Evaluation of cytotoxicity and genotoxicity of Hancornia speciosa latex in Allium cepa root model / Avaliação da citotoxicidade e genotoxicidade do látex de Hancornia speciosa usando o modelo da raiz de Allium cepa

Abstract The latex obtained from Hancornia speciosa Gomes (Mangabeira tree) is widely used in traditional medicine to treat a variety of diseases, including diarrhea, ulcer, gastritis, tuberculosis, acne and warts. In this study, the cytotoxicity and genotoxicity effects of H. speciosa latex on the root meristem cells of Allium cepa were examined. Onion bulbs were exposed to different concentrations of latex and then submitted to microscopic analysis using Giemsa stain. Water was used as a negative control and sodium azide as a positive control. The results showed that, under the testing conditions, the mitotic index (MI) of the onion roots submitted to latex treatment did not differ significantly from the negative control, which suggests that the latex is not cytotoxic. Low incidence of chromosome aberrations in the cells treated with H. speciosa latex was also observed, indicating that the latex does not have genotoxic effect either. The MI and the chromosome aberration frequency responded to the latex concentration, requiring more studies to evaluate the dosage effect on genotoxicity. The results indicate that in tested concentrations H. speciosa latex is probably not harmful to human health and may be potentially used in medicine.

Resumo O látex obtido de Hancornia speciosa é amplamente utilizado na medicina popular para tratar uma variedade de doenças, tais como: diarreia, úlcera, gastrite, tuberculose, acne e verrugas. Nesse estudo, foram avaliados os efeitos citotóxicos e genotóxicos do látex de H. speciosa sobre as células meristemáticas das raízes de Allium cepa. Os bulbos das cebolas foram expostos a diferentes concentrações de látex e depois submetidos à analise microscópica usando o corante Giemsa. A água foi usada como controle negativo e a ázida sódica como controle positivo. Os resultados mostraram que o índice mitótico (IM) das raízes de cebola submetidas ao tratamento com látex, nas condições testadas, não diferiram significativamente do controle negativo, e sugerem que o látex não é citotóxico. Também foi observada uma baixa incidência de aberrações cromossômicas nas células tratadas com látex de H. speciosa, o que sugere que o látex também não possui efeito genotóxico. O IM e a frequência de aberrações cromossômicas foram dependentes da concentração de látex. Outros estudos devem ser realizados para avaliar o efeito da dose na genotoxidade. Os resultados indicam que o látex de mangabeira, nas concentrações testadas, provavelmente não é danoso para saúde humana e pode ter potencial para ser usado na medicina.

Evaluation of DNA damage in vivo by comet assay and chromosomal aberrations for pyrethroid insecticide and the antimutagenic role of curcumin

Background: Esfenvelerate a synthetic pyrethroid insecticide, is widely used in the home environment and in agriculture because of its high activity against a broad spectrum of insect pests and its low animal toxicity

Objective of this study was to evaluate the genotoxicity of esfenvelerate and the possible protective role of curcumin against this genotoxicity

Material and methods: Forty male albino rats were divided into 8 groups of 5 rats each: G1 served as control and G2 served as positive control received [100mg/kg curcumin], G3,G4 and G5 were orally administrated with [1/20 LD50, 1/40 LD50 and 1/60 LD50 of esfenvelerate] respectively and the last three groups[G6,G7and G8] were received the same doses of pesticide plus 100mg /kg curcumin for 28 days daily. Animals were sacrificed and bone marrow samples were collected for chromosomal aberration assay test and liver samples were used for DNA damage detection by comet assay

Results: chromosome aberration assay revealed that all the tested doses induced chromosomal aberrations [CA] such as centromeric gaps, chromatid gaps, chromatid deletion, dicentric chromosome, and ring chromosome. The alkaline comet assay showed significantly increased tail moment, tail length and tailed DNA % in liver cells of animals treated with esfenvelerate alone compared to control group. On the other hand, oral curcumin significantly ameliorated the genotoxicity induced by esfenvelrat. All these results clarified the efficacy of curcumin in amelioration of chromosomal aberrations of structures as well as DNA damage which may result from its antioxidant properties

Protective effect of liposomal formulation of tuftsin (a naturally occurring tetrapeptide) against cyclophosphamide-induced genotoxicity and oxidative stress in mice.

