Influence of temperature and soil moisture on the toxic potential of clothianidin to collembolan Folsomia candida in a tropical field soil

Climate change can alter the toxic effects of pesticides on soil invertebrates. However, the nature and magnitude of the influence of climatic factors on clothianidin impacts in tropical soils are still unknown. The influence of increasing atmospheric temperature and the reduction in soil moisture on the toxicity and risk of clothianidin (seed dressing formulation Inside FS^®) were assessed through chronic toxicity tests with collembolans Folsomia candida in a tropical field soil (Entisol). The risk of clothianidin for collembolans was estimated using the Toxicity-Exposure Ratio (TER) approach. Organisms were exposed to increasing clothianidin concentrations at 20, 25 and 27?°C in combination with two soil moisture conditions (30 and 60% of the maximum water holding capacity—WHC). The effect of temperature and soil moisture content on clothianidin toxicity was verified through the number of F. candida juveniles generated after 28 days of exposure to the spiked soil. The toxicities estimated at 25?°C (EC₅₀__30%WHC?=?0.014?mg?kg^?1; EC_{50_60%WHC}?=?0.010?mg?kg^?1) and 27?°C (EC_{50_30%WHC}?=?0.006?mg?kg^?1; EC_{50_60%WHC}?=?0.007?mg?kg^?1) were 2.9–3.0-fold (25?°C) and 4.3–6.7-fold (27?°C) higher than those found at 20?°C (EC_{50_30%WHC}?=?0.040?mg?kg^?1; EC_{50_60%WHC}?=?0.030?mg?kg^?1), indicating that clothianidin toxicity increases with temperature. No clear influence of soil moisture content on clothianidin toxicity could be observed once the EC₅₀ values estimated at 30% and 60% WHC, within the same temperature, did not significantly differ. A significant risk was detected in all temperatures and soil moisture scenarios studied, and the TER values indicate that the risk can increase with increasing temperatures. Our results revealed that temperature could overlap with soil moisture in regulating clothianidin toxicity and reinforce the importance of including climatic factors in the prospective risk assessment of pesticides.

     

Metabolism of tetrachlorophenols in the rat

The three isomers of tetrachlorophenol were administrated intraperitoneally to rats and the urinary excretion products studied. Tetrachloro-p-hydroquinone was identified as a major metabolite of 2,3,5,6-tetrachlorophenol, constituing about 35% of the dose given. Trichloro-p-hydroquinone was identified as a minor metabolite of both 2,3,4,5- and 2,3,4,6-tetrachlorophenol. 2,3,5,6-tetrachlorophenol was eliminated within 24 h, 2,3,4,6-tetrachlorophenol within 48 h while only 60% of the given dose of 2,3,4,5-tetrachlorophenol could be recovered within 72 h.The acute toxicity of the tetrachlorophenols and tetrachloro-p-hydroquinone was studied in mice upon oral and intraperitoneal administration. 2,3,5,6-tetrachlorophenol (LD₅₀ p.o. 109 mg · kg^–1) was the most toxic compound followed y 2,3,4,6- and 2,3,4,5-tetrachlorophenol (LD₅₀ p.o. 131 and 400 mg · kg^–1, respectively). Tetrachloro-p-hydroquinone proved to have low oral toxicity (LD₅₀ p.o. 500 mg · kg^–1) but was more toxic than the tetrachlorophenols when administered intraperitoneally. The oral LD₅₀ for pentachlorophenol, under identical experimental conditions, was found to be 74 mg · kg^–1.

