Acute Administration In Mice Research Articles

Anxiolytic activity of Berberis aristata root extract in mice

BACKGROUND: Anxiety is a common emotional response in humans and it is one of most common psychiatric illnesses. Interest in herbal drugs is growing nowadays for the optimum treatment of anxiety. The aim of the present study was to explore the anxiolytic effect of berberine chloride (BER). MATERIALS AND METHODS: Elevated plus maze model was used to know its anxiolytic effect and possible mechanism on acute administration in mice. Six groups of mice with six in each group were used. Group I served as control group; Group II received diazepam (0.5 mg/kg); and Groups III, IV, and V received BER in doses of 2.5, 5, and 10 mg/kg, respectively. Group VI received BER 5 mg/kg after flumazenil 5 mg/kg. RESULTS: As compared to control, berberine chloride solution at all three doses 2.5 mg/kg (P CONCLUSION: Anxiolytics effect of berberine is comparable to diazepam, likely to be mediated by gamma-aminobutyric acid A – Cl− channel complex as effects of berberine were blocked by prior administration of flumazenil. Further studies are needed to identify the phytoconstituents of the berberine which mediated the observed anxiolytic effects.

Safety assessment of MEFAS: an innovative hybrid salt of mefloquine and artesunate for malaria treatment

Malaria is a global public health problem that causes approximately 445 000 deaths annually worldwide, especially in underdeveloped countries. Because of the high prevalence and mortality of the disease, new and less toxic therapeutic agents need to be developed, such as MEFAS, a low-cost hybrid salt that consists of artesunate and mefloquine. However, the efficacy of MEFAS has been systematically demonstrated, its safety requires further investigation. This study investigated the acute toxicity of MEFAS and its precursors, artesunate, and mefloquine. A total of 42 female Swiss mice were divided into seven groups (n = 6/group) that were treated orally by gavage with vehicle (filtered water, negative control), MEFAS (50, 500, and 1000 mg/kg), and 1:1 concentrations of artesunate + mefloquine (50, 500, and 1000 mg/kg). Clinical signs of toxicity were observed for 14 d after treatment. On day 15, the animals were weighed, deeply anesthetized with isoflurane, and euthanized for subsequent collection of the liver, spleen, and kidneys. The relative organ weights were determined, followed by histopathological analysis. Artesunate + mefloquine produced toxic effects compared with the negative control group, reflected by changes in clinical signs, relative organ weights, and histopathological alterations. In MEFAS-treated animals, no changes were observed compared with the negative control group. These findings demonstrate that MEFAS is safer than artesunate + mefloquine after acute administration in mice.

Chemical characterisation and toxicity assessment in vitro and in vivo of the hydroethanolic extract of Terminalia argentea Mart. leaves

