In-vitro inhibition of NLRP3 inflammasome by 3,6-dihydroxyflavone (3,6-DHF): a therapeutic strategy for the treatment of chronic inflammatory and autoimmune diseases.

Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex has an important role in immune system and its abnormal activation is associated with the pathogenesis of various inflammatory and auto-immune diseases. The study reveals the anti-inflammatory effects of 3,6-dihydroxyflavone (3,6-DHF). Here, we aimed to determine the inhibitory effects of 3,6-DHF on NLRP3 inflammasome and its associated components, thereby determining the signaling pathways involved in the inhibition. Reactive oxygen species (ROS) and nitric oxide (NO) were quantified by chemiluminescence and Griess methods, respectively. Inflammatory cell model was induced in human leukemic monocytes (THP-1). mRNA levels were estimated through real-time RT-PCR, protein expressions were evaluated by protein slot blot and immunocytochemistry, MTT and alamar blue assays were employed for toxicity studies. The compound 3,6-DHF was found to be the potent inhibitor of NLRP3 inflammasome by targeting the molecules involve in its activation pathway. Anti-inflammatory effects were revealed by inhibition of ROS and NO, reduction in the transcription of caspase-1, ASC, IL-1ß and TLR-4 was observed along with the marked inhibition of NLRP3, IL-18, NF-κB and pNF-κB at translational level. 3,6-DHF was non-toxic on normal human fibroblast (BJ) and THP-1 cells and, could be a potential therapeutic agent in NLRP3 inflammasome driven diseases.

Liver tryptophan 2,3-dioxygenase: a determinant of anxiety-like behaviour - studies with chronic nicotine administration in rats.

Deletion of the tryptophan 2,3-dioxygenase ( TDO2 ) gene induces an anxiolytic-like behaviour in mice and TDO inhibition by allopurinol elicits an antidepressant-like effect in rats exposed to restraint stress. Chronic nicotine administration inhibits TDO activity, enhances brain serotonin synthesis and exerts anxiolytic- and antidepressant-like effects in rodent models. There is a strong association between anxiety, depression and tobacco use, which is stronger in women than in men. The present study aimed to examine the relationship between behavioural measures of anxiety and depression with liver TDO activity, brain tryptophan concentration and serotonin synthesis in rats treated chronically with nicotine. Behavioural measures included the elevated plus maze (EPM), open field (OFT) and forced swim (FST) tests. Biochemical measures included TDO activity, serum corticosterone and brain Trp, 5-HT and 5-HIAA concentrations. Anxiolytic-like and antidepressant-like effects of chronic nicotine were confirmed in association with TDO inhibition and elevation of brain Trp and 5-HT. Sex differences in behaviour were independent of the biochemical changes. At baseline, female rats performed better than males in OFT and FST. Nicotine was less anxiolytic in females in the open arm test. Nicotine treatment did not elicit different responses between sexes in the FST. Our findings support the notion that liver TDO activity exhibits a strong association with behavioural measures of anxiety and depression in experimental models, but provide little evidence for sex differences in behavioural response to nicotine. The TDO-anxiety link may be underpinned by kynurenine metabolites as well as serotonin.

Association of IL-6 & IL-1ß (pro-inflammatory cytokines) and related biochemical indexes in newly diagnosed diabetics subjected to glucose tolerance test.

The study proposed to find out the association of pro-inflammatory cytokines (IL-6 & IL-1ß) and related biochemical indexes in newly diagnosed diabetes (NDD) subjects as compared to healthy subjects. This clinical prospective research was done with collaboration of University of Karachi and Baqai Institute of Diabetology and Endocrinology between November 2018 to May 2019. Demographics and anthropometric details were noted on predesigned questionnaire. Subjects were identified on the basis of Oral Glucose Tolerance Test (OGTT). Samples of blood at baseline were gained for IL-6 & IL-1ß (pro-inflammatory cytokines) and related biochemical indexes. Total of 34 subjects were included both males 19 (55.9%) and females 15 (44.1%) having mean age 49.65±1.95 years. On the basis of OGTT, 17(50%) were healthy subjects and 17(50%) were NDD. Mean ± SE value of IL-1ß was 208.56±23.53 in healthy subjects and 1510.47±494.16 in NDD subjects, while, IL-6 was 57.51±13.02 and 119.51±36.60, respectively. Non-significant correlation was observed between IL-6 and IL- 1ß (r= 0.20, P=0.475) among healthy subjects. While, significant correlation was observed between IL- 6 and IL- 1ß (r=0.774, P<0.0001) among NDD subjects. With increased levels of both IL-6 and IL-1ß in NDD subjects only IL-1ß showed significant correlation as compared to IL-6. In addition, significant correlation of IL-1ß with various biochemical parameters as compared to IL-6 were also observed to be involved in progression from normoglycemia to type 2 DM.

