Melatonin in Plants and Plant Culture Systems: Variability, Stability and Efficient Quantification

Area of Science:

• Plant biochemistry
• Analytical chemistry
• Molecular biology

Background:

• Melatonin and serotonin are crucial plant compounds, but their stability is debated due to varied analytical methods.
• Conflicting research results hinder understanding of melatonin's role in plant physiology.

Purpose of the Study:

• To develop and validate a robust method for quantifying melatonin, serotonin, and their precursors in diverse plant species.
• To investigate the stability of melatonin and serotonin in plant tissue culture systems under various conditions.

Main Methods:

• Liquid chromatography-single quadrupole mass spectrometry (LC-MS) was used for quantifying tryptophan, tryptamine, N-acetylserotonin, serotonin, and melatonin.
• A fully validated method was developed with high reproducibility (%RSD 1-10%) and recovery (82-113%).
• Plant tissue cultures were used to assess the stability of melatonin and serotonin concerning media composition and light exposure.

Main Results:

• The LC-MS method demonstrated excellent reproducibility and sensitivity for indoleamine quantification.
• Melatonin and serotonin stability was unaffected by media composition or light cycles.
• Temperature was identified as a key factor in melatonin degradation, with significant losses observed after 28 days.

Conclusions:

• A reliable and accessible LC-MS method is established for plant indoleamine analysis.
• Melatonin and serotonin exhibit significant stability in plant systems for over three weeks, despite temperature-induced degradation.
• This validated method and stability data support further research into the physiological roles of these compounds in plants.