Production Inhibitory Activity Research Articles

Mono‐ and Dihydroxylated Metabolites of Thalidomide: Synthesis and TNF‐α Production—Inhibitory Activity.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

In Vitro and In Vivo Antiallergic Effects of Glycyrrhiza glabra and Its Components

Licorice (Glycyrrhiza glabra L., Leguminosae) is frequently used in traditional medicine to treat inflammatory and allergic diseases. In this study, the main components (glycyrrhizin, 18beta-glycyrrhetinic acid, isoliquiritin, and liquiritigenin) were isolated from licorice, and their anti-allergic effects, such as antiscratching behavior and IgE production-inhibitory activity, were evaluated both in vitro and in vivo. Liquiritigenin and 18beta-glycyrrhetinic acid most potently inhibited the degranulation of RBL-2H3 cells induced by IgE with the antigen (DNP-HSA) and rat peritoneal mast cells induced by compound 48/80. Liquiritigenin and 18beta-glycyrrhetinic acid potently inhibited the passive cutaneous anaphylactic reaction as well as the scratching behavior in mice induced by compound 48/80. These components inhibited the production of IgE in ovalbumin-induced asthma mice but liquiritigenin had little effect. This suggests that the antiallergic effects of licorice are mainly due to glycyrrhizin, 18beta-glycyrrhetinic acid, and liquiritigenin, which can relieve IgE-induced allergic diseases such as dermatitis and asthma.

An antibiotic produced by an insect-pathogenic bacterium suppresses host defenses through phenoloxidase inhibition

Photorhabdus is a virulent pathogen that kills its insect host by overcoming immune responses. The bacterium also secretes a range of antibiotics to suppress the growth of other invading microorganisms. Here we show that Photorhabdus produces a small-molecule antibiotic (E)-1,3-dihydroxy-2-(isopropyl)-5-(2-phenylethenyl)benzene (ST) that also acts as an inhibitor of phenoloxidase (PO) in the insect host Manduca sexta. The Photorhabdus gene stlA encodes an enzyme that produces cinnamic acid, a key precursor for production of ST, and a mutation in stlA results in loss of ST production and PO inhibitory activity, which are both restored by genetic complementation of the mutant and also by supplying cinnamic acid. ST is produced both in vitro and in vivo in sufficient quantities to account for PO inhibition and is the only detectable solvent-extractable inhibitor. A Photorhabdus stlA- mutant is significantly less virulent, proliferates slower within the host, and provokes the formation of significantly more melanotic nodules than wild-type bacteria. Virulence of the stlA- mutant is also rescued by supplying cinnamic acid. The proximate cause of the virulence effect, however, is the inhibition of PO, because the effect of the stlA- mutation on virulence is abolished in insects in which PO has been knocked down by RNA interference (RNAi). Thus, ST has a dual function both as a PO inhibitor to counter host immune reactions and also as an antibiotic to exclude microbial competitors from the insect cadaver.

Correlation between Flavonoid Content and the NO Production Inhibitory Activity of Peel Extracts from Various Citrus Fruits

We investigated the correlation between the flavonoid content and NO production inhibitory activity of fruit peel extracts using 20 citrus plants. The contents of seven flavonoids (naringin, naringenin, hesperidin, hesperetin, rutin, nobiletin, and tangeretin) were determined by HPLC analysis. Each citrus peel extract varied in flavonoid content, but the contents of nobiletin and tangeretin, which were contained in all 20 fruit peels, showed a positive and significant correlation with each other (r=0.879, p<0.0005 for immature fruit peels; r=0.858, p<0.0005 for mature fruit peels). All citrus peel extracts dose-dependently inhibited LPS-induced NO production in RAW 264.7 cells. This inhibitory effect was significantly and positively correlated with the content of nobiletin and tangeretin. Nobiletin showed a more potent NO production inhibitory activity (IC50=26.5 microM) compared to tangeretin (IC50=136.6 microM). This result supports the premise that nobiletin-rich citrus may provide protection against disease resulting from excessive NO production.