Isolation of Ceramides from Tagetes patula L. Yellow Flowers and Nematicidal Activity of the Fractions and Pure Compounds against Cyst Nematode, Heterodera zeae.

Investigation of yellow flower extract of Tagetes patula L. led to the identification of an aggregate of five phytoceramides. Among them, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]icosanamide, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]heneicosanamide, (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]docosanamide, and (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]tricosanamide were identified as new compounds and termed as tagetceramides, whereas (2R)-2-hydroxy-N-[(2S,3S,4R,8E)-1,3,4-trihydroxyicos-8-en-2-yl]tetracosanamide was a known ceramide. A steroid (ß-sitosterol glucoside) was also isolated from the subsequent fraction. The structures of these compounds were determined on the basis of spectroscopic analyses, as well as chemical method. Several other compounds were also identified by GC/MS analysis. The fractions and some commercial products, a ceramide HFA, ß-sitosterol, and stigmasterol were evaluated against an economically important cyst nematode, Heterodera zeae. Ceramide HFA showed 100 % mortality, whereas, ß-sitosterol and stigmasterol were 40-50 % active, at 1 % concentration after 24 h of exposure time, while ß-sitosterol glucoside revealed no activity against the nematode.

Chronic administration of St. John's Wort attenuates alcohol intake and brain indoleamine 2, 3-dioxygenase activity in mice.

Present study aims to elucidate the effects of chronic administration of St. John's Wort (SJW) (500mg/kg) on brain tryptophan (TRP) metabolites and indoleamine 2-3 dioxygenase (IDO) activity in alcohol treated mice. Locally bred Albino BALB/c mice, weighing 20-25g were divided into three groups (untreated controls, Alcohol, Alcohol +Drug) having 6 mice in each. Freshly prepared ethanol solution was administered in drinking water in the proportion of 5% for three days or 8% for 3 weeks to two groups. After 3 weeks drug group was treated with SJW (dissolved in ethanol: saline 1:3 v/v) at a dose of 500mg/kg was administered orally for 1 week. During treatment alcohol intake was monitored .In present finding chronic administration of SJW significantly reduced ethanol intake by 78.6% (P<0.001) in mice. Data analyzed by student's t-test indicates that SJW remarkably reduce kynurenine (KYN) by 60.9% (P<0.001) and KYN/TRP ratio (IDO) activity) by 70.9% (P<0.001) in brain. Low serotonin level promotes alcohol intake. Presentresults suggest that SJW decreases alcohol intake by inhibiting IDO thereby shifting TRP catabolism towards serotonin synthesis.

Increased HPA Axis Activity and Serum Tryptophan in Naswar (Dipping Tobacco) Users: A Case-Control Study.

Nicotine is the principal addictive agent present in Naswar, a smokeless dipping tobacco product. 5-Hydroxytryptamine (5-HT) has been implicated in the reinforcement properties of nicotine. Also, the hypothalamic-pituitary-adrenal (HPA) axis is of vital importance in evaluating the response to stress and nicotine addiction. The study aimed to evaluate serum tryptophan and cortisol levels in Naswar users in relation to addiction. Additionally, serum cotinine levels were also determined to assess daily nicotine exposure. The study comprised 90 healthy Naswar users and 68 non-tobacco users. Estimation of serum cortisol, tryptophan and albumin was carried out. From the Naswar user group, 20 were selected for the estimation of serum cotinine for which blood was drawn twice first in the morning and then in the evening. Serum tryptophan and cortisol levels in Naswar users were significantly raised compared to the control group. However, no difference in the levels of albumin between Naswar users and the control group were found. The mean cotinine values rose from the morning value of 366.0 ± 40.69 ng/ml (mean ± SEM) to an evening value of 503.1 ± 42.96 ng/ml that in turn is equivalent to consumption of 40 cigarettes. Elevated cortisol levels might constitute an important aspect of Naswar addiction. Additionally, raised levels of serum tryptophan in Naswar users could lead to raised concentration of 5-HT which also might be a significant factor contributing to Naswar addiction. Also, serum cotinine concentrations equivalent to an intake of about 40 cigarettes per day is quite alarming.

