In vivo assessment of genotoxic effects of Annona squamosa seed extract in rats

Widespread use of pesticides represents a potential risk to human and environmental health. Hence, biopesticides from plants are some of the future strategies for plant protection. In this regard, a seed extract of Annona squamosa was prepared and found to be a promising pesticide. In order to establish the inherent toxicity and non-target safety required for registration and marketing of pesticides, toxicological studies are conducted. The genotoxicity potential was evaluated in rats with 75, 150 and 300 mg/kg Annona squamosa by the comet assay in leucocytes, micronucleus and chromosomal aberration tests in bone marrow. We also studied the effects of 300 mg/kg of extract on lipid peroxidation, reduced glutathione level and glutathione S transferase activity in liver, lungs, brain, kidneys, heart and spleen of treated rats. The comet assay showed a statistically significant dose related increase in DNA migration. The micronucleus and chromosomal aberration tests revealed a significant induction in frequency of micronuclei and chromosomal aberrations at 150 and 300 mg/kg. Annona squamosa treatment significantly enhanced lipid peroxidation, decreased glutathione and glutathione S transferase levels revealing the oxidative stress condition. Our results warrant careful use of Annona squamosa seed extract as a biopesticide till more tests are carried out.     

Protective effect of aqueous Curry leaf (Murraya koenigii) extract against cadmium-induced oxidative stress in rat heart

Treatment of rats with a low dose of cadmium chloride caused a significant damage in the rat cardiac tissue indicated by the increase in the level of serum glutamate oxaloacetate transaminase and lactate dehydrogenase1 activities. Histological studies confirmed the damage due to cadmium. That cadmium-induced tissue damage was caused due to oxidative stress was evident from the changes observed in the levels of lipid peroxidation and reduced glutathione, the protein carbonyl content, and the alterations in the activities of cardiac antioxidant and pro-oxidant enzymes. Treatment of rats with cadmium also caused alterations in the activities of mitochondrial Kreb’s cycle as well as respiratory chain enzymes. All these changes were ameliorated when the rats were pre-treated with an aqueous extract of Curry leaf (Murraya koenigii). The studies indicated that the aqueous extract of Curry leaf protects the rat cardiac tissue against cadmium-induced oxidative stress possibly through its antioxidant activity. As curry leaf is consumed by people as part of their diet in India and South-East Asian and some European countries as well, and, as it has no reported side-effects, the results seem to have relevance at places where humans are exposed to cadmium environmentally or occupationally.     

Protective effects of vitamin E and C on cisplatin nephrotoxicity in developing rats

The kinetics of vitamin E was followed in serum, liver and kidney of 10- and 55-day-old rats after the administration of a single i.m. dose of 100 mg α-tocopherol acetate/100 g body wt. The basal levels without vitamin E administration were significantly higher in serum and liver of 10- than 55-day-old rats. The effect of vitamin E on cisplatin (CP; 0.6 mg/100 g body wt., i.p.) nephrotoxicity was investigated by determining urinary volume and protein excretion, as well as the concentration of blood urea nitrogen (BUN) and lipid peroxides in renal tissue (LPO). Previously described age differences in CP nephrotoxicity were confirmed. The administration of vitamin E, 12 h prior to CP, diminished the toxic effect of CP in young and adult rats. This effect could not be enhanced by a second administration of vitamin E. The simultaneous administration of vitamin E and C 12 h prior to CP intensified the protective effect of a single administration of vitamin E in 10- and 55-day-old rats without influencing the concentration of platinum in renal tissue. Received: 10 April 1997 / Accepted: 10 June 1997     

Allicin from garlic neutralizes the hemolytic activity of intra- and extra-cellular pneumolysin O in vitro