Tuftsin, a naturally occurring tetrapeptide with a sequence Thr-Lys-Pro-Arg was evaluated for its in vivo protective effect against cyclophosphamide-induced genotoxicity and oxidative stress in Swiss albino mice. The anticancer drug cyclophosphamide (CP) was administered intra-peritonially to induce mutagenic effect. The drug treatment caused significant increase in chromosomal aberrations, formation of micronucleated polychromatic erythrocytes (MNPCE's), as well as oxidative stress and decrease in lipid peroxidation in liver of the animals. The pretreatment with tuftsin abolished such effects in dose-dependent manner and also increased mitotic index in the experimental animals. Results of the present study validated chemo-preventive properties of tuftsin against CP-induced chromosomal mutations and cellular injury of liver by oxidative stress.

Expression and identification of folate-sensitive fragile sites in British Suffolk sheep (Ovis aries).

An investigation to understand the dynamics and biological significance of fragile site expression, and identification of 5-fluorodeoxyuridine (FUdR) induced chromosomal gaps/breaks, were carried out in an experimental flock of 45 Suffolk sheep. The statistical comparison revealed, highly significant variation in the frequency of chromosomal fragile site expression between control and FUdR cultures. Mean (+/- S.D.) values for cells with gaps and breaks, or aberrant cell count (AC), and the number of aberrations (NoA) per animal were 2.02 +/- 0.34, 2.42 +/- 0.48, 13.26 +/- 0.85 and 21.87 +/- 1.88 (P lessthan 0.01) in control and FUdR cultures, respectively. The comparison of age revealed nonsignificant variation between control and FUdR cultures. The G-band analysis of fragile site data revealed gaps in 29 autosomal and two X-chromosomal bands in the control cultures, whereas FUdR treated cultures scored 78 unstable bands in autosomes of which 56 were significantly fragile. X-chromosomes expressed breaks and gaps in six G-negative bands and five of them (Xq13, Xq15, Xq17, Xq24 and Xq26) were significantly fragile. The distribution comparison of autosomal fragile sites between sex groups did not reveal any significant variation. Female X-chromosomes were significantly more fragile than the male X-chromosomes. The distribution comparison for age groups (lambs versus adults) revealed significantly higher number of fragile bands in adults. Comparison of published data on reciprocal translocations in sheep with the fragile-site data obtained in this study indicated that the break sites of both phenomena were correlated. Similarities were also found between fragile sites and breakpoints of evolutionary significance in family Bovidae.

Antimutagenic effects of piperine on cyclophosphamide-induced chromosome aberrations in rat bone marrow cells.

Piperine is a major pungent substance and active component of black pepper (Piper nigrum Linn.) and long pepper (Piper longum Linn.). Both plants are used worldwide as household spices and condiments. They are also used as important ingredients in folklore medicine in many Asian countries. Therefore, it is of interest to study antimutagenic effects of piperine. In this study, its influence on chromosomes was investigated in rat bone marrow cells. Male Wistar rats were orally administered piperine at the doses of 100, 400 and 800 mg/kg body weight for 24 hours then challenged with cyclophosphamide at a dose of 50 mg/kg body weight by intraperitoneal injection. Twenty-four hours thereafter, all animals were sacrificed and bone marrow samples were collected for chromosomal analysis. The results demonstrated that piperine at a dose of 100 mg/kg body weight gave a statistically significant reduction in cyclophosphamide-induced chromosomal aberrations. In conclusion, piperine may have antimutagenic potential. The underlying molecular mechanisms now require attention.

Protective role of nordihydroguaiaretic acid (NDGA) against the genotoxic damage induced by ethynodiol diacetate in human lymphocytes in vitro.

Antioxidants and plant products are reported to reduce the genotoxic damage of steroids. In our present study we have tested different dosages of nordihydroguaiaretic acid (NDGA) against the genotoxic damage induced by ethynodiol diacetate in the presence of S9 mix. Treatments with nordihydroguaiaretic acid (NDGA) results in the reduction of the genotoxic damage. A significant decrease was observed at all the tested doses of NDGA in sister chromatic exchanges of number of abnormal cells. The results suggest a protective role of NDGA against the genotoxic damage.

In vivo studies on the effect of Ocimum sanctum L. leaf extract in modifying the genotoxicity induced by chromium and mercury in Allium root meristems.

