Genotoxicity of aloeemodin in vitro and in vivo

The present in vitro and in vivo experiments were undertaken to clarify the genotoxic potential of the hydroxyanthrachinone aloeemodin which can be found in different plant derived products for therapy of constipation. The results demonstrate that aloeemodin is able to induce mutagenic effects in vitro. Positive results were obtained in the chromosomal aberration assay with CHO cells, as well as in the Salmonella reverse mutation assay (frameshift mutations in strains TA 1537, TA 1538 and TA 98). No mutagenic potential of aloeemodin, however, was observed in the gene mutation assay with mammalian cells in vitro (HPRT assay in V79 cells). Each assay was performed in the presence and absence of an extrinsic metabolic activation system (S9-mix). In in vivo studies (micronucleus assay in bone marrow cells of NMRI mice; chromosome aberration assay in bone marrow cells of Wistar rats; mouse spot test [DBA/2J × NMRI]) no indication of a mutagenic activity of aloeemodin was found. Information about a possible reaction of aloeemodin with DNA was derived from an in vivo UDS assay. Hepatocytes of aloeemodin-treated male Wistar rats did not show DNA damage via repair synthesis. All these data suggest that aloeemodin is able to interact with DNA under certain in vitro conditions. However, in vivo the results that were negative did not indicate a genotoxic potential. Therefore, it may be assumed that a genotoxic risk for man might be unlikely.     

Evaluation of the genotoxic potential of the natural neurotoxin Tetrodotoxin (TTX) in a battery of in vitro and in vivo genotoxicity assays

The genotoxic potential of the natural neurotoxin Tetrodotoxin (TTX) was evaluated in a battery of in vitro and in vivo genotoxicity assays. These comprised a bacterial reverse-mutation assay (Ames test), an in vitro human lymphocyte chromosome-aberration assay, an in vivo mouse bone-marrow micronucleus assay and an in vivo rat-liver UDS assay. Maximum test concentrations in in vitro assays were determined by the TTX limit of solubility in the formulation vehicle (0.02% acetic acid solution). In the Ames test, TTX was tested at concentrations of up to 200 microg/plate. In the chromosome-aberration assay human lymphocytes were exposed to TTX at concentrations of up to 50 microg/ml for 3 and 20 h in the absence of S9, and for 3h in the presence of S9. For the in vivo assays, maximum tested dose levels were determined by the acute lethal toxicity of TTX after subcutaneous administration. In the mouse micronucleus assay TTX dose levels of 2, 4 and 8 microg/kg were administered to male and female animals, and bone-marrow samples taken 24 and 48 h (high-dose animals only) after administration. In the UDS assay, male rats were given TTX on two occasions with a 14-h interval at dose levels of 2.4 and 8 microg/kg, the last dose being administered 2h before liver perfusion and hepatocyte culturing. Relevant vehicle and positive control cultures and animals were included in all assays. TTX was clearly shown to lack in vitro or in vivo genotoxic activity in the assays conducted in this study. The results suggest that administration of TTX as a therapeutic analgesic agent would not pose a genotoxic risk to patients.     

Genotoxic activity of newly synthesized derivatives of cyano-pyridone in murine cells in vivo and in vitro

Possible genotoxic activity of two newly synthesized cyanopyridone compounds [4-(N-methyl-phalimidyl-3)-3-cyano-4-methyl-pyridone-2 (MPhCMP) and 1-(4-hydroxyphenyl)-3-cyano-4-methyl-pyridone-2 (HCMP)] with in vitro antitumor activity was studied both in in vitro and in vivo murine test systems. In L5178Y mouse lymphoma cells, HCMP did not induce micronuclei (MN) at the highest available (because of toxicity) concentration (100 microg/ml), while MPhCMP at dose of 50 microg/ml induced 2.6-fold, and at dose of 100 microg/ml 3.95-fold increase of number of the cells with MN. The concentration of 100 microg/ml is a threshold of toxicity of MPhCMP. In experiments on possible DNA damaging activity (the comet assay) of both substances using the same doses as in in vitro mutagenesis assay, we did not reveal any evidence of DNA damage. The acute toxicity of compounds was studied on male Swiss albino mice. LD50 values of MPhCMP and HCMP were 177.5 and 288 mg/kg, respectively. MPhCMP was more potent MN inductor than HCMP (2.5-fold at doses equivalent to 1/2 of LD50). Both substances possessing in vitro antitumor activity along with weak genotoxicity have a good chance for successful in vivo antitumor studies in rodents.     