Pro inflammatory interleukins and thyroid function in Naswar (dipping tobacco) users: a case control study.

BACKGROUND: Naswar is a type of finely ground, moistened smokeless dipping tobacco product being commonly used in Pakistan. Although, nicotine is the most important psychoactive agent present in Naswar, it also exerts immunosuppressive effects and could alter the levels of cytokines. Additionally, the effects of Naswar consumption on thyroid hormones are not known. METHODS: Eighty healthy males aged 16-43 years were selected for the study and were divided into a control group comprising 31 healthy subjects with no history of tobacco use in any form, with age matched test group comprising 49 exclusive Naswar users who were consuming Naswar for at least 1 year. Estimation of serum interleukin (IL)-1ß, IL-6, free thyroxine (FT4), free triiodothyronine (FT3) and thyroid stimulating hormone (TSH) was carried out. The data was analyzed by statistical programme (SPSS) using student's independent samples t-test. One way Anova followed by post hoc Tukey test was applied to assess parameters in Naswar users grouped according to duration of Naswar usage. Pearson's correlation coefficient was applied to assess correlations between parameters. RESULTS: IL-1ß was found to be significantly lowered in Naswar users compared to the control group whereas serum FT3 and FT4 levels in Naswar users were significantly raised compared to the control group. However, no differences in the levels of serum IL-6 and TSH between Naswar users and the control group were found. Also, serum FT3 and FT4 were consistently raised whereas IL-1ß was lowered in Naswar users irrespective of duration of Naswar consumption. IL-1ß was negatively correlated with FT3 in Naswar users. CONCLUSION: The findings suggest that Naswar users might be in an immune suppressive state as evident by the lowered levels of interleukin 1ß. Additionally, alterations in the levels of thyroid hormones signify the impact of Naswar consumption on thyroid function.

Elevation of Kynurenine Metabolites in Rat Liver and Serum: A Potential Additional Mechanism of the Alcohol Aversive and Anti-cancer Effects of Disulfiram?

AIMS: The tryptophan metabolites 3-hydroxykynurenine (3-HK) and 3-hydroxyanthranilic acid (3-HAA) inhibit the liver mitochondrial low Km aldehyde dehydrogenase and possess alcohol-aversive and immunosuppressant properties. As the disulfiram (DS) metabolite carbon disulphide activates enzymes forming 3-HK and 3-HAA, we investigated if repeated disulfiram treatment increases the hepatic and serum levels of these 2 metabolites. METHODS: Livers and sera of male Wistar rats were analysed for tryptophan and kynurenine metabolites after repeated DS treatment for 7 days. RESULTS: DS increased liver and serum [3-HK] and [3-HAA] possibly by increasing the flux of tryptophan down the hepatic kynurenine pathway and activation of kynurenine hydroxylase and kynureninase. CONCLUSIONS: We provisionally suggest that elevation of some kynurenine metabolites may be an additional mechanism of the alcohol-aversive and anticancer effects of disulfiram.

Cytotoxic and antioxidant properties of phenolic compounds from Tagetes patula flower.