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Zusammenfassung Die drei Isomeren von Tetrachlorphenol wurden an Ratten intraperitoneal verabreicht und die Ausscheidungsprodukte in Harn untersucht. Tetrachlor-p-hydrochinon erwies sich als Hauptmetabolit von 2,3,5,6-Tetrachlorphenol, entsprechend etwa 35% der zugeführten Menge. Bei sowohl 2,3,4,5-als auch 2,3,4,6-Tetrachlorphenol wurde Trichlor-p-hydrochinon als Metabolit identifiziert, jedoch in geringer Menge. Das 2,3,5,6-Tetrachlorphenol wurde innerhalb von 24 Std und das 2,3,4,6-Tetrachlorphenol innerhalb von 48 Std eliminiert, während bei 2,3,4,5-Tetrachlorphenol innerhalb von 72 Std nur 60% der gegebenen Menge erfaßt werden konnte.Die akute Toxizität von Tetrachlorphenolen und Tetrachlor-p-hydrochinon wurden an Mäusen oral sowie intraperitoneal studiert. 2,3,5,6-Tetrachlorphenol erwies sich als die toxischste der Substanzen (LD₅₀ p.o. 109 mg · kg^–1), gefolgt von 2,3,4,6- und 2,3,4,5-Tetrachlorphenol (LD₅₀ p.o. 131 mg · kg^–1 und 400 mg · kg^–1). Tetrachlor-p-hydrochinon zeigte nur geringe Toxizität, wenn oral verabreicht (LD₅₀ 500 mg · kg^–1), war aber toxischer als die Tetrachlorphenole, wenn intraperitoneal gegeben.

     

An in vitro and in vivo evaluation of the efficacy of recombinant human liver prolidase as a catalytic bioscavenger of chemical warfare nerve agents

In this study, we determined the ability of recombinant human liver prolidase to hydrolyze nerve agents in vitro and its ability to afford protection in vivo in mice. Using adenovirus containing the human liver prolidase gene, the enzyme was over expressed by 200- to 300-fold in mouse liver and purified to homogeneity by affinity and gel filtration chromatography. The purified enzyme hydrolyzed sarin, cyclosarin and soman with varying rates of hydrolysis. The most efficient hydrolysis was with sarin, followed by soman and by cyclosarin {apparent k_cat/K_m [(1.9?±?0.3), (1.7?±?0.2), and (0.45?±?0.04)]?×?10^5?M^?1?min^?1, respectively}; VX and tabun were not hydrolyzed by the recombinant enzyme. The enzyme hydrolyzed P (+) isomers faster than the P (?) isomers. The ability of recombinant human liver prolidase to afford 24 hour survival against a cumulative dose of 2?×?LD₅₀ of each nerve agent was investigated in mice. Compared to mice injected with a control virus, mice injected with the prolidase expressing virus contained (29?±?7)-fold higher levels of the enzyme in their blood on day 5. Challenging these mice with two consecutive 1?×?LD₅₀ doses of sarin, cyclosarin, and soman resulted in the death of all animals within 5 to 8?min from nerve agent toxicity. In contrast, mice injected with the adenovirus expressing mouse butyrylcholinesterase, an enzyme which is known to afford protection in vivo, survived multiple 1?×?LD₅₀ challenges of these nerve agents and displayed no signs of toxicity. These results suggest that, while prolidase can hydrolyze certain G-type nerve agents in vitro, the enzyme does not offer 24 hour protection against a cumulative dose of 2?×?LD₅₀ of G-agents in mice in vivo.     

Volatile,non-volatile composition and insecticidal activity of Eupatorium adenophorum Spreng against diamondback moth,Plutella xylostella (L.), and aphid,Aphis craccivora Koch

Essential oil (EO) from aerial parts of Eupatorium adenophorum Spreng was extracted by steam distillation and characterized by Gas chromatography (GC) and gas chromatography–mass spectrometry (GC-MS). α-epi-cadinenol (16.63%), O-cymene (13.54%), bornyl acetate (7.70%), β-phellandrene (7.46%), and σ-2-carene (5.77%) were the major terpenoids. The EO showed promising toxicity (median lethal concentration, LC₅₀?=?3176.54?mg?L^?1) and repellent activity (median repellent concentration, RC₅₀?=?2070.99?mg L^?1) to larvae of Plutella xylostella within 24?h. Among fractions, hexane fraction was more effective to P. xylostella (LC₅₀?=?5056.74?mg L^?1), whereas methanol fraction to Aphis craccivora (LC₅₀?=?1175.83?mg L^?1).     

