Synthesis and biological evaluation of some novel sulfamoylphenyl-pyridazinone as anti-inflammatory agents (Part-II)

Seven novel 6-aryl-2-(p-sulfamoylphenyl)-4,5-dihydropyridazin-3(2H)-ones (2a-g) were synthesized by the condensation of appropriate aroylpropionic acid and 4-hydrazinobenzenesulfonamide hydrochloride in ethanol. Structure of all compounds have been elucidated by elemental analysis, IR, ¹H NMR, ¹³C NMR, DEPT and MS spectrscopy. These compounds were tested for their anti-inflammatory activity in carrageenan-induced rat paw edema model. Compound 2b exhibited anti-inflammatory activity comparable to that of celecoxib (at 5?h). Two other compounds 2d and 2g showed promising anti-inflammatory activity (edema reduction more than 80% at 5?h). These compounds (2b, 2d and 2g) did not produce any ulceration in gastric region.     

Hernandulcin Production in Cell Suspensions of Phyla Scaberrima: Exploring Hernandulcin Accumulation through Physical and Chemical Stimuli

Hernandulcin (HE) is a non-caloric sweetener synthesized by the Mexican medicinal plant Phyla scaberrima. Herein we present the results of HE production through cell suspensions of P. scaberrima as well as the influence of pH, temperature, biosynthetic precursors and potential elicitors to enhance HE accumulation. The incorporation of mevalonolactone (30–400 mg L⁻¹) farnesol (30–400 mg L⁻¹), AgNO3 (0.025–0.175 M), cellulase (5–60 mg L⁻¹; 0.3 units/mg), chitin (20–140 mg L⁻¹) and (+)-epi-α-bisabolol (300-210 mg L⁻¹) to the cell suspensions, resulted in a differential accumulation of HE and biomass. Among elicitors assayed, chitin, cellulase and farnesol increased HE production from 93.2 to ∼160 mg L⁻¹ but, (+)-epi-α-bisabolol (obtained by a synthetic biology approach) increased HE accumulation up to 182.7 mg L⁻¹. HE produced by the cell suspensions was evaluated against nine strains from six species of gastrointestinal bacteria revealing moderate antibacterial activity (MIC, 214–465 μg mL⁻¹) against Staphylococcus aureus, Escherichia coli and Helicobacter pylori. Similarly, HE showed weak toxicity against Lactobacillus sp. and Bifidobacterium bifidum (>1 mg mL⁻¹), suggesting a selective antimicrobial activity on some species of gut microbiota. According to our results, chitin and (+)-epi-α-bisabolol were the most effective molecules to enhance HE accumulation in cell suspensions of P. scaberrima.     

Effect of feeding precursors on phenylalanine ammonia-lyase activity and coumarin accumulation in leaves of <Emphasis Type="Italic">Matricaria chamomilla</Emphasis> L.

Four-week-old chamomile (Matricaria chamomilla) plants were exposed for 72 h to 0.01, 0.1 and 1 mM phenylalanine (Phe) or tyrosine (Tyr). Phe at all concentrations significantly increased phenylalanine ammonia-lyase (PAL) activity (by 30, 76 and 90%, respectively) as well as accumulation of coumarin-related compounds (herniarin and its precursors (Z)- and (E)-2-β-D-glucopyranosyloxy-4-methoxycinnamic acids). Free Phe content increased significantly at the highest dose tested. Lower Tyr concentrations (0.01 and 0.1 mM) significantly increased PAL activity and increased free Tyr content, however free Phe content decreased. This indicated that Tyr-mediated stimulation of PAL is coupled to Phe consumption. Notwithstanding, Tyr had no effect on coumarin accumulation. Therefore we speculate that in chamomile a regulation/signalling mechanism could be operating in the pathway leading to coumarin synthesis. The malondialdehyde accumulation, an usual marker of stress in plants, was not significantly changed by amino acid supplements, suggesting that membrane damage is not the signal causing coumarin accumulation. In parallel experiment we observed that neither lower (0.25 × full strength), nor higher (3 × full strength) nitrogen concentration of nutrient solution compared to normal (1 × full strength, 205 mg N l^-1) solution used for Phe/Tyr supply affected herniarin and GMCAs accumulation. This indicates that Phe had stimulatory effect on PAL activity and coumarin metabolism.     

