Presence Of Mimosine Research Articles

Potential of Leucaena leucocephala and Leucaena esculenta Seeds in Human Nutrition: Composition, Techno-functional Properties, Toxicology and Pretreatment Technologies

The consumption of legume seeds has benefits for human nutrition and health. Seeds of Leucaena leucocephala and Leucaena esculenta are fast-growing legumes that are used for a variety of purposes. In general, they are used to preserve/restore the soil; the foliage can be used as fodder for livestock and the seeds for human consumption in rural populations. Leucaena seeds are a source of nutrition, since they contain proteins, carbohydrates and lipids (including omega 3, 6 and 9 unsaturated acids). The protein fraction has shown pharmaceutical effects of interest (analgesic, lipolytic, emollient, anticancer, anti-inflammatory, anti-coagulant and anti-diabetic) and some techno-functional properties for the food industry. However, the main limitation to the human consumption of leucaena seeds is the presence of mimosine, an antinutrient that produces side effects such as alopecia, growth retardation, cataracts and infertility in animals. In this sense, some technological processes that could contribute to its decrease. This work was carried out at the Nutraceuticals Department of the Interdisciplinary Research Center for Integral Regional Development, Oaxaca Unit, Mexico. A comprehensive and integrative review of research work carried out in different parts of the world was conducted. The bibliographic search was carried out from January 2020 to January 2022. Several databases such as Scopus, Latindex, Dialnet, Redalyc.org, FAO and Academic Google were explored. A total of 81 documents were used to prepare this review document. This review integrates aspects related to the potential use of leucaena seeds in human nutrition: nutritional composition, pharmacological, techno-functional properties, the processes to improve digestibility and reduce toxicity.

Brief Review: The Negative Impact Of Mimosin in L. leucocephala in Ruminant Animals and Processing Methods to Reduce Poisoning Effects on Ruminant Livestock

Leucaena leucocephala, a high-quality ruminant feed, is essential for livestock production in the tropics, despite the presence of mimosine in the leaves. Mimosine, in high concentrations, can severely affect animal health and performance. Mimosine and its metabolites, 3-hydroxy-4-(1H)-piridon (DHP), are toxic to ruminants and caused hair loss, slow growth, and oral ulceration, whereas DHP is goitrogenic because it is analogous to tyrosine so resulting in goiter. Mimosine and its metabolites are the main hindrance blocks for the utilization of L.leucocephala as animal feed. Characteristic signs of L.leucocephala toxicity are alopecia, anorexia, reduced weight gain, and weight loss, excessive salivation, esophageal lesions, enlarged thyroid and low circulating concentrations of thyroid hormones. Therefore, the research workers had tried to develop different methods to eliminate the toxicological effects of mimosine and its metabolites. This paper aims to briefly review the negative effects of mimosine from L. leucocephala and its processing to reduce the toxic effects on ruminants. Keywords: Leucaena leucocephala , mimosine, toxicity, metabolites

Leucaena toxicity: a new perspective on the most widely used forage tree legume

The tree legume Leucaena leucocephala (leucaena) is a high quality ruminant feed, vitally important for livestock production in the tropics, despite the presence of mimosine in the leaves. This toxic non-protein amino acid has the potential to limit productivity and adversely affect the health of animals. In the 1980s, the ruminal bacterium Synergistes jonesii was discovered and subsequently distributed in Australia as an oral inoculum to overcome these toxic effects. However, in recent times, a number of factors, including: surveys of the status of toxicity worldwide; improved understanding of the chemistry and mode of action of the toxins; new techniques for molecular sequencing; and concerns about the efficacy of the in vitro inoculum; have cast doubt on some past understanding of leucaena toxicity and provide new insights into the geographical spread of S. jonesii . There is also confusion and ignorance regarding the occurrence and significance of toxicity in many countries worldwide. Ongoing research into the taxonomy and ecology of the Synergistetes phylum, improved methods of inoculation, and improved management solutions, along with aware-ness-raising extension activities, are vital for the future success of leucaena feeding systems.

Mimosine arrests the cell cycle prior to the onset of DNA replication by preventing the binding of human Ctf4/And-1 to chromatin via Hif-1α activation in HeLa cells

Though the G1 checkpoint in mammalian cells has been known for decades, the molecular targets that prevent S-phase entry remain unknown. Mimosine is a rare plant amino acid that arrests the cell cycle in the G1 phase before entry into S phase. Here, we show that mimosine interrupts the binding of Ctf4 to chromatin, which is essential for the initiation of DNA replication in HeLa cells, and this effect is mediated by the Hif-1α-dependent increase in the level of p27. Depletion of Hif-1α results in an increased binding of Ctf4 to chromatin and the entry of cells into S phase even in the presence of mimosine. These results suggest that the binding of Ctf4 to chromatin is the target of the Hif-1α-dependent checkpoint pathway for cell cycle arrest in G1 phase. Although we observed Hif-1α-dependent arrest in mimosine-treated cells, it is possible that Ctf4 may act as a common target for G1 arrest in various other checkpoint pathways.

