RESUMEN
Fructose-6-phosphate aldolase (FSA) is an important enzyme for the C-C bond-forming reactions in organic synthesis. The present work is focused on the synthesis of a precursor of D-fagomine catalyzed by a mutant FSA. The biocatalyst has been immobilized onto several supports: magnetic nanoparticle clusters (mNC), cobalt-chelated agarose (Co-IDA), amino-functionalized agarose (MANA-agarose) and glyoxal-agarose, obtaining a 29.0%, 93.8%, 89.7% and 53.9% of retained activity, respectively. Glyoxal-agarose FSA derivative stood up as the best option for the synthesis of the precursor of D-fagomine due to the high reaction rate, conversion, yield and operational stability achieved. FSA immobilized in glyoxal-agarose could be reused up to 6 reaction cycles reaching a 4-fold improvement in biocatalyst yield compared to the non-immobilized enzyme.
Asunto(s)
Aldehído-Liasas/química , Enzimas Inmovilizadas/química , Iminopiranosas/química , Nanopartículas de Magnetita/química , Aldehído-Liasas/metabolismo , Catálisis , Cobalto/química , Enzimas Inmovilizadas/metabolismo , Escherichia coli/enzimología , Fructosafosfatos/metabolismo , Iminopiranosas/síntesis química , Sefarosa/químicaRESUMEN
Iminosugars are one of the compounds that mimic the structure of monosaccharides. Such sugar mimics have the ability to effectively and specifically inhibit various glycosidases and glycosyltransferases. After studying iminopyranose, miglitol, which has α-glucosidase inhibitory activity, was approved and used in the clinical treatment of diabetes. This study focused on l-iminofuranose derivatives to develop new anti-diabetic drug. As a result, it was found that l-iminofuranose having an alkyl group at C1 position show potent α-glucosidase inhibitory activity. Further structural-activity relationship studies were conducted, and interesting findings were obtained. This paper describes the details of those research developments.
Asunto(s)
1-Desoxinojirimicina/análogos & derivados , Diabetes Mellitus/tratamiento farmacológico , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes , Iminopiranosas/síntesis química , Iminopiranosas/farmacología , 1-Desoxinojirimicina/síntesis química , 1-Desoxinojirimicina/química , 1-Desoxinojirimicina/farmacología , 1-Desoxinojirimicina/uso terapéutico , Animales , Humanos , Iminopiranosas/química , Iminopiranosas/uso terapéutico , Relación Estructura-Actividad , alfa-GlucosidasasRESUMEN
Glycosidase inhibitors have shown great potential as pharmacological chaperones for lysosomal storage diseases. In light of this, a series of new cyclopentanoid ß-galactosidase inhibitors were prepared and their inhibitory and pharmacological chaperoning activities determined and compared with those of lipophilic analogs of the potent ß-d-galactosidase inhibitor 4-epi-isofagomine. Structure-activity relationships were investigated by X-ray crystallography as well as by alterations in the cyclopentane moiety such as deoxygenation and replacement by fluorine of a "strategic" hydroxyl group. New compounds have revealed highly promising activities with a range of ß-galactosidase-compromised human cell lines and may serve as leads towards new pharmacological chaperones for GM1-gangliosidosis and Morquio B disease.