Abstract Ethnopharmacological relevance Terminalia argentea Mart. (Combretaceae), known mainly as “capitao”, is a native tree, not endemic, that occurs in the Amazon, Caatinga, Cerrado and Atlantic Forest in Brazil. Leaf infusion is popularly mentioned by riverine communities that inhabit the microregion of Northern Araguaia (Mato Grosso, Brazil) for the treatment of gastric ulcer, bronchitis and haemorrhage. Considering the wide medicinal use, lack of studies that evaluate the safety of use and the scarcity of phytochemical studies of T. argentea leaves, this work was carried out with the objective of evaluating the toxicity of the hydroethanolic extract of the leaves of T. argentea Mart. (HETa) in experimental models in vivo and in vitro, as well as to advance the phytochemical analysis of HETa. Materials and methods HETa was prepared by macerating the leaf powder in hydroethanolic solution. Phytochemical characterisation was carried out by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and mass spectrometry through direct flow infusion coupled with electrospray ionization and ion-trap analyzer (DFI-ESI-IT-MS analyses) The contents of phenols, flavonoids and phytosterols were analysed by colorimetric methods. Cytotoxicity was assessed by the Alamar blue assay on Chinese hamster ovary epithelial cells (CHO-K1) and human gastric adenocarcinoma cells (AGS). In vitro genotoxicity of HETa (10, 30 or 100 μg/mL) was assessed by micronucleus (MN) and comet tests using CHO-K1 cells. The acute toxicity assessment was performed by oral administration of HETa in single dose Swiss mice (males and females) up to 2000 mg/kg and sub-chronic toxicity by daily oral administration of HETa (50, 200 and 800 mg/kg) in Wistar rats for 30 days. The parameters related to the clinical and toxicological observations were determined every 6 days and at the end of the treatment the blood was collected for biochemical and haematological analysis, and some organs were removed for macroscopic and histopathological analysis. Results Preliminary phytochemistry and TLC analysis of HETa revealed the presence of phenolic compounds (18.8%), flavonoids (10.8%), saponins, tannins and phytosterols (19%). The HPLC data revealed the presence of gallic acid, rutin, ellagic acid, catechin, quercetin and kaempferol. In the analysis by DFI-ESI-IT-MS, the presence of gallic acid, rutin, ellagic acid and quercetin was confirmed and identified caffeic acid, quinic acid, galloylmucic acid, quercetin xyloside, quercetin rhamnoside, quercetin glucoside, caffeoyl ellagic acid, quercetin galloyl xyloside, terminalin, quercetin galloyl glucose, corilagin, quercetin digalloyl xyloside, quercetin digalloyl glucoside, punicalin and punicalagin. HETa showed no cytotoxic effect on CHO-K1 and AGS cells. In the MN assay, HETa increased the number of MNs and nuclear buds (NBUDs) in binucleate cells at the three concentrations tested and the nucleoplasmic bridges (NPBs) number at 30 μg/mL. In the comet test, HETa (10 and 100 μg/mL) alone showed a genotoxic effect on CHO-K1 cells. In pre-treatment, HETa at all concentrations tested prevented DNA damage induced by H2O2. In co-treatment with H2O2, HETa showed genotoxic effects at the three concentrations, and post-treatment DNA damage in exposed CHO-K1 cells to H2O2 was repaired in 22.5% with 10 μg/mL HETa. In the acute toxicity test, the HETa did not cause death in the mice, being verified only by piloerection and reversible in 2 h in males and in 4 days in females. No macroscopic changes were observed in the analysed organs. In the sub-chronic toxicity test, the HETa did not cause death in the rats after 30 days and the few changes were: absolute (103/mm3) and relative (%) values of basophils increased by 477.8% and 423% (p Conclusions The results demonstrated that HETa had no cytotoxic in vitro effects for CHO-K1 and AGS cells. In in vitro genotoxicity assays, the HETa induced different responses, according to concentration and experimental condition. In the MN test the HETa presented genotoxic potential by increasing the number of MNs, NBUDs and NPBs. In the comet assay, HETa was genotoxic by itself and in the co-treatment protocol with H2O2. In pre-treatment or post-treatment protocols with H2O2, HETa presented an antigenotoxic effect by preventing or repairing, respectively, the genotoxicity induced by H2O2. In the in vivo models, HETa was shown to be relatively safe after acute administration in mice [no-observed-adverse effect level (NOAEL) of 2000 mg/kg] and sub-chronic in rats (NOAEL of 800 mg/kg), confirming the riverine information that it is non-toxic in the dosage used. Phytochemical analysis of HETa revealed the presence of phenolic compounds, flavonoids, saponins, tannins and phytosterols. Among the flavonoids and tannins, we highlight gallic acid, rutin, ellagic acid, quercetin, caffeic acid, quinic acid, corilagin, punicalin and punicalagin. Thus, it can be stated that HETa has a good safety margin for therapeutic use.

Skeletal muscle relaxant effect of a standardized extract of Valeriana officinalis L. after acute administration in mice

Valeriana officinalis L. root extracts are traditionally taken for their sedative and anxiolytic properties and are also used for muscle relaxation. Relaxant effects were clearly observed on smooth muscle whereas data on effects on skeletal muscle are scarce and inconsistent. The aim of this study was to assess whether a standardized extract (SE) of V. officinalis had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone in mice. Mice received an acute dose of V. officinalis SE (2 or 5 g/kg per os) or tetrazepam (10 mg/kg ip), a standard myorelaxant drug. Thirty minutes later, the maximal muscle strength was measured using a grip test, while global skeletal muscle function (endurance and neuromuscular tone) was assessed in a wire hanging test. Compared to tetrazepam, both doses of V. officinalis SE induced a pronounced decrease in skeletal muscle strength without any significant effects on endurance and neuromuscular tone. This study provides clear evidence that the extract of V. officinalis tested has a relaxant effect on skeletal muscle. By decreasing skeletal muscle strength without impacting endurance and neuromuscular tone, V. officinalis SE could induce less undesirable side effects than standard myorelaxant agents, and be particularly useful for avoiding falls in the elderly.