Assessment of the potential germ cell mutagenicity of industrial and plant protection chemicals as part of an integrated study of genotoxicity in vitro and in vivo

An approach is described that enables the germ cell mutagenicity of chemicals to be assessed as part of an integrated assessment of genotoxic potential. It is recommended, first, that the genotoxicity of a chemical be defined by appropriate studies in vitro. This should involve use of the Salmonella mutation assay and an assay for the induction of chromosomal aberrations, but supplementary assays may be indicated in specific instances. If negative results are obtained from these 2 tests there is no need for the conduct of additional tests. Agents considered to be genotoxic in vitro should then be assessed for genotoxicity to rodents. This will usually involve the conduct of a bone marrow cytogenetic assay, and in the case of negative results, a genotoxicity test in an independent tissue. Agents found to be non-genotoxic in vivo are regarded as having no potential for germ cell mutagenicity. Agents found to be genotoxic in vivo may either be assumed to have potential as germ cell mutagens, or their status in this respect may be defined by appropriate germ cell mutagenicity studies. The basis of the approach, which is supported by the available experimental data, is that germ cell mutagens will be evident as somatic cell genotoxins in vivo, and that these will be detected as genotoxins in vitro given appropriate experimentation. The conduct of appropriate and adequate studies is suggested to be of more value than the conduct of a rigid set of prescribed tests.     

Comparative in vivo and in vitro genotoxicity studies of airborne particle extract in mice

The genotoxicity of an acetone extract of locally collected airborne particles was evaluated both in vitro and in vivo using the sister-chromatid exchange (SCE) assay in mice. At the highest concentration (5.36 mg/5 ml culture), the extract caused approximately a 3-fold increase in SCEs over controls in mouse bone marrow and spleen primary cells in vitro. However, the same airborne particle extract did not induce a significant increase in the SCE level over controls in vivo in mouse bone marrow and spleen cells when administered intraperitoneally or through oral gavage. This indicates that bone marrow and spleen primary cell cultures can be used in in vitro genotoxicity studies of complex mixtures, and that the genotoxicity of airborne particles detected in the in vitro system cannot always be detected in vivo with the same cell types. In addition, the same acetone extract of airborne particles caused dose-related his+ revertants in the strain TA98 of Salmonella typhimurium, both with and without S9 activation. The significant finding of this study is that the in vitro genotoxicity results of airborne particle extract may not be very meaningful in an in vivo situation.     

Genotoxicity testing of fluconazole in vivo and in vitro

The genotoxic effects of the antifungal drug fluconazole (trade name triflucan) were assessed in the chromosome aberration (CA) test in mouse bone-marrow cells in vivo and in the chromosome aberration, sister chromatid exchange (SCE) and micronucleus (MN) tests in human lymphocytes. Fluconazole was used at concentrations of 12.5, 25.0 and 50.0 mg/kg for the in vivo assay and 12.5, 25.0 and 50.0 microg/ml were used for the in vitro assay. In both test systems, a negative and a positive control (MMC) were also included. Six types of structural aberration were observed: chromatid and chromosome breaks, sister chromatid union, chromatid exchange, fragments and dicentric chromosomes. Polyploidy was observed in both the in vivo and in vitro systems. In the in vivo test, fluconazole did not significantly increase the frequency of CA. In the in vitro assays, CA, SCE and MN frequencies were significantly increased in a dose-dependent manner compared with the negative control. The mitotic, replication and cytokinesis-block proliferation indices (CBPI) were not affected by treatments with fluconazole. According to these results, fluconazole is clastogenic and aneugenic in human lymphocytes, but these effects could not be observed in mice. Further studies should be conducted in other test systems to evaluate the full genotoxic potential of fluconazole.     