Synthesis and Anti-Inflammatory Activity Evaluation of Benzoxazole Derivatives as New Myeloid Differentiation Protein 2 Inhibitors

Myeloid differentiation protein 2 (MD2), a key TLR4 adaptor protein for sensing LPS, plays an important role in inflammatory process and has been identified as a promising target for the treatment of a variety of inflammatory diseases. In our study, a series of benzoxazolone derivatives were synthesized, characterized and tested for anti-inflammatory activity in vitro. The compounds 3c , 3d and 3g demonstrated the greatest anti-inflammatory activity against IL-6 with IC₅₀ values of 10.14±0.08, 5.43±0.51 and 5.09±0.88 μM, respectively. Furthermore, the bis-ANS displacement assay revealed that these compounds competitively inhibited the binding between the probe bis-ANS and the MD2 protein. The most active compound 3g , revealed a directly bind with MD2 protein via Arg90 binding and a dissociation constant value of 1.52×10⁻⁶ mol L⁻¹ as determined by the biological layer interference (BLI) assay. Our finding suggested that compounds 3g could be a promising lead compound as MD2 inhibitor for further anti-inflammatory agent development.     

5-Thioxoimidazolidine-2-one derivatives: Synthesis,anti-inflammatory activity,analgesic activity,COX inhibition assay and molecular modelling study

A series of 5-imino-4-thioxo-2-imidazolidinone derivatives with different substituents at N¹ and N³ was synthesized with high yield and excellent purity by the reaction of different N-arylcyanothioformamide derivatives with isocyanate derivatives. Treatment 5-imino-4-thioxo-2-imidazolidinone derivatives with acidic medium afforded 4-thioxoimidazolidin-2,5-dione derivatives. The structures of the obtained products were established based on spectroscopic IR, ¹H NMR, ¹³C NMR, ¹H, ¹H-COSY, HSQC and elemental analyses. The anti-inflammatory activity of the synthesized compounds through the carrageenan-paw edema model as well as in vitro COX-1 and COX-2 inhibition assay were evaluated where most of the synthesized compounds showed significant anti-inflammatory activity. Mostly, all of our synthesized compounds have greater activity more than celecoxib toward both cyclooxygenase enzymes. All of the tested compounds (except one compound) exhibited IC₅₀ valves for COX-2 ranged from 0.001 × 10⁻³ to 0.827 × 10⁻³ µM while the reference drug has IC₅₀ 40.0 × 10⁻³ µM. Furthermore, the analgesic activity of such compounds was also determined. Molecular modeling study was also conducted to rationalize the potential as anti-inflammatory agents of our synthesized compounds by predicting their binding modes, binding affinities and optimal orientation at the active site of the COX enzymes.     

Design,synthesis, and pharmacological evaluation of novel oxadiazole and oxadiazoline analogs as anti-inflammatory agents

Two novel series of oxadiazole and oxadiazoline analogs possessing an indole nucleus were synthesized for their potential anti-inflammatory activity. The structures of the compounds were elucidated by elemental and spectral (IR, ¹H-NMR, ¹³C-NMR, and MS) analysis. Most of the test compounds demonstrated appreciable anti-inflammatory activities. The anti-inflammatory activity of oxadiazoles at doses of 100?mg/kg was shown by their ability to provide 27–66%, 14–32%, and 20-51%. protection against carrageenan-induced rat paw edema, moist cotton pellet-induced, and dry cotton pellet-induced granuloma, respectively. On the other hand, the anti-inflammatory properties of oxadiazolines at doses of 100?mg/kg were reflected by their ability to provide 20-56%, 11–26%, and 25–47% protection against carrageenan-induced rat paw edema, moist cotton pellet-induced, and dry cotton pellet-induced granuloma, respectively. The ulcerogenic potential of the compounds was determined. Structure–activity relationships among synthesized compounds were also established.     