Induction, isolation and purification of mimosine degradation enzyme from newly isolated Pseudomonas putida STM 905

A bacterial isolate STM 905, having high mimosine degradation ability, was isolated from the rhizosphere of Leucaena leucocephala. The cells of this strain were rod shaped, Gram negative, motile, could grow in pH range of 5.0–11.0 and temperature range 15–42 °C. On 16S rDNA sequence analysis based identification the strain STM 905 was found to be closest to Pseudomonas putida strain BH. Growth of this bacterium in the presence of mimosine, as the sole source of carbon and nitrogen, was correlated with the induction of an enzyme capable of mimosine degradation. This enzyme catalyses the degradation of mimosine to their corresponding 3-hydroxy-4(1 H)-pyridone (DHP), pyruvic acid and ammonia. The maximum induction of mimosine degradation enzyme activity has been observed at 15-h growth of culture. The presence of glucose in the culture medium inhibited the mimosine degradation enzyme induction by mimosine, while the presence of NH 4Cl in the growth medium had no significant effect of inhibition on mimosine degradation enzyme induction. The mimosine degradation enzyme was purified with 47% recovery in three steps, ammonium sulphate fractionation, ion exchange and size exclusion-chromatography, with overall 34.59-fold purification. The purified native form had an estimated molecular mass of 280 kDa and was found to composed of four subunits each of molecular mass ∼70 kDa as determined by SDS-PAGE. Km for mimosine was found to be 1.3 mM. The purified enzyme showed sharp pH optima at 7.2.

BAD Detects Coincidence of G2/M Phase and Growth Factor Deprivation to Regulate Apoptosis

BAD, a member of the Bcl-2 protein family, promotes mitochondria-dependent apoptosis. Here, we report that BAD dissociates from 14-3-3zeta at each G2/M phase of proliferating lymphoid cells. The cell cycle-dependent dissociation of BAD was associated with phosphorylation at Ser-128, whereas mutant S128A-BAD, in which Ser-128 was converted to alanine, remained associated with 14-3-3zeta throughout the cell cycle. Although the cell cycle-dependent dissociation of BAD per se did not induce apoptosis, growth factor deprivation induced prompt apoptosis at the G2/M phase but not at the G1 phase. In cells expressing S128A-BAD, growth factor deprivation-induced apoptosis was markedly delayed and was accompanied by a delayed dephosphorylation of growth factor-dependent regulatory serine residues. These results indicate that BAD induces apoptosis upon detecting the coincidence of G2/M phase and growth factor deprivation.

Mimosine Arrests Cells in G1 by Enhancing the Levels of p27Kip1

The plant amino acid mimosine, an effective inhibitor of DNA replication, has been demonstrated to arrest cell cycle progression in late G1. To understand further the molecular mechanism by which mimosine affects the cell cycle, we treated quiescent cells with serum in the presence of 800 μM mimosine. The cells did not enter S phase and were completely arrested in G1 phase. Although neither the mitogenic induction of the G1 cyclins nor the protein levels of cdk2 or cdk4 were affected, serum-dependent activation of cdk2 was blocked. This corresponded to elevated levels of the cdk inhibitor p27Kip1. This was not mediated through inhibition of degradation but rather involved increased synthesis of both p27Kip1 mRNA and protein. Mimosine did not appear to affect mitogen-dependent signals that normally lead to p27Kip1 downregulation since the inhibitor was induced to even greater levels in quiescent, unstimulated cells. In the presence of mimosine, actinomycin D treatment for 2 h prevented the increase of p27Kip1 mRNA, but p27Kip1 protein levels were still enhanced under these conditions. We propose that mimosine blocks the cell cycle in late G1 phase by upregulation of p27Kip1 protein levels through transcriptional and posttranscriptional regulatory mechanisms.

Oxidative stress during selenium deficiency in seedlings of Trigonella foenum-graecum and mitigation by mimosine Part II. Glutathione metabolism.

Adaptive alterations in glutathione (GSH) metabolism were studied during oxidative stress induced by selenium (Se) deficiency in germinating seedlings of Trigonella foenum-graecum grown for 72 h and the response to supplementation individually of Se or mimosine was explored. Growth enhancement with improved mitochondrial efficiency was elicited by supplementation of Se at 0.5-0.75 ppm or mimosine at 0.1-0.2 mM. Total thiol and protein levels of mitochondrial and soluble fractions, in general, did not vary significantly with supplementation of either Se or mimosine except that the mitochondrial protein levels in mimosine groups (0.1-0.2 mM) decreased by 20-30%. Mitochondrial glutathione peroxidase (GSH-Px) increased by twofold in activity toward H2O2, cumene hydroperoxide (CHP), and t-butyl hydroperoxide (tBHP) in Se groups, and by 50-60% increase toward H2O2 and CHP but by a twofold enhancement in enzyme activity with tBHP in mimosine groups. Soluble GSH-Px activity increased by 30-40% only in mimosine groups and remained unaltered in Se groups. Glutathione S-transferase activity (GST) in the soluble fraction of both Se and mimosine groups increased dramatically by fivefold to sixfold. Distinct differences were noted in the response of the stressed seedlings toward exposure to Se or mimosine and included a decline in glutathione reductase (GR) activity by 50-60% in both mitochondria and soluble fractions of Se groups and an increase in GR activity of the mitochondria by twofold and of the soluble enzyme activity by 30% in the mimosine groups. Mimosine exposure resulted in a dose-dependent decrease in the gamma-glutamyl transpeptidase levels, but, in contrast, a significant enhancement by 50% was noted in the Se group at 0.75 ppm. The results including the differential response of GR activity to Se or mimosine supplementation are reflective of an effective reductive environment in Se groups and increased turnover of GSH in the presence of mimosine.

