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At least 19 recordsLinked to original sources
PubMed1970

Metabolism and binding of C-maleic hydrazide.

Maleic hydrazide (MH) is taken up by corn and pea seedling roots and bound to some material which is insoluble in 80% ethanol or 5% trichloroacetic acid. (14)C-MH is stable metabolically; chromatography of the 80% ethanol-soluble (14)C from treated corn roots and tobacco pith gives no indication of degradation. Very little (14)C-MH is bound in the zone of cell division (where MH acts to inhibit root elongation) or even in the region of cell enlargement in corn roots and most is bound 1 or more centimeters behind the tip. Likewise, very little MH is bound in corn coleoptile and tobacco pith sections. About 90% of (14)C-MH bound in corn roots is associated with large particles which may be cell wall fragments. The binding is blocked by azide and dinitrophenol, indicating a requirement for metabolic energy; however, inhibitors of protein synthesis (chloramphenicol, puromycin, cycloheximide) and DNA synthesis (fluorodeoxyuridine) do not inhibit binding. Only very small amounts of MH are bound in root homogenates, providing further evidence that the binding process is active. Once the MH is bound in the roots, the complex is stable for at least 1 week. Treatment with 2-aminoethanol releases MH.

Journal Article↗
PubMed2006

Spectroscopic and thermal studies of chromium(III), molybdenum(VI) and ruthenium(0) complexes of maleic hydrazide.

Interaction of maleic hydrazide (LH(2)) with [Cr(CO)(6)] in air at atmospheric pressure resulted in the formation of the complex [(LH)Cr(mu-O)(2)Cr(LH)] (1). Reaction of LH(2) with [Mo(CO)(6)] in air also gave the complex [(LH(2))O(2)Mo(mu-O)(2)MoO(2)(LH(2))] (2). Under the same conditions, the reaction of LH(2) with [Ru(3)(CO)(12)] resulted in the formation of the tricarbonyl complex [Ru(CO)(3)(LH(2))] (3). The complexes were characterized by elemental analysis, IR, and (1)H NMR spectroscopy. The thermal properties of the complexes were investigated by thermogravimetry technique.

Chromium↗
PubMed1978

Cytotoxic effects of maleic hydrazide.

Since 1950, maleic hydrazide (MH) has been introduced into agriculture as a major commercial herbicide and a depressant of plant growth in numerous circumstances such as suppression of sprouting of vegetables and stored food crops, control of sucker growth on tobacco plants, ratardation of flowering and prolongation of dormancy period. Since 1951 MH has been known as an effective chromosome-breaking agent in higher plants, in sharp contrast with its low effect on the chromosomes and general health of tested mammals. The selectivity of action of MH in plants and animals was obviously the main reason of low interest devoted to the chemical by people working the field of environmental mutagenesis. In early works the inhibitory effects of MH on plant growth were mainly considered to result from the suppression of plant metabolism (inhibition of enzymic activity) and interference of the compound with plant hormones and growth regulators. More recently, numerous experiments performed with various plant species have shown that MH acts as an inhibitor of the synthesis of nucleic acids and proteins. Similar results have been obtained with animal tumour cells. The chromosome-breaking effect of MH on plant chromosomes resembles very closely the chromosome-breaking properties of alkylating agents and other mutagenic compounds such as mitomycin C. MH-induced chromosomal aberrations have also been recorded in grasshoppers, fish and mice, although tests with some mammalian cell lines gave negative results. Among higher plants, selective sensitivity to the toxic effects of MH is well proved. This phenomenon seems to be due to the differential ability of various plant species to detoxicate the chemical. Plants can break down MH into several products, one of which, hydrazine, is a well-known mutagen and carcinogen. MH does not seem to be toxic to bacteria and fungi. The compound is degraded by soil microflora and hence can be utilized as a source of nitrogen nutrition. MH proved to be of low toxicity to mammals, but in some instances it decreased the fertility of rats. The reported carcinogenic effects of MH in mice and rats raise the question of its risks to man.

Animals↗
PubMed1981

Maleic hydrazide, carcinogenicity study in rats.