Pneumolysin (PLY) is a key virulence factor contributes to the pathogenesis of Streptococcus pneumoniae. In this study we investigated the effect of allicin and aqueous garlic extracts on hemolytic activity of PLY both in prelysed and intact cells. Additionally the antimicrobial activity of allicin was tested against the bacteria. All tested materials potently inhibited the PLY hemolytic activity. Allicin neutralizes PLY in a concentration- and time-dependent manner. Twenty five minute incubation of PLY (2 HU/mL) with 0.61 μM/mL concentration of allicin, totally inhibited hemolytic activity of PLY (IC50 = 0.28 μM/mL). The inhibitory activity of old extract of garlic was similar to pure allicin (IC50 = 50.46 μL/mL; 0.31 μM/mL; P < 0.05). In contrast fresh extract of garlic inhibits the PLY hemolytic activity at lower concentrations (IC50 = 13.96 μL/mL; 0.08 μM/mL allicin). Exposure of intact cells to allicin (1.8 μM) completely inhibited hemolytic activity of PLY inside bacterial cells. The inhibitory effect of the allicin was restored by addition of reducing agent DTT at 5 mM, proposing that allicin likely inhibits the PLY by binding to cysteinyl residue in the binding site. The MIC value of allicin was determined to be 512 μg/mL (3.15 μM/mL). These results indicate that PLY is a novel target for allicin and may provide a new line of investigation on pneumococcal diseases in the future.     

Reduction of teratogenic effects of ethylenethiourea in rats by interaction with sodium nitrite in vivo

Nitrites are present in a wide variety of foods and their daily intake in man has been estimated at 1·5 mg. Ethylenethiourea (ETU), a major food contaminant resulting from degradation of ethylenebisdithiocarbamate fungicides, is a potent rat teratogen. The co-administration of ETU (60 or 40 mg/kg) and NaNO₂ (80 mg/kg) to rats by gavage on day 15 of gestation resulted in a higher survival of progeny than occurred with the corresponding dose of ETU alone. In a second study, ETU (60 mg/kg) and NaNO₂ (80, 100 or 120 mg/kg) were administered, either individually or in combination, as a single dose on day 13 of gestation. Administered alone, NaNO₂ did not produce any teratogenic response in full-term foetuses, whereas ETU produced a high incidence of various anomalies. However, the combined dosing resulted in the elimination of almost all the anomalies. The reducing effect of NaNO₂ on ETU-induced malformations was reversed when the animals were pretreated with 200 mg ascorbic acid/kg or 360 mg sodium ascorbate/kg. Since both of these are well-known inhibitors of N-nitrosation reactions, it was presumed that the simultaneous oral dosing of ETU and NaNO₂ resulted in the formation of N-nitrosoethylenethiourea.     

Estrogenic/antiestrogenic activities of a Epimedium koreanum extract and its major components: in vitro and in vivo studies

The estrogenic and antiestrogenic activities of Epimedii Herba, which is a traditional medicinal herb used in Korea and China were investigated in this study. The in vitro estrogen receptor (ER) mediated estrogenic/antiestrogenic activities of an Epimedii Herba extract (Epi ext) and its major components were determined using an estrogen responsive element driven reporter gene assay in MCF-7/ERE and HEK293T cells. The Epi ext exhibited ERα- and ERβ-mediated estrogenic activity with an EC₅₀ of 5.0 and 17.8 μM in HEK293T cells, respectively. Prenylflavonoid glycosides such as icariin (ICA), epimedin A, B, and C did not show any in vitro estrogenic or antiestrogenic activities. Icaritin (ICT) and quercetin exhibited in vitro ER mediated estrogenic activity with a more potent interaction with ERβ. In vivo estrogenic activities of the Epi ext, ICA and ICT were compared using an uterotrophic assay. Although the potency of in vitro estrogenic activity was in the order of ICT > Epi ext > ICA, ICA had the strongest estrogenic activity and next ICT in ovariectomized rats. These results collectively suggest that phytoestrogens possess both estrogenic and antiestrogenic activity, and that the differential expression of these two compounds with opposing activities is dependent on the physiological environment in terms of estrogen level, which may be the case in humans.     