Asunto(s)
Ciclopentanos/farmacología , Galactosidasas/metabolismo , Iminopiranosas/farmacología , Lisosomas/enzimología , Chaperonas Moleculares/metabolismo , Cristalización , Ciclopentanos/síntesis química , Ciclopentanos/química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Galactosidasas/antagonistas & inhibidores , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/química , Ligandos , Lisosomas/efectos de los fármacos , Conformación Molecular , Proteínas Mutantes/metabolismoRESUMEN
(5aR)-5a-C-pentyl-4-epi-isofagomine 1 is a powerful inhibitor of lysosomal ß-galactosidase and a remarkable chaperone for mutations associated with GM1-gangliosidosis and Morquio disease type B. We report herein an improved synthesis of this compound and analogs (5a-C-methyl, pentyl, nonyl and phenylethyl derivatives), and a crystal structure of a synthetic intermediate that confirms its configuration resulting from the addition of a Grignard reagent. These compounds were evaluated as glycosidase inhibitors and their potential as chaperones for mutant lysosomal galactosidases determined. Based on these results and on docking studies, the 5-C-pentyl derivative 1 was selected as the optimal structure for further investigations: this compound induces the maturation of mutated ß-galactosidase in fibroblasts of a GM1-gangliosidosis patient and promote the decrease of keratan sulfate and oligosaccharide load in patient cells. Compound 1 is clearly capable of restoring ß-galactosidase activity and of promoting maturation of the protein, which should result in significant clinical benefit. These properties strongly support the development of compound 1 for the treatment of GM1-gangliosidosis and Morquio disease type B patients harboring ß-galactosidase mutations sensitive to pharmacological chaperoning.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Gangliosidosis GM1/tratamiento farmacológico , Iminopiranosas/química , Iminopiranosas/farmacología , Mucopolisacaridosis IV/tratamiento farmacológico , beta-Galactosidasa/antagonistas & inhibidores , Descubrimiento de Drogas , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/uso terapéutico , Gangliosidosis GM1/enzimología , Gangliosidosis GM1/genética , Gangliosidosis GM1/metabolismo , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/uso terapéutico , Simulación del Acoplamiento Molecular , Mucopolisacaridosis IV/enzimología , Mucopolisacaridosis IV/genética , Mucopolisacaridosis IV/metabolismo , Mutación/efectos de los fármacos , Relación Estructura-Actividad , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismoRESUMEN
By Morita-Baylis-Hillman reaction of 2,3-O-isopropylidene-D-glyceraldehyde with α,ß-unsaturated carbonyl as well as hetero analogous carbonyl compounds such as acrylonitrile, suitable precursors of isofagomine and of 4-epi-isofagomine are available. Elaboration of the structures by amine introduction, followed by intramolecular ring closure and subsequent hydroboration of the double bond provides 4-epi-isofagomine derivatives featuring chain extensions at C-5a which are determined by the structures of the carbonyl compounds employed. As an example, the synthesis of C-(5aR)- and C-(5aS)-5a-C-pentyl-4-epi-isofagomines, powerful inhibitors of ß-galactosidases, is outlined. In line with reported data, the (C-5aR) epimer was found a highly potent experimental pharmacological chaperone for GM1-associated human lysosomal ß-galactosidase mutant R201C.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Glicósido Hidrolasas/antagonistas & inhibidores , Iminopiranosas/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Glicósido Hidrolasas/metabolismo , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/química , Lisosomas/enzimología , Estructura Molecular , Relación Estructura-ActividadRESUMEN
This report is about the identification, synthesis and initial biological characterization of derivatives of 4-epi-isofagomine as pharmacological chaperones (PC) for human lysosomal ß-galactosidase. The two epimers of 4-epi-isofagomine carrying a pentyl group at C-5a, namely (5aR)- and (5aS)-5a-C-pentyl-4-epi-isofagomine, were prepared by an innovative procedure involving in the key step the addition of nitrohexane to a keto-pentopyranoside. Both epimers were evaluated as inhibitors of the human ß-galactosidase: the (5aR)-stereoisomer (compound 1) was found to be a very potent inhibitor of the enzyme (IC50 = 8 nM, 30× more potent than 4-epi-isofagomine at pH 7.3) with a high selectivity for this glycosidase whereas the (5aS) epimer was a much weaker inhibitor. In addition, compound 1 showed a remarkable activity as a PC. It significantly enhanced the residual activity of mutant ß-galactosidase in 15 patient cell lines out of 23, with enhancement factors greater than 3.5 in 10 cell lines and activity restoration up to 91% of normal. Altogether, these results indicated that (5aR)-5a-C-pentyl-4-epi-isofagomine constitutes a promising PC-based drug candidate for the treatment of GM1-gangliosidosis and Morquio disease type B.