The carcinogenicity of maleic hydrazide is discussed by several national and international organizations because of contradictory results of a number of carcinogenicity studies carried out in the past. Because maleic hydrazide is used in agriculture on edible crops, an oral carcinogenicity study with rats was carried out for 28 months at dietary levels of 0, 1.0 and 2.0% maleic hydrazide which contained less than 1.5 mg hydrazine/kg product as impurity. In this study as well as in an experiment with mice carried out with the same batch of maleic hydrazide at the International Agency for Research on Cancer (IARC) in Lyon, France, treatment did not affect tumor incidence and it was concluded that maleic hydrazide itself is not a carcinogen. Most likely the presence of relatively high levels of hydrazine as an impurity was responsible for the contradictory results in studies as reported previously. Furthermore the results of this study showed that 1.0 and 2.0% maleic hydrazide in the diet caused proteinuria and increased protein/creatinine ratio's in the urine in both sexes without detectable histopathological changes in kidney or urinary tract. From this study, based on the effects of kidney function the "no-toxic" effect level is considered to be lower than 1.0% maleic hydrazide in the diet of rats.

Animals↗
PubMed1992

Determination of maleic hydrazide residues in cured tobacco by gas chromatography.

A rapid and sensitive method for measuring maleic hydrazide (6-hydroxy-2H-pyridazin-3-one) residues in cured tobacco is described. A mixture of free and bound maleic hydrazide is extracted with hydrochloric acid in which maleic hydrazide glycoside is simultaneously hydrolysed. The free maleic hydrazide obtained is methylated using dimethyl sulphate and the derivative is partitioned into chloroform and determined by capillary gas chromatography using a nitrogen-phosphorus detector. The limit of detection of maleic hydrazide is 5 ppm.

Chromatography, Gas↗
PubMed1983

The immunomodulatory effects of two plant growth regulators, cycloheximide and maleic hydrazide, in white mice.

The immunomodulatory effects of two plant regulators, cycloheximide and maleic hydrazide, were investigated by injecting the compounds twice weekly for 4 weeks in female Swiss Webster white mice. The animals were antigenically challenged with sheep red blood cells on day 24 of the study. Although humoral immunity was the primary system examined, analysis included all of the following parameters: spleen plaque forming cells (PFC's), lymphocyte viability, spleen lymphocyte counts, hemolysin titers, total plasma proteins, total white blood cells counts, hematocrit, total body weight, and liver, thymus and spleen weights. Cyclophosphamide and physiological saline were used as the respective positive and negative control substances. The dosing was as follows: cyclophosphamide at 50 mg/kg/injection, cycloheximide at 12.5, 25 and 50 mg/kg/injection and maleic hydrazide at 125 and 250 mg/kg/injection. Cycloheximide significantly (P less than .05) reduced, in a dose-dependent fashion, the thymus wt/gram of body weight, the number of PFC's/gram of spleen, total lymphocytes/gram of spleen, PFC's per 10(6) viable spleen lymphocytes and the hemolysin antibody titer levels. Maleic hydrazide significantly reduced thymus weights and moderately lowered the ratio of PFC's per 10(6) viable spleen lymphocytes. Maleic hydrazide significantly elevated total lymphocytes per gram of spleen and the hemolysin titer (up to 133% over saline control values). There was an elevation in the number of PFC's per gm of spleen by maleic hydrazide and the overall effects were dose related. Cycloheximide, a known inhibitor of protein synthesis, was distinctly the most suppressive of the two plant growth regulators. Both agents are widely utilized on agricultural products and the results suggest the need for care in their application and residue removal. Used properly, the plant growth regulators may pose little or no human health hazard, but this report documents a new biological activity for these agents.

Animals↗
PubMed2002

[Simple analysis of maleic hydrazide in agricultural products by HPLC].

