Synthesis and glycosidase inhibition of conformationally locked DNJ and DMJ derivatives exploiting a 2-oxo-C-allyl iminosugar.

A series of analogs of the iminosugars 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), in which an extra five or six-membered ring has been fused to the C1-C2 bond have been prepared. The synthetic strategy exploits a key 2-keto-C-allyl iminosugar, easily accessible from gluconolactam, which upon Grignard addition and RCM furnishes a bicyclic scaffold that can be further hydroxylated at the C[double bond, length as m-dash]C bond. This strategy furnished DNJ mimics with the piperidine ring locked in a 1C4 conformation with all substituents in axial orientation when fused to a six-membered ring. Addition of an extra ring to DNJ and DMJ motif proved to strongly modify the glycosidase inhibition profile of the parent iminosugars leading to modest inhibitors. The 2-keto-C-allyl iminosugar scaffold was further used to access N-acetylglycosamine analogs via oxime formation.

Isolation from Stevia rebaudiana of DMDP acetic acid, a novel iminosugar amino acid: synthesis and glycosidase inhibition profile of glycine and ß-alanine pyrrolidine amino acids.

DMDP acetic acid [N-carboxymethyl-2,5-dideoxy-2,5-imino-D-mannitol] 5 from Stevia rebaudiana is the first isolated natural amino acid derived from iminosugars bearing an N-alkyl acid side chain; it is clear from GCMS studies that such derivatives with acetic and propionic acids are common in a broad range of plants including mulberry, Baphia, and English bluebells, but that they are very difficult to purify. Reaction of unprotected pyrrolidine iminosugars with aqueous glyoxal gives the corresponding N-acetic acids in very high yield; Michael addition of both pyrrolidine and piperidine iminosugars and that of polyhydroxylated prolines to tert-butyl acrylate give the corresponding N-propionic acids in which the amino group of ß-alanine is incorporated into the heterocyclic ring. These easy syntheses allow the identification of this new class of amino acid in plant extracts and provide pure samples for biological evaluation. DMDP N-acetic and propionic acids are potent α-galactosidase inhibitors in contrast to potent ß-galactosidase inhibition by DMDP.

Comparing Antimicrobial Susceptibilities among Mycoplasma pneumoniae Isolates from Pediatric Patients in Japan between Two Recent Epidemic Periods.

We compared the antimicrobial susceptibility of Mycoplasma pneumoniae isolates from pediatric patients in Japan in 2011-2012 and 2015-2016, when epidemics occurred. The antimicrobial activity of macrolides and tetracyclines against M. pneumoniae infection tended to be restored in 2015-2016. There was no change in the antimicrobial activity of quinolones against M. pneumoniae infection.

Structure of constituents isolated from the bark of Cassipourea malosana and their cytotoxicity against a human ovarian cell line.

Three aromatic compounds, 2α,3α-epoxyflavan-5,7,4'-triol-(4ß â†’ 8)-afzelechin (1), 2ß,3ß-epoxyflavan-5,7,4'-triol-(4α → 8)-epiafzelechin (2), and methyl 4-ethoxy-2-hydroxy-6-propylbenzoate (3), as well as eight known compounds (4-11) were isolated from the bark of Cassipourea malosana (Rhizophoraceae). Their structures were determined on the basis of an analysis of spectroscopic data. The in vitro cytotoxic activities of these compounds against human ovarian cancer cell line TOV21G were evaluated. Most compounds showed little activity; however, the methyl derivatives of flavan dimers (1a and 2a) showed higher activity (IC50 value of 30.3 and 75.4 µM) than parent compounds 1 and 2.

Macrolide-Resistant Mycoplasma pneumoniae Infection, Japan, 2008-2015.

We evaluated isolates obtained from children with Mycoplasma pneumoniae infection throughout Japan during 2008-2015. The highest prevalence of macrolide-resistant M. pneumoniae was 81.6% in 2012, followed by 59.3% in 2014 and 43.6% in 2015. The prevalence of macrolide-resistant M. pneumoniae among children in Japan has decreased.

Tuning of ß-glucosidase and α-galactosidase inhibition by generation and in situ screening of a library of pyrrolidine-triazole hybrid molecules.