Nitric oxide inhibitory substances from the rhizomes of Dioscorea membranacea

Thai medicinal plants locally known as Hua-Khao-Yen were examined for their inhibitory activities against lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 cell lines. Among the plant species studied, an ethanolic extract of Dioscorea membranacea exhibited the most potent inhibitory activity, with an IC 50 value of 23.6 μg/ml. From this extract, eight compounds [two naphthofuranoxepins ( 1, 2), one phenanthraquinone ( 3), three steroids ( 4– 6) and two steroidal saponins ( 7, 8)] were isolated and further investigated for their inhibitory properties of NO production. It was found that diosgenin-3- O-α- l-rhamnosyl (1 → 2)-β- d-glucopyranoside ( 7) possessed the highest activity (IC 50 = 3.5 μM), followed by dioscoreanone ( 3, IC 50 = 9.8 μM) and dioscorealide B ( 2, IC 50 = 24.9 μM). Regarding structural requirements of diosgenin derivatives for NO production inhibitory activity, compound 7 which has a rhamnoglucosyl moiety at C-3 exhibited much higher activity than compounds that have either a diglucosyl substitution ( 8) or its aglycone ( 9); whereas, hydroxyl substitution at position 8 of naphthofuranoxepin derivatives conferred higher activity than the methoxyl group. It is concluded that diosgenin-3- O-α- l-rhamnosyl (1 → 2)-β- d-glucopyranoside ( 7), dioscoreanone ( 3) and dioscorealide B ( 2) are active principles for NO inhibitory activity of Dioscorea membranacea. Compounds 1– 3 were also tested for the inhibitory effect on LPS-induced TNF-α release in RAW 264.7 cells. The result revealed that 3 possessed potent activity against TNF-α release with an IC 50 value of 17.6 μM, whereas, 1 and 2 exhibited mild activity. The present study may support the use of Dioscorea membranacea by Thai traditional doctors for treatment of the inflammatory diseases.

Stilbene Derivatives from Pholidota chinensis and Their Anti-inflammatory Activity

Ethyl acetate extract of Pholidota chinensis L. showed strong NO production inhibitory activity in murine macrophage-like cell line, RAW 264.7, which was activated by a lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Fractionation of the active extract led to the isolation of two new stilbene derivatives, 2,3'-dihydroxy-5-methoxy-3,4-methylenedioxydihydrostilbene (Pholidotol A) and 2-hydroxy-5-methoxy-3,4,3',4'-dimethylenedioxydihydrostilbene (Pholidotol B) together with six known stilbene derivatives. Pholidotols A both B and inhibited Nitric oxide (NO) production with an IC(50) value at 24.3 and 17.1 microM, respectively.

Mono- and Dihydroxylated Metabolites of Thalidomide: Synthesis and TNF-.ALPHA. Production-Inhibitory Activity

Mono- and dihydroxylated metabolites of thalidomide were efficiently prepared and characterized, and their inhibitory activity on tumor necrosis factor (TNF)-alpha production in the human monocytic leukemia cell line THP-1 was evaluated. 5,N-Dihydroxythalidomide was a much more potent TNF-alpha production inhibitor than thalidomide.

New Lignans from Kadsura coccinea and Their Nitric Oxide Inhibitory Activities

In vitro anti-allergic screening of medicinal herbal extracts revealed that the chloroform extract of the rhizoma of Kadsura coccinea inhibited nitric oxide (NO) production in a lipopolysaccharide (LPS) and recombinant mouse interferon-gamma (IFN-gamma) activated murine macrophage like cell line RAW 264.7. Further fractionation of the chloroform extract led to the isolation of three new lignans, including two dibenzocyclooctadiene lignans and one arylnaphthalene lignan, together with other three known dibenzocyclooctadiene lignans. This is the first report of NO production inhibitory activity of Kadsura coccinea and first report about the isolation of arylnaphthalene lignan from K. coccinea.

