Distribution Analysis of Plant Alkaloids in Narcissus, by MS Imaging

Significance of the Topic

Plant-derived alkaloids such as galanthamine are critical therapeutic agents, notably as acetylcholinesterase inhibitors in Alzheimer’s disease treatment. Optimizing their production through rapid screening and spatial mapping of biosynthetic compounds in source plants enhances pharmaceutical yield and reduces extraction costs.

Objectives and Study Overview

This study aimed to establish a two-step workflow: rapid qualitative screening of alkaloids in Narcissus tazetta using probe electrospray ionization (PESI) combined with quadrupole time-of-flight mass spectrometry (Q-TOF), followed by mass spectrometry imaging (MSI) via atmospheric MALDI to visualize the spatial distribution of key alkaloids in bulb and leaf tissues.

Methodology and Instrumentation

Sample Preparation and Analysis Conditions:

• Plant Material: Narcissus tazetta leaves (~15 cm growth) and bulbs.
• Extraction: Freeze-dried leaves extracted with 50 % aqueous ethanol.
• PESI Screening: Direct analysis using DPiMS QT probe with LCMS-9030 Q-TOF in positive mode; single acquisition in ~0.5 min.
• MSI Sample Prep: 20 µm cryosections mounted on ITO slides; CHCA matrix applied by sublimation (0.7 µm) via iMLayer system.
• MALDI-MSI: iMScope QT coupled to LCMS-9030; spatial resolutions of 25 and 10 µm; laser settings: diameter 1/2, intensity 50/60, repetition 20 kHz.

Used Instrumentation

• DPiMS QT probe electrospray ionization kit
• iMScope QT atmospheric MALDI imaging mass microscope
• LCMS-9030 quadrupole time-of-flight mass spectrometer
• iMLayer matrix sublimation apparatus
• LabSolutions Insight Explore and IMAGEREVEAL MS data analysis software

Main Results and Discussion

PESI-Q-TOF Screening:

• Detected galanthamine, lycorine, tazettine, choline, and hexose sugars with mass accuracy within 1 mDa.
• Enabled sub-minute qualitative confirmation of target alkaloids.

MSI Distribution Analysis:

• Strong ion signals of galanthamine, lycorine, and tazettine in bulb and leaf sections.
• Galanthamine predominantly localized in bulb regions destined for leaf development; lycorine and tazettine displayed distinct spatial patterns.
• Analysis times ranged from ~28 min (leaf at 25 µm) to ~4 h 20 min (bulb at 25 µm), shortened to ~1 h 12 min at 10 µm resolution.

Benefits and Practical Applications

• Rapid alkaloid screening accelerates selection of high-yield plant varieties.
• Spatial mapping guides targeted tissue harvesting and purification workflows.
• Modular instrument configuration allows seamless switching between PESI and MALDI modes.

Future Trends and Possibilities of Use

Advancements may include integration of higher-resolution imaging, automated matrix application, AI-driven data interpretation, and extension to broader metabolomic profiling in plant breeding, quality control, and natural product research.

Conclusion

The combined use of PESI-Q-TOF and MALDI-MSI on a unified platform enables ultrafast, accurate detection and visualization of plant alkaloids. This approach supports efficient discovery of metabolite-rich tissues, enhancing extraction yields and lowering production costs in pharmaceutical applications.

References

1. Planta Med. 2003;69:1166–1168.