Assays to predict the genotoxicity of the chromosomal mutagen etoposide -- focussing on the best assay

The topoisomerase II inhibitor etoposide is used routinely to treat a variety of cancers in patients of all ages. As a result of its extensive use in the clinic and its association with secondary malignancies it has become a compound of great interest with regard to its genotoxic activity in vivo. This paper describes a series of assays that were employed to determine the in vivo genotoxicity of etoposide in a murine model system. The alkaline comet assay detected DNA damage in the bone marrow mononuclear compartment over the dose range of 10--100mg/kg and was associated with a large and dose dependent rise in the proportion of cells with severely damaged DNA. In contrast, the bone marrow micronucleus assay was found to be sensitive to genotoxic damage between the doses of 0.1--1mg/kg without any corresponding increases in cytotoxicity. An increase in the mutant frequency was undetectable at the Hprt locus at administered doses of 1 and 10mg/kg of etoposide, however, an increase in the mutant frequency was seen at the Aprt locus at these doses. We conclude that the BMMN assay is a good short-term predictor of the clastogenicity of etoposide at doses that do not result in cytotoxic activity, giving an indication of potential mutagenic effects. Moreover, the detection of mutants at the Aprt locus gives an indication of the potential of etoposide to cause chromosomal mutations that may lead to secondary malignancy.     

Anti‐proliferative effect of rhein,an anthraquinone isolated from Cassia species,on Caco‐2 human adenocarcinoma cells

In recent years, the use of anthraquinone laxatives, in particular senna, has been associated with damage to the intestinal epithelial layer and an increased risk of developing colorectal cancer. In this study, we evaluated the cytotoxicity of rhein, the active metabolite of senna, on human colon adenocarcinoma cells (Caco‐2) and its effect on cell proliferation. Cytotoxicity studies were performed using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT), neutral red (NR) and trans‐epithelial electrical resistance (TEER) assays whereas ³H‐thymidine incorporation and Western blot analysis were used to evaluate the effect of rhein on cell proliferation. Moreover, for genoprotection studies Comet assay and oxidative biomarkers measurement (malondialdehyde and reactive oxygen species) were used. Rhein (0.1–10 μg/ml) had no significant cytotoxic effect on proliferating and differentiated Caco‐2 cells. Rhein (0.1 and 1 μg/ml) significantly reduced cell proliferation as well as mitogen‐activated protein (MAP) kinase activation; by contrast, at high concentration (10 μg/ml) rhein significantly increased cell proliferation and extracellular‐signal‐related kinase (ERK) phosphorylation. Moreover, rhein (0.1–10 μg/ml): (i) did not adversely affect the integrity of tight junctions and hence epithelial barrier function; (ii) did not induce DNA damage, rather it was able to reduce H₂O₂‐induced DNA damage and (iii) significantly inhibited the increase in malondialdehyde and reactive oxygen species (ROS) levels induced by H₂O₂/Fe²⁺. Rhein was devoid of cytotoxic and genotoxic effects in colon adenocarcinoma cells. Moreover, at concentrations present in the colon after a human therapeutic dosage of senna, rhein inhibited cell proliferation via a mechanism that seems to involve directly the MAP kinase pathway. Finally, rhein prevents the DNA damage probably via an anti‐oxidant mechanism.     