Barrier protective effects of rutin in LPS-induced inflammation in vitro and in vivo

Rutin, an active flavonoid compound, is well known to possess potent antiplatelet, antiviral and antihypertensive properties. In this study, we first investigated the possible barrier protective effects of rutin against pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) induced by lipopolysaccharide (LPS) and the associated signaling pathways. The barrier protective activities of rutin were determined by measuring permeability, monocytes adhesion and migration, and activation of pro-inflammatory proteins in LPS-activated HUVECs. We found that rutin inhibited LPS-induced barrier disruption, expression of cell adhesion molecules (CAMs) and adhesion/transendothelial migration of monocytes to human endothelial cells. Rutin also suppressed acetic acid induced-hyperpermeability and carboxymethylcellulose-induced leukocytes migration in vivo. Further studies revealed that rutin suppressed the production of tumor necrosis factor-α (TNF-α) and activation of nuclear factor-κB (NF-κB) by LPS. Collectively, these results suggest that rutin protects vascular barrier integrity by inhibiting hyperpermeability, expression of CAMs, adhesion and migration of leukocytes, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases.     

Evaluation of the adjuvant effect of silver nanoparticles both in vitro and in vivo

The immunological adjuvant effect of silver nanoparticles (AgNPs) was investigated both in vitro and in vivo. The in vivo adjuvant effect of AgNPs was evaluated with model antigen ovalbumin (OVA) and bovine serum albumin (BSA) in mice by intraperitoneal and subcutaneous immunization. Serum antigen-specific IgG level significantly increased in AgNPs-treated mice comparing to the control group. AgNPs induced the increase of IgG1/IgG2a ratio and antigen-specific IgE, indicating that AgNPs elicited Th2-biased immune responses. By in vitro assay, the mechanism of adjuvant effect was explored. After 48 h treatment with AgNPs, both the number of leukocytes and levels of cytokines TNF-α and IFN-γ in abdominal lavage fluid of mice increased. The expression of the major histocompatibility complex class II molecule on the surface of peritoneal macrophages significantly increased. AgNPs can be easily phagocytosed by peritoneal macrophages, while do not affect antigen uptake by the cell. We therefore conclude that AgNPs have significant adjuvant effect and the mechanism of this effect is mainly ascribed to the recruitment and activation of local leukocytes and especially macrophages. For the first time we found the remarkable adjuvant effect of AgNPs, and the result is beneficial for the future applications, especially in biomedicine.     

In vitro and in vivo studies on some toxic effects of the venom from Hemiscorpious lepturus scorpion

The aim of this laboratory-based study was to investigate some of the toxic effects induced by the venom from Hemiscorpious lepturus (H. lepturus). For this aim, pharmacological, histological, biochemical methods as well as complete blood cell count were used to assess these toxic actions. In addition, in vitro haemolysis studies on human washed blood suspension and cytotoxicity on cultured fibroblasts were also undertaken. In vitro pharmacological test was made on rat isolated ileal segment. To this end, the effects of the venom on the contractile responsiveness to acetylcholine were recorded using F30 transducer and Darco chart recorder. For assessment of the haemolytic potency, varying concentrations (2, 10, 20 and 40 μg/ml) of the venom were added to 0.5 ml of 5% washed human blood and after 30 min, 2, 4, 8, 12 and 24 h of exposure, the degree of lysis (extent of redness developed in the supernatant solution after centrifugation) were measured by ELISA method. Cytotoxicity potential of the venom was assessed by trypan blue exclusion test. The venom (0.1, 1 and 10 μg/ml) was mixed with confluent fibroblast cell culture and the extent cytotoxicity was assessed microscopically. In vivo studies were conducted by a subcutaneous administration of sub-lethal dose (10 μg) of the venom and after 7 days the skin, at the site of injection, and kidney samples were stained by H & E method and examined microscopically. In addition, biochemical assessments including measurement of serum aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and amylase levels and urine analysis were made. The results showed that the venom prevented the relaxation phase of the acetylcholine-induced contractions on the isolated ileal segments and finally produced sustained spasmodic contractions. This spasmodic action was abolished by 1 μM atropine. The venom produced haemolysis of red blood cells in a concentration-dependent and duration-of-exposure manner, with 100% of haemolysis produced after 24 h following exposure to 40 μg/ml of venom. While cultured fibroblasts cells were more sensitive and disintegrated after 15 min of exposure to 1 μg/ml of the venom. Histological findings showed evidences of excessive inflammatory responses accompanied with signs of necrosis in the skin at the site of injection as well as structural damage in the nephrones. There was a significant rise in the serum enzymes. In addition, the number of the RBCs were reduced. The urine showed positive readings for proteinuria, blood and intact RBCs. The overall results suggest that the venom from H. lepturus primarily is a cytotoxic agent and has haemolytic, nephrotoxic and to some extent hepatotoxic activity.     