“Curcumin-loaded Poly (d, l-lactide-co-glycolide) nanovesicles induce antinociceptive effects and reduce pronociceptive cytokine and BDNF release in spinal cord after acute administration in mice”

Given the poor bioavailability of curcumin, its antinociceptive effects are produced after chronic intravenous administration of high doses, while poly (d,l-lactide-co-glycolide)-loaded vesicles (PLGA) can improve drug delivery. This paper investigates the antinociceptive effects of curcumin-loaded PLGA nanovesicles (PLGA-CUR) administered via intravenous (i.v.) or intrathecal (i.t.) routes at low and high doses. The following models of pain were used: formalin test, zymosan-induced hyperalgesia and sciatic nerve ligation inducing neuropathic allodynia and hyperalgesia. PLGA-CUR administered intravenously was able to reduce the response to nociceptive stimuli in the formalin test and hyperalgesia induced by zymosan. Curcumin, instead, was inactive. Low-dose i.t. administration of PLGA-CUR significantly reduced allodynia produced by sciatic nerve ligation, whereas low doses of curcumin did not change the response to nociceptive stimuli. Long-lasting antinociceptive effects were observed when high doses of PLGA-CUR were administered intrathecally. At high doses, i.t. administration of curcumin only exerted rapid and transient antinociceptive effects. Measurement of cytokine and BDNF in the spinal cord of neuropathic mice demonstrate that the antinociceptive effects of PLGA-CUR depend on the reduction in cytokine release and BDNF in the spinal cord. The results demonstrate the effectiveness of PLGA-CUR and suggest that PLGA-CUR nanoformulation might be a new potential drug in the treatment of pain.

Antianxiety Activity of Fractions and Isolated Compounds of Verbena officinalis Aerial Parts

Verbena officinalis L. (Vervain; family-Verbenaceae) has long been used in the treatment of mental disorders, but not validated systemically for traditional claims. The ethyl acetate fraction (rich in flavonoids) of V. officinalis aerial parts was subjected to bioactivity-guided fractionation to isolate main chemical constituents responsible for antianxiety activity. The column chromatography of ethyl acetate fraction yielded five fractions F1-F5, which were screened for antianxiety activity employing elevated plus maze model. F2 produced significant antianxiety activity at the dose of 16 mg/kg, p.o., upon acute administration in mice. F2 was also subjected to column chromatography, and yielded four sub fractions (F2.1 F2.4). Upon acute oral administration of sub fractions, antianxiety activity was evaluated. Only F2.3 exhibited significant antianxiety activity, which was statistically equivalent to the standard drug (Diazepam, 2 mg/kg, p.o.). Three compounds (VO-1, VO-2 and VO-3) were isolated during the process of fractionation of bioactive fraction and sub fraction. After antianxiety evaluation of compounds, it was observed that VO-2 and VO-3 exhibit antianxiety activity.

Screening of Antianxiety Activity of Extracts and Fractions of Verbena officinalis Aerial Parts

Verbena officinalis L. (Vervain; family-Verbenaceae) has been traditionally used in the treatment of various ailments especially in mental disorders, but no systematic work has been carried out to validate traditional claims of plant. Therefore, it was planned to screen antianxiety activity of extracts and fractions of V. officinalis aerial parts. Crude extracts of V. officinalis aerial parts were prepared by extracting the plant material successively with n-hexane, chloroform, methanol and water. The antianxiety activity of crude extracts was performed at the doses of 200 or 400 mg/kg, p.o., upon acute administration in mice using elevated plus maze model. The bioactive extract was partitioned using ethyl acetate, and ethyl acetate fraction (50 or 100 mg/kg, p.o.) and remaining bioactive extract (150 or 300 mg/kg, p.o.) were also screened for antianxiety activity. The statistical significance was checked by comparing with standard drug and control using one way analysis of variance (ANOVA), which was followed by post hoc analysis – StudentNewman-Keul’s test. The methanol extract and ethyl acetate fraction exhibited significant antianxiety activity at the dose of 400 mg/kg and 100 mg/kg, respectively, with respect to control and statistically equivalent to the standard drug (Diazepam, 2 mg/kg, p.o.). The bioactive ethyl acetate fraction is rich in phenolic compounds and flavonoids. Finally, it is concluded that these are major anxiolytic constituents of V. officinalis.