Protective effect of xanthohumol against age-related brain damage

It has been recently shown that xanthohumol, a flavonoid present in hops, possesses antioxidant, anti-inflammatory and chemopreventive properties. However, its role in the aging brain has not been addressed so far. Therefore, this study aimed to investigate the possible neuroprotective activity of xanthohumol against age-related inflammatory and apoptotic brain damage in male senescence-accelerated prone mice (SAMP8). Animals were divided into 4 groups: Untreated young mice, untreated old mice and old mice treated either with 1 mg kg⁻¹ day⁻¹ or 5 mg kg⁻¹ day⁻¹ xanthohumol. Young and old senescence accelerated resistant mice (SAMR1) were used as controls. After 30 days of treatment, animals were sacrificed and their brains were collected and immediately frozen in liquid nitrogen. mRNA (GFAP, TNF-α, IL-1β, AIF, BAD, BAX, XIAP, NAIP and Bcl-2) and protein (GFAP, TNF-α, IL-1β, AIF, BAD, BAX, BDNF, synaptophysin and synapsin) expressions were measured by RT-PCR and Western blotting, respectively. Significant increased levels of pro-inflammatory (TNF-α, IL-1β) and pro-apoptotic (AIF, BAD, BAX) markers were observed in both SAMP8 and SAMR1 old mice compared to young animals (P<.05) and also in SAMP8 untreated old mice compared to SAMR1 (P<.05). These alterations were significantly less evident in animals treated with both doses of xanthohumol (P<.05). Also, a reduced expression of synaptic markers was observed in old mice compared to young ones (P<.05) but it significantly recovered with 5 mg kg⁻¹ day⁻¹ xanthohumol treatment (P<.05). In conclusion, xanthohumol treatment modulated the inflammation and apoptosis of aged brains, exerting a protective effect on damage induced by aging.     

Primary Production and Effects of Enrichment with Nitrate and Phosphate on Phytoplankton in the Barra Bonita Reservoir (State of São Paulo,Brazil)

Primary productivity of the phytoplankton was evaluated by the ¹⁴C and dissolved oxygen methods in December 1981 at the Barra Bonita Reservoir (São Paulo State, Brazil). The primary production varied between 0.17 to 14.51 mg C m⁻³h⁻¹ at 4 and 0 m depth, respectively. About 57 to 94% of the photosynthetic activity was due to phytoplankton > 50 μm. The highest value of assimilation rate (3.36 mg C mg Chl⁻¹h⁻¹) was found in the surface water. Dissolved nutrient concentrations were very high and consisted mainly of nitrate. Light penetration was low, the aphotic zone accounting for about 90% of the water column. Enrichment with nitrate and phosphate showed that both N and P stimulated the production of biomass (chlorophyll a), mainly due to the addition of phosphate. The enrichment experiment also indicated that phosphate addition has a significant stimulatory effect on the growth of Melosira sp. The limiting effect of light penetration on photosynthetic activity is more severe than that of nutrients.     

Gas-phase degradation of VOCs using supported bacteria biofilms

Herein we report the use of Pseudomonas putida F1 biofilms grown on carbonized cellulosic fibers to achieve biodegradation of airborne volatile organic compounds (VOCs) in the absence of any bulk aqueous-phase media. It is believed that direct exposure of gaseous VOC substrates to biomass may eliminate aqueous-phase mass transfer resistance and facilitate VOC capture and degradation. When tested with toluene vapor as a model VOC, the supported biofilm could grow optimally at 300 p.p.m. toluene and 80% relative humidity, with a specific growth rate of 0.425 day⁻¹. During long-term VOC biodegradation tests in a tubular packed bed reactor, biofilms achieved a toluene degradation rate of 2.5 mg g_DCW⁻¹ h⁻¹ during the initial growth phase. Interestingly, the P. putida F1 film kept biodegrading activity even at the stationary nongrowth phase. The supported biofilms with a biomass loading of 20% (wt) could degrade toluene at a rate of 1.9 mg g_DCW⁻¹ h⁻¹ during the stationary phase, releasing CO₂ at a rate of 6.4 mg g_DCW⁻¹ h⁻¹ at the same time (indicating 100% conversion of substrate carbon to CO₂). All of these observations promised a new type of “dry” biofilm reactors for efficient degradation of toxic VOCs without involving a large amount of water.     