Insecticidal activity and structure–activity relationship of sugar embedded macrocycles for the control of aphid (Aphis craccivora Koch)

Abstract

Toxicity of sugar embedded macrocycles was evaluated for their toxicity against nymphs of aphid, Aphis craccivora Koch (Hemiptera: Aphididae) in the laboratory conditions. Most of the compounds showed toxicity to A. craccivora. However, the activity of different macrocycles varied depending on the nature and position of various functional groups possess by these compounds. Results revealed that among them, compound 3c found more effective for the control of A. craccivora (LC₅₀?=?413?mg?L^–1) and was followed by 3b (LC₅₀?=?442.62?mg?L^?1) and 3e (LC₅₀?=?480.19?mg?L^?1).     

In vivo anti-inflammatory properties of aerial parts of Nasturtium officinale

Context: Nasturtium officinale R. Br. (watercress) has long been used in Iranian folk medicine to treat hypertension, hyperglycemia, and renal colic. Moreover, anticancer, antioxidant, and hepatoprotective properties of N. officinale have been reported.

Objective: In this study, anti-inflammatory activity of the hydro-alcoholic extract from aerial parts of N. officinale was investigated.

Materials and methods: Oral administration of the hydro-alcoholic extract of N. officinale (250, 500 and 750?mg?kg^?1) was investigated on two well-characterized animal models of inflammation, including carrageenan- or formalin-induced paw edema in rats. Then, the topical anti-inflammatory effect of N. officinale (2 and 5?mg/ear) was studied on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema. Finally, biopsy of the paw or ear was performed for pathological evaluation.

Results: Acute toxicity tests of N. officinale in rats established an oral LD₅₀ of >5?g?kg^?1. The extract of watercress (250, 500 and 750?mg?kg^?1) significantly inhibited carrageenan-induced paw edema 1, 2, 3 and 4?h after carrageenan challenge (p??1) also showed considerable activity against formalin-evoked paw edema over a period of 24?h (p?N. officinale (5?mg/ear) reduced TPA-induced ear edema (p?Discussion and conclusion: Our findings indicate potent anti-inflammatory activity of N. officinale in systemic and topical application and propose its potential as an anti-inflammatory agent for treatment of inflammatory conditions.     

Biotransformation and pharmacokinetics of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A

The biotransformation of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A by rat liver microsomes and its pharmacokinetics in male rats were studied. Incubation of dioncophylline A with rat liver microsomes resulted in the formation of the major metabolite 5′-O-demethyldioncophylline A, and a second minor metabolite, corresponding to the mass of an as yet unknown 4-hydroxydioncophylline A. Kinetic constants of the formation of 5′-O-demethyldioncophylline A were K_m?=?32?nmol and V_max?=?20?pmol?min^?1?mg^?1). Administration of dioncophylline A at a dose of 6.67?mg?kg^?1 body weight to rats intravenously and orally (n?=?4 per group) resulted in peak plasma levels of 0.84 and 0.11?µg?ml^?1, respectively. Levels of metabolites were below the limit of quantitation (LOQ). The following pharmacokinetic parameters of dioncophylline A were determined: oral bioavailability of 25%, plasma half-life of 2.5?h and partition volume of 8?l?kg^?1 body weight. Concentrations of dioncophylline A metabolites in all plasma and urine samples were below the limit of detection (LOD) and recovery of dioncophylline A in urine was very low, suggesting distribution into lipid rich tissues.     