Protection against radiation clastogenecity in mouse bone marrow by Phyllanthus niruri

The effects of aqueous (PnAq) and alcoholic (PnA1 extract (50-250 mg/kg) of P. niruri on in vivo gamma radiation induced chromosome aberration and in vitro antioxidant activity (50-500 microg/ml) were studied. The antioxidant activity was studied by measuring inhibition of hydroxyl radicals generated by the fenton reaction along with pro-oxidant and iron chelating ability. PnA1 showed highly significant in vitro free radical scavenging ability when compared to DMSO above 250 microg/ml concentration. PnAq showed significant pro-oxidant activity while PnA1 was devoid of it at the tested concentrations. Exposure to gamma radiation (4 Gy) caused 29.10 % increase in the frequency of chromosomal aberrations. Administration of PnA1 (250 mg/kg) showed highly significant decrease in chromosomal aberrations compared to radiation treated group. Radioprotective potential of alcoholic extract was found to be more effective than the aqueous extract. Qualitative phytochemical investigation of PnAq and PnA1 revealed the presence of sugars, flavonoids, alkaloid, lignans, polyphenols, tannins, coumarins and saponins. Higher radioprotective effect of the alcoholic extract may be attributed to rich presence of antioxidant polyphenolic compounds.     

Concomitant observations of UDS in the liver and micronuclei in the bone marrow of rats exposed to cyclophosphamide or 2-acetylaminofluorene

Oral dosing of between 5–30 mg/kg of cyclophosphamide (CP) to Alderley Park rats induced micronuclei in the bone marrow between 12 and 36 h after dosing, but failed to induce unscheduled DNA synthesis (UDS) in the liver at similar dose levels and treatment periods. Dose levels of > 30 mg/kg were toxic to the liver. In contrast, 2-acetylaminofluorene (2AAF) induced UDS in the rat liver between 4–36 h after dosing, but gave only a weak response in the bone marrow assay at dose levels between 0.5 and 2 g/kg. Selected observations were made for each chemical using both tissues of the same test animal.

It is concluded that an assessment of the genotoxicity in vivo of chemicals defined as genotoxic in vitro will contribute to an assessment of their possible mammalian carcinogenicity, and that these should involve assays conducted using both the bone marrow and the liver of rodents. Due to its relative ease of commission, the bone marrow micronucleus assay will usually be conducted first; in the case of negative results it is recommended that a liver genotoxicity assay should also be conducted. The case for employing in vivo short-term genotoxicity tests to predict the possible organotropic carcinogenicity or germ cell mutagenicity of a new in vitro genotoxin is discussed.     

Genotoxicity tests with 6-acetyl-1,1,2,4,4,7-hexamethyltetraline and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyr an

6-Acetyl-1,1,2,4,4,7-hexamethyltetraline (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-ben zopyran (HHCB), synthetic fragrance ingredients, were evaluated for potential genotoxicity in a battery of short-term tests. Salmonella typhimurium/Escherichia coli plate incorporation and liquid preincubation assays were conducted on AHTN using tester strains TA97, TA98, TA100, TA102, TA1535, TA1537 and WP2 uvrA +/- S9 activation at doses from 8 to 5000 micrograms/plate. The plate incorporation mutagenicity assay was conducted on HHCB using tester strains TA98, TA100, TA1535, TA1537, TA1538 and WP2 uvrA +/- S9 activation at doses from 10 to 5000 micrograms/plate. An in vitro cytogenetics assay in Chinese hamster ovary (CHO) cells was conducted with AHTN and HHCB at three concentrations each with +/- S9 activation. In the non-activated study, the exposure/harvest periods were 4/20-, 20/20- and 44/44-h. In the S9 activated study, the exposure/harvest periods were 4/20- and 4/44-h. In vitro unscheduled DNA synthesis (UDS) assays were conducted in primary rat hepatocytes at concentrations between 0.15 and 50 micrograms/ml for AHTN and HHCB. In vivo mouse micronucleus assays were conducted with high doses of 1600 mg AHTN/kg and of 1500 mg HHCB/kg in corn oil. No positive responses were observed in any of the tests with HHCB. With AHTN, no positive responses were observed except for cells with structural aberrations in the in vitro cytogenetics assay in CHO cells with S9 activation at the treatment/harvest time of 4/20 h. In initial studies with AHTN, the high dose of 7.8 micrograms/ml showed 0.5% aberrant cells, with the mitotic index at 41% relative to vehicle control and cell growth inhibition in the range of 25-50%. Thus the genotoxicity findings with AHTN were limited to this one positive response; all other genotoxicity tests with AHTN were considered as negative. In particular, the negative finding in the in vivo assay supports AHTN as not likely to be mutagenic in mammalian systems. These considerations, along with other negative published data, lead to the conclusion that both AHTN and HHCB do not have significant potential to act as genotoxic carcinogens.     

