جستجوی مقالات مرتبط با کلیدواژه "lethal dose 50" در نشریات گروه "پزشکی"

The natural origin of medicinal plants does not guarantee their safety, as there are no sufficient studies on the safety, efficacy, and toxicity to support their benefit claims.

This study aimed at investigating the oral acute toxicity of Adansonia digitata L. (A. digitata) fruit shell extract in mice.

The maceration method was employed for the extraction of the A. digitata fruit shell using methanol. The extract was then screened for its phytochemical constituents both qualitatively and quantitatively. Lorke’s method was followed for the toxicity study, and the mice were observed for clinical signs of toxicity and mortality. Further, serum was analyzed for liver and kidney function biomarkers besides the histology of the liver, kidney, and cerebellum.

No single death was recorded and no sign of toxicity persisted for more than 2 hours post-administration to the extracts up to 5000 mg/kg. Therefore, the - of A. digitata fruit shell is above 5000 mg/kg. Additionally, no changes were observed in the weights as well as the relative organ weight of the mice. Further, no statistically significant changes were seen in their liver and kidney function biomarkers, besides the relatively intact histological appearance of their liver, kidney, and cerebellum.

The oral acute toxicity of methanol extract of A. digitata fruit shell is above 5000 mg/kg; hence, it is relatively safe to use it for medicinal purposes. However, a longer study duration is recommended to evaluate its toxic effects on fertility, teratogenicity, and carcinogenic potentials.  

To study the anticancer activity of Plantago major, we assessed the effect of ethanolic, methanolic and acetonic extracts of this plant on HCT-116, SW-480, and HEK-293 cell lines as control.

The cytotoxic activity, biocompatibility, and toxicity were evaluated by MTT assay, hemolysis, and Artemia salina-LD50 (on mice) tests, respectively. The analysis of the extracts of compounds was performed by GC-MS analysis.

The results showed that all the extracts had the most antiproliferative properties on the HCT-116 cell line. The root extract of P. major was more effective than the aerial parts, and IC50 values of ethanolic, methanolic and acetonic root extracts were 405.59, 470.16, and 82.26 µg/mL, respectively on HCT-116 cell line at 72 h. Hemolysis degree of the ethanolic extract of P. major aerial and root parts were approximately 1% at 400 μg/mL. No significant interference of the RBC was observed. The ethanolic extracts, the Artemia survived every concentration used, and no toxicity was observed. One week after the oral administration of different parts of P. major extracts, none of the mice died, even those were preserved with 2000 mg/kg. These results of GC/MS analysis showed that P. major extracts contain potential anticancer compounds, such as stearic acid (8.61%) in aerial parts of methanolic extract and 1,2- Benzenedicarboxylic acid, mono(2-ethylhexyl)ester (88.07% and 40.63%) in aerial and root parts of acetonic extract of P. major.

Our findings suggest that the P. major is a source of important pharmaceutical compounds with antiproliferative properties.

The antiviral property of aqueous garlic extract against a virulent velogenic field isolate of Newcastle disease virus (NDV) was investigated in a time of addition assay in embryonated chicken eggs (ECEs).

The ECEs were inoculated with the lowest concentration of the virus with HA (haemagglutination) positive activity. After determination of extract toxicity in ECEs, administration of different concentrations of the extract (0.5, 1, 2, 4 mg/mL) or ribavirin (comparative control) was performed 8 hours before (pretreatment), simultaneously (cotreatment) or 8 hours after (post treatment) virus injection. Allantoic fluids were harvested for infectivity determination, transmission electron microscopy (TEM) and viral load (HA titer) assay. In vitro HA blocking activity test was also performed.

Allicin content of the extract was 16.6% by HPLC method. The best viability results were related to the extract in pretreatment and ribavirin in co-treatment trials (p<0.05 as compared to infected ECEs with no treatment). Pre and co-treatment assays showed better results on HA titer of garlic treated groups. In infectivity assay, the 50% embryo lethal dose (ELD50) values of NDV were roughly 500 and 50 folds of ELD50 of the untreated virus in pre and co-treatment, respectively. No change was observed in viral shapes in TEM analysis nor HA blocking activity in vitro.

Aqueous extract of garlic shows antiviral effects against a velogenic strain of NDV in ovo accompanied by a reduction in virus infectivity and titer. These effects are most pronounced in pretreatment trial.