A simplified HPLC determination method for maleic hydrazide in agricultural products was developed, and commercial agricultural crops were investigated. The homogenate of agricultural products was extracted with water. The crude extract was purified on an ACCUCAT Bond Elut extraction cartridge using water. Maleic hydrazide was analyzed by HPLC with UV detection (303 nm). The HPLC separation was performed on a ZORBAX SB-Aq column with acetonitrile-water-phosphoric acid(5:95:0.01) as the mobile phase. Recoveries of maleic hydrazide from 15 agricultural products fortified at 1.0 and 10 micrograms/g were in the ranges of 92.6-104.9% and 94.2-101.3%, respectively. The limit of detection was 0.5 microgram/g in samples. The proposed method was applied to the determination of 242 commercial vegetables and fruits. Maleic hydrazide was detected in 2 samples of imported onion at the levels of 4.9 and 7.2 micrograms/g.

Chromatography, High Pressure Liquid↗
PubMed1983

A review of environmental and health risks of maleic hydrazide.

The cellular metabolism, acute toxicity, mutagenicity, and carcinogenicity of maleic hydrazide have been reviewed. It seems that this chemical is a mutagen and a carcinogen in cell cultures and animals, but no evidence is available on human carcinogenicity regardless of population exposure in manufacturing, agriculture, and the food chain (i.e., potatoes, potato chips). Because of the level of exposure of the general public to this compound, an epidemiologic survey should be conducted to ascertain possible human health effects. Long-term feeding experiments should be conducted in several animal species to establish whether maleic hydrazide is carcinogenic by this route. Biotransformation and pharmacokinetic studies should be undertaken to obtain better understanding of the chemical's metabolism and excretion. Such investigations would firmly establish whether the tolerance for maleic hydrazide should remain unchanged or whether the use of the compound should be more restricted.

Animals↗
PubMed1983

Gas chromatographic determination of maleic hydrazide residues in potato tubers.

A gas chromatographic (GC) method is described for the determination of maleic hydrazide residues in potato tubers by oxidation of maleic hydrazide with aqueous lead dioxide to 3,6-pyridazinedione in the presence of cyclopentadiene. The reaction product, a volatile Diels-Alder adduct, could be detected in potatoes at levels in excess of 0.05 ppm with an electron capture detector. Recoveries of maleic hydrazide (as the Diels-Alder adduct) from potatoes at fortification levels of 0.1 to 10 ppm averaged 91.7%.

Chromatography, Gas↗
PubMed1996

Genotoxicity of the herbicides alachlor and maleic hydrazide in cultured human lymphocytes.

The herbicides alachlor and maleic hydrazide were evaluated for genotoxicity in peripheral blood human lymphocyte cultures. Sister-chromatid exchanges (SCE), chromosome aberrations (CA) and micronuclei (MN) were scored as genetic endpoints. To detect possible metabolic modifications in the genotoxicity of both herbicides, the cultures for SCE and MN demonstration were also treated with S9 fraction. From our results we conclude that, in the absence of metabolic activation, the two herbicides induce significant increases in the frequency of SCE, although the concentrations needed to be effective are very different. Thus, alachlor gave positive results at concentrations ranging from 1 microg/ml, and maleic hydrazide at concentrations ranging from 100 microg/ml. In addition, alachlor appears to be clastogenic in both the CA and MN assays, but only at the highest concentration tested (20 microg/ml). The co-treatment with the S9 fraction produced a slight decrease in the induction of SCE with both herbicides: nevertheless, it does not seem to affect the response in the MN assay.

Acetamides↗
PubMed1997

Genotoxicity of humic acid in cultured human lymphocytes and its interaction with the herbicides alachlor and maleic hydrazide.

The genotoxicity of humic acid and its possible interaction with the herbicides alachlor and maleic hydrazide have been evaluated in cultured human lymphocytes from two donors. Humic acid and the two herbicides have been tested (alone and combined) for sister-chromatid exchange (SCE) induction. In addition, the effect of two different preincubation times, 2 and 24 hr, was analyzed. The results indicate that humic acid and the herbicides alachlor and maleic hydrazide appear to significantly enhance the frequency of SCE, the effect of the herbicides being more pronounced. With reference to the possible interaction of humic acid with the herbicides, the results do not show a common pattern, although mainly an additive effect was obtained. Nevertheless, there is some evidence suggesting that antagonism may occur, especially in the combined treatment of humic acid and maleic hydrazide.