Chronic Administration Does Not Alter the Pharmacokinetic Profile of l-Dopa in the Rat

Abstract— Chronic administration of l-dopa (200 mg kg^?1 day^?1 for 12 months) plus carbidopa (25 mg kg^?1 day^?1) or carbidopa (25 mg kg^?1 day^?1) alone did not alter the t½, AUC_0–∞ k₁₀, k₁₂, k₂₁, CL_p or Vd_ss of l-dopa following intra-aortic (i.a.) administration (50 mg kg^?1) alone or after carbidopa (25 mg kg^?1, i.p.) pretreatment, or the t½, AUC_0–∞, t_max or the bioavailability (F) of l-dopa (50 mg kg^?1) administered orally, alone or after acute pretreatment with carbidopa (25 mg kg^?1 i.p.). The peripheral metabolism of l-dopa was unaltered by chronic administration of l-dopa plus carbidopa or carbidopa alone as measured by unaltered AUC_{0·360 min} for 3-O-methyldopa, dopamine, DOPAC or homovanillic acid in the plasma of rats following acute administration of l-dopa (50 mg kg^?1, p.o. or i.a.) alone or following pretreatment with carbidopa, and unaltered hepatic dopa decarboxylase activity.     

Chemical composition of essential oil and oleoresins of Zingiber officinale and toxicity of extracts/essential oil against diamondback moth (Plutella xylostella)

Abstract

Essential oil (EO) of ginger and oleoresins isolated from extraction solvents by GC–MS. Zingiberene was the major constituent in all the samples, and ethanol could extract the maximum quantity (21.2%) from the dried de-oiled cake (EDD) followed by EO (20.3%) as compared to oleoresins. Hydro-distilled EO contains higher oxygenated monoterpenes (22.4%) than oleoresins. EDD showed more toxicity to larvae of Plutella xylostella (LC₅₀?=?4957.9?mg L^?1) after 96?h and was followed by EDW (LC₅₀?=?5067.6?mg L^?1) and EF (LC₅₀?=?6631.2?mg L^?1). EO also showed promising efficacy (LC₅₀?=?5875.9?mg L^?1) and repellency (97.1%) against P. xylostella.     

Acaricidal activities of essential oils against two-spotted spider mite,Tetranychus urticae Koch

Eleven essential oils (EOs) were screened for their fumigant and repellent activity against two-spotted spider mite, Tetranychus urticae Koch (Acarina: Tetranychidae) under laboratory conditions. Results showed that, in fumigant toxicity assay, Mentha longifolia L. showed more toxic to T. urticae (LC₅₀?=?11.08?mg?L^?1 air) and was followed by Mentha piperita L. (LC₅₀?=?15.86?mg?L^?1 air), Cymbopogon flexuosus (Nees ex Steud.) W. Watson (LC₅₀?=?17.23?mg?L^?1 air) and Chrysopogon zizanioides (L.) (LC₅₀?=?18.82?mg L^?1 air). In repellent activity test, Acorus calamus (L.), M. piperita and C. flexuosus showed 100% repellent activity to T. urticae as compared to Cedrus deodara (Roxb.) and Aegle marmelos (L.) (76.67%).     

Use of a semi-physiological pharmacokinetic model to investigate the influence of itraconazole on tacrolimus absorption,distribution and metabolism in mice

1.?The aim of this study was to investigate the influence of itraconazole (ITCZ) on tacrolimus absorption, distribution and metabolism by developing a semi-physiological pharmacokinetic model of tacrolimus in mice.

2.?Mice were randomly divided into four groups, namely control group (CG, taking 3?mg kg^?1 tacrolimus only), low-dose group (LDG, taking tacrolimus with 12.5?mg kg^?1 ITCZ), medium-dose group (MDG, taking tacrolimus with 25?mg kg^?1 ITCZ) and high-dose group (HDG, taking tacrolimus with 50?mg kg^?1 ITCZ).