Since heavy metals can accumulate in the tissues of aquatic organisms, they can cause a range of hazardous effects which can become harmful to humans. The aim of this study was to investigate the acute effects of some heavy metals as potential dangerous substances by assessing the mortality effects of Mercuric Chloride (HgCl2), Lead Chloride (PbCl2) and Zinc Sulfate (ZnSO4) pollutants on a freshwater fish, silver dollar (Metynnis fasciatus). Fish samples were exposed to different concentrations of mercuric chloride (HgCl2), lead chloride (Pbcl2) and zinc sulfate (ZnSO4) for 96h and their cumulative mortality was calculated in 24h intervals.Results were analyzed by SPSS 16 to obtain number of cumulative mortality and lethal concentrations (LC10-99). LC50-96h was 0.94±0.41ppm, 86.84±1.04ppm and 32.24±1.41ppm for mercuric chloride, lead chloride and zinc sulfate, respectively. So, mercury had the highest toxicity to silver dollar fish. Mercuric chloride and lead chloride has the lowest and highest rate of mortality among these tree metals on silver dollar fish; however, the mortality rate was increased with increasing concentrations of toxins with time.

Clostridium perfringens is one of the most important pathogen in human and animals and protection against this bacteria in domestic animals will be only achieved by vaccination, otherwise, high mortality rate and great financial burden will be issued.. We aimed to evaluate the effects of C. perfringens Type D prototoxin and toxin on the mouse body weight.. After preparation of filtrate and freeze dried crude prototoxin, three series of experiments were set up. At the first step, minimal lethal dose per milliliter (MLD/mL) was determined and according to MLD, 50% endpoint (LD50) was determined. Finally, mice with 18 to 20 g body weight were injected with the different concentrations of activated freeze dried prototoxin.. Two days after injection, a decrease in body weight was observed while no decrease in body weight was observed in the control group. The results indicated that the activated C. perfringens culture filtrate temporarily inhibits mouse general metabolism.. As secreted prototoxin is activated in the small intestine of infected animals, vaccination of the domestic animals in the proper time by the appropriate vaccine could prevent these effects..

Iron, manganese, and aluminum are three abundant metals on earth and their concentrations have increased in aquatic environments as a result of natural and industrial activities. This study was undertaken to report the median acute toxicity (LC50) and accumulation of the sub-lethal concentration (10% 96-h LC50) of iron (Fe), manganese (Mn) and aluminum (Al) in kutum (Rutilus kutum) fingerlings. For the 96-h LC50, the fish were exposed to concentrations of 105, 111, 117, 123, 129 and 135 mg/l of Fe and 40, 45, 50, 55, 60, and 65 mg/l of Mn and 18, 22, 26, 30, 34 and 38 mg/l of aluminum for 4 days. For sublethal exposure, they were exposed to mediums with concentrations of 12.3, 5.4 and 2.9 for Fe, Mn, and aluminum, respectively. Metal concentrations were determined by atomic absorption spectrophotometry in the gill tissues. Probit analysis showed the 96-h LC50 values of 122.98, 54.39, and 28.89 mg/l for Fe, Mn, and aluminum, respectively. Sub-lethal tests were conducted with nominal concentrations of 12.3, 5.4, and 2.9 mg/l of Fe, Mn, and aluminum for four days, respectively. Significant accumulations were observed in gills for all tested metals as compared to the control groups in short-term exposure (P<0.05). Obtained results clearly show that aluminum is the most toxic metal among tested ones for kutum fingerlings and it has the highest branchial AF value during sub-lethal exposure.

The development of toxicity tests regarding toxic responses of different fish species could be more effectively used in predictive toxicology and risk assessment. In this study lethal concentrations (LC50-96 h) values of copper sulphate; an important toxic industrial pollutant, on Capoeta fusca were determined. Behavioral changes at different concentrations of CuSO4 were determined for the C.fusca. The sample fishes were collected from Qanat in Birjand and were transported to the laboratory in polythene bags. The exposure time of fish to CuSO4 was 96 hours. Mortalities were recorded at 24, 48, 72, and 96 hours of exposure, and the dead fish were removed regularly from the test aquariums. Physicochemical parameters, such as dissolved oxygen, pH and Total hardness of aquaria were monitored daily. The LC50 values for CuSO4 at 24, 48, 72, and 96 h of exposure, were 43.62, 12.6, 7.66, and 6.85 mg/L, respectively. The median LC50 value of CuSO4 for C.fusca was found to be 6.928 mg/L by EPA method and estimated to be 6.787 mg/L with SPSS statistical software. The mortality decreased with time, and most of the deaths occurred during the first 24 h. In addition, behavioural changes increased with increased concentration. This metal is an important constituent in industrial effluents discharged into freshwaters. The results obtained in this study clearly revealed the fact that it is necessary to control the use of a heavy metal such as copper.