4-Hydroxynonenal-induced GPR109A (HCA2 receptor) activation elicits bipolar responses, Gαi -mediated anti-inflammatory effects and Gßγ -mediated cell death.

BACKGROUND AND PURPOSE: In this study, we examined the possibility that 4-hydroxynonenal (4-HNE) acting as a ligand for the HCA2 receptor (GPR109A) elicits both anti-inflammatory and cell death responses. EXPERIMENTAL APPROACH: Agonistic activity of 4-HNE was determined by observing the inhibition of cAMP generation in CHO-K1-GPR109A-Gi cell line, using surface plasmon resonance (SPR) binding and competition binding assays with [3 H]-niacin. 4-HNE-mediated signalling pathways and cellular responses were investigated in cells expressing GPR109A and those not expressing these receptors. KEY RESULTS: Agonistic activity of 4-HNE was stronger than that of niacin or 3-OHBA at inhibiting forskolin-induced cAMP production and SPR binding affinity. In ARPE-19 and CCD-841 cells, activation of GPR109A by high concentrations of the agonists 4-HNE (≥10 µM), niacin (≥1000 µM) and 3-OHBA (≥1000 µM) induced apoptosis accompanied by elevated Ca2+ and superoxide levels. This 4-HNE-induced cell death was blocked by knockdown of GPR109A or NOX4 genes, or treatment with chemical inhibitors of Gßγ (gallein), intracellular Ca2+ (BAPTA-AM), NOX4 (VAS2870) and JNK (SP600125), but not by the cAMP analogue 8-CPT-cAMP. By contrast, low concentrations of 4-HNE, niacin and 3-OHBA down-regulated the expression of pro-inflammatory cytokines IL-6 and IL-8. These 4-HNE-induced inhibitory effects were blocked by a cAMP analogue but not by inhibitors of Gßγ -downstream signalling molecules. CONCLUSIONS AND IMPLICATIONS: These results revealed that 4-HNE is a strong agonist for GPR109A that induces Gαi -dependent anti-inflammatory and Gßγ -dependent cell death responses. Moreover, the findings indicate that specific intracellular signalling molecules, but not GPR109A, can serve as therapeutic targets to block 4-HNE-induced cell death.

n-Butyl-α-D-fructofuranoside Isolated from Ulmus davidiana Enhances Nrf2 Activity Through Activation of JNK.

BACKGROUND: The root bark of Ulmus davidiana Nakai (Ulmaceae), a traditional Korean medicinal plant, is used for treating inflammatory diseases. OBJECTIVE: We investigated the Nrf2-activating effect of U. davidiana and identified a novel Nrf2 activator from its constituent compounds. METHODS: Cytotoxicity was measured by MTT assay, and the Nrf2 activity was examined by luciferasereporter assay and western blot analysis. The expression of Nrf2-dependent antioxidant genes was estimated by RT-PCR. The signal pathway related to Nrf2 activation was analyzed by treating specific signaling inhibitors. Anti-inflammatory effects were determined using an NO assay and western blot analysis. RESULTS: Ulmus davidiana and its constituent compounds, including catechin-3-O-α-L-rhamnopyranoside, α-nigerose, n-butyl α-D-fructofuranoside (NBF), and procyanidin B3, enhanced the transcriptional activity of Nrf2. Of these compounds, only NBF possessed a distinctive structure and exhibited ROS-independent Nrf2 activation. In addition, NBF significantly increased the nuclear translocation of Nrf2 and the expression of Nrf2-dependent detoxifying enzymes, including HO-1 and NQO-1, in dose-dependent manner. The Nrf2 activation induced by NBF was mediated by the phosphorylation of JNK. Consequently, pretreatment with NBF inhibited the LPS-induced expression of pro-inflammatory genes. CONCLUSION: To the best of our knowledge, this is the first study to report on the Nrf2-activating effect of U. davidiana and NBF. Given the importance of Nrf2 as a negative regulator in various inflammatory diseases, NBF could be considered as a novel candidate for the prevention and treatment of inflammatory diseases.

(--)-Catechin glycosides from Ulmus davidiana.