3.?Liver clearance (CL_li) decreased significantly (**p?<?0.01) in LDG (35.3%), MDG (45.2%) and HDG (58.7%) mice compared to CG mice. With respect to gut clearance (CL_gu), significant (**p?<?0.01) decrease was also revealed in LDG (35.9%), MDG (50.2%) and HDG (64.6%) mice. A significant (**p?<?0.01) higher tacrolimus brain-to-blood partition coefficient (K_t,br) was found in MDG (25.3%) and HDG (55.9%) mice than in CG mice. Moreover, a significant (*p?<?0.05) increase (16.3%) was found in the absorption rate constant (K_a) in HDG mice compared to CG mice. There was a significant (**p?<?0.01) association between ITCZ dose and the change in CL_gu (ΔCL_gu, r=??0.790), the change in CL_li (ΔCL_li, r=??0.787) and the change in K_t,br (ΔK_t,br, r?=?0.727), while the association between ITCZ dose and the change in K_a (ΔK_a) was not significant (p?>?0.05).

4.?These findings could be useful in predicting the efficacy and toxicity of tacrolimus, and drug–drug interaction of ITCZ and tarcolimus in human.     

Preclinical stereoselective disposition and toxicokinetics of two novel MET inhibitors

1. The R- and S-enantiomer of N-(4-(3-(1-ethyl-3,3-difluoropiperidin-4-ylamino)-1H-pyrazolo[3,4-b]pyridin-4-yloxy)-3-fluorophenyl)-2-(4-fluorophenyl)-3-oxo-2,3-dihydropyridazine-4-carboxamide are novel MET kinase inhibitors that have been investigated as potential anticancer agents. The effect of the chirality of these compounds on preclinical in vivo pharmacokinetics and toxicity was studied.

2. The plasma clearance for the S-enantiomer was low in mice and monkeys (23.7 and 7.8?mL min^?1 kg^?1, respectively) and high in rats (79.2?mL min^?1 kg^?1). The R/S enantiomer clearance ratio was 1.5 except in rats (0.49). After oral single-dose administration at 5?mg kg^?1 the R/S enantiomer ratio of AUC_inf was 0.95, 1.9 and 0.41 in mice, rats and monkeys, respectively.

3. In an oral single-dose dose-ranging study at 200 and 500?mg kg^?1 and multi-dose toxicity study in mice plasma AUC exposure was approximately 2- to 3-fold higher for the R-enantiomer compared to the S-enantiomer. Greater toxicity of the S-enantiomer was observed which appeared to be due to high plasma C_min values and tissue concentrations approximately 24?h after the final dose.

4. Both enantiomers showed low to moderate permeability in MDCKI cells with no significant efflux, no preferential distribution into red blood cells and similar plasma protein binding in vitro.

5. Overall, the differences between the enantiomers with respect to low dose pharmacokinetics and in vitro properties were relatively modest. However, toxicity results warrant further development of the R-enantiomer over the S-enantiomer.

     

Effect of T-2 toxin-injected shrimp muscle extracts on mouse macrophage cells (RAW264.7)

Following intramuscular injections of 0.1?mL, 3?mg?kg^?1?BW^?1(1/10 LD₅₀) T-2 toxin (T-2), the tissue concentration of T-2 in shrimp was quantitatively detected using LC-MS/MS. The biological half-time (t_1/2) of T-2 in blood was 40.47?±?0.24?min. The highest number of intramuscular T-2 shrimp could tolerate when given at blood t_1/2 intervals was 4. The shrimps which were injected 5 T-2 died. The T-2 toxin highest accumulation was 0.471?±?0.012?ng?g^?1?BW^?1. The effect of toxic shrimp muscle subjected to different processing conditions (high pressure, trifluoroacetic acid, acid and alkali digestions, artificial digestive juice [to simulate exposure to gastric and intestinal juices]) on mouse macrophage cells (RAW267.4) were evaluated by the MTT assay. The inhibition ratio of 2% muscle extract on RAW267.4 was 85.70?±?2.63%. The immunocytotoxicity of muscle extracts to RAW264.7 was highest in muscle extracts subjected to physical and chemical digestion (high pressure >?NaOH?> trifluoroacetic acid >?0.02 M HCl?>?0.2 M HCl?>?controls), and also artificial digestion (artificial intestinal juice >?artificial gastric juice >?N type intestinal juice >?N type gastric liquid >?controls). Results showed that high-pressure and artificial intestinal juice were most effective in the release of modified T-2 to free T-2 thus enhancing toxicity. These results can be interpreted as measurement of T-2 in food being of little value because of enhanced toxicity of T-2-contaminated food as they pass through the gastrointestinal tract.     