Evaluation of the in vivo anti-inflammatory activity of a flavonoid glycoside from Boldoa purpurascens

The anti-inflammatory effect of 4′,5-dihydroxy-6,7-methylenedioxyflavonol 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-d-xylopyranoside, a constituent of the leaves of Boldoa purpurascens Cav. (Nyctaginaceae), was evaluated for its anti-inflammatory activity in the dextran 1% induced rat paw oedema model (acute inflammation) and the cotton pellet induced granuloma rat model (chronic inflammation). Flavonoid glycoside at doses of 2.5, 5 and 10 mg/kg, indomethacin at a dose of 7 mg/kg and the vehicle were administered orally. The compound showed significant anti-inflammatory activity in the acute phase in a dose dependent manner, most notably at the highest test dose 10 mg/kg. Also in the cotton pellet induced granuloma model, the compound showed a dose-dependent anti-inflammatory activity, with the highest effect at 10 mg/kg. In both assays, the test compound was more active than indomethacin tested at 7 mg/kg.     

Enhancing fluxes through the mevalonate pathway in Saccharomyces cerevisiae by engineering the HMGR and β-alanine metabolism

Mevalonate (MVA) pathway is the core for terpene and sterol biosynthesis, whose metabolic flux influences the synthesis efficiency of such compounds. Saccharomyces cerevisiae is an attractive chassis for the native active MVA pathway. Here, the truncated form of Enterococcus faecalis MvaE with only 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity was found to be the most effective enzyme for MVA pathway flux using squalene as the metabolic marker, resulting in 431-fold and 9-fold increases of squalene content in haploid and industrial yeast strains respectively. Furthermore, a positive correlation between MVA metabolic flux and β-alanine metabolic activity was found based on a metabolomic analysis. An industrial strain SQ3-4 with high MVA metabolic flux was constructed by combined engineering HMGR activity, NADPH regeneration, cytosolic acetyl-CoA supply and β-alanine metabolism. The strain was further evaluated as the chassis for terpenoids production. Strain SQ3-4-CPS generated from expressing β-caryophyllene synthase in SQ3-4 produced 11.86 ± 0.09 mg l⁻¹ β-caryophyllene, while strain SQ3-5 resulted from down-regulation of ERG1 in SQ3-4 produced 408.88 ± 0.09 mg l⁻¹ squalene in shake flask cultivations. Strain SQ3-5 produced 4.94 g l⁻¹ squalene in fed-batch fermentation in cane molasses medium, indicating the promising potential for cost-effective production of squalene.     

PROPERTIES OF TYROSINE HYDROXYLASE IN PERIPHERAL NERVES

Approximately 80 per cent of tyrosine hydroxylase activity in bovine mandibular nerve and rabbit sciatic nerve was soluble, and the rest of the activity was particle-bound. The soluble enzyme in bovine mandibular nerve was isolated by ammonium sulphate fractionation (25–35 per cent saturation). The enzyme had a pH optimum at 5·9 in Tris-acetate buffer, and at 6·5 in Tris-HCl or phosphate buffer. The enzyme required a tetrahydropteridine cofactor. K_m values toward various tetrahydropteridines such as l -erythro-tetrahydrobiopterin (a probable natural cofactor), 2-amino-4-hydroxy-6-methyltetrahydropteridine, and 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine were 2 × 10⁻⁵m , 5 × 10⁻⁵m and 4 × 10⁻⁴m , respectively. The K_m value for tyrosine at 1 × 10⁻³m -2-amino-4-hydroxy-6-methyltetrahydropteridine as a cofactor was 5 × 10⁻⁵m . The enzyme activity was markedly stimulated with Fe²⁺ or catalase, but Fe²⁺ gave higher activity. The activity was inhibited with α, α′-dipyridyl, l -α-methyl-p-tyrosine, and various catecholamines. Among catecholamines, dopamine was the most potent inhibitor. l -5-Hydroxytryptophan was an inhibitor as potent as dopamine. Neither d -5-hydroxytryptophan nor 5-hydroxytryptamine inhibited the enzyme. The inhibition by l -5-hydroxytryptophan was partially competitive with tetrahydrobiopterin at concentrations higher than 9 × 10⁻⁵m , and partially uncompetitive at concentrations lower than 9 × 10⁻⁵m . The addition of heparin or lysolecithin did not affect enzyme activity with tetrahydrobiopterin as cofactor.     

