Leucaena leucocephala Mimosine

Mimosine (= Leucaenol) Leucaena leucocephala (jumbie (pyridinone amino acid) bean), Mimosa pudica (Fabaceae)... 

L-Mimosine (18) (Fig. 13.5) is a toxic heterocyclic amino acid that has been reported from several legumes. Among the plants that contain mimosine are Mimosa pudica and Leucaena leucocephala. The latter is often cultivated in tropical countries as a windbreak, a forage crop, and as a shade crop for coffee, tea and cacao (Rosenthal, 1991). This native of Mexico is capable of fixing nitrogen and is a quite agres-sive species. 

Non-protein amino acids have previously been implicated in allelopathy. For example, mimosine has been associated with allelopathy of the legume tree Leucaena leucocephala [168]. l-DOPA, a compound structurally related to uj-tyrosine (Fig. 5), has been implicated in allelopathy of Mucuna pruriens ([158] and Section Rice Allelochemicals). Roots of pea (Pisum sativa) exude j3-(3-isoxazolin-5-on-2yl)-alanine which inhibits root growth on nonlegume plant species [169], although this non-protein amino acid is much less phytotoxic than m-tyrosine. 

The pyridine (dihydropyridine) derived amino acid P-(3-hydroxy-4-pyridon-l-yl)-L-alanine, L-mimosine (2-62), is thyreotoxic (causes over-activity of the thyroid gland) to nonruminant animals. It occurs in the subfamily Mimosoideae of the legume family Fabaceae, in plants of the genera Mimosa and Leucaena. Leucaena leucocephala (syn. Mimosa glauca) is native to the tropical and subtropical Americas, known as White Leadtree, and is used as livestock fodder. The mimosine content in seeds can reach up to 5% of dry matter (see Section 10.3.2.7.1). The amino acid pyridosine arising from lysine in the Maillard reaction can also be considered a dihydropyridine derivative (see Section 4.7.5.12.3). 

An important amino acid toxic to Hvestock is L-mimosine, P-(3-hydroxy-4-pyridone-l-yl)-L-alanine (see 2-62). It occurs in plants of genera Leucaena and Mimosa of the family Mimosaceae. Its quantity in the fodder plant L. leucocephala can reach up to 30-50 g/kg of dry matter. 

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