Neoflavonoids and Related Constituents from Nepalese Propolis and Their Nitric Oxide Production Inhibitory Activity

A methanolic extract of Nepalese propolis yielded 10 new open-chain neoflavonoids (1-10), a new chalcone (11), and eight previously reported compounds (12-19). Their structures were determined on the basis of spectroscopic data and chemical conversion. The isolated compounds other than 5, 8, and 16 showed dose-dependent inhibitory activities on nitric oxide production in lipopolysaccharide-activated macrophage-like J774.1 cells and were more active than a positive control, N(G)-monomethyl-L-arginine (IC(50), 27.1 microM). The most potent activities, of 6 and 7 (IC(50), 0.5 microM), were greater than another positive control, caffeic acid phenethyl ester (IC(50), 4.8 microM).

Inhibitors of Nitric Oxide Production from the Rhizomes of Alpinia galanga: Structures of New 8-9' Linked Neolignans and Sesquineolignan

The 80% aqueous acetone extract from the rhizomes of Alpinia galanga showed nitric oxide (NO) production inhibitory activities in mouse peritoneal macrophages. From the aqueous acetone extract, three new 8-9' linked neolignans, galanganal, galanganols A and B, and a sesquineolignan, galanganol C, were isolated together with nine known phenylpropanoids and p-hydroxybenzaldehyde. The structures of new neolignans were determined on the basis of physicochemical and chemical evidence. In addition, the inhibitory effects of the constituents from the rhizomes of A. galanga on NO production induced by lipopolysaccharide in mouse peritoneal macrophages were examined. Among them, galanganal (IC50=68 microM), galanganols B (88 microM) and C (33 microM), 1'S-1'-acetoxychavicol acetate (2.3 microM), 1'S-1'-acetoxyeugenol acetate (11 microM), trans-p-hydroxycinnamaldehyde (ca. 20 microM), trans-p-coumaryl alcohol (72 microM), and trans-p-coumaryl diacetate (19 microM) were found to show inhibitory activity.

Anti-inflammatory Activity of New Guaiane Type Sesquiterpene from Wikstroemia indica

In our investigation of in vitro anti-allergic screening of medicinal herbal extracts, the ethyl acetate extract of the root of Wikstroemia indica was observed to inhibit nitric oxide (NO) production in a lipopolysaccharide (LPS) and recombinant mouse interferon-gamma (IFN-gamma) activated murine macrophage-like cell line, RAW 264.7. Fractionation of the active extract led to the isolation of one new guaiane type sesquiterpene, indicanone (1), and two known biflavonoids, sikokianin B (2) and sikokianin C (3). 1 inhibited NO production with IC50 values at 9.3 microM and also inhibit the inducible nitric oxide synhase (iNOS) gene expression. This is the first report of NO production inhibitory activity of Wikstroemia indica and supports the pharmacological use of it, which has been employed as an herbal medicine for the treatment of inflammation.

Anti-inflammatory and related pharmacological activities of cultured mycelia and fruiting bodies of Cordyceps militaris

This study aimed to elucidate pharmacological activities of Cordyceps militaris. The 70% ethanolic extracts of cultured mycelia (CME) and fruiting bodies (FBE) of Cordyceps militaris were prepared. CME was able to directly scavenge the stable free radical diphenyl-2-picrylhydrazyl (DPPH), indicating its antioxidant activity. Both CME and FBE showed topical anti-inflammatory activity in the croton oil-induced ear edema in mice. CME was found to contain acute anti-inflammatory activity, which was evaluated using the carrageenin-induced edema, and also strong antinociceptive activity in writhing test. CME and FBE contain potent inhibitory activity on the chick embryo chorioallantoic membrane (CAM) angiogenesis in a dose-dependent manner. Cordycepin, a metabolite of Cordyceps militaris, appeared to be at least partly responsible for its anti-inflammatory and anti-angiogenic activities. CME concentration-dependently inhibited the NO production and iNOS expression upon stimulation by lipoposaccharide in RAW 264.7, a murine macrophage cell line. In brief, we demontrate that Cordyceps militaris possesses anti-inflammatory and antinociceptive activites, and related antioxidant, anti-angiogenic, and NO production-inhibitory activities.