Effect of Argemone mexicana on Local Edema and LPS-Induced Neuroinflammation

Argemone mexicana L. is a widely used plant in Mexican traditional medicine to treat inflammatory and nervous medical conditions. It has been subjected to several pharmacological and chemical studies in which acute anti-inflammatory activity is indicated. This work aimed at finding an extract and fraction with anti-inflammatory activity by means of 2-O-tetradecanoylphorbol-13-acetate (TPA)-induced auricular edema. Afterward, the extract and the fraction were tested on neuroinflammation caused by lipopolysaccharides (LPS). Treatments obtained from A. mexicana included the methanolic extract (AmMeOH), a fraction extracted with ethyl acetate (AmAcOEt), and four sub-fractions (AmF-1 to AmF-4), which were evaluated in auricular edema with the TPA assay. Both treatments with the most significant inhibitory effect were employed to test these in the LPS neuroinflammation model. AmAcOEt and AmF-3 induced a higher inhibition of edema (%), and both diminished ear inflammation when viewed under a microscope. These treatments also raised an increase in spleen, but not in brain of mice with neuroinflammation. They were able to decrease the concentration of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) in both organs. Furthermore, the accumulation of amyloid-β (Aβ) in hippocampus was not visible. AmF-3 contains the flavonoids isoquercetin, luteolin, and rutin, the former being the most concentrated.     

The effect of evapoconcentration on dissolved organic carbon concentration and quality in lakes of SW Greenland

1. Dissolved organic carbon (DOC) concentration was determined for a range of lakes of varying conductivity (30–4000 μS cm⁻¹) in the low Arctic of SW Greenland. DOC concentration range from <1 to >100 mg C L⁻¹, occasionally approaching 200 mg C L⁻¹ in meromictic, oligosaline lakes. DOC concentration was strongly related to [log₁₀] conductivity and total nitrogen. 2. Peak DOC concentrations (>80 mg L⁻¹) occur in lakes located approximately 50 km from the present ice sheet margin, a zone of low effective precipitation; evaporative concentration is the first‐order control on DOC concentration. Lakes at the coast and closer to the ice margin had lower DOC concentrations (<20 mg C L⁻¹). Local factors, notably the presence or absence of an outflow and catchment morphometry, resulted in considerable variability in concentration (20–100 mg C L⁻¹) within the area of maximum concentration around 51°W. 3. Despite their high DOC concentration, these lakes are essentially colourless. Dissolved organic matter (DOM) absorption (a₃₇₅) was low in most lakes (<10 m⁻¹) with maximum values (approximately 20 m⁻¹) occurring in one humic‐stained lake in the area. Absorption values corrected for DOC concentration () were very low (<0.6 m² g⁻¹ C) for all lakes apart from those at the coast, perhaps reflecting greater allochthonous inputs at these sites. 4. S, the spectral slope coefficient, ranged from 16 to 27 μm⁻¹ and was weakly correlated with DOC concentration. Both a₃₇₅ and S showed similar distribution patterns along the sampling gradient as did DOC, with maximum values at approximately 51°W. High and low S may indicate fresher, more rapidly flushed, systems with less degraded DOM or greater inputs from their catchments. 5. The lakes closer to the head of the fjord with higher conductivity, had low (<0.2 m² g⁻¹ C) and high S (>21 μm⁻¹) and this may reflect increasingly longer lake water residence times, greater DOM age and photochemical degradation.     

Phytochemical Variation within Aerial Parts of Ferula cupularis Populations,an Endangered Medicinal Plant from Iran