The preliminary screening of two libraries of epimeric (pyrrolidin-2-yl)triazoles (14a-s and 22a-s), generated via click chemistry, allowed the rapid identification of four α-galactosidase (coffee beans) inhibitors (22b,k,p,r) and two ß-glucosidase (almond) inhibitors (14b,f) in the low µM range. The additional biological analysis of 14b,f towards ß-glucocerebrosidase (human lysosomal ß-glucosidase), as target enzyme for Gaucher disease, showed a good correlation with the inhibition results obtained for the plant (almond) enzyme. Surprisingly, although these compounds showed inhibition towards ß-glucocerebrosidase as acid hydrolase, they did not inhibit bovine liver ß-glucosidase as neutral hydrolase. In contrast to what was observed for ß-glucosidase inhibition, the coffee bean α-galactosidase inhibitors of the epimeric library (22b,k,p,r) only showed weak inhibition towards human lysosomal α-galactosidase.

Discovery of hyaluronidase inhibitors from natural products and their mechanistic characterization under DMSO-perturbed assay conditions.

The present study discovered four novel hyaluronan-degrading enzyme (hyaluronidase) inhibitors including chikusetsusaponins and catechins through the activity-guided separation of Panax japonicus and Prunus salicina, respectively. Although the discovery resulted in identification of usual frequent hitters, subsequent mechanistic characterizations under our DMSO-perturbed assay conditions and related protocols revealed that chikusetusaponin IV would serve as an aggregating and non-specific binding inhibitor, while (-)-epicatechin would interact specifically with enzyme at the catalytic site or more likely at a kind of catechin-binding site with a relatively week inhibitory activity. The latter description might provide a possible explanation for the well-known fact that a series of catechin have been described as frequent hitters in biological assays with a moderate activity. Thus, the present study demonstrated a practical and robust methodology to characterize initial screening hits mechanistically molecule-by-molecule in the early stage of natural product-based drug discovery.

Immunonutrition suppresses acute inflammatory responses through modulation of resolvin E1 in patients undergoing major hepatobiliary resection.

BACKGROUND: Although several studies have reported the effects of immunonutrition on clinical outcomes, detailed mechanisms of immunonutrition after an operation are still unclear. It was recently reported that resolvin E1, a novel lipid mediator generated from eicosapentaenoic acid (EPA), activates factors that reduce inflammation. This randomized clinical trial was designed to investigate not only the effect of immunonutrition on postoperative complications but also the participation of resolvin E1 on anti-inflammatory effects of immunonutrition in patients undergoing major hepatobiliary resection. METHODS: Forty patients who underwent major hepatobiliary resection were divided into 2 groups. Twenty patients received oral supplementation enriched with EPA, arginine, and nucleotides before the operation (group IN). Twenty patients (control group) received no artificial nutrition before the operation (group C). RESULTS: The rate of infectious complications and severity of complications in group IN was significantly lower than in group C (P < .05). Immediately after the operation, plasma resolvin E1 levels were significantly higher in group IN than in group C (P < .05), and plasma interleukin-6 levels were significantly lower in group IN than in group C (P < .05). Preoperative serum EPA levels correlated with plasma resolvin E1 levels immediately after the operation. Plasma resolvin E1 levels correlated with plasma interleukin-6 levels immediately after the operation. CONCLUSION: Preoperative immunonutrition reduced inflammatory responses and protected against the aggravation of postoperative complications in patients undergoing major hepatobiliary resection. Resolvin E1 may play a key role in the resolution of acute inflammation when immunonutrition is supplemented with EPA. (ClinicalTrials.gov Identifier: NCT01256047.).

Preoperative immunonutrition decreases postoperative complications by modulating prostaglandin E2 production and T-cell differentiation in patients undergoing pancreatoduodenectomy.