Evaluation of the potential in vivo genotoxicity of quercetin

Quercetin, a naturally occurring flavonol commonly detected in apples, cranberries, blueberries, and onions, has been reported to possess antioxidant, anti-carcinogenic, anti-inflammatory, and cardioprotective properties. While positive results have been consistently reported in numerous in vitro mutagenicity and genotoxicity assays of quercetin, tested in vivo, quercetin has generally produced negative results in such studies. Furthermore, no evidence of carcinogenicity related to the oral administration of quercetin was observed in chronic rodent assays. In order to further define the in vivo genotoxic potential of quercetin, a bone marrow micronucleus assay and an unscheduled DNA synthesis (UDS) assay were conducted in Wistar rats. Administered orally to male rats at dose levels of up to 2000 mg/kg body weight, quercetin did not increase the number of micronucleated polychromatic erythrocytes (MN-PCE) 24 or 48 h following dosing in the micronucleus assay. Likewise, orally administered quercetin (up to 2000 mg/kg body weight) did not induce UDS in hepatocytes of male or female rats. While measurable levels of metabolized quercetin were observed in rat plasma samples for up to 48 h after dosing, peaking at 1h following treatment administration, the unmetabolized aglycone was not identified in either plasma or bone marrow. With the exception of only a few rats, the aglycone was also not detected in liver tissue. These results demonstrate that quercetin is not genotoxic under the conditions of these assays and further support the negative results of previously conducted in vivo assays.     

A review of the genotoxicity of ethylbenzene

Ethylbenzene is an important industrial chemical that has recently been classified as a possible human carcinogen (IARC class 2B). It induces tumours in rats and mice, but neither the relevance of these tumours to humans nor their mechanism of induction is clear. Considering the carcinogenic potential of ethylbenzene, it is of interest to determine whether there is sufficient data to characterize its mode of action as either genotoxic or non-genotoxic. A review of the currently available genotoxicity data is assessed. Ethylbenzene is not a bacterial mutagen, does not induce gene conversion or mutations in yeast and does not induce sister chromatid exchanges in CHO cells. Ethylbenzene is not clastogenic in CHO or rat liver cell lines but was reported to induce micronuclei in SHE cells in vitro. No evidence for genotoxicity has been seen in humans exposed to relatively high levels of ethylbenzene. Mouse lymphoma gene mutation studies produced a mixed series of responses that have proved difficult to interpret. An increase in morphological transformation of SHE cells was also found. Results from a more relevant series of in vivo genotoxicity studies, including acute and sub-chronic micronucleus tests and the mouse liver UDS assay, indicate a lack of in vivo genotoxic activity. The composite set of results from both in vitro and in vivo tests known to assess direct damage to DNA have been predominantly negative in the absence of excessive toxicity. The available data from the standard battery of genotoxicity assays do not support a genotoxic mechanism for ethylbenzene-induced kidney, liver or lung tumors in rats and mice.     