Evaluation of the anti-inflammatory activity of N,N′-bis(3-dimethylamino-1-phenyl-propylidene)hydrazine dihydrochloride

This study investigated the anti-inflammatory effect of N, N′-bis(3-dimethylamino-1-phenyl-propylidene)hydrazine dihydrochloride, D1, on carrageenan-induced edema. In addition, its effect on hyaluronidase-induced vascular permeability was also tested. D1 was synthesized, and anti-inflammatory activity was determined by carrageenan-induced hind paw edema in rats (n?=?30) at 50, 100, and 200?mg kg^?1 doses of D1 and also a 25?mg kg^?1 dose of indomethacin. The effects of D1 and indomethacin on hyaluronidase-induced capillary permeability were investigated in rabbits (n?=?18) at a 100?mg kg^?1 dose of D1 and 25?mg kg^?1 dose of indomethacin. D1 inhibited carrageenan-induced inflammation by 40, 20, and 10% at 50, 100, and 200?mg kg^?1 doses after 1?h. The inhibitions were 22.5, 32.7, 28.6% and 15.6, 33.4, 8.9% at 2?h and 3?h, respectively. The inhibitions due to indomethacin (25?mg kg^?1 dose) were 67.5, 87.8, and 91.1%, at 1?h, 2?h, and 3?h, respectively. The subcutaneous spreading areas of Trypan blue at 1, 5, 30, and 60?min after subcutaneous injection of hyaluronidase were 172.6?±?41.6, 210.2?±?39.7, 363?±?50, and 400.2?±?46.7?mm² in the D1 (100?mg kg^?1) treated group. The spreading areas at these time periods were 38.8?±?3.7, 48.2?±?4.5, 100.6?±?6.9, and 119.8?±?22.5?mm² in the indomethacin treated group. Our results showed that D1 inhibits carrageenan-induced inflammation in rats. A tendency to decrease the capillary permeability suggested that the mechanism of action of the anti-inflammatory effect of D1 may partly depend on inhibition of the hyaluronidase enzyme.     

Differential effects of adrenaline and noradrenaline on the hepatic expression of immediate early genes in mice

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Dopamine Antagonists Can Inhibit Methamphetamine Sensitization,But Not Cocaine Sensitization,When Assessed by Ambulatory Activity in Mice

Abstract— The repeated subcutaneous administration of methamphetamine (2 mg kg^?1) and cocaine (10 mg kg^?1) at 3–4 day intervals induced sensitization to their ambulation-increasing effects in mice. Subcutaneous administration of SCH 23390 (R-(+)-7-chloro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine; 0·003–0·03 mg kg^?1) and YM-09151–2 (cis-N-(1-benzyl-2-methylpyrrolidin-3-yl)-5-chloro-2-methoxy-4-methylaminobenzamide; 0·003–0·03 mg kg^?1), the selective dopamine D₁ and D₂ antagonists, respectively, reduced dose-dependently the acute ambulation-increasing effect of methamphetamine. The development of methamphetamine sensitization was inhibited when it was administered in combination with either SCH 23390 or YM-09151–2 in the repeated administration schedule. Although SCH 23390 (0·01–0·1 mg kg^?1) and YM-09151–2 (0·01–0·1 mg kg^?1) also reduced the ambulation-increasing effect of cocaine (10 mg kg^?1), neither drug inhibited the cocaine sensitization. Mice given cocaine with SCH 23390 (0·03 mg kg^?1) or YM-09151–2 (0·03 and 0·1 mg kg^?1) showed higher sensitivity than those given cocaine alone. The present results suggest that, although both the dopamine D₁ and D₂ antagonists reduce the acute stimulant effects of both methamphetamine and cocaine, they are only effective for inhibition of the methamphetamine sensitization. Mechanisms other than the dopaminergic system appear to be involved in the cocaine sensitization.     