In vitro and in vivo hepatoprotective effects of the aqueous extract from Taraxacum officinale (dandelion) root against alcohol-induced oxidative stress

The protective effects of Taraxacum officinale (dandelion) root against alcoholic liver damage were investigated in HepG2/2E1 cells and ICR mice. When an increase in the production of reactive oxygen species was induced by 300 mM ethanol in vitro, cell viability was drastically decreased by 39%. However, in the presence of hot water extract (TOH) from T. officinale root, no hepatocytic damage was observed in the cells treated with ethanol, while ethanol-extract (TOE) did not show potent hepatoprotective activity. Mice, which received TOH (1 g/kg bw/day) with ethanol revealed complete prevention of alcohol-induced hepatotoxicity as evidenced by the significant reductions of serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase activities compared to ethanol-alone administered mice. When compared to the ethanol-alone treated group, the mice receiving ethanol plus TOH exhibited significant increases in hepatic antioxidant activities, including catalase, glutathione-S-transferase, glutathione peroxidase, glutathione reductase, and glutathione. Furthermore, the amelioration of malondialdehyde levels indicated TOH’s protective effects against liver damage mediated by alcohol in vivo. These results suggest that the aqueous extract of T. officinale root has protective action against alcohol-induced toxicity in the liver by elevating antioxidative potentials and decreasing lipid peroxidation.     

Mitigative role of garlic and vitamin E against cytotoxic,genotoxic, and apoptotic effects of lead acetate and mercury chloride on WI-38 cells

Background

Lead acetate (Led) and mercury chloride (Mer) represent important ecological and public health concerns due to their hazardous toxicities. Naturally found products play a vital role in chemopreventive agent innovation. The current study aimed to assess the modifying effect of garlic (Gar) and/or vitamin E (Vit E) against the half-maximal inhibitory concentration (IC50) Led and/or Mer-induced cytotoxic, genotoxic and apoptotic effects.

The effect of cimetidine on in vitro and in vivo microsomal drug metabolism in the rat

The effect of cimetidine on rat liver microsomal drug metabolism in vitro and in vivo was studied. Cimetidine inhibits aminopyrine N-demethylation and benzo[a]pyrene hydroxylation in a noncompetitive manner with inhibition constants between 1 and 10 mM. Benzo[a]pyrene hydroxylation in liver microsomes from 3-methylcholanthrene-pretreated rats is not appreciably inhibited by cimetidine indicating some specificity in terms of different cytochrome P-450 forms. Cimetidine gives rise to a type II spectral change with a spectral dissociation constant of about 0.1 mM. The prolonged administration of cimetidine does not result in the induction of hepatic drug metabolism. Pretreatment of rats with cimetidine prolongs aminopyrine half-life and hexobarbital sleeping time. These results demonstrate that cimetidine is an in vitro inhibitor of microsomal drug metabolism in the rat and this inhibition leads to pharmacokinetic drug-drug interactions in vivo.     

AZT dilates rat cardiac intercalated discs, and the effect is prevented by vitamin C

We investigated whether chronic zidovudine (AZT) administration in rats could impair cardiac function by affecting intercellular junctions and whether vitamin C could prevent these possible effects. Rats were treated for 8 months with AZT, vitamin C, and AZT plus vitamin C. Cardiac fractional shortening (FS) was assessed by echocardiographic examination, intercellular junctions morphology was detected by electron microscopy (EM) and immunocytochemistry (ICC). AZT-treated rats showed a reduced FS that was not prevented by vitamin C. EM revealed that AZT treatment did not affect coronary endothelial intercellular junctions whereas it caused an enlargement of fascia adherens of the intercalated discs that was prevented by vitamin C. AZT treatment did not induce either alterations of gap junctions morphology or distribution of connexin-43, the major protein expressed in the gap junctions. We conclude that AZT treatment may be potentially deleterious to the heart by inducing a ROS-mediated damage of cardiac intercalated discs.     