In vitro and in vivo leishmanicidal activity of Dysoxylum binectariferum and its fractions against Leishmania donovani

The leishmanicidal effect of crude ethanolic extract of stem bark of Dysoxylum binectariferum and its fractions has been investigated against Leishmania donovani, the causative agent of visceral leishmaniasis. Ethanolic extract was lethal to promastigotes as well as amastigote forms in macrophage system at the concentration of 100 microg/ml. Chloroform fraction significantly inhibited promastigote multiplication and was also active against amastigotes in infected J774A.1 macrophages at 100 microg/ml. Hexane fraction was moderately active and the other fractions were inactive against both the forms. When tested in vivo in hamsters, ethanolic extract was toxic at 500 mg/kg whereas exhibited marginal activity (67.7+/-5.3%) at 250 mg/kg x 5, p.o. on day 7 post treatment (p.t.) which increases slightly (69+/-4.7) by day 30 p.t. Chloroform and n-hexane fractions exhibited 64.3+/-4% and 47.8+/-4.6% parasite inhibition at the dose of 100 mg/kg x 5 p.o., respectively. The pure compound, rohitukine, obtained from chloroform fraction showed weaker in vitro activity and was ineffective in infected hamsters. The lead potential of this plant need further investigations.     

Induction of unscheduled DNA synthesis in primary rat hepatocytes by benzidine-congener-derived azo dyes in the in vitro and in vivo/in vitro assays

The genotoxicity of the benzidine-congener-derived azo dyes. Direct Blue 1 ( DB1 ), Direct Blue 14 ( DB14 ), Direct Brown 95 ( DB95 ), and Direct Red 46 ( DR46 ) was studied in the in vitro and in vivo/in vitro unscheduled DNA synthesis (UDS) assays in primary rat hepatocytes to determine if in vivo metabolism of these compounds was required for induction of UDS. Hepatocytes were isolated, cultured, and treated with the azo dyes and [3H]thymidine (in vitro assay); alternatively, in the in vivo/in vitro assay, rats were intubated with the azo dyes, the hepatocytes isolated at 17 h after dosing and incubated in a medium containing [3H]thymidine. UDS was quantified by an autoradiographic method. None of the azo dyes induced UDS in the in vitro assay. However, DR46 did induce marginal, but significant UDS in 1 experiment (1.2 net grains at 500 micrograms/ml media). No significant UDS was observed when DR46 was tested in a subsequent in vitro assay. In the in vivo/in vitro assay, DB95 (100 mg/kg), DB14 (125 mg/kg), and DR46 (100 mg/kg) induced significant UDS (12, 2.1, and 3.5 net grains, respectively). None of the azo dyes tested was mutagenic in the Salmonella/microsome assay in the presence and absence of rat liver enzymes. Therefore, in vivo reduction of azo dyes, presumably by the gut microflora, is a requirement for the genotoxicity of these azo dyes in the primary rat hepatocyte UDS assay.     

Evaluation of the potential in vivo genotoxicity of quercetin

Quercetin, a naturally occurring flavonol commonly detected in apples, cranberries, blueberries, and onions, has been reported to possess antioxidant, anti-carcinogenic, anti-inflammatory, and cardioprotective properties. While positive results have been consistently reported in numerous in vitro mutagenicity and genotoxicity assays of quercetin, tested in vivo, quercetin has generally produced negative results in such studies. Furthermore, no evidence of carcinogenicity related to the oral administration of quercetin was observed in chronic rodent assays. In order to further define the in vivo genotoxic potential of quercetin, a bone marrow micronucleus assay and an unscheduled DNA synthesis (UDS) assay were conducted in Wistar rats. Administered orally to male rats at dose levels of up to 2000 mg/kg body weight, quercetin did not increase the number of micronucleated polychromatic erythrocytes (MN-PCE) 24 or 48 h following dosing in the micronucleus assay. Likewise, orally administered quercetin (up to 2000 mg/kg body weight) did not induce UDS in hepatocytes of male or female rats. While measurable levels of metabolized quercetin were observed in rat plasma samples for up to 48 h after dosing, peaking at 1 h following treatment administration, the unmetabolized aglycone was not identified in either plasma or bone marrow. With the exception of only a few rats, the aglycone was also not detected in liver tissue. These results demonstrate that quercetin is not genotoxic under the conditions of these assays and further support the negative results of previously conducted in vivo assays.     