In vivo cytogenetic assay in Allium cepa root tip cells has been carried out to detect the modifying effect of Ocimum sanctum aqueous leaf extract against chromium (Cr) and mercury (Hg) induced genotoxicity. It was observed that the roots post-treated with the leaf extract showed highly significant (p < 0.001) recovery in mitotic index (MI) and chromosomal aberrations (CA) when compared to pre-treated (Cr/Hg) samples and the lower doses of the leaf extract were found to be more effective than higher doses. The present study reveals that the Ocimum sanctum leaf extract possesses the protective effect against Cr/Hg induced genetic damage.

Anticlastogenic action of vitamin C against genotoxicity of estrogenic drug diethylstilbestrol (DES) in the human lymphocyte chromosomes.

Several sex steroids and estrogenic drugs are genotoxic in varying conditions and cause oxidative stress, which has been a field of interest to study the molecular mechanism of the genetic damage. Among the estrogenic drugs, a strong toxic effect is exerted by diethylstilbestrol (DES). In the present study it has been attempted to study its genotoxic effects in human lymphocyte assay system along with ameliorative or anticlastogenic effects of vitamin C. The drug was used with different dosage of concentrations on human lymphocytes administered in vitro. The parameters used were Sister Chromatid Exchanges (SCEs) and Chromosomal Aberrations (CAs). Higher levels of clastogeny and SCEs have been observed indicating significant damaging effect by the drug. Interesting ameliorating effects were observed in the presence of vitamin C which is a well-known antioxidant. The results support the possibility of practical application of natural protectors against the mutagenic/oenotoxic action of chemical mutagens.

Efficiency of Coleus aromaticus extract in modifying cyclophosphamide and mitomycin-C induced clastogenicity in mouse bone marrow cells.

The anticlastogenic potency of the ethanolic extract of a medicinal plant, C. aromaticus was investigated by taking bone marrow chromosomal aberration assay and micronucleus (MN) test as the test parameters. Swiss albino mice were fed orally with different doses (10,15, 25, 50 and 100 mg/kg body weight) of ethanolic extract for 7 days and on the 7th day, two doses each of anticancer drugs cyclophosphamide (CP; 25 and 50 mg/kg body weight) and mitomycin-C (MMC; 4 and 8 mg/kg body weight) were injected, ip, to different groups of animals. Bone marrow MN preparations were made at 24 and 48 hr time intervals. Coleus extract reduced CP and MMC induced MN and lower doses of the extract were found to be more effective than higher doses. The effective doses of extract in MN test were selected to study the anticlastogenic effects against CP (25 and 50 mg/kg body weight) and MMC (2 and 4 mg/kg body weight) induced chromosomal aberrations. The results indicate the protective effect of C. aromaticus against CP and MMC induced cytogenetic damage.

Clastogenic effects of dietary supplement--Spirulina alga, and some medicinal plant products from Boswellia serrata, Withania somnifera on mice.

Pretreatment of aqueous extracts of Zyrulina (Spirulina), Aswagandha (Withania) and Nopane (Boswellia) on colchicine induced chromosome damage showed weakness of clastogenic activity in Swiss albino mice. None of the treatments increased significantly the number of chromosome aberrations.

In vivo radioprotective effect of Moringa oleifera leaves.

Radioprotective property of Moringa oleifera leaves was investigated in healthy adult Swiss albino mice. Animals were injected (ip) with 150 mg/kg body weight of 50% methanolic extract (ME) of M. oleifera leaves, as a single dose, or in 5 daily fractions of 30 mg/kg each, and exposed to whole body gamma irradiation (RT, 4 Gy) 1 hr later. Five animals from each group were sacrificed at 1, 2 and 7 days after treatment. Bone marrow protection was studied by scoring aberrations in metaphase chromosomes and micronucleus induction in polychromatic erythrocytes and normochromatic erythrocytes. Pretreatment with a single dose of 150 mg/kg ME significantly reduced the percent aberrant cells to 2/3rd that of RT alone group on day 1 and brought the values to normal range by day 7 post-irradiation. A similar effect was also seen for the micronucleated cells. Fractionated administration of ME (30 mg/kg x 5) gave a higher protection than that given by the same dose administered as a single treatment. ME also inhibited the Fenton reaction-generated free radical activity in vitro in a concentration dependent manner. These results demonstrate that pretreatment with the methanolic leaf extract of M. oleifera confers significant radiation protection to the bone marrow chromosomes in mice and this may lead to the higher 30 day survival after lethal whole body irradiation.