The ameliorating effects of selenium and vitamin C against fenitrothion-induced blood toxicity in Wistar rats

Fenitrothion is widely used organophosphate pesticide in agriculture and health programs, but besides, it causes several toxic effects. The present study was designed to evaluate the possible protective effects of selenium (0.5 mg/kg b.w.) and vitamin C (100 mg/kg b.w) on altered haematological, biochemical and oxidative stress parameters in the blood of rats orally treated with fenitrothion (20 mg/kg b.w) for 30 days. Fenitrothion caused changes in body weight, food and water intake, and some haematological and biochemical parameters. Fenitrothion altered the glutathione redox status (GSH and GSSG) and decreased activity of antioxidant enzymes (GSH-Px, GST, SOD and CAT), leading to a lipid peroxidation. Selenium and vitamin C, by improving the activity of antioxidants, reduced oxidative stress and a lipid peroxidation, maintaining the values of examined parameters to optimal levels. Therefore, selenium and vitamin C could be useful in providing protection of exposed non-target organisms including people from fenitrothion.     

Stability of nitrosoacetoxymethylmethylamine in in vitro systems and in vivo and its excretion by the rat organism

The stability of the carcinogen nitrosoacetoxymethylmethylamine (NAMM) was determined in water, serum and blood as well as in an in vivo assay. The half lifes of NAMM in the different media show that the dominant enzymatic degradation occurs within a few seconds after intravenous application. Nevertheless NAMM is stable enough for a passage through the body, which is also indicated by the determination of traces of NAMM in urine and exhalation air. This could explain the carcinogenesis of NAMM away from the application site.     

Protective effects of garlic powder against potassium dichromate-induced oxidative stress and nephrotoxicity.

Potassium dichromate (K(2)Cr(2)O(7))-induced nephrotoxicity is associated with oxidative stress. In the present work the effect of garlic powder, a recognized antioxidant, on K(2)Cr(2)O(7)-induced nephrotoxicity and oxidative stress was studied. Rats were fed a 2% garlic powder diet for 1 month. A single injection of K(2)Cr(2)O(7) (15 mg/kg) to rats induced tubule interstitial damage and an increase in the following markers of renal injury 2 days later: blood urea nitrogen (4.6-fold), serum creatinine (9.7-fold), proteinuria (35.9-fold), urinary excretion of N-acetyl-beta-d-glucosaminidase (12.9-fold) and glutathione-S-transferase (2.3-fold) and a decrease of 65% in serum glutathione peroxidase activity. In addition, K(2)Cr(2)O(7) injection increased the following nitrosative and oxidative stress markers in kidney: 3-nitrotyrosine (1.9-fold), 4-hydroxy-2-nonenal (2.1-fold), malondialdehyde (1.8-fold) and protein carbonyl content (1.7-fold). It was found that garlic powder feeding was able to prevent by 44-71% the alterations in the markers of renal injury studied, by 55% the histological damage, and by 47-100% the increase in markers of oxidative and nitrosative stress. It is concluded that the ability of garlic powder to ameliorate K(2)Cr(2)O(7)-induced renal injury is associated with its antioxidant properties. Our data support the use of garlic powder as a renoprotective agent.     