Effect of tetrandrine on micronucleus formation and sister-chromatid exchange in both in vitro and in vivo assays

The genotoxicity of tetrandrine, a drug potentially useful for the treatment of silicosis, was studied using the micronucleus and the sister-chromatid exchange (SCE) assay systems. Cultured Chinese hamster lung (V79) cells were used for the in vitro micronucleus and sister-chromatid exchange studies. Mouse bone marrow was used for the in vivo micronucleus assay and mouse spleen cells for the in vivo/in vitro sister-chromatid exchange analysis. The results show that SCE levels in V79 and in spleen cells were significantly elevated by treatment with tetrandrine at doses above 0.08 mg/ml and 100 mg/kg bw, respectively. Increased tetradrine-induced SCE in vitro was metabolic activation dependent. Tetrandrine failed to induce micronuclei at any of the doses tested. A decrease of replicative index with an increase in the concentration of tetrandrine was found both in vitro and in vivo. These results indicate that tetrandrine is a weak indirect-acting genotoxicant.     

Hypoglycemic effect of methanol extract of Phyllanthus amarus Schum & Thonn on alloxan induced diabetes mellitus in rats and its relation with antioxidant potential

Methanolic extract of P. amarus was found to have potential anti-oxidant activity as it could inhibit lipid peroxidation, and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 104 microg/ml and the concentrations needed to scavenge hydroxyl and superoxide radicals were 117 and 19 microg/ml respectively. The extract was found to reduce the blood sugar in alloxan diabetic rats at 4th hr by 6% at a dose level of 200 mg/kg body wt and 18.7% at a concentration of 1000 mg/kg body wt. Continued administration of the extract for 15 days produced significant (P < 0.001) reduction in blood sugar. On 18th day after alloxan administration values were almost similar to normal in the group taking 1000 mg/kg body wt.     

An in vivo mouse micronucleus assay on musk ketone

Musk ketone (3,5-dinitro-2,6-dimethyl-4-tert-butyl-acetophenone) was evaluated in an in vivo mouse micronucleus assay. Male and female mice were dosed with 250, 500 or 1000 mg musk ketone/kg body weight by a single intraperitoneal injection in corn oil. Results of the assay showed that under the conditions of this test evaluated at 24, 48 and 72 h after dosing, musk ketone did not induce a significant increase in micronucleated polychromatic erythrocytes in either male or female mice at any dose or any time period. Musk ketone was considered to be negative in the mouse in vivo micronucleus test as well as in a battery of previously published in vitro genotoxicity tests. Based on the total weight of evidence available, it was concluded that musk ketone does not have significant potential to act as a genotoxic carcinogen.     

Protective effects of a standard extract of Mangifera indica L. (VIMANG) against mouse ear edemas and its inhibition of eicosanoid production in J774 murine macrophages

A standard aqueous extract of Mangifera indica L., used in Cuba as antioxidant under the brand name VIMANG, was tested in vivo for its anti-inflammatory activity, using commonly accepted assays. The standard extract of M. indica, administered orally (50-200mg/kg body wt.), reduced ear edema induced by arachidonic acid (AA) and phorbol myristate acetate (PMA) in mice. In the PMA model, M. indica extract also reduced myeloperoxidase (MPO) activity. In vitro studies were performed using macrophage cell line J774 stimulated with pro-inflammatory stimuli lipopolysaccharide-interferon gamma (LPS-IFNgamma) or calcium ionophore A23187 to determine prostaglandin PGE(2) or leukotriene LTB(4) release, respectively. The extract inhibited the induction of PGE(2) and LTB(4) with IC(50) values of 21.7 and 26.0microg/ml, respectively. Mangiferin (a glucosylxanthone isolated from the extract) also inhibited these AA metabolites (PGE(2), IC(50) value=17.2microg/ml and LTB(4), IC(50) value=2.1microg/ml). These results represent an important contribution to the elucidation of the mechanism involved in the anti-inflammatory and anti-nociceptive effects reported for the standard extract of M. indica VIMANG.