Comparative study of the antagonism of bemegride and picrotoxin on behavioural depressant effects of diazepam in rats and mice

Experiments carried out on rats and mice showed that bemegride and diazepam acted as antagonists. Bemegride (at doses ranging from 4 to 16 mg.kg^?1 i.p.) counteracted diazepam (8 mg.kg^?1 i.p.)-induced hypokinesia and amnesic-like activity, diazepam (4 mg.kg^?1 i.p.)-induced motor inco-ordination and diazepam (2 mg.kg^?1 i.p.)-induced reduced grip strength. A GABA receptor blocking agent, picrotoxin (2–4 mg.kg^?1 i.p.) also markedly antagonized all (except for hypokinesia) these diazepam effects. Diazepam (1. 2, 4, 8 mg.kg^?1 i.p.) exerted similar dose-related antagonisms on bemegride (24 mg.kg^?1 i.p.) and on picrotoxin (8 mg.kg^?1 i.p.)-induced seizures. Both antagonisms were observed at lower doses than were required for strychnine (6 mg.kg^?1 i.p.)-induced seizures inhibition. Picrotoxin/ diazepam antagonism seems to further support the possibility of a gabaminergic mechanism of action of benzodiazepines depressant effects. Bemegride/diazepam antagonism is discussed in terms of a possible inhibitory role of bemegride on gabaminergic transmission.     

A safety study on single intravenous dose of tetrachloro-diphenyl glycoluril [iodogen] dissolved in dimethyl sulphoxide (DMSO)

Abstract

1. Iodogen (tetrachloro-diphenyl glycoluril) dissolved in DMSO (dimethyl sulphoxide) appears indispensable in radioiodination of hypericin for a new anticancer strategy. We studied the safety of intravenously administered iodogen/DMSO in mice (n?=?132).

2. Median lethal dose (LD₅₀) of iodogen/DMSO was determined with doses of 40.0, 50.0, 55.0, 60.0, 65.0 and 70.0?mg/kg. Next, toxicity of iodogen/DMSO at 30.0?mg/kg was evaluated using saline and DMSO as controls. Changes in behaviour, body weight and serum biochemistry were evaluated. Histopathology of lungs, heart, liver and kidney was performed.

3. LD₅₀ values of iodogen/DMSO were 59.5?mg/kg (95% confidence limits (CI): 54.1–65.4?mg/kg) and 61.0?mg/kg (95%CI: 56.2–66.2?mg/kg) for female and male mice, respectively. Similar to that of control groups, no animal deaths were encountered after iodogen/DMSO administration at 30.0?mg/kg. Body weights over 24?h were not altered in all groups, but significantly higher in iodogen/DMSO and DMSO groups (p?<?0.05) 14?d post-injection. Blood urea nitrogen and alkaline phosphatase increased (p?<?0.05) in iodogen/DMSO group without clinical symptoms. No pathologies were found by gross and microscopic inspection.

4. A single dose of iodogen/DMSO up to 30.0?mg/kg, over 3000 times the dose in potential human applications, appears safe, with an LD₅₀ doubling that dose in mice.     