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Gangliosidosis GM1/genética , Iminopiranosas/farmacología , Lisosomas/enzimología , Mucopolisacaridosis IV/genética , Mutación , beta-Galactosidasa/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Fibroblastos/efectos de los fármacos , Gangliosidosis GM1/enzimología , Gangliosidosis GM1/patología , Calor , Humanos , Concentración de Iones de Hidrógeno , Iminopiranosas/síntesis química , Iminopiranosas/química , Mucopolisacaridosis IV/enzimología , Mucopolisacaridosis IV/patología , Desnaturalización Proteica , beta-Galactosidasa/química , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismoRESUMEN
From an easily available partially protected analog of 1-deoxy-L-gulo-nojirimycin, by chain-branching at C-4 and suitable modification, lipophilic analogs of the powerful ß-D-galactosidase inhibitor 4-epi-isofagomine have been prepared. New compounds exhibit considerably improved inhibitory activities when compared with the unsubstituted parent compound and may serve as leads toward new pharmacological chaperones for GM1-gangliosidosis and Morquio B disease.
Asunto(s)
1-Desoxinojirimicina/análogos & derivados , Iminopiranosas/síntesis química , beta-Galactosidasa/antagonistas & inhibidores , 1-Desoxinojirimicina/química , Gangliosidosis GM1/tratamiento farmacológico , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Iminopiranosas/química , Mucopolisacaridosis IV/tratamiento farmacológico , beta-Galactosidasa/químicaRESUMEN
From an easily available partially protected formal derivative of 1-deoxymannojirimycin, by hydroxymethyl chain-branching and further elaboration, lipophilic analogs of the powerful ß-d-galactosidase inhibitor 4-epi-isofagomine have become available. New compounds exhibit improved inhibitory activities comparable to benchmark compound NOEV (N-octyl-epi-valienamine) and may serve as leads towards improved and more selective pharmacological chaperones for GM1-gangliosidosis.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Gangliosidosis GM1/enzimología , Iminopiranosas/farmacología , Lisosomas/enzimología , beta-Galactosidasa/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Gangliosidosis GM1/patología , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/química , Lisosomas/efectos de los fármacos , Modelos Moleculares , Estructura Molecular , Relación Estructura-Actividad , beta-Galactosidasa/metabolismoRESUMEN
Electrophilic fluorination of an exocyclic methoxymethylene enol ether derived from N-tert-butyloxycarbonyl-1,5-dideoxy-1,5-imino-3,4-O-isopropylidene-D-erythro-pent-2-ulose (11) provided the 5-fluoro derivative of the powerful ß-galactosidase inhibitor 4-epi-isofagomine (8). This structural alteration, in combination with N-alkylation, led to considerably improved α-galactosidase selectivity. New compounds may serve as leads en route to new pharmacological chaperones for Fabry's disease.
Asunto(s)
Inhibidores Enzimáticos/síntesis química , Galactosidasas/antagonistas & inhibidores , Iminopiranosas/síntesis química , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Enfermedad de Fabry/tratamiento farmacológico , Enfermedad de Fabry/enzimología , Gangliosidosis GM1/tratamiento farmacológico , Gangliosidosis GM1/enzimología , Halogenación , Humanos , Iminopiranosas/química , Iminopiranosas/farmacología , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Allylic azide rearrangement is used in tandem with intramolecular azide-alkene cycloaddition to give a triazoline that when subsequently decomposed in the presence of a nucleophile gives piperidines. The tandem reaction gives two stereocenters that are generated with high control. The formation of the piperidines required the presence of innate conformational constraint. The applicability of the annulation reaction is demonstrated by the synthesis of iminosugars. A proposal is included to account for the observed stereoselectivity, which is influenced by the precursor structure.
