMQC, HMBC, and NOESY) and HR-MS. Compound 1 was a relatively rare rearranged eudesmane sesquiterpene in terpenoids. All isolates were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15). Compounds 3 and 6 showed significant cytotoxicity against SK-MEL-2 and HCT-15 cell lines with IC50 values ranging from 9.98 to 12.20 µM. We also investigated the anti-neuroinflammatory activities of the isolates (1-6) in the lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cell line by measuring nitric oxide (NO) levels. All isolates significantly inhibited NO production with IC50 values of 3.67-26.48 µM without inducing 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.

A new triterpene glycoside from the stems of Lagerstroemia indica.

A bioassay-guided fractionation and chemical investigation of the stems of Lagerstroemia indica resulted in the isolation and identification of a new triterpene glycoside, lagerindiside (1), along with nine known triterpenes (2-10). The structure of this new compound was elucidated on the basis of 1D and 2D nuclear magnetic resonance spectroscopic data analysis as well as chemical method. The cytotoxic activities of the isolates (1-10) 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 bioassay. Compounds 3 and 4 showed potent cytotoxicity on the tumor cell lines with IC50 values ranging from 3.38 to 6.29 µM.

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.

Salicin derivatives from Salix glandulosa and their biological activities.

Two new salicin derivatives, saliglandin (1) and 6'-O-(Z)-p-coumaroylsalicin (2), along with fourteen known analogues (3-16) were isolated from the twigs of Salix glandulosa Seemen. The structures of 1-16 were characterized by the use of NMR methods ((1)H and (13)C NMR, (1)H-(1)H COSY, HSQC and HMBC), chemical hydrolysis, and GC/MS. The full NMR data assignment of the known compounds 6, 13, and 14 are reported for the first time. Isolated compounds were evaluated for their nitric oxide (NO) inhibitory efficacy in lipopolysaccharide (LPS)-activated microglial cell (BV-2). Compounds 2, 5, 8-16 significantly inhibited NO production, compound 11 being the most efficacious (IC50 13.57 µM) respectively. Moreover, compound 16 dramatically increased the nerve growth factor (NGF) production (165.24 ± 11.1%) in C6 glioma cells. Taken together, these results revealed that salicin derivatives from Salix glandulosa might have potent effect as anti-neuroinflammatory agents.

Identification of cytotoxic and anti-inflammatory constituents from the bark of Toxicodendron vernicifluum (Stokes) F.A. Barkley.

ETHNOPHARMACOLOGICAL RELEVANCE: Toxicodendron vernicifluum (Stokes) F.A. Barkley (Anacardiaceae) has traditionally been used as a food supplement and in traditional herbal medicine to treat inflammatory diseases and cancers for centuries in Korea. This study was designed to isolate the bioactive constituents from the ethanol extract of Toxicodendron vernicifluum bark and evaluate their cytotoxic and anti-inflammatory activities. MATERIAL AND METHODS: Bioassay-guided fractionation and chemical investigation of the ethanol extract of Toxicodendron vernicifluum bark resulted in the isolation and identification of three new polyphenols (1-3) and six flavonoids (4-9). The structures of the isolated compounds were elucidated by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR) ((1)H, (13)C, COSY, HMQC and HMBC experiments), and high resolution (HR)-mass spectrometry, and their absolute configurations were further confirmed by chemical methods and circular dichroism (CD) data analysis. Compounds 1-9 were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and anti-inflammatory activities by measuring nitric oxide (NO) levels in the medium of murine microglia BV-2 cells. RESULTS: The isolated compounds were characterized as in the following: three new polyphenols, rhusopolyphenols G-I (1-3) and six flavonoids including two aurones, 2-benzyl-2,3',4',6-tetrahydroxybenzo[b]furan-3(2H)-one (4), sulfuretin (5), two dihydroflavonols, (+)-(2S,3R)-fustin (6), (+)-epitaxifolin (7), one chalcone, butein (8), and one flavonol, fisetin (9). The published NMR assignments of 4 were corrected by the detailed analysis of spectroscopic data in this study. Among the tested compounds, compounds 4-9 showed antiproliferative activity against the tested cells, with IC50 values of 4.78-28.89 µM. Compounds 5 and 8 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated BV-2 cells with IC50 values of 23.37 and 11.68 µM, respectively. CONCLUSIONS: Polyphenols including flavonoids were one of the main constituents of Toxicodendron vernicifluum bark, and activities demonstrated by the isolated compounds support the ethnopharmacological use of Toxicodendron vernicifluum as anti-cancer and/or anti-inflammatory agents.