Extensive chromatographic separation of the n-BuOH soluble fraction obtained from the stem and root barks of U. davidiana resulted in five hitherto unknown compounds together with a known one (-)-catechin 1. Structures of the five compounds were elucidated by chemical and spectroscopic analyses, to be (-)-catechin-7-O-gallate-5-O-(5″″-trans-caffeoyl)-ß-D-apiofuranoside-3-O-ß-D-apiofuranosyl-(1 → 2)-ß-D-glucopyranoside 2, (-)-catechin-7-O-gallate-5-O-(5″″-trans-caffeoyl)-ß-D-apiofuranoside-3-O-ß-D-glucopyranoside 3, (-)-catechin-7-O-gallate-5-O-ß-D-apiofuranoside-3-O-(2″-O-galloyl)-ß-D-glucopyranoside 4, (-)-catechin-7-O-gallate-5-O-(5″″-trans-caffeoyl)-ß-D-apiofuranoside 5, and (-)-catechin-7-O-gallate-5-O-(5″″-trans-feruloyl)-ß-D-apiofuranoside 6.

Inhibition of DNA topoisomerases I and II of compounds from Reynoutria japonica.

Three anthraquinones (1, 2 and 4), three stilbenes (5, 6 and 7) and 3,5-dihydroxybenzyl alcohol (3) were isolated from Reynoutria japonica. Their structures were identified as emodin (1), emodin-8-O-ß-D-glucoside (2), 3,5-dihydroxybenzyl alcohol (3), citreorosein (4), cis-resveratrol (5), trans-resveratrol (6) and trans-resveratrol-5-O-ß-D-glucopyranoside (7) by comparing their physicochemical and spectral data with published data. Compound 3 was isolated for the first time from the Polygonaceae family. Among the purified compounds, 3 showed more potent inhibitory activity against topoisomerase I (IC50: 4 µM) than camptothecin, as the positive control (IC50: 18 µM). Compounds 3, 4, 5, 6 and 7 showed stronger inhibitory activities toward DNA topoisomerase II (IC50: 0.54, 14, 15, 0.77 and 3 µM, respectively) than the positive control, etoposide (IC50: 44 µM). Compounds 1 and 4 displayed weak cytotoxicities against human lung cancer (A549), ovarian cancer (SK-OV-3), human liver hepatoblastoma (HepG2) and colon adenocarcinoma (HT-29) cell lines.

Protective constituents against sepsis in mice from the root barks of Ulmus davidiana var. japonica.

In the course of isolating preventive agents against sepsis based on the in vivo assay model, eleven known compounds, (-)-catechin (1), catechin-7-O-ß-apiofuranoside (2), catechin-7-O-α-Lrhamnopyranoside (3), catechin-3-O-α-L-rhamnopyranoside (4), catechin-7-O-ß-D-glucopyranoside (5), butyl (+)-5'-methoxyisolariciresinol-9'-O-ß-D-xylopyranoside (6), lyoniside (7), nudiposide (8), α-nigerose (9), butyl α-D-fructofuranoside (10), and procyanidin B(3) (11) were isolated from the root barks of Ulmus davidiana var. japonica. Compounds 2, 6, and 8 significantly protected against sepsis in a mouse model with survival rates of mice exposed to 10 mg/kg of LPS/D-GalN ranged from 80%-100%. Among them, 8 exhibited the most potent protective effect and decreased the plasma levels of TNF-α, IL-10 and ALT activity.

Inhibition of DNA topoisomerases I and II and cytotoxicity of compounds from Ulmus davidiana var. japonica.