CONTEXT: Tagetes patula Linn. (Asteraceae) (French Marigold) flowers are used by local practitioners for cancer treatment; however, it lacks scientific justification. OBJECTIVE: Identification of bioactive compounds in T. patula flower for cytotoxic and growth inhibition in human cancer cell lines along with its antioxidant properties using chemical and cell based systems. MATERIALS AND METHODS: The T. patula flower methanol extract, its seven fractions, and three phenolic compounds including methyl protocatechuate (1), patuletin (2), and patulitrin (3) were evaluated using sulforhodamine-B assay against HeLa, HT-144, NCI-H460, MCF-7, PC-3, and SF-268 human cancer cell lines. In parallel, antioxidant activity was evaluated using chemical (DPPH(·), deoxyribose, and lipid peroxidation assays) and cell-based chemiluminescence systems (human neutrophils and mice macrophages). RESULTS: The methanol extract and ethyl acetate insoluble fraction exhibited cytotoxic and growth inhibitory effects against HeLa in which 2 exhibited highest cell growth inhibition (GI50: 0.6 ± 0.1 µg/ml) and cytotoxicity (LC50: 2.5 ± 0.1 µg/ml). It also scavenged LOO(·) (IC50: 6.5 ± 0.7 µg/ml) and [Formula: see text] (IC50: 27.5 ± 1.3 µg/ml) in chemical systems and human neutrophils, respectively. However, 1 preferably scavenged H2O2-Cl(-) (IC50: 0.5 ± 0.01 µg/ml) in mice macrophages. DISCUSSION AND CONCLUSION: Compound 2 from T. patula flower exhibited both growth inhibitory and cytotoxic properties while 1 and 3 were only growth inhibitory against HeLa. 1-3 also displayed antioxidant properties implying its probable role in growth inhibition/cytotoxic action. The present study provides scientific evidence for the use of T. patula flower in cancer treatment by traditional healer.

Serotonergic activity and hypothalamic-pituitary-adrenal axis response in alcohol administered and subsequently withdrawn rats.

Present study aims to depict the role of serotonergic pathways in discrete brain areas (hypothalamus, amygdala, and hippocampus) and their interaction with hypothalamic pituitary adrenal (HPA) axis in alcohol dependence and subsequent withdrawal syndrome in rats. Albino Wistar rats were fed a liquid diet containing alcohol for 4 weeks. Matched control rats were fed isocaloric amounts of the alcohol-free liquid diet, in which the alcohol contribution was substituted with maltose-dextrin. Brain regional tryptophan, 5-hydroxytryptamine (5-HT), 5-Hydroxyindoleacetic acid (5-HIAA) concentrations were determined using high performance liquid chromatography with flourimetric detector. Serum corticosterone was determined spectrofluorimetrically. Data analysis showed that there was significant increase in tryptophan (hippocampus), 5-HT (hippocampus and amygdala) and 5-HT turnover in all the three regions examined when alcohol administered rats were compared with matched controls. In contrast withdrawal from alcohol decreased brain tryptophan, 5-HT and its turnover. It is concluded that the prolong alcohol use boost functions of serotonergic neuronal pathways, in particular, hypothalamus that regulate HPA-axis function and develop tolerance and adaptation. In addition, withdrawal from alcohol exacerbates serotonergic functions that results in failure to suppress corticosterone levels and hence induce low mood states and other signs and symptoms of alcohol withdrawal syndrome.

Effects of smokeless dipping tobacco (Naswar) consumption on antioxidant enzymes and lipid profile in its users.

Dipping tobacco, traditionally referred to as moist snuff, is a type of finely ground, moistened smokeless tobacco product. Naswar is stuffed in the floor of the mouth under the lower lip, or inside the cheek, for extended periods of time. Tobacco use causes dyslipidemia and also induces oxidative stress, leading to alteration in levels of antioxidant enzymes. Dyslipidemia and oxidative stress in turn play a vital role in the development of cardiovascular disease (CVD). Studies conducted on smokeless tobacco products reveal contradictory findings regarding its effects on lipid profile and antioxidant enzymes. As use of Naswar is quite common in Pakistan, the current study aimed to evaluate levels of the antioxidant enzymes viz glutathione per oxidase (GPx) and super oxide dismutase (SOD), alongside lipid profile parameters such as total cholesterol, triglycerides, High density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) to assess the risk of adverse cardiovascular events in Naswar users.90 Healthy males aged 16-43 years, who consumed Naswar daily, were selected for the study, alongside 68 age-matched non-tobacco users as controls. Both GPx and SOD levels as well as serum HDL-C were significantly reduced (P<0.01) in Naswar users, whereas serum total cholesterol, LDL-C, triglycerides and LDL-C/HDL-C ratio were significantly increased (P<0.01) in Naswar consumers compared to controls. Our findings indicate deleterious effects of Naswar usage on health by causing altered lipid profile and antioxidant enzymes thereby placing its consumers at an increased risk of cardiovascular disease.

Assessment of cardiovascular disease risk in depressed women of reproductive and menopausal age.