Absolute stereostructures of polypodane- and octanordammarane-type triterpenes with nitric oxide production inhibitory activity from guggul-gum resins

The methanolic extract from guggul-gum resin, the resin of Balsamodendron mukul, was found to inhibit nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages (IC 50 = 13 μg/mL). From the methanolic extract, three new polypodane-type triterpenes, myrrhanol B and myrrhanones B and A acetate, and a new octanordammarane-type triterpene, epimansumbinol, were isolated together with 17 known compounds including progesterone and the related steroids. The absolute stereostructures of new triterpenes were elucidated on the basis of chemical and physicochemical evidence. The several constituents showed inhibitory effects on nitric oxide production and induction of inducible nitric oxide synthase.

Structural Requirements of Flavonoids for Nitric Oxide Production Inhibitory Activity and Mechanism of Action

To clarify the structure–activity relationships of flavonoids for nitric oxide (NO) production inhibitory activity, we examined the inhibitory effects of 73 flavonoids on NO production in lipopolysaccharide-activated mouse peritoneal macrophages. Among those flavonoids, apigenin (IC 50=7.7 μM), diosmetin (8.9 μM), and tetra- O-methylluteolin (2.4 μM), and hexa- O-methylmyricetin (7.4 μM) were found to show potent inhibitory activity, and the results suggested the following structural requirements of flavonoids: (1) the activities of flavones were stronger than those of corresponding flavonols; (2) the glycoside moiety reduced the activity; (3) the activities of flavones were stronger than those of corresponding flavanones; (4) the flavones and flavonols having the 4′-hydroxyl group showed stronger activities than those lacking the hydroxyl group at the B ring and having the 3′,4′-dihydroxyl group; (5) the flavonols having the 3′,4′-dihydroxyl group (catechol type) showed stronger activities than those having the 3′,4′,5′-trihydroxyl group (pyrogallol type); (6) the 5-hydroxyl group tended to enhance the activity; (7) methylation of the 3-, 5-, or 4′-hydroxyl group enhanced the activity; (8) the activities of isoflavones were weaker than those of corresponding flavones; (9) methylation of the 3-hydroxyl group reduced the cytotoxicity. In addition, potent NO production inhibitors were found to inhibit induction of inducible nitric oxide synthase (iNOS) without iNOS enzymatic inhibitory activity.

Identification of a Neuropeptide Modified with Bromine as an Endogenous Ligand for GPR7

We isolated a novel gene in a search of the Celera data base and found that it encoded a peptidic ligand for a G protein-coupled receptor, GPR7 (O'Dowd, B. F., Scheideler, M. A., Nguyen, T., Cheng, R., Rasmussen, J. S., Marchese, A., Zastawny, R., Heng, H. H., Tsui, L. C., Shi, X., Asa, S., Puy, L., and George, S. R. (1995) Genomics 28, 84-91; Lee, D. K., Nguyen, T., Porter, C. A., Cheng, R., George, S. R., and O'Dowd, B. F. (1999) Mol. Brain Res. 71, 96-103). The expression of this gene was detected in various tissues in rats, including the lymphoid organs, central nervous system, mammary glands, and uterus. GPR7 mRNA was mainly detected in the central nervous system and uterus. In situ hybridization showed that the gene encoding the GPR7 ligand was expressed in the hypothalamus and hippocampus of rats. To determine the molecular structure of the endogenous GPR7 ligand, we purified it from bovine hypothalamic tissue extracts on the basis of cAMP production-inhibitory activity to cells expressing GPR7. Through structural analyses, we found that the purified endogenous ligand was a peptide with 29 amino acid residues and that it was uniquely modified with bromine. We subsequently determined that the C-6 position of the indole moiety in the N-terminal Trp was brominated. We believe this is the first report on a neuropeptide modified with bromine and have hence named it neuropeptide B. In in vitro assays, bromination did not influence the binding of neuropeptide B to the receptor.