Twenty five compounds including ten triterpenes (1-3, 5-11), six flavonoids (12-15, 24, 25), five lignans (17, 18, 21-23), two butenyl clohexnone glycosides (19-20), one fructofuranoside (16) and one fatty acid (4) were isolated from the roots of Ulmus davidiana var. japonica. The structures of those compounds were identified by comparing their physicochemical and spectral data with those of published in literatures. All the compounds were evaluated for DNA topoisomerase inhibitory activities and cytotoxicities. Among the purified compounds, 4 and 19 showed more potent inhibitory acitivities (IC(50): 39 and 19 µM, respectively) than camptothecin, as the positive control (IC(50): 46 µM) against topoisomerase I. Compounds, 4, 10, 12, 19, 24 and 25 showed strong inhibitory activities toward DNA topoisomerase II (IC(50): 0.1, 0.52, 0.47, 0.42, 0.17 µM and 17 nM, respectively), which were more potent than that of etoposide as positive control (IC(50): 20 µM). In A549 cell line, 5 and 6 showed cytotoxicities (IC(50): 4 µM and 3 µM, respectively, with IC(50) of camptothecin as positive control: 10.3 µM). In the HepG2 cell line, 3, 5 and 7 showed cytotoxicity (IC(50): 4, 3 and 4 µM, respectively, with IC(50) of camptothecin: 0.3 µM). Compounds 6, 12 and 23 showed cytotoxicities in the HT-29 cell line (IC(50): 19, 19 and 15 µM, respectively, with IC(50) of camptothecin: 2 µM).

Anti-inflammatory and anti-arthritic activity of total flavonoids of the roots of Sophora flavescens.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Sophora flavescens have long been used in Chinese medicine for the treatment of fever, inflammatory disorders, ulcers and skin burns. Sophora flavescens contains flavonoids and alkaloids. AIM OF THE STUDY: This study was conducted to develop a plant-based anti-inflammatory agent focused on chronic inflammatory disorders. To accomplish this, the alkaloid-free prenylated flavonoid-enriched fraction (PFS) of rhizomes of Sophora flavescens was prepared and its in vitro and in vivo anti-inflammatory activities were then evaluated for the first time. MATERIALS AND METHODS: The inhibitory activity of PFS on PGE(2), NO, IL-6 and TNF-alpha production of lipopolysaccharide (LPS)-treated RAW 264.7 cells was measured. Additionally, adjuvant-induced arthritis in rats was used as an animal model of chronic inflammation to establish the in vivo anti-inflammatory effects of PFS. RESULT: PFS inhibited cyclooxygenase-2 (COX-2)-catalyzed PGE(2) and inducible nitric oxide synthase (iNOS)-catalyzed NO production by lipopolysaccharide (LPS)-treated RAW 264.7 cells at 10-50 microg/ml, and these effects primarily occurred via COX-2 inhibition and iNOS down-regulation, respectively. PFS also inhibited IL-6 and TNF-alpha production. When tested against adjuvant-induced arthritis in rats (chronic inflammation), PFS strongly inhibited arthritic inflammation when administered orally at doses of 10-100mg/kg/day. In addition, PFS administered orally potently inhibited acetic acid-induced writhing in mice. CONCLUSIONS: Our results suggest that PFS inhibits chronic inflammatory response and the inhibition of proinflammatory molecules such as COX-2, iNOS and IL-6 may contribute, at least in part, to the anti-inflammatory activity in vivo. Overall, these results indicate that PFS from Sophora flavescens may have the potential for treatment of chronic inflammatory disorders such as rheumatoid arthritis.

Inhibition of DNA topoisomerases I and II and cytotoxicity by lignans from Saururus chinensis.

Thirteen lignans, erythro-austrobailignan-6 (1), meso-dihydroguaiaretic acid (2), sauchinone (3), 1'-epi-sauchinone (4), saucerneol D (5), manassantin B (6), manassantin A (7), nectandrin B (8), machilin D (9), saucerneol F (10), saucerneol G (11), saucerneol H (12) and saucerneol I (13), were isolated from the ethyl acetate extract of the roots of Saururus chinensis. Among these compounds, 5 showed potent inhibitory activities against DNA topoisomerase I and II, and 5, 6, 7 and 10 showed mild cytotoxicities against HT-29 (IC(50) values; 13, 12, 11, and 10 microM, respectively) and HepG2 cell lines (IC(50) values; 16, 11, 12, and 11 microM, respectively).

Protective effect of lignans against sepsis from the roots of Saururus chinensis.