Asunto(s)
Glicósidos/síntesis química , Iminopiranosas/síntesis química , Piperidinas/síntesis química , Alquenos/química , Azidas/química , Catálisis , Ciclización , Reacción de Cicloadición , Glicósidos/química , Iminopiranosas/química , Conformación Molecular , Estructura Molecular , Piperidinas/química , EstereoisomerismoRESUMEN
ß-Glucocerebrosidase deficiency leads to Gaucher disease and is a potential marker of Parkinson's disease. We have identified N-octyl conduritol aziridine as a potent and specific covalent inactivator of GBA1 in living cells. This compound is a promising lead towards a positron emission tomography probe intended to image GBA1 activity.
Asunto(s)
Aziridinas/química , Aziridinas/farmacología , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Glucosilceramidasa/antagonistas & inhibidores , Inositol/análogos & derivados , Alquilación , Aziridinas/síntesis química , Aziridinas/farmacocinética , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacocinética , Enfermedad de Gaucher/enzimología , Glucosilceramidasa/metabolismo , Células HeLa , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/química , Iminopiranosas/farmacocinética , Iminopiranosas/farmacología , Inositol/síntesis química , Inositol/química , Inositol/farmacocinética , Inositol/farmacología , Enfermedad de Parkinson/enzimologíaRESUMEN
N-(10-Chloro-9-anthracenemethyl)isofagomine 5 and N-(10-chloro-9-anthracenemethyl)-1-deoxynojirimycin 6 were prepared, and their inhibition of almond ß-glucosidase was measured. The isofagomine derivative 5 was found to be a potent inhibitor, while the 1-deoxynojirimycin derivative 6 displayed no inhibition at the concentrations investigated. Fluorescence spectroscopy of 5 with almond ß-glucosidase at different pH values showed that the inhibitor nitrogen is not protonated when bound to the enzyme. Analysis of pH inhibition data confirmed that 5 binds as the amine to the enzyme's unprotonated dicarboxylate form. This is a radically different binding mode than has been observed with isofagomine and other iminosugars in the literature.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Iminopiranosas/química , beta-Glucosidasa/antagonistas & inhibidores , Técnicas de Química Sintética , Inhibidores Enzimáticos/metabolismo , Glucosamina/análogos & derivados , Glucosamina/síntesis química , Glucosamina/química , Glucosamina/metabolismo , Glucosamina/farmacología , Concentración de Iones de Hidrógeno , Iminopiranosas/síntesis química , Iminopiranosas/metabolismo , Iminopiranosas/farmacología , Cinética , Protones , Prunus dulcis/enzimología , Espectrometría de Fluorescencia , Relación Estructura-Actividad , beta-Glucosidasa/metabolismoRESUMEN
A series of pentahydroxylated pyrrolidines, displaying five contiguous stereogenic centres and epimeric to α-glucosidase inhibitor homoDMDP, have been synthesized. The key step involves a γ-aminoalcohol rearrangement applied to polyhydroxylated azepanes. These five-membered iminosugars demonstrate micromolar inhibition of glycosidases.
Asunto(s)
Amino Alcoholes/química , Azepinas/química , Inhibidores de Glicósido Hidrolasas/síntesis química , Manitol/análogos & derivados , Pirrolidinas/síntesis química , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/farmacología , Iminopiranosas/síntesis química , Iminopiranosas/química , Iminopiranosas/farmacología , Manitol/síntesis química , Manitol/química , Manitol/farmacología , Estructura Molecular , Pirrolidinas/química , Relación Estructura-Actividad , alfa-Glucosidasas/metabolismoRESUMEN
Highly regioselective 1,3-dipolar cycloadditions between d-arabinose-derived nitrones and d-mannitol-derived trans-olefins have been utilized to synthesize isofagomine-pyrrolidine hybrid sugars, hydroxymethylated analogues of (-)-steviamine and analogues of (+)-hyacinthacine C5. All of the new compounds were subsequently tested against several commercially available glycosidases, and some of them showed good and selective glycosidase inhibition.