It is well documented that depression increases the risk of cardiovascular disease (CVD). Women of age 55 and younger with depression are more likely to have CVD. The present study aims to investigate CVD risk in depressed women of reproductive age (RA) and menopausal age (MA). Adult women of RA and MA were divided in to two groups; healthy and depressed. Women were screened for depression (ICD-10 criteria) at outpatients department of local psychiatric hospital. Fasting serum cortisol, estradiol and lipid profile levels were determined. Data was analyzed using two-way ANOVA followed by Newman's Keuls q-test. Total cholesterol (TC), low-density lipoproteins (LDL) and triglycerides (TGs) were raised in MA women however high density lipoprotein (HDL) and estradiol were lower as compared to RA women. Depressed RA women showed increased TC, LDL and HDL but decreased estradiol as compared to healthy women of similar age group. MA depressed women showed increased TC and LDL but decreased HDL and estradiol as compared to healthy controls. We found that MA depressed women had low HDL and estradiol as compared to RA depressed women. Circulating cortisol levels were increased in both depressed RA and MA women compared to respective healthy controls. Low HDL/LDL ratio was found in both healthy and depressed MA women when compared with respective RA women. A significant negative correlation of estradiol and cortisol was found in depressed RA women. It is concluded that low HDL/LDL ratio and hypercortisolemia in both healthy and depressed MA women make them more vulnerable to CVD.

Docking studies of antidepressants against single crystal structure of tryptophan 2, 3-dioxygenase using Molegro Virtual Docker software.

Tryptophan 2, 3-dioxygenase (TDO) a heme containing enzyme found in mammalian liver is responsible for tryptophan (Trp) catabolism. Trp is an essential amino acid that is degraded in to N-formylkynurenine by the action of TDO. The protein ligand interaction plays a significant role in structural based drug designing. The current study illustrates the binding of established antidepressants (ADs) against TDO enzyme using in-silico docking studies. For this purpose, Fluoxetine, Paroxetine, Sertraline, Fluvoxamine, Seproxetine, Citalopram, Moclobamide, Hyperforin and Amoxepine were selected. In-silico docking studies were carried out using Molegro Virtual Docker (MVD) software. Docking results show that all ADs fit well in the active site of TDO moreover Hyperforin and Paroxetine exhibited high docking scores of -152.484k cal/mol and -139.706k cal/mol, respectively. It is concluded that Hyperforin and Paroxetine are possible lead molecules because of their high docking scores as compared to other ADs examined. Therefore, these two ADs stand as potent inhibitors of TDO enzyme.

St. John's Wort increases brain serotonin synthesis by inhibiting hepatic tryptophan 2, 3 dioxygenase activity and its gene expression in stressed rats.

We aimed to investigate the effects of herbal St. John's Wort (SJW) on transcriptional regulation of hepatic tryptophan 2, 3 - dioxygenase (TDO) enzyme activity and brain regional serotonin (5-HT) levels in rats exposed to forced swim test (FST). TDO mRNA expression was quantified using real-time reverse transcription polymerase chain (RT-PCR) reaction and brain regional indoleamines were determined by high performance liquid chromatography coupled to fluorescence detector. Behavioral analysis shows significant reduction in immobility time in SJW (500mg/kg/ml) administered rats. It was found that pretreatment of SJW to rats did not prevent stress-induced elevation in plasma corticosterone levels however it increases serotonin synthesis by virtue of inhibiting hepatic TDO enzyme activity and its gene expression, ascertaining the notion that there exists an inverse relationship between hepatic TDO enzyme activity and brain 5-HT. The drug also decreases serotonin turnover in all the brain areas (hypothalamus, hippocampus amygdala) in stressed rats endorsing its monoamine oxidase inhibition property. Inhibition of TDO enzyme activity and its gene expression by the drug provides new insights for the development of therapeutic interventions for stress related mental illnesses.

Kynurenine pathway of tryptophan metabolism in pathophysiology and therapy of major depressive disorder.