Bioassay-guided Isolation of Antiproliferative Triterpenoids from Euonymus alatus Twigs.

Euonymus alatus (Celastraceae) has been used as an anticancer agent in Korean traditional medicine. However, the potential bioactive contributors to the anticancer effects have not been thoroughly studied. Our screening test revealed that the MeOH extract of E. alatus twigs exhibited significant cytotoxicity against A549, SK-OV-3, and SK-MEL-2 cell lines. A bioassay-guided separation of the MeOH extract of E. alatus twigs resulted in the isolation and identification of 14 triterpenes as main phytochemicals. The structures of the compounds were elucidated on the basis of spectroscopic evidence as lupeol (1), betulin (2), 3ß,28,30-lup-20(29)-ene triol (3), lupenone (4), betulone (5), 28,30-dihydroxy-3-oxolup-20(29)-ene (6), messagenin (7), glut-5-en-3ß-ol (8), maslinic acid (9), hederagenin (10), 3-oxo-11α-methoxyolean-12-ene (11), 3ß-hydroxy-1-oxo-olean-12-en-28-oic acid (12), ursolic acid (13), and 2a-hydroxy- ursolic acid (14). Of these compounds, 3, 6-8, and 10-14 were isolated for the first time from this plant. All isolated triterpenoids had consistent antiproliferative activities against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines. Compounds 2, 5, and 7 showed significant cytotoxicity against all four cell lines tested, with IC50 values of 3.26-8.61 µM.

Anti-inflammatory and antitumor phenylpropanoid sucrosides from the seeds of Raphanus sativus.

A bioassay-guided fractionation and chemical investigation of the MeOH extract of Raphanus sativus seeds resulted in the isolation and identification of eight phenylpropanoid sucrosides (1-8) including two new compounds, named raphasativuside A and B (1-2) from the most active CHCl3-soluble fraction. The structures of these new compounds were elucidated through spectral analysis, including extensive 2D-NMR data, and chemical reaction experiments. We evaluated the anti-inflammatory effects of 1-8 in lipopolysaccharide (LPS)-stimulated murine microglia BV2 cells. Compounds 2 and 5 exhibited significant inhibitory effect on nitric oxide production in LPS-activated BV-2 cells with IC50 values of 21.63 and 26.96 µM, respectively. All isolates were also evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15). Compounds 1-7 showed consistent cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 6.71-27.92 µM. Additionally, the free-radical scavenging activity of 1-8 was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay where compounds 1, 3, and 4 scavenged DPPH radical strongly with IC50 values of 23.05, 27.10, and 29.63 µg/mL, respectively.

Two minor chalcone acetylglycosides from the roots extract of Glycyrrhiza uralensis.

An extensive phytochemical investigation on the roots of Glycyrrhiza uralensis led to the isolation of two new minor chalcone acetylglycosides, i.e., 6″-O-acetylisoliquiritin (1) and 6″-O-acetylneoisoliquiritin (2), including 16 kinds of known constituents (3-18) of flavonoids, chalcones and triterpene saponins. The chemical structures of 1 and 2 were established by spectroscopic analyses of them, particularly by the aid of two-dimensional NMR experiments, COSY, DEPT, HSQC and HMBC. Some isolated components except 1 and 2 exhibited significant inhibitory effects on the proliferation of cultured tumor cell lines, such as A549, SK-OV-3, A-498, and HCD15, in vitro.

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.

Discovery of substituted 6-pheny-3H-pyridazin-3-one derivatives as novel c-Met kinase inhibitors.