BACKGROUND: An immune-enhancing diet has been used to alter eicosanoid synthesis, cytokine production, and immune function in an attempt to limit the undesired immune reactions after injury from surgery. This prospective randomized study was designed to investigate the effect of preoperative immunonutrition on operative complications, and the participation of prostaglandin E2 (PGE2) on T-cell differentiation in patients undergoing a severely stressful surgery. METHODS: The enrolled patients who were scheduled to undergo pancreatoduodenectomy were randomized into two groups. Patients in the immunonutrition group (n = 25) received oral supplementation containing arginine, ω-3 fatty acids, and RNA for 5 days before the procedure in addition to a 50% reduction in the amount of regular food. Patients in the control group (n = 25) received no artificial nutrition and were allowed to consume regular food before surgery. All patients received early postoperative enteral infusion of a standard formula intended to provide 25 kcal/kg/day. The primary endpoint was the rate of infectious complications; the secondary endpoint was immune responses. This study is registered with ClinicalTrials.gov (NCT01256034). RESULTS: Infectious complication rate and severity of complications (Clavien-Dindo classification) were lesser in the immunonutrition group than in the control group. mRNA expression levels of T-bet were greater in the immunonutrition group than in the control group (P < .05). Serum eicosapentaenoic acid and eicosapentaenoic acid/arachidonic acid ratios were greater in the immunonutrition group than in the control group (P < .05). The levels of plasma PGE2 were lesser in the immunonutrition group than in the control group (P < .05). CONCLUSION: Preoperative immunonutrition modulates PGE2 production and T-cell differentiation and may protect against the aggravation of operative complications in patients undergoing pancreatoduodenectomy.

Effects of eugenol-reduced clove extract on glycogen phosphorylase b and the development of diabetes in db/db mice.

We found that the 50% aqueous EtOH extract of clove (Syzygium aromaticum) had potent dose-dependent inhibitory activity toward glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes. Among the components, eugeniin inhibited glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes, with IC50 values of 0.14 and 4.7 µM, respectively. In sharp contrast, eugenol showed no significant inhibition toward glycogen phosphorylase b, even at a concentration of 400 µM. Eugenol-reduced clove extracts (erCE) were prepared and when fed to a db/db mouse they clearly suppressed the blood glucose and HbA1c levels. Furthermore, plasma triglyceride and non-esterified fatty acid levels in 5% and 10% erCE-fed db/db mice were significantly lowered, compared with control db/db mice without erCE supplementation. These results suggested that dietary supplementation with the erCE could beneficially modify glucose and lipid metabolism and contribute to the prevention of the progress of hyperglycemia and metabolic syndrome.

Chemical composition of desert willow (Salix psammophila) grown in the Kubuqi Desert, Inner Mongolia, China: bark extracts associated with environmental adaptability.

Bark of desert willow (Salix psammophila, Spsa) grown in Inner Mongolia was successively extracted with n-hexane, diethyl ether, acetone, methanol, and hot water to examine chemical components associated with its environmental adaptability to desert conditions. The yield of n-hexane extract (5.0% based on dry bark), mainly composed of wax, was higher than those of acetone and methanol extracts (3.7% and 4.2%, respectively), whereas the yields of n-hexane extract (1.4%) from willow bark grown in humid areas were much lower than those of acetone (17.4% and 19.9%) and methanol (12.5% and 14.0%) extracts. Unlike other willow bark samples, Spsa bark contained a certain amount of sugar alcohols. In particular, we identified arabinitol (0.21%), which has not previously been reported as a major component of extracts of willow bark. The high content of wax and sugar alcohol would be associated with the ability of Spsa to survive in desert conditions. Accumulation of wax on the outer bark surface would reduce water loss, while sugar alcohols might improve freezing tolerance.

Pyrenes and pyrendiones from Uvaria lucida.

A chemical investigation of the chloroform extract of the roots of Uvaria ludida Benth. (Annonaceae), an important African traditional medicine, led to the isolation of six new compounds; three pyrenes, 2-hydroxy-1,8-dimethoxypyrene (1), 8-methoxy-1,2-methylenedioxypyrene (2), and 7-hydroxy-8-methoxy-1,2-methylenedioxypyrene (3), two pyrenediones, 2-hydroxy-1,8-pyrenedione (4) and 2-methoxy-1,8-pyrenedione (5), and a sesquiterpene, (-)-10-oxo-isodauc-3-en-15-oic acid (6), together with eight known compounds (7-14). The structural elucidation by spectroscopic studies of the compounds isolated is described. While pyrenes did not exhibit strong cytotoxicity against human promyelocytic leukemia HL-60 cells, pyrenediones showed strong cytotoxicity. The IC(50) of 4 was 70 ng mL(-1), which was close to that of etoposide (IC(50) = 60 ng mL(-1)).

Iminosugars as therapeutic agents: recent advances and promising trends.