Serotonin deficiency in major depressive disorder (MDD) has formed the basis of antidepressant drug development and was originally attributed to induction of the major tryptophan (Trp)-degrading enzyme, liver Trp 2,3-dioxygenase (TDO), by cortisol, leading to decreased Trp availability to the brain for serotonin synthesis. Subsequently, the serotonin deficiency was proposed to involve induction of the extrahepatic Trp-degrading enzyme indoleamine 2,3-dioxygenase (IDO) by proinflammatory cytokines, with inflammation being the underlying cause. Recent evidence, however, challenges this latter concept, as not all MDD patients are immune-activated and, when present, inflammation is mild and/or transient. A wide range of antidepressant drugs inhibit the activity of liver TDO and bind specifically to the enzyme, but not to IDO. IDO induction is not a major event in MDD, but, when it occurs, its metabolic consequences may be masked and overridden by upregulation of kynurenine monooxygenase (KMO), the gateway to production of modulators of immune and neuronal functions. KMO appears to be activated in MDD by certain proinflammatory cytokines and antidepressants with anti-inflammatory properties may block this activation. We demonstrate the ability of the antidepressant ketamine to dock (bind) to KMO. The pathophysiology of MDD may be underpinned by both the serotonin deficiency and glutamatergic activation mediated respectively by TDO induction and N-methyl-D-aspartate receptor activation. Inhibition of TDO and KMO should be the focus of MDD pharmacotherapy.

Antihypertensive effect of patulitrin and other constituents from Tagetes patula L. (French marigold) in acute L-NAME induced hypertensive rats.

The work is aimed to evaluate the blood pressure reducing effect of constituents from methanol extract and associated constituents of Tagetes patula flowers in normotensive and L-NAME induced hypertensive rats. The HPLC analysis of methanol extract of Tagetes patula flowers (JFM) resulted in the quantitative identification and percent comparison of four phenolic constituents, protocatechuic acid (PA), methyl protocatechuate (MPA), patulitrin (TRIN) and patuletin (PAT). All the extracts, fractions and compounds examined showed significant blood pressure lowering activity. Patulitrin (TRIN) which has emerged as the major constituent (15.33%) of T. patula flowers showed significant 30% and 68% fall in blood pressure in normotensive and L-NAME induced hypertensive rats respectively. The patuletin (PAT), which is an aglycone of TRIN displayed high percentage (84%) of antihypertensive activity. Further, comprehensive and advanced studies on these constituents may result in preparation of an effective blood pressure lowering medicine with active precious rare flavonoids, patuletin and patulitrin.

Inflammation and serotonin deficiency in major depressive disorder: molecular docking of antidepressant and anti-inflammatory drugs to tryptophan and indoleamine 2,3-dioxygenases.

The roles of the kynurenine pathway (KP) of tryptophan (Trp) degradation in serotonin deficiency in major depressive disorder (MDD) and the associated inflammatory state are considered in the present study. Using molecular docking in silico, we demonstrate binding of antidepressants to the crystal structure of tryptophan 2,3-dioxygenase (TDO) but not to indoleamine 2,3-dioxygenase (IDO). TDO is inhibited by a wide range of antidepressant drugs. The rapidly acting antidepressant ketamine does not dock to either enzyme but may act by inhibiting kynurenine monooxygenase thereby antagonising glutamatergic activation to normalise serotonin function. Antidepressants with anti-inflammatory properties are unlikely to act by direct inhibition of IDO but may inhibit IDO induction by lowering levels of proinflammatory cytokines in immune-activated patients. Of six anti-inflammatory drugs tested, only salicylate docks strongly to TDO and apart from celecoxib, the other five dock to IDO. TDO inhibition remains the major common property of antidepressants and TDO induction the most likely mechanism of defective serotonin synthesis in MDD. TDO inhibition and increased free Trp availability by salicylate may underpin the antidepressant effect of aspirin and distinguish it from other nonsteroidal anti-inflammatory drugs. The controversial findings with IDO in MDD patients with an inflammatory state can be explained by IDO induction being overridden by changes in subsequent KP enzymes influencing glutamatergic function. The pathophysiology of MDD may be underpinned by the interaction of serotonergic and glutamatergic activities.

Tryptophan in alcoholism treatment II: inhibition of the rat liver mitochondrial low Km aldehyde dehydrogenase activity, elevation of blood acetaldehyde concentration and induction of aversion to alcohol by combined administration of tryptophan and benserazide.