Ferula cupularis (Boiss.) Spalik et S. R. Downie is an endangered endemic Iranian medicinal plant with occurrence restricted to Fars and Kohkilooyeh Boyerahmad provinces, Iran. F. cupularis is cited for strong antibacterial activity, usages in foodstuffs preservation, and has long been used by local peoples for ulcer treatment. In this research, the aerial parts of F. cupularis wild populations were collected from three natural habitats: Eqlid-Kaftar (FC1), Kakan (FC2), and Sepidan-Komohr (FC3), to assess phytochemical diversity and antioxidant activity. The quantity of essential oil (EO) ranged remarkably from 0.42 to 0.72 % v/w among the populations. Results obtained from the EO analysis by GC-FID and GC/MS detected up to 56 compounds. α-Pinene (21.65–31.53 %), sabinene (4.74–11.39 %), phellandrene (1.78–5.1 %), δ-3-carene (1.85–7.18 %), limonene (4.12–7.45 %), (Z)-β-ocimene (9.08–17.64 %), and elemicin (0.23–5.74 %) were the major compounds of EOs varied significantly among the populations. Moreover, total phenol content (250.54 to 387.45 mg gallic acid/100 g dry weight (DW)) and flavonoids (34.38 to 41.12 mg quercetin/100 g DW) of methanolic extracts varied substantially among the populations. Antioxidant activities of F. cupularis EOs and extracts were assessed by DPPH (2,2,1-diphenyl-1-picrylhydrazyl) radical scavenging method. EOs exhibited EC₅₀ values ranging from 8.88 to 9.67 μg mL⁻¹ and the EC₅₀ values for the extract ranged from 941.36 to 1335.96 μg mL⁻¹ within the populations. Results demonstrated significantly different levels of antioxidant capacities among the studied populations. Monitoring the data, the population collected from Eqlid-Kaftar (FC1) was selected as the most potent population concerning the highest EO content and antioxidant activity level. The obtained data provided new insights for an initial source of breeding plans and ultimately massive production for food and pharmaceutical industries.     

Proanthocyanidins block aldosterone-dependent up-regulation of cardiac gamma ENaC and Nedd4-2 inactivation via SGK1

Aldosterone plays a central role in the development of cardiac pathological states involving ion transport imbalances, especially sodium transport. We have previously demonstrated a cardioprotective effect of proanthocyanidins in aldosterone-treated rats. Our objective was to investigate for the first time the effect of proanthocyanidins on serum and glucocorticoid-regulated kinase 1 (SGK1), epithelial Na⁺ channel (γ-ENaC), neuronal precursor cells expressed developmentally down-regulated 4-2 (Nedd4-2) and phosphoNedd4-2 protein expression in the hearts of aldosterone-treated rats. Male Wistar rats received aldosterone (1 mg kg⁻¹ day⁻¹)+1% NaCl for 3 weeks. Half of the animals in each group were simultaneously treated with the proanthocyanidins-rich extract (80% w/w) (PRO80, 5 mg kg⁻¹ day⁻¹). Hypertension and diastolic dysfunction induced by aldosterone were abolished by treatment with PRO80. Expression of fibrotic, inflammatory and oxidative mediators were increased by aldosterone–salt administration and blunted by PRO80. Antioxidant capacity was improved by PRO80. The up-regulated aldosterone mediator SGK1, ENaC and p-Nedd4-2/total Nedd4-2 ratio were blocked by PRO80. PRO80 blunted aldosterone–mineralocorticoid-mediated up-regulation of ENaC provides new mechanistic insight of the beneficial effect of proanthocyanidins preventing the cardiac alterations induced by aldosterone excess.     

拟草果总黄酮制备纯化及抗炎活性研究

该文在前期研究的基础上,以拟草果的甲醇粗提液为原料,研究了拟草果总黄酮成分的纯化方法以及考察拟草果总黄酮的抗炎活性。结果表明:采用静态吸附-洗脱试验筛选HP-20为纯化拟草果总黄酮的最佳大孔吸附树脂; 以吸附率、解吸率等参数为指标,考察上样液和洗脱液的质量浓度、体积、流速等因素对纯化工艺的影响,确定最佳工艺条件:上样液质量浓度为0.5 mg·mL^-1、上样体积流量为4 mL·min^-1、上样体积为15 BV、洗脱剂乙醇浓度为70%、洗脱流速为2 mL·min^-1、洗脱剂用量为10 BV,在此条件下纯化的总黄酮保留率为65.48%; 通过检测获得的拟草果总黄酮对脂多糖刺激的小胶质BV2细胞中白介素(IL)-6水平的影响发现,其可显著下调炎症因子IL-6的表达,具有一定的抗炎活性。     

Synthesis,anti-inflammatory activity and modeling studies of cycloartane-type terpenes derivatives isolated from Parthenium argentatum

