L-DOPA Trends in Different Tissues at Early Stages of Vicia faba Growth: Effect of Tyrosine Treatment

Claudia Oviedo-Silva,Mhartyn Elso-Freudenberg,Mario Aranda-Bustos

doi:10.3390/app8122431

Claudia Oviedo-Silva, Mhartyn Elso-Freudenberg + Show 1 more

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https://doi.org/10.3390/app8122431

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Abstract

The nonprotein amino acid Levo-3,4-dihydroxyphenylalanine (L-DOPA) has insecticidal, allelochemical, and antiparkinsonian effects. The aim of this research was to assess L-DOPA content in different tissues of Vicia faba (cv. Super Agua Dulce), and to verify if treatment with the phenolic amino acid L-4-hydroxyphenylalanine (tyrosine) had an effect on such content. Under light germination, control and tyrosine-treated early seedling stages of V. faba were studied and L-DOPA was quantified spectrophotometrically (Arnow’s method) and by high-performance thin-layer chromatography (HPTLC), as well. Additionally, tyrosinase (TYROX) and guaiacol peroxidase (GPX) activities (considered markers of a phenolic compounds metabolism) were quantified as germination proceeded. Different organs (roots, sprouts, and seeds) and different developmental stages were considered. Steady high L-DOPA concentrations were found in untreated sprouts and roots compared to seeds, as time progressed. While TYROX activity was not detected in these experiments, GPX had diverse trends. In control tissues, GPX increased in seed tissue as germination progressed, whereas in roots and sprouts, a decreasing GPX activity was observed. Tyrosine exposure decreased L-DOPA content, and decreased or did not change GPX activity (depending on the organ). Both Arnow’s and HPTLC methods were consistent in terms of tendencies, except for the scarce contents found in seeds, in which HPTLC was more sensitive. The richest source of L-DOPA was found in shoots (untreated), reaching as high as 125 mg g−1 DW (12% in DW) (the highest content reported in fava bean seedlings until now), whereas the smallest L-DOPA content was found in seeds. The importance of light germination conditions is discussed in terms of L-DOPA yield and from a physiological perspective. It is concluded that V. faba (cv. Super Agua Dulce) shoots are a good source of L-DOPA and that tyrosine addition (0.55 mM) decreases L-DOPA content in actively growing tissues (shoots and roots).

Highlights

Levo 3,4-dihydroxyphenylalanine (L-DOPA) therapy is necessary for Parkinson’s disease for its powerful antiparkinsonian effect [1]
With regard to L-DOPA concentration in control tissues: low contents were found in seeds, an increasing tendency in time could be observed until stage S3 (2–4 leaves emerged, 15 days approx), reaching concentrations up to 14.2 ± 0.38 mg g−1 DW (1.42 ± 0.03% DW) (Figure 1)
We found that tyrosine treatment decreased decreased DOPA content, and this could be related to tyrosine degradation as an energy source content, and this could be related to tyrosine degradation as an energy

Summary

Introduction

Levo 3,4-dihydroxyphenylalanine (L-DOPA) therapy is necessary for Parkinson’s disease for its powerful antiparkinsonian effect [1]. L-DOPA is a nonprotein amino acid with biological activity, found in animals and in some plants [2]. It is the precursor of catecholamine type neurotransmitters (dopamine, norepinephrine, and epinephrine), being involved in melanin synthesis as well [3]. Sci. 2018, 8, 2431 role against insects [4]. It is considered an allelochemical, i.e., a compound released into the environment affecting the growth and development of neighboring plants [1,5,6]

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