In the course of isolating preventive agents from sepsis based on the in vivo assay model from the EtOAc extract of the roots of Saururus chinensis, twelve lignans, sarisan (1), erythro-austrobailignan-6 (2), meso-dihydroguaiaretic acid (3), saucerneol B (4), manassantin B (5), manassantin A (6), rel-(8R,8'R)-dimethyl-(7S,7'R)-bis(3,4-methylenedioxyphenyl)tetrahydro-furan (7), (+)-saururinone (8), sauchinone (9), sauchinone B (10), nectandrin B (11) and machilin D (12), were isolated. Compounds 9 and 10, at a dose of 10 mg/kg, increased survival rates to 80% from 20% for the control experiment, and decreased the plasma levels of tumor necrosis factor-alpha (TNF-alpha) and alanine aminotransferase (ALT) activity in mice administered LPS/D-GalN.

Cytotoxic and DNA topoisomerases I and II inhibitory constituents from the roots of Aralia cordata.

Bioactivity-guided fractionation, based on the DNA topoisomerase inhibitory activity, lead to the isolation of five compounds (1-5) from the methylene chloride extract of the roots of Aralia cordata Thunb. (Araliaceae). These compounds were identified as ent-pimara-8(14), 15-dien-19-oic acid (1), ent-pimara-8(14), 15-dien-18-oic acid (2), 16alpha-hydrogen-17-isovaleryloxy-ent-kauran-19-oic acid (3), 16alpha-hydroxy-17-isovaleryloxy-ent-kauran-19-oic acid (4) and dehydrofalcarindiol-8-acetate (5) from their spectral data. Compound 3 was isolated for the first time from this plant, and also showed the strongest inhibition of both DNA topoisomerase I and II activities, with 53 and 96% inhibitions, respectively, at a concentration of 20 microM. However, all the compounds exhibited either weak or no cytotoxicities against the human colon carcinoma cell line (HT-29), the human breast carcinoma cell line (MCF-7) and human hepato blastoma cell line (HepG-2).

Two new benzofurans from Gastrodia elata and their DNA topoisomerases I and II inhibitory activities.

Two new benzofurans, 1-furan-2-yl-2-(4-hydroxyphenyl)-ethanone (1) and 5-(4-hydroxybenzyloxymethyl)-furan-2-carbaldehyde (2), together with five known compounds, 4-hydroxybenzyl methyl ether (3), 5-(hydroxymethyl)-furfural (4), gastrodin (5), beta-sitosterol (6) and beta-sitosterol glucoside (7) were isolated from the rhizome of Gastrodia elata Blume. In DNA topoisomerase I and II inhibition assays in vitro at a concentration of 20 microM, 1 showed potent inhibitory activity, 66% and 71% inhibition, respectively, compared to the positive control compounds, camptothecin and etoposide, 71% and 22% inhibition, respectively. All of these compounds exhibited weak or no cytotoxicities against human colon carcinoma cell line (HT-29), human breast carcinoma cell line (MCF-7) and human hepatocellular carcinoma cell line (HepG-2).

Meliae cortex extract exhibits anti-allergic activity through the inhibition of Syk kinase in mast cells.

The anti-allergic action of various Oriental medicinal herbs was investigated using in vitro and in vivo experimental models. Of these extracts, the ethanol extract of Meliae cortex (MC) exhibited the most potent activity in mast cells; its IC(50) values were 29+/-1.5 microg/ml for antigen stimulation and 57+/-3.4 microg/ml for thapsigargin stimulation. It inhibited compound-48/80-induced systemic anaphylaxis by 52.9% at a dose of 300 mg/kg in mice; it also inhibited the expression of the proinflammatory mediator TNF-alpha. With regard to its mechanism of action, MC suppressed the activating phosphorylation of Syk, a key enzyme in mast-cell signaling processes and that of Akt in a dose-dependent manner. It also inhibited the MAP kinase ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. Taken together, these results suggest that the anti-allergic activity of MC may be due to the inhibition of histamine secretion and cytokine expression through the Syk inhibition in mast cells.

Agents protecting against sepsis from the roots of Angelica dahurica.

In the course of isolating agents preventing sepsis from the EtOAc extract of the roots of Angelica dahurica, four known furanocoumarins, isoimperatorin (1), oxypeucedanin (2), (+/-)-byakangelicin (3), and (+)-oxypeucedanin hydrate (4), were isolated as active compounds based on the in vivo assay model of sepsis induced by lipopolysaccharide (LPS) and D-galactosamine (D-GalN). Among them, 3 showed the highest survival rate (100% with a dose of 30 mg/kg versus 20% for the control experiment) and decreased the plasma levels of tumor necrosis factor-alpha and alanine aminotransferase in mice adminstered LPS/D-GalN.