Drug distribution and a pulmonary adverse effect of intraperitoneally administered doxorubicin niosomes in the mouse

Niosomes (non-ionic surfactant vesicles) prepared from C₁₆G₂ (a hexadecyl-diglycerol ether), and loaded with doxorubicin, were administered intraperitoneally to male AKR mice at dose levels of 0, 2.5, 5.0, and 10.0 mg kg^?1. Free drug was given at 10.0 mg kg^?1 by the intraperitoneal route. At a dose level of 10.0 mg kg^?1, peak doxorubicin levels in the central compartment were attained faster with the free drug than with the niosome formulation. However, the peak plasma levels were similar for the free drug and the niosome preparation at the 10 mg kg^?1 dose level. With doxorubicin administered as the niosome preparation by the intraperitoneal route at 2.5, 5.0, and 10.0 mg kg^?1, mean peak plasma concentrations of the drug showed a tendency to be dose-related although the differences were not significant. Over the 24 h period of the experiment, with doxorubicin at 10 mg kg^?1, the niosome formulation delivered significantly more drug to the plasma compartment than the free drug (p <0.05). When doxorubicin was given in niosomes at 2.5, 5.0 and 10.0 mg kg^?1 by the intraperitoneal route, the resulting levels of doxorubicin in cardiac tissue were not dose related and the differences not significant and, although the mean peak cardiac-tissue concentration was higher in animals receiving the free drug at 10.0 mg kg^?1 intraperitoneally than in mice given intaperitoneal doxorubicin niosomes at this dose level, the differences were again not significant. There were clinical signs of toxicity in mice given doxorubicin-containing niosomes intraperitoneally at 5.0 and 10.0 mg kg^?1, and at post-mortem an accumulation of fluid in the pleural cavity was evident. These changes were not seen in mice dosed intraperitoneally with free drug at 10 mg kg^?1, or in animals given doxorubicin niosomes intraperitoneally at 2.5 mg kg^?1. In mice dosed intraperitoneally with doxorubicin niosomes at 12.0 mg kg^?1 and at a dose volume of 0.2–0.4 mL, histological examination of the lungs demonstrated a congestion of the alveolar capillaries, and an increased number of acute inflammatory cells in the alveolar walls. There was no histological evidence of lung toxicity in mice dosed with doxorubicin niosomes at 12.0 mg kg^?1 when the formulation was administered with the higher dose volume of 1.8–2.0 mL. Importantly there was no histological evidence of lung toxicity in mice dosed with empty niosomes intraperitoneally or with doxorubicin niosomes given itravenously at 12.0 mg kg^?1.     

Pharmacological evaluation of the anxiolytic-like effects of Lippia graveolens and bioactive compounds

Context: Lippia species (Verbenaceae) are widely used in Latin America and Africa as folk medicine for their tranquilizing properties.

Objective: To evaluate the anxiolytic-like effects and safety of Lippia graveolens Kunth. by exploring its aqueous and organic leaf extracts and identifying the responsible chemical constituents.

Material and methods: Aqueous and organic extracts (hexane, ethyl acetate and methanol) were pharmacologically evaluated at several doses. Chemical constituents were identified using MS, NMR and GC-MS analysis. The isolated compounds (3?mg/kg, i.p.), extracts (1, 3, 10 and 30?mg/kg, i.p.), and the reference drug diazepam (0.1?mg/kg, i.p.) were assessed in CD-1 mice using experimental behavioural models: open-field, cylinder, hole-board, plus-maze and sodium pentobarbital-induced hypnosis, as well as their acute toxicity (LD₅₀).

Results: After administration of the extracts and bioactive compounds, a significant anxiolytic-like response from 1?mg/kg, i.p. was observed, resembling the effect of diazepam. Major presence of thymol (33.40%) was observed in the hexane extract; whereas for the first time in this species a p-cymene?+?thymol mixture (9.78%), naringenin (0.18%) and cirsimaritin (1.16%) were obtained as bioactive constituents of the ethyl acetate crude extract. Acute toxicity was calculated to be LD₅₀ =?1000?mg/kg for the crude hexane extract, lower in comparison to the other extracts analyzed (LD₅₀ >?2000?mg/kg).

Discussion and conclusion: Our results suggest that L. graveolens exerts anxiolytic-like activity involving many kinds of constituents, mainly of the terpenoid and flavonoid nature. These results reinforce the potential use of this species in the therapy of anxiety.