Asunto(s)
Carbohidratos/síntesis química , Inhibidores Enzimáticos/síntesis química , Glicósido Hidrolasas/antagonistas & inhibidores , Iminopiranosas/síntesis química , Iminoazúcares/síntesis química , Indolicidinas/síntesis química , Pirrolidinas/síntesis química , Alcaloides de Pirrolicidina/síntesis química , Carbohidratos/química , Reacción de Cicloadición , Inhibidores Enzimáticos/química , Glicósido Hidrolasas/química , Iminopiranosas/química , Iminoazúcares/química , Indolicidinas/química , Estructura Molecular , Pirrolidinas/química , Alcaloides de Pirrolicidina/química , EstereoisomerismoRESUMEN
A range of enantiopure polyhydroxylated piperidines, including (2R,3S,4R)-dihydroxypipecolic acid, (-)-3-epi-fagomine, (2S,3S,4R)-dihydroxyhomopipecolic acid, (2S,3R,4R)-dihydroxyhomopipecolic acid, and two trihydroxy-substituted homopipecolic acids, have been prepared using diastereoselective olefinic oxidations of a range of enantiopure tetrahydropyridines as the key step. The requisite substrates were readily prepared from tert-butyl sorbate using our diastereoselective hydroamination or aminohydroxylation protocols followed by ring-closing metathesis. After diastereoselective olefinic oxidation of the resultant enantiopure tetrahydropyridines and deprotection, enantiopure polyhydroxylated piperidines were isolated as single diastereoisomers (>99:1 dr) in good overall yield.
Asunto(s)
Iminopiranosas/síntesis química , Ácidos Pipecólicos/química , Piperidinas/química , Iminopiranosas/química , Estructura Molecular , Oxidación-Reducción , EstereoisomerismoRESUMEN
A series of hybrid analogues was designed by combination of the iminoxylitol scaffold of parent 1C9-DIX with triazolylalkyl side chains. The resulting compounds were considered potential pharmacological chaperones in Gaucher disease. The DIX analogues reported here were synthesized by CuAAC click chemistry from scaffoldâ 1 (α-1-C-propargyl-1,5-dideoxy-1,5-imino-D-xylitol) and screened as imiglucerase inhibitors. A set of selected compounds were tested as ß-glucocerebrosidase (GBA1) enhancers in fibroblasts from Gaucher patients bearing different genotypes. A number of these DIX compounds were revealed as potent GBA1 enhancers in genotypes containing the G202R mutation, particularly compound DIX-28 (α-1-C-[(1-(3-trimethylsilyl)propyl)-1H-1,2,3-triazol-4-yl)methyl]-1,5-dideoxy-1,5-imino-D-xylitol), bearing the 3-trimethylsilylpropyl group as a new surrogate of a long alkyl chain, with approximately threefold activity enhancement at 10â nM. Despite their structural similarities with isofagomine and with our previously reported aminocyclitols, the present DIX compounds behaved as non-competitive inhibitors, with the exception of the mixed-type inhibitor DIX-28.
Asunto(s)
Inhibidores Enzimáticos/química , Glucosilceramidasa/antagonistas & inhibidores , Xilitol/química , Células Cultivadas , Química Clic , Fibroblastos/citología , Enfermedad de Gaucher/metabolismo , Enfermedad de Gaucher/patología , Genotipo , Glucosilceramidasa/genética , Glucosilceramidasa/metabolismo , Humanos , Iminopiranosas/síntesis química , Iminopiranosas/química , Iminopiranosas/metabolismo , Mutación , Unión Proteica , Xilitol/síntesis química , Xilitol/metabolismoRESUMEN
A new Staudinger/aza Wittig/Strecker multicomponent reaction sequence to C-1-cyano iminoalditols has been developed. When applied to 5-azidodeoxy-d-xylose and -d-glucose as substrates the method leads smoothly in good yield and with excellent stereoselectivity to respectively, 1,5-dideoxy-1,5-imino-d-idurono nitrile and 2,6-didesoxy-2,6-imino-d-glycero-d-ido-heptononitrile.