Protective constituents against sepsis in mice from the root cortex of Paeonia suffruticosa.

The bioassay-guided fractionation of protective agents against sepsis-induced lethality from the root cortex of Paeonia suffruticosa ANDREWS (Ranunculaceae) led to the isolation of eight known compounds: paeonol (1), 2,5-dihydroxy-4-methoxyacetophenone (2), acetovanillone (3), paeonoside (4), paeoniflorin (5), oxypaeoniflorin (6), apiopaeonoside (7), and methyl 3-hydroxy-4-methoxybenzoate (8). Among them, 3 showed the highest survival rate (100% with a dose of 30 mg/kg versus 17% for the control experiment) and reduced alanine aminotransferase level to be a half of the control value on the sepsis model induced by lipopolysaccharide/D-galactosamine.

Cytotoxicity and DNA topoisomerases inhibitory activity of constituents from the sclerotium of Poria cocos.

The bioactivity-guided fractionation of the methylene chloride extract of the sclerotium of Poria cocos led to the isolation of (S)-(+)-turmerone (1), ergosterol peroxide (2), polyporenic acid C (3), dehydropachymic acid (4), pachymic acid (5), and tumulosic acid (6). Compounds 4-6 exhibited moderate cytotoxicities, with IC50 values of 20.5, 29.1, and 10.4 microM, respectively, against a human colon carcinoma cell line. However, 3-6 not only showed inhibitory activities as potent as etoposide used as a positive control on DNA topoisomerase II (36.1, 36.2, 43.9 and 66.7% inhibition at a concentration of 20 microM, respectively), but also inhibition of DNA topoisomerase I (55.8, 60.7, 43.5, and 83.3% inhibition at a concentration of 100 microM, respectively).

Preventive agents against sepsis and new phenylpropanoid glucosides from the fruits of Illicium verum.

The bioassay-guided fractionation of preventive agents against lethality due to septic shock from the fruits of Illicium verum led to the isolation of two known racemic mixtures of phenylpropanoids, [1-(4'-methoxyphenyl)-(1 R,2 S and 1 S,2 R)-propanediol (1) and 1-(4'-methoxyphenyl)-(1 R,2 R and 1 S,2 S)-propanediol (2)], along with two known phenylpropanoid glucosides, [1-(4'-methoxyphenyl)-(1 S,2 R)-propan-1-ol 2-O-beta-D-glucopyranoside (3) and 1-(4'-methoxyphenyl)-(1 R,2 S)-propan-1-ol 2-O-beta-D-glucopyranoside ( 5)], and two new phenylpropanoid glucosides, [1-(4'-methoxyphenyl)-(1 S,2 S)-propan-1-ol 2- O-beta- D-glucopyranoside (4) and 1-(4'-methoxyphenyl)-(1 R,2 R)-propan-1-ol 2-O-beta-D-glucopyranoside (6)]. Their chemical structures were elucidated on the basis of spectroscopic studies. Among them, 1 exhibited the highest survival rate in a dose-dependent manner (100 % with a dose of 10 mg/kg against 40 % for the control experiment) and showed a reduction of the plasma alanine aminotransferase (ALT) value on the in vivo assay model of septic shock induced by tumor necrosis factor (TNF)-alpha.

Tyrosinase inhibitory prenylated flavonoids from Sophora flavescens.

For the purpose of the development of a skin-whitening agent, Sophora flavescens was evaluated for tyrosinase inhibitory activity and its active principles were identified following activity-guided isolation. The ethanol extract and dichloromethane fraction from S. flavescens showed significant inhibition of mushroom tyrosinase. From the dichloromethane fraction, three known prenylated flavonoids, sophoraflavanone G, kuraridin, and kurarinone, were isolated. Compared with kojic acid (IC(50)=20.5 microM), these compounds possessed more potent tyrosinase inhibitory activity. The IC(50) values were 6.6, 0.6, and 6.2 microM for sophoraflavanone G, kuraridin, and kurarinone, respectively.