SCREENING OF ANTICONVULSANT ACTIVITY OF VISCUM ALBUM L. AND ESTIMATION OF HESPERITIN IN PLANT USING TLC DENSITOMETRY

Viscum album L. (Ujjral; family – Viscaceae) has long tradition of use as anticonvulsant, but traditional claims of the plant have not been validated scientifically. Therefore, it was envisaged to subject V. album extracts and fractions for screening anticonvulsant activity. Various extracts of V. album aerial parts were screened for anticonvulsant activity at doses of 200 or 400 mg/kg, p.o., upon acute administration in mice using maximal electroshock test. The bioactive extract was partitioned successively to obtain n-hexane fraction (HF), ethyl acetate fraction (EAF) and 1-butanol fraction (BF), which were also screened for anticonvulsant activity at the doses of 25 or 50 mg/kg, p.o. The methanol extract, EAF and BF significantly abolished duration of tonic extension in mice with respect to control. The content of bioactive principle of V. album aerial parts i.e. hesperitin was estimated using validated TLC densitometric method, and was found to be 0.00210% w/w.

Screening of antidepressant activity and estimation of quercetin from Coccinia indica using TLC densitometry

Context: Coccinia indica Naud (Cucurbitaceae) has been traditionally used for the treatment of depression but these claims have not been validated.Objectives: The objective of this study is to investigate antidepressant activity of various extracts and fractions of C. indica aerial parts, and to estimate content of quercetin in the plant using TLC densitometry.Materials and methods: Coccinia indica aerial parts were successively extracted using solvents in increasing order of polarity, namely n-hexane, chloroform, methanol, and water. Various extracts were evaluated for antidepressant activity at doses of 200 or 400 mg/kg, p.o., upon acute administration in mice using the forced swim test (FST). The bioactive extract was partitioned successively using solvents in increasing order of polarity, namely n-hexane, ethyl acetate, and n-butanol. All fractions were also screened for antidepressant activity at doses of 25 or 50 mg/kg, p.o., upon acute administration in mice.Results: The methanol extract significantly reduced the duration of immobility in FST at dose of 400 mg/kg without affecting locomotor activity in open field test, thus, confirmed its antidepressant activity, which was statistically equivalent to the standard drug (imipramine, 15 mg/kg, i.p.). Ethyl acetate fraction (EAF) exhibited antidepressant activity at 50 mg/kg. Comparative TLC fingerprint studies confirmed the presence of quercetin in methanol extract and EAF. Quercetin was used as a chemical marker to standardize C. indica aerial parts using the validated TLC densitometric method, and the content of quercetin was found to be 0.00172% w/w.Conclusions: The present studies scientifically validated traditional claims of C. indica for antidepressant activity.

Synthesis and immunological activities of novel Toll-like receptor 7 and 8 agonists

Single-stranded oligoribonucleotides (ORNs) stimulate innate immune responses through TLR7 and TLR8. Specific linkages and chemical modifications incorporated into synthetic ORN can greatly enhance nuclease stability, selectivity, and potency. In the present study, we have synthesized 15 ORN containing different sequence compositions and chemical modifications and studied their TLR7- and TLR8-mediated immune response profiles in HEK293 cells expressing human TLR7 or TLR8, human PBMCs, mDCs and pDCs, non-human primate (NHP) PBMCs, and in vivo in mice and NHPs. Based on the results obtained, eight of the ORNs containing specific chemical modifications induced immune responses through both TLR7 and TLR8, including activation of NF-κB in TLR7- and TLR8-transfected cell lines; induction of IFN-α, IL-6, TNF-α, IL-12, and IP-10 in human PBMCs; IFN-α induction in human pDCs; CD80 upregulation in human pDCs and mDCs; IL-12 induction following acute administration in mice; IFN-α, IP-10, IL-6, and IL-12 induction in NHP PBMCs; and IFN-α, IP-10, and IL-6 induction following acute administration in NHPs. Seven of the ORNs show selectivity for TLR8-induced responses; they specifically activate only TLR8-transfected cell lines, induce cytokines other than IFN-α in human and NHP PBMCs, activate mDCs more than pDCs, and do not induce IL-12 acutely in mice, consistent with the lack of functional TLR8 in mice. The novel TLR8-selective ORNs also induce cytokines other than IFN-α acutely in NHPs. In conclusion, we have designed and synthesized novel ORNs with varying sequence compositions and chemical modifications, which selectively act as agonists of TLR8 or dual agonists of TLR7 and TLR8.