For the purpose of this article, iminosugars are polyhydroxylated secondary and tertiary amines in which the molecules resemble monosaccharide sugars in which the ring oxygen is replaced by the nitrogen. The bicyclic structures may biologically resemble disaccharides. Very few iminosugars have been available up to now for evaluation of their pharmaceutical applications. The early compounds were discovered and selected for study due to glycosidase inhibition, which is now known to not be necessary for pharmacological activity and may cause off-target effects. Glyset® and Zavesca®, derived from the glucosidase-inhibiting natural product 1-deoxynojirimycin, are the first two examples of iminosugar drugs. Since the discovery of this first generation, many new natural products have been identified with a wide range of biological activities but few are widely available. Among the biological properties of these compounds are good oral bioavailability and very specific immune modulatory and chaperoning activity. Although the natural products from plants and microorganisms can have good specificity, modifications of the template natural products have been very successful recently in producing bioactive compounds with good profiles. The field of iminosugars continues to open up exciting new opportunities for therapeutic agent discovery and offers many new tools for precisely modifying carbohydrate structures and modulating glycosidase activity in vivo. Current efforts are directed towards a greater range of structures and a wider range of biochemical targets.

A concise stereoselective synthesis of (-)-erycibelline.

(-)-Erycibelline, the dihydroxynortropane alkaloid isolated from Erycibe elliptilimba Merr. et Chun., was synthesized using a cyclic nitrone as advanced intermediate, wherein the key step was the SmI(2)-induced intramolecular reductive coupling of cyclic nitrone with aldehyde which resulted in good yield and stereoselectivity.

Chemical studies on the roots of Uvaria welwitschii.

A chemical investigation of the chloroform extract of the roots of Uvaria welwitschii (Annonaceae), an African traditional medicine taken for stomach ache, led to the isolation of eight new compounds, named welwitschins A-H (1-8), together with five known compounds (9-13). The structural elucidation by spectroscopic studies of the compounds isolated is described. All new compounds were flavonoids having a 2-hydroxy-3,4,6-trimethoxyphenyl moiety in the A-ring, and unsubstituted phenyl in the B-ring. Four of them (1-4) were monomeric flavonoids while the others (5-8) were dimeric flavonoids. The cytotoxicity of the isolated compounds against human promyelocytic leukemia HL-60 cells was investigated.

2,5-Dideoxy-2,5-imino-d-altritol as a new class of pharmacological chaperone for Fabry disease.

Chromatographic separation of the extract from roots of Adenophora triphylla resulted in the isolation of two pyrrolidines, six piperidines, and two piperidine glycosides. The structures of new iminosugars were elucidated by spectroscopic methods as 2,5-dideoxy-2,5-imino-d-altritol (DIA) (2), beta-1-C-butenyl-1-deoxygalactonojirimycin (8), 2,3-dideoxy-beta-1-C-ethyl-1-deoxygalactonojirimycin (9), and 6-O-beta-d-glucopyranosyl-2,3-dideoxy-beta-1-C-ethyl-1-deoxygalactonojirimycin (10). beta-1-C-Butyl-1-deoxygalactonojirimycin (7) and compound 8 were found to be better inhibitors of alpha-galactosidase than N-butyl-1-deoxygalactonojirimycin. The present work elucidated that DIA was a powerful competitive inhibitor of human lysosome alpha-galactosidase A (alpha-Gal A) with a K(i) value of 0.5muM. Furthermore, DIA improved the thermostability of alpha-Gal A in vitro and increased intracellular alpha-Gal A activity by 9.6-fold in Fabry R301Q lymphoblasts after incubation for 3days. These experimental results suggested that DIA would act as a specific pharmacological chaperone to promote the smooth escape from the endoplasmic reticulum (ER) quality control system and to accelerate transport and maturation of the mutant enzyme.

Effects of perioperative immunonutrition on cell-mediated immunity, T helper type 1 (Th1)/Th2 differentiation, and Th17 response after pancreaticoduodenectomy.