We report a series of phenyl substituted pyridazin-3-ones substituted with morpholino-pyrimidines. The SAR of the phenyl was explored and their c-Met kinase and cell-based inhibitory activity toward c-Met driven cell lines were evaluated. Described herein is a potent c-Met inhibitor by structural modification of the parent morpholino-pyridazinone scaffold, with particular focus on the phenyl and pyrimidine substituents.

Five new oxylipins from Chaenomeles sinensis.

In the course of our continuing search for bioactive constituents of Korean medicinal plants, we isolated five new oxylipins, chaenomic acid A-E (1-5), and six known ones (6-11) from the twigs of Chaenomeles sinensis. The structures of the new compounds (1-5) were determined by spectroscopic methods, including 1D and 2D NMR ((1)H and (13)C NMR, (1)H-(1)H COSY, HMQC, HMBC, and NOESY), olefin cross-metathesis, and LC/MS analysis. The known compounds (6-11) were identified by comparison of their spectroscopic data and specific optical rotation with the reported data. The isolated compounds (1-11) were tested for their inhibitory effects on nitric oxide production in lipopolysaccharide-activated murine microglial cells and for their cytotoxic activities against four human cancer cell lines (A549, SK-OV-3, A498, and HCT-15).

Phenolic Glycosides from the Twigs of Salix glandulosa.

As a part of an ongoing search for bioactive constituents from Korean medicinal plants, the phytochemical investigations of the twigs of Salix glandulosa afforded 12 new phenolic glycosides (1-12) and a known analogue (13). The structures of 1-13 were characterized by a combination of NMR methods ((1)H and (13)C NMR, (1)H-(1)H COSY, HMQC, and HMBC), chemical hydrolysis, and GC/MS. The absolute configuration of 13 [(1R,2S)-2-hydroxycyclohexyl-2'-O-trans-p-coumaroyl-ß-d-glucopyranoside] was determined for the first time. Compounds 1-3, 6, and 7 exhibited inhibitory effects on nitric oxide production in lipopolysaccharide-activated murine microglial cells (IC50 values in the range 6.6-20.5 µM).

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.

4-Methylthio-butanyl derivatives from the seeds of Raphanus sativus and their biological evaluation on anti-inflammatory and antitumor activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Raphanus sativus seeds (Brassicaceae) known as Raphani Semen have long been used as anti-cancer and/or anti-inflammatory agents in Korean traditional medicine. This study was designed to isolate the bioactive constituents from the seed extracts of Raphanus sativus and evaluate their anti-inflammatory and antitumor activities. MATERIAL AND METHODS: Bioassay-guided fractionation and chemical investigation of a methanolic extract of the seeds of Raphanus sativus led to the isolation and identification of seven 4-methylthio-butanyl derivatives. Structural elucidation of the isolated compounds was carried out using 1D and 2D nuclear magnetic resonance (NMR) spectroscopy techniques ((1)H, (13)C, COSY, HMQC and HMBC experiments) and mass spectrometry. RESULTS: The isolated compounds were characterized as in the following: three new 4-methylthio-butanyl derivatives, sinapoyl desulfoglucoraphenin (1), (E)-5-(methylsulfinyl)pent-4-enoxylimidic acid methyl ester (2), and (S)-5-((methylsulfinyl)methyl)pyrrolidine-2-thione (3), together with four known compounds, 5-(methylsulfinyl)-4-pentenenitrile (4), 5-(methylsulfinyl)-pentanenitrile (5), sulforaphene (6), and sulforaphane (7). Full NMR data assignments of the three known compounds 4-6 were also reported for the first time. We evaluated the anti-neuroinflammatory effect of 1-7 in lipopolysaccharide-stimulated murine microglia BV2 cells. Compound 1 significantly inhibited nitrite oxide production with IC50 values of 45.36 µM. Moreover, it also reduced the protein expression of inducible nitric oxide synthase. All isolates were also evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and all of them showed antiproliferative activity against the HCT-15 cell, with IC50 values of 8.49-23.97 µM. CONCLUSIONS: 4-Methylthio-butanyl derivatives were one of the main compositions of Raphanus sativus seeds, and activities demonstrated by the isolated compounds support the ethnopharmacological use of Raphanus sativus seeds (Brassicaceae) as anti-cancer and/or anti-inflammatory agents.