Asunto(s)
Iminopiranosas/síntesis química , Nitrilos/química , Compuestos Aza/química , Cristalografía por Rayos X , Iminopiranosas/química , Espectroscopía de Resonancia Magnética , Estructura Molecular , EstereoisomerismoRESUMEN
A novel and concise scheme has been developed successfully for the syntheses of N-substituted fagomine derivatives. The transformation of lactone (2) to 1,5-diol (3) was carried on with high yield (93-95%). The cyclization of 4 to 5 is a high stereoselective reaction (de value > 98%). It is disclosed that bulky substituent at N atom of the piperidine decreases the inhibition activity except those substituents having the ability of solvation or forming disulfide bond with M444 at the active site of α-glycosidase, which enhance the interaction with enzyme. Compounds with S-configuration at C-3 show greater activity than those with R-configuration. The structure-activity relationship study is also supported by molecular docking analysis.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Inhibidores de Glicósido Hidrolasas/farmacología , Iminopiranosas/farmacología , alfa-Glucosidasas/metabolismo , Cristalografía por Rayos X , Ciclización , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Inhibidores de Glicósido Hidrolasas/síntesis química , Inhibidores de Glicósido Hidrolasas/química , Iminopiranosas/síntesis química , Iminopiranosas/química , Simulación del Acoplamiento Molecular , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Mannosidases catalyze the hydrolysis of a diverse range of polysaccharides and glycoconjugates, and the various sequence-based mannosidase families have evolved ingenious strategies to overcome the stereoelectronic challenges of mannoside chemistry. Using a combination of computational chemistry, inhibitor design and synthesis, and X-ray crystallography of inhibitor/enzyme complexes, it is demonstrated that mannoimidazole-type inhibitors are energetically poised to report faithfully on mannosidase transition-state conformation, and provide direct evidence for the conformational itinerary used by diverse mannosidases, including ß-mannanases from families GH26 and GH113. Isofagomine-type inhibitors are poor mimics of transition-state conformation, owing to the high energy barriers that must be crossed to attain mechanistically relevant conformations, however, these sugar-shaped heterocycles allow the acquisition of ternary complexes that span the active site, thus providing valuable insight into active-site residues involved in substrate recognition.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Imidazoles/farmacología , Iminopiranosas/farmacología , Manosidasas/antagonistas & inhibidores , Termodinámica , Cristalografía por Rayos X , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Imidazoles/síntesis química , Imidazoles/química , Iminopiranosas/síntesis química , Iminopiranosas/química , Manosidasas/química , Manosidasas/metabolismo , Modelos Moleculares , Conformación Molecular , Relación Estructura-ActividadRESUMEN
A divergent asymmetric synthesis of the titled iminosugars has been formulated starting from a chiral homoallyl alcohol as the versatile intermediate. The homoallyl alcohol was prepared by a highly diastereoselective Barbier reaction on a d-glucose-derived aldehyde. The protection of its hydroxyl function followed by reductive ozonolysis of the olefin and a subsequent one-pot three-step protocol involving a Staudinger reaction, reductive amination, and benzyloxy carbonyl protection yielded an important bicyclic furanopiperidine derivative. This was converted to the target compounds by following standard reactions. Among the synthesized compounds, 4-epi-fagomine (2b) was the best ß-galactosidase inhibitor, and it also prevented LPS-mediated activation of Raw 264.7 macrophage cells. Its congener, 3,4-dihydroxypipecolic acid (4b) also showed similar trends in its cytokine- and enzyme-inhibitory properties at a low concentration (10 µM) but was proinflammatory at higher concentrations. The bicyclic compound dihydroxyindolizidine (21) reduced the proinflammatory cytokine (IL-1ß and TNF-α) levels in the LPS-activated Raw 264.7 cells without showing any enzyme-inhibition activity.