BACKGROUND: The mechanisms of immunonutrition on reducing infectious complications are still poorly understood. This prospective randomized study was designed to determine whether immunonutrition influences the following factors: cell-mediated immunity, differentiation of T helper type 1 (Th1) and Th2 cells, interleukin (IL)-17-producing CD4(+) helper T (Th17) cell response, and infectious complication rate after pancreaticoduodenectomy. METHODS: Thirty patients who underwent pancreaticoduodenectomy were divided into 3 groups. Ten patients in the perioperative group received immune-enhancing diets enriched with arginine, omega-3 fatty acids, and RNA for 5 days before operative resection, which was prolonged after operative resection by enteral infusion. Ten patients in the postoperative group received early postoperative enteral infusion of the same enriched formula with no artificial nutrition before operative resection. Ten patients in the control group received total parenteral nutrition postoperatively. The primary endpoint was immune responses; the secondary endpoint was the rate of infectious complications. RESULTS: Concanavalin A (Con A)- or phytohemagglutinin (PHA)-stimulated lymphocyte proliferation and natural killer cell activity were significantly higher in the perioperative group than in the other groups. Messenger RNA (mRNA) expression levels of T-bet, interferon-gamma (IFN-gamma), related orphan receptor gammat (RORgammat), and interleukin-17F (IL-17F) were significantly higher in the perioperative group than in the other groups. In the perioperative group, the rate of infectious complications was significantly reduced compared with that in the other groups. CONCLUSION: Perioperative immunonutrition reduced stress-induced immunosuppression after a major stressful operative resection. The modulation of Th1/Th2 differentiation and Th17 response may play important roles in this immunologic effect.

Hydroxyespintanol and schefflerichalcone: two new compounds from Uvaria scheffleri.

A chemical investigation of the petroleum ether extract and chloroform extract of the root of Uvaria scheffleri Diels (Annonaceae) led to the isolation of two new compounds, named hydroxyespintanol (1) and schefflerichalcone (2), together with eight known compounds (3-10). The structural elucidation of compounds 1 and 2 by spectroscopic studies is described. The cytotoxicity of the isolated compounds against human promyelocytic leukemia HL-60 cells was studied. Among these, 2'-hydroxy-3',4',6'-trimethoxychalcone (5) exhibited cytotoxicity (IC(50) 12 microM), and espintanol (3), which was the main ingredient, also showed some cytotoxicity (IC(50) 44 microM).

Antinociceptive effects of the extracts of Xylopia parviflora bark and its alkaloidal components in experimental animals.

In the present study, we attempted to elucidate the antinociceptive activity of Xylopia parviflora bark using the acetic acid-induced writhing test, hot plate test, and formalin test in mice. The MeOH extract (100 and 200 mg/kg, administered intraperitoneally (i.p.)) had an antinociceptive effect demonstrated by its inhibitory effects on writhing number induced by acetic acid. Three alkaloidal fractions exhibited significant antinociceptive effects in three animal models; the chloroform-soluble fraction, including secondary and tertiary alkaloids, exhibited the strongest effect. This result supported its use in folk medicine as an analgesic agent. We tested the main alkaloids of these fractions for their antinociceptive effects to clarify the active components. (+)-Corytuberine (6.3 and 12.5 mg/kg, i.p.) showed very strong activity, had a significant antinociceptive effect in the acetic acid-induced writhing test (with 49.4 and 98.9% reduction of writhes), in the hot plate test, and in the formalin test (with 55.4 and 90.6% inhibition during the first phase, and 73.9 and 99.9% during the second phase, respectively). (+)-Glaucine (12.5 and 25 mg/kg, i.p.) showed strong activity in three animal models, too. The activity of these compounds was also observed following oral administration in the acetic acid-induced writhing test.

Protective effects of dietary chamomile tea on diabetic complications.

Matricaria chamomilla L., known as "chamomile", has been used as an herbal tea or supplementary food all over the world. We investigated the effects of chamomile hot water extract and its major components on the prevention of hyperglycemia and the protection or improvement of diabetic complications in diabetes mellitus. Hot water extract, esculetin (3) and quercetin (7) have been found to show moderate inhibition of sucrase with IC50 values of 0.9 mg/mL and 72 and 71 microM, respectively. In a sucrose-loading test, the administration of esculetin (50 mg/kg body weight) fully suppressed hyperglycemia after 15 and 30 min, but the extract (500 mg/kg body weight) and quercetin (50 mg/kg body weight) were less effective. On the other hand, a long-term feed test (21 days) using a streptozotocin-induced rat diabetes model revealed that the same doses of extract and quercetin showed significant suppression of blood glucose levels. It was also found that these samples increased the liver glycogen levels. Moreover, chamomile extract showed potent inhibition against aldose reductase (ALR2), with an IC50 value of 16.9 microg/mL, and its components, umbelliferone (1), esculetin (3), luteolin (6), and quercetin (7), could significantly inhibit the accumulation of sorbitol in human erythrocytes. These results clearly suggested that daily consumption of chamomile tea with meals could contribute to the prevention of the progress of hyperglycemia and diabetic complications.