Acetamides↗
PubMed1998

The carry-through of residues of maleic hydrazide from treated potatoes, following manufacture into potato crisps and 'jacket' potato crisps.

Potatoes, which had been treated 'in the field' with a commercial formulation of maleic hydrazide, were processed into potato crisps and jacket potato crisps on a factory production line using standard manufacturing conditions. Samples were taken at strategic points throughout the process and analysed to determine the degree of carry-through of residues. Results demonstrated that ca 56% of the maleic hydrazide residue in a potato could be carried through into the potato crisps, irrespective of which type of crisp was being manufactured. Results from a similarly constructed study investigating the fate of pesticides applied post-harvest showed that carry-through was less than 10%. This difference is explained in terms of the different modes of action of the two classes of pesticides being investigated. It is known that, as maleic hydrazide is a systemic pesticide, it will be located within the flesh of the potato tuber and is therefore likely to be protected from the various stages of the crisping process. However, the post-harvest non-systemic pesticides are applied to the exterior surface of the tuber and are therefore not likely to be protected in the same way. The results also showed that, due to the concentration effect caused by the loss of moisture during crisp manufacture, the levels of maleic hydrazide residues in crisps (on a mg/kg product basis) were approximately twice those measured in the original potatoes.

Agrochemicals↗
PubMed2002

Genotoxicity of maleic hydrazide, acridine and DEHP in Allium cepa root cells performed by two different laboratories.

The purpose of this paper was to compare the results of the Allium cepa chromosome aberration assay between two laboratories under the same test protocol and at the same time, use chemicals and onions obtained in their own homeland. For this study three chemicals were selected: di(2-ethylhexyl)phthalate (DEHP), maleic hydrazide, and acridine. Both laboratories found genotoxicity with a positive dose-response relationship for maleic hydrazide and acridine. However, for DEHP the results were quite different--one of the laboratories found this compound not genotoxic but the other found a positive response. Although the comparative study was inconclusive for DEHP, it was successful for the maleic hydrazide, acridine and also for the positive control (methyl methanesulfonate). Further studies need to be performed in the case of DEPH.

Acridines↗
PubMed1982

Carcinogenicity study of the pesticide maleic hydrazide in mice.

The carcinogenicity of the pesticide maleic hydrazide (MH) was studied in C57BL/B6 mice. After subcutaneous (s.c.) administration no significant increase in the incidence of liver-cell tumours was seen over that in solvent-treated controls, and although a statistically significant difference in the incidence of liver-cell tumours was observed between treated and untreated males, this was considered biologically inadequate as evidence of carcinogenic effect. When MH was administered orally, no significant increase in the incidence of liver-cell tumours was seen. These results partially confirm the negative finding of a recent parallel study in rats [1].

Administration, Oral↗
PubMed2004

Cytotoxicity and mode of action of maleic hydrazide in root tips of Allium cepa L.

Maleic hydrazide (MH) is an herbicide and is a regulator of the growth of buds in vegetables during storage. It is used in agriculture-in despite its known effect as a mutagenic and clastogenic agent. In this research the effect of MH on the root tips of Allium cepa L. was determined; correlations between the effects of different concentrations and exposure times on the mitotic index (MI) and induction of chromosomal aberrations (ChA) were also examined. Experiments were carried out in triplicate, using aqueous solutions of MH to concentrations of 10(-6), 10(-5), 10(-4) and 10(-3)M, at intervals of 0, 4, 8, 12, 24, and 48 h, with a control for each combination (with the MH substituted by distilled water). The results revealed an inhibition of the MI linked to the concentration and time of treatment (F=845.51, P<0.01 and F=427.58, P<0.01, respectively). For all the concentrations used and exposure periods longer than 12 h, different types of ChA were present, with significantly increased frequencies with increases in the concentration and time of exposure (P<0.01). To determine the mechanism through which the herbicide exerts its toxicity, ultrastructural electron microscopy was conducted. The results reveal nucleolar alterations, suggesting an inhibitory effect of biosynthetic activity.

Allium↗