On the mechanism of antidepressant-like action of berberine chloride

Berberine, an alkaloid isolated from Berberis aristata Linn. has been used in the Indian system of medicines as a stomachic, bitter tonic, antiamoebic and also in the treatment of oriental sores. Evidences have demonstrated that berberine possesses central nervous system activities, particularly the ability to inhibit monoamine oxidase-A, an enzyme involved in the degradation of norepinephrine and serotonin (5-HT). With this background, the present study was carried out to elucidate the antidepressant-like effect of berberine chloride in different behavioural paradigms of despair. Berberine (5, 10, 20 mg/kg, i.p.) inhibited the immobility period in mice in both forced swim and tail-suspension test, however, the effect was not dose-dependent. Berberine (5 and 10 mg/kg, i.p.) also reversed the reserpine-induced behavioral despair. Berberine (5 mg/kg, i.p.) enhanced the anti-immobility effect of subeffective doses of various typical but not atypical antidepressant drugs in forced swim test. Berberine (5 mg/kg, i.p.) following its acute administration in mice resulted in increased levels of norepinephrine (31%), serotonin (47%) and dopamine (31%) in the whole brain. Chronic administration of berberine (5 mg/kg, i.p.) for 15 days significantly increased the levels of norepinephrine (29%), serotonin (19%) as well as dopamine (52%) but at higher dose (10 mg/kg, i.p.), there was no change in the norepinephrine (12%) levels but a significant increase in the serotonin (53%) and dopamine (31%) levels was found. The antidepressant-like effect of berberine (5 mg/kg, i.p.) in forced swim test was prevented by pretreatment with l-arginine (750 mg/kg, i.p.) or sildenafil (5 mg/kg, i.p.). On the contrary, pretreatment of mice with 7-nitroindazole (7-NI) (25 mg/kg, i.p.) or methylene blue (10 mg/kg, i.p.) potentiated the effect of berberine (2 mg/kg, i.p.) in the forced swim test. Pretreatment of mice with (+)-pentazocine (2.5 mg/kg, i.p.), a high-affinity sigma1 receptor agonist, produced synergism with subeffective dose of berberine (2 mg/kg, i.p.). Pretreatment with various sigma receptor antagonists viz. progesterone (10 mg/kg, s.c.), rimcazole (5 mg/kg, i.p.) and N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine (BD1047; 1 mg/kg, i.p.) reversed the anti-immobility effects of berberine (5 mg/kg, i.p.). Berberine at lower dose did not affect the locomotor activity and barbiturate-induced sleep time. It produced mild hypothermic action in rats and displayed analgesic effect in mice. Taken together, theses findings demonstrate that berberine exerted antidepressant-like effect in various behavioural paradigms of despair possibly by modulating brain biogenic amines (norepinephrine, serotonin and dopamine). Further, nitric oxide pathway and/or sigma receptors are involved in mediating its antidepressant-like activity in mouse forced swim test.

Anxiolytic properties of green tea polyphenol (−)-epigallocatechin gallate (EGCG)

Naturally occurring polyphenols are potent antioxidants. Some of these compounds are also ligands for the GABA A receptor benzodiazepine site. This feature endows them with sedative properties. Here, the anxiolytic activity of the green tea polyphenol (−)-epigallocatechin gallate (EGCG) was investigated after acute administration in mice, using behavioral tests (elevated plus-maze and passive avoidance tests) and by electrophysiology on cultured hippocampal neurons. Patch-clamp experiments revealed that EGCG (1–10 μM) had no effect on GABA currents. However, EGCG reversed GABA A receptor negative modulator methyl β-carboline-3-carboxylate (β-CCM) inhibition on GABA currents in a concentration dependent manner. This was also observed at the level of synaptic GABA A receptors by recording spontaneous inhibitory synaptic transmission. In addition, EGCG consistently inhibited spontaneous excitatory synaptic transmission. Behavioral tests indicated that EGCG exerted both anxiolytic and amnesic effects just like the benzodiazepine drug, chlordiazepoxide. Indeed, EGCG in a dose-dependent manner both increased the time spent in open arms of the plus-maze and decreased the step-down latency in the passive avoidance test. GABA A negative modulator β-CCM antagonized EGCG-induced amnesia. Finally, state-dependent learning was observable after chlordiazepoxide and EGCG administration using a modified passive avoidance procedure. Optimal retention was observed only when animals were trained and tested in the same state (veh–veh or drug–drug) and significant retrieval alteration was observed in different states (veh–drug or drug–veh). Moreover, EGCG and chlordiazepoxide fully generalized in substitution studies, indicating that they induced indistinguishable chemical states for the brain. Therefore, our data support that EGCG can induce anxiolytic activity which could result from an interaction with GABA A receptors.