AIMS: The aims were to provide proofs of mechanism and principle by establishing the ability of the amino acid L-tryptophan (Trp) combined with the kynureninase inhibitor benserazide (BSZ) to inhibit the liver mitochondrial low K(m) aldehyde dehydrogenase (ALDH) activity after administration and in vivo and to induce aversion to alcohol. METHODS: Trp, BSZ or both were administered to male Wistar rats and ALDH activity was determined both in vitro in liver homogenates and in vivo (by measuring acetaldehyde accumulation in blood after ethanol administration). Alcohol consumption was studied in an aversion model in rats and in alcohol-preferring C57 mice. RESULTS: Combined administration of Trp + BSZ, but neither compound alone, produced a strong inhibition of ALDH activity and an increase in blood acetaldehyde concentration after ethanol, and induced aversion to alcohol in rats and decreased preference in mice. Another kynureninase inhibitor, carbidopa, induced aversion to alcohol by itself, which was reversed by Trp co-administration. CONCLUSIONS: The present results establish a prior art for the use of a combination of Trp plus BSZ in the treatment of alcoholism by aversion, which merits rapid clinical development.

Tryptophan in alcoholism treatment I: kynurenine metabolites inhibit the rat liver mitochondrial low Km aldehyde dehydrogenase activity, elevate blood acetaldehyde concentration and induce aversion to alcohol.

AIMS: The aims were to provide proofs of mechanism and principle by establishing the ability of kynurenine metabolites to inhibit the liver mitochondrial low K(m) aldehyde dehydrogenase (ALDH) activity after administration and in vivo, and to induce aversion to alcohol. METHODS: Kynurenic acid (KA), 3-hydroxykynurenine (3-HK) and 3-hydroxyanthranilic acid (3-HAA) were administered to normal male Wistar rats and ALDH activity was determined both in vitro in liver homogenates and in vivo (by measuring blood acetaldehyde following ethanol administration). Alcohol consumption was studied in an aversion model in rats and in alcohol-preferring C57 mice. RESULTS: ALDH activity was significantly inhibited by all three metabolites by doses as small as 1 mg/kg body wt. Blood acetaldehyde accumulation after ethanol administration was strongly elevated by KA and 3-HK and to a lesser extent by 3-HAA. All three metabolites induced aversion to alcohol in rats and decreased alcohol preference in mice. CONCLUSIONS: The above kynurenine metabolites of tryptophan induce aversion to alcohol by inhibiting ALDH activity. An intellectual property covering the use of 3-HK and 3-HAA and derivatives thereof in the treatment of alcoholism by aversion awaits further development.

Bioassay-guided isolation of antioxidant agents with analgesic properties from flowers of Tagetes patula.

CONTEXT: Tagetes patula L. is one of the French marigold group of the Asteraceae family. It is recognized in folklore for its medicinal and pesticidal properties. OBJECTIVE: In search of more effective, but non-toxic compounds with antioxidative potential led to the bioassay guided isolation studies on the extracts of T. patula. MATERIALS AND METHODS: The bioassay on Tagetes patula flowers were carried out guided by in vitro antioxidant activity using DPPH assay. A minor but proven plant constituent methyl protocatechuate (1) was isolated by column chromatography, while patuletin (2) and patulitrin (3) obtained in bulk by employing solvent partition of methanol extract. Derivatization of patuletin into benzoyl, cinnamoyl and methyl was conducted to establish the structure activity relationship (SAR). Analgesic activity of compound 2 was evaluated using acetic acid-induced writhing test and hot-plate test in mice. The toxicity of methanol extract and compound 2 were also determined. RESULTS: Polar extracts, fractions and phases demonstrated better antioxidant activity. The synthetic methyl protocatechuate (1) showed IC(50) value of 2.8 ± 0.2 µg/mL, whereas patuletin (2) (IC(50) = 4.3 ± 0.25 µg/mL) was comparable to quercetin and rutin but significantly better than patulitrin (3) (IC(50) = 10.17 ± 1.16 µg/mL). Toxicity test for the methanol extract and compound 2 did not elicit any behavioral changes or cause mortality in mice. Compound 2 also demonstrated mild analgesic property. DISCUSSION AND CONCLUSION: These findings demonstrate that the plant polar extracts and fractions possess significant antioxidant property with non-toxic effect. Compound 1 is a genuine plant constituent of T. patula.