Mimosine, a toxin produced by the tree-legume leucaena provides a nodulation competition advantage to mimosine-degrading rhizobium strains

The trees and shrubs of different Leucaena spp. contain a non-protein amino acid, mimosine which is toxic to animals and microorganisms. We found small amounts of mimosine in the nodules and the root exudate of Leucaena leucocephala. Some Leucaena-nodulating strains of Rhizobium degrade mimosine (Mid +) and use it as a source of nutrients. To determine if the ability to catabolize mimosine by Rhizobium has a role in symbiosis, we constructed mutants that cannot degrade mimosine (Mid −) from a Mid + competitive strain and tested them for growth in the presence of mimosine. When mimosine was added to a complete medium, it stimulated the growth of the Mid + wild-type strain but inhibited the growth of a mutant in which the gene encoding a mimosine-degrading enzyme was disrupted. L. leucocephala and Phaseolus vulgaris plants inoculated with these mutants formed effective nodules showing that mimosine catabolism by the microsymbiont has no direct effect on symbiosis. When mixtures of the wild-type strain and the Mid − mutants were used to inoculate L. leucocephala and P. vulgaris seedlings, most nodules in L. leucocephala were occupied by the wild-type strain, whereas, the nodule occupancies in P. vulgaris were proportional to the inoculant mixtures. These results show that the Mid − mutants are defective in nodulation competition on Leucaena but not on beans. This indicates that mimosine present in Leucaena provides a nodulation competition advantage to the mimosine degrading Rhizobium strains.

Chemical Examination ofLeucaena glaucaSeeds

Leucaena gluucu Bentham (Leguminosae) is reported to be toxic: cattle fed with its leaves suffer from loss of their hair and from skin disorders. No systematic work appears to have been carried out with the seed, although the toxicity of the seeds is considered to be due to the presence of mimosine.' An amino acid, 5-hydroxy pipecolic acid2 was reported to be present in the free state in the seed. The present investigation was carried out with the seeds obtained from Hawaii. The seeds were procured with a view to cultivate the plant on a piece of land. The seeds (average wt. 35mg and size 7mm x 4mm) were shiny, flat and oblong, difficult to decorticate. Analysis: moisture, 4.7%; carbohydrate (total) 45%; protein 31.9% (nitrogen 5.1%), and fat 6.2%. The freshly pulverised seeds (900g) were successively extracted with petrol-ether and ethanol. The petroleum ether extract was 6.5% whereas the ethanol extract was 1.3%. The residual meal yielded 6.6% water soluble gummy material. The crude fat had the following characteristics: Colour (Lovibond. 1 cm, 7.5 R, 27.4 Y); iodine value, 122; saponification value, 192; acid value, 6.4; and alcohol-soluble matter 33 'Yo. The alcohol-soluble material appeared to be mostly carbohydrate accompanied by some phenolic constituents and free amino acids. It showed UV absorption at 283 nm (cf. ultra voilet absorption of leucenol at 282nm4). The alcoholic extract freed of petrol ether-soluble fractions of the seed material yielded a sterol, m.p. 138-139'; acetate, m.p. 129', (C, 82.4; H, 11.23%; Calcd. for C31HszOz: C,81; 48; H, 11.4%) and benzoate (benzoyl chloride-pyridine), m.p. 142°C (C, 83.32; H, 10.40; Calcd. for C36Hs40z; C, 83.39; H, 10.42%), which was found to be identical with p-sitosterol by its IR spectra superposable with that of an authentic sample.

Toxic action of mimosine—I. Inhibition of mitosis and DNA synthesis of H.Ep-2 cell by mimosine and 3,4-dihydroxypyridine

The effect of mimosine, (β-N(3-hydroxy-4-pyridone)-α-amino propionic acid), and 3,4-dihydroxypyridine on cell growth, mitotic frequency, DNA, RNA and protein synthesis of H.Ep-2 cell cultures has been studied. Thymidine-H 3, uridine-H 3 and l-phenylalanine-C 14 incorporation were measured in a liquid scintillation counter and thymidine-H 3 uptake by an autoradiographic technique. Cell growth, mitotic frequency and thymidine-H 3 incorporation were all decreased by the presence of mimosine or 3,4-dihydroxypyridine. The toxic effects of these compounds were decreased by the presence of Al 3+. RNA synthesis was less inhibited than DNA synthesis and practically no inhibition of protein synthesis was observed in the presence of mimosine or 3,4-dihydroxypyridine.