A study of anti-cancer effects of Funalia trogii in vitro and in vivo

Extracts of natural products have been used for many years for health benefits. We report on an in vitro and in vivo study into the anti-tumour efficacy of an aqueous extract of the mycelial form of basidiomycete, Funalia trogii. A variety of biological assays were used to show that a 4 h exposure of HT29, LNCaP, PC3, MCF-7 and MDA-MB-231 tumour cells to extract (0.5-5.0 mg/ml) resulted in significant cytotoxicity. In a clonogenic assay, IC₅₀ values were found to range from 0.4-0.72 mg/ml; exposing fibroblast cells to the extract resulted in no cell kill. The extract resulted in significant cell kill in proliferating endothelial cells but had no toxicity to quiescent cells, this is useful in targeting tumour tissue since endothelial cells in tumours proliferate more rapidly that those found in other parts of the body. When tumours grown in immune compromised mice were injected intratumourally with extract (5 mg/ml twice a week for two weeks), a 9 day tumour growth delay was observed. The results indicate that the mycelial extract of F. trogii has a promising anti-tumour property.     

In vivo and in vitro effects of bromoacetylcholine on rat brain acetylcholine levels and choline acetyltransferase activity

Intraventricular injection of bromoacetylcholine to rats did not lower brain acetylcholine levels, nor did it inhibit choline acetyltransferase activity. In vitro experiments indicated that bromoacetylcholine can penetrate intact neuronal tissue and inhibit choline acetyltransferase, but that in vivo it is most likely hydrolyzed by cholinesterase before it can exert any inhibitory action. For this reason bromoacetylcholine is unsuitable for in vivo inhibition of choline acetyltransferase.     

Effects of Areca catechu L. containing procyanidins on cyclooxygenase-2 expression in vitro and in vivo

Polyphenols are widely distributed in plants and known for antioxidant and anti-inflammatory properties. Areca nut, rich in polyphenols, is the major component of betel quid and we have previously shown that the extract of areca nut can induce oxidative stress in vitro. In this study, we have further pinpointed that areca nut extract (ANE) contains catechin based procyanidins which range from dimers to decamers and polymers; this was carried out by HPLC and electrospray ionization/mass spectrometry (ESI/MS). To quantify their antioxidant potential, oligomeric and polymeric procyanidins of ANE were separated and evaluated using the Trolox equivalent antioxidant capacity (TEAC) assay. The results clearly demonstrated that the antioxidant capacity of the ANE procyanidins increased with the degree of polymerization. The anti-inflammatory potential of ANE was also tested using 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated human oral cancer SAS cells. ANE inhibited TPA-induced cyclooxygenase-2 (COX-2) protein expression at low doses, which correlated with the inhibition of ERK phosphorylation in the SAS cells. Furthermore, feeding rats with ANE at 1 and 10 mg/kg/day for 5 days significantly repressed carrageenan-induced inflammatory exudates and PGE₂ formation. In conclusion, ANE, which contains catechins based oligomeric and polymeric procyanidins, regulates COX-2 expression in vitro and possess anti-inflammatory potential in vivo.     

Lack of cytotoxic and genotoxic effects of Minthostachys verticillata essential oil: Studies in vitro and in vivo

Minthostachys verticillata (peperina) is an aromatic and medicinal plant with several uses and ethnobotanical properties. Numerous studies have demonstrated that its essential oil (Mv-EO) presents antimicrobial capacity and shows immunomodulating and anti-allergic properties in human cell lines. Thus, the goal of this study was to investigate the main chemical composition, analyzed by GC–FID, and the cyto-genotoxic effects of Mv-EO, using Vero cells, human PBMCs and mice bone marrow cells. The Mv-EO was rich in pulegone 60.5% and menthone 18.2%. Our results clearly show that Mv-EO is not cyto-genotoxic in vitro nor in vivo. It not induced cytotoxic effects, as indicated by trypan blue dye exclusion and NRU assays both in Vero cells and human PBMCs. In addition, Mv-EO (100–1000 μg/mL) not induced apoptotic effects on human PBMCs, as indicated by Hoechst staining and DNA fragmentation analysis by agarose gel electrophoresis. The in vivo assay showed that Mv-EO (25–500 mg/kg) not increased the frequency of micronucleus in bone marrow cells of mice. Further, the ratio of polychromatic/normochromatic erythrocytes was not modified. These findings suggest that Mv-EO appears to be safe as a therapeutic agent.