The 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema model in mice determined the anti-inflammatory activities in vivo of argentatins A, B and D, the main cycloartenol-type triterpenes present in Parthenium argentatum. Our results showed that argentatin B (ED₅₀ = 1.5 × 10⁻⁴ mmol/ear) and argentatin A (ED₅₀ = 2.8 × 10⁻⁴ mmol/ear) were more potent anti-inflammatory agents than indomethacin (ED₅₀ = 4.5 × 10⁻⁴ mmol/ear), the reference drug. Based on these findings, we decided to evaluate 13 derivatives of argentatins A and B. All the derivatives showed anti-inflammatory activity in the TPA-induced edema model in mice. The most active compound was 25-nor-cycloart-3, 16-dione-17-en-24-oic acid, obtained from argentatin A (ED₅₀ = 1.4 × 10⁻⁴ mmol/ear). Argentatin B was assayed as inhibitor of COX-2 activity one of the key enzymes involved in the TPA assay. The results showed that argentatin B at 15 μM doses inhibited 77% COX-2 activity. Docking studies suggest that argentatin B interacts with Arg 120, a key residue for COX-2 activity.     

The effects of copper, iron and zinc on digestive enzyme activity in the hybrid tilapia Oreochromis niloticus (L.) ×Oreochromis aureus (Steindachner)

The present experiment was conducted to study effects of Cu, Fe and Zn on activities of digestive enzymes of the hybrid tilapia Oreochromis niloticus×Oreochromis aureus. The acidic protease activities increased 65·5 and 55·1% by addition of homogenates of digesta‐containing stomach with copper (75 mg l⁻¹) and zinc (50 mg l⁻¹) respectively. Addition of Cu and Zn increased the activities of protease in the hepatopancreas homogenates by 132·7 and 38·1% respectively, and reduced the activity of protease in the digesta‐containing intestine homogenates by 11·0 and 13·8% respectively. Addition of Fe (50 mg l⁻¹) increased the acidic protease activity by 96·7% but did not alter the activities of protease in the intestine and hepatopancreas. Addition of Cu markedly inhibited activities of amylase in intestine and hepatopancreas homogenates, while Zn addition showed no effects. Addition of Fe reduced activities of amylase in the intestine homogenates by 47·9% but had no effect on amylase activities in the hepatopancreas. When Cu (75 mg kg⁻¹), Fe (50 mg kg⁻¹) and Zn (50 mg kg⁻¹) were supplemented to basal diet for 3 weeks, the activities of amylase in hepatopancreas homogenates increased 125·3, 215·6 and 70·0%, respectively, the activities of amylase in intestine increased 79·8, 74·6 and 48·5%, respectively, and the activities of lipase in intestine increased 90·5, 149·8 and 84·0%, respectively. Supplementation of Cu, Fe or Zn into diet had no effects on activity of protease in all digestive organs. Therefore, the results suggest that effects of Cu, Fe and Zn on activity of digestive enzymes in vitro were different from those seen in vivo, and that the positive effects of Cu, Fe and Zn supplemented to fish diet would be valuable information for formulating fish feed.     

Production,purification and characterisation of a novel halostable xylanase from Bacillus sp. NTU-06

Bacillus sp. NTU-06 was used to produce xylanase, which is an important industrial enzyme used in the pulp and paper industry. The enzyme was purified by fast protein liquid chromatography (FPLC) and had a molecular mass of 24 kDa. The enzyme was active over a concentration range of 0–20% sodium chloride in culture broth, although its activity was optimal in 5% sodium chloride. A salinity stability test showed that 43% of the enzyme activity was retained after 4 h in 20% sodium chloride. Xylanase activity was maximal at pH 8.0 and 40°C. The enzyme was somewhat thermostable, retaining 20% of the original activity after incubation at 70°C for 4 h. The xylanase had K_m and V_max values of 3.45 mg mL⁻¹ and 387.3 µmol min⁻¹mg⁻¹, respectively. The deduced internal amino acid sequence of Bacillus sp. NTU-06 xylanase resembled the sequence of beta-1,4-endoxylanase, which is a member of glycoside hydrolase family 11. Some of the novel characteristics that make this enzyme potentially effective in xylan biodegradation are discussed.