Absolute stereostructures of novel norcadinane- and trinoreudesmane-type sesquiterpenes with nitric oxide production inhibitory activity from Alpinia oxyphylla

Novel 14-norcadinane-type sesquiterpenes, oxyphyllenodiols A and B, and 11,12,13-trinoreudesmane-type sesquiterpenes, oxyphyllenones A and B, were isolated from the methanolic extract of kernels of Alpinia oxyphylla. The absolute stereostructures of these norsesquiterpenes were determined on the basis of physicochemical and chemical evidence. In addition, oxyphyllenodiol A and oxyphyllenone A were found to inhibit the NO production in lipopolysaccharide-activated macrophages.

Inducible nitric oxide synthase inhibitors of Chinese herbs. Part 2: Naturally occurring furanocoumarins

Inducible nitric oxide synthase (iNOS)-dependent production of nitric oxide (NO) plays an important role in inflammation. The effects of various naturally occurring furanocoumarins on NO production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophage cells were evaluated in vitro. The results showed that angelicin, pimpinellin, sphondin, byakangelicol, oxypeucedanin, oxypeucedanin hydrate, xanthotoxin, and cnidilin are potential NO production inhibitors, and their IC 50 values for inhibition of nitrite production were 19.5, 15.6, 9.8, 16.9, 16.8, 15.8, 16.6, and 17.7 μg/mL, respectively. Distinct structure–activity relationships were also revealed for the NO production inhibitory activities of these furanocoumarins. Activities of the angelicin type such as pimpinellin and sphondin were more potent than those of the psoralen type. Presence of a methoxy at the C 6 position in the angelicin type seemed to be essential to augment the activity. Western blot analysis demonstrated that only sphondin dose-dependently inhibited the expression of the iNOS protein at 2.5–20 μg/mL. However, iNOS enzyme activity was stimulated with LPS for 12 h and sphondin was administered (20 μg/mL) for 24 h, which did not reasonably inhibit iNOS enzyme activity. l-NAME (100 μM), a known specific inhibitor of iNOS, was employed as a positive control with the same protocol and showed more than 50% inhibition activity. The results demonstrate that the NO production inhibitory activity of sphondin is due to the effect of iNOS expression, but not by direct inhibition of iNOS enzyme activity. Thus, sphondin may act as a potent inhibitor of NO production under tissue-damaging inflammatory conditions.

Hepatoprotective and nitric oxide production inhibitory activities of coumarin and polyacetylene constituents from the roots of Angelica furcijuga.

The methanolic extract from the roots of Angelica furcijuga KITAGAWA was found to exhibit protective effects on liver injury induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). From the methanolic extract, seventeen coumarins, two phenylpropanoids, and two polyacetylenes were isolated and examined their in vitro and in vivo hepatoprotective effects and inhibitory activity of NO production in macrophages. A acylated khellactone, isoepoxypteryxin, showed protective activity against D-GalN-induced cytotoxicity in primary cultured rat hepatocytes. On the other hand, six acylated khellactones (hyuganins A, B, C, and D, anomalin, isopteryxin) and two polyacetylenes [(-)-falcarinol and falcarindiol] strongly inhibited NO production induced by LPS in cultured mouse peritoneal macrophages, and also other acylated khellactones (isoepoxypteryxin, pteryxin, and suksdorfin) and a coumarin glycosides (praeroside II) were found to show the activity. By comparison of the inhibitory activities for acylated khellactones with those for other coumarins, acyl groups were found to be essential to exerting potent activity.

Synthesis and Potent Tumour Necrosis Factor-α Production Inhibitory Activity of N-Pyridinylphthalimides and Derivatives

A series of N-azaaryl(alkyl)phthalimides incorporating amino(alkyl)pyridines were synthesized and tested as inhibitors of TNF-α production. The most potent compounds were N-(4, 6-dimethyl-pyridin-2-yl)tetrafluorophthalimide (8, 40% inhibition at 10μM), N-(3-methylpyridinyl)-5-fluorophthalimide (12, 48%) and N-(3-methylpyridinyl)tetrafluorophthalimide (13, 68%). The analogues without (tetra)fluorine substitution on the aromatic ring were less active inhibitors.