Non-targeted metabolite profiling highlights the potential of strawberry leaves as a resource for specific bioactive compounds.
BACKGROUND
The non-edible parts of horticultural crops, such as leaves, contain substantial amounts of valuable bioactive compounds which are currently only little exploited. For example, strawberry (Fragaria × ananassa) leaves may be a promising bioresource for diverse health-related applications. However, product standardization sets a real challenge, especially when the leaf material comes from varying cultivars. The first step towards better quality control of berry fruit leaf-based ingredients and supplements is to understand metabolites present and their stability in different plant cultivars, so this study surveyed the distribution of potentially bioactive strawberry leaf metabolites in six different strawberry cultivars. Non-targeted metabolite profiling analysis using LC/qTOF-ESI-MS with data processing via principal component analysis and k-means clustering analysis was utilized to examine differences and commonalities between the leaf metabolite profiles.


RESULTS
Quercetin and kaempferol derivatives were the dominant flavonol groups in strawberry leaves. Previously described and novel caffeic and chlorogenic acid derivatives were among the major phenolic acids. In addition, ellagitannins were one of the distinguishing compound classes in strawberry leaves. In general, strawberry leaves also contained high levels of octadecatrienoic acid derivatives, precursors of valuable odour compounds.


CONCLUSIONS
The specific bioactive compounds found in the leaves of different strawberry cultivars offer the potential for the selection of optimized leaf materials for added-value food and non-food applications. © 2016 Society of Chemical Industry.
Institute of Public Health and Clinical Nutrition, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland.
Anna
A
Kårlund
Institute of Public Health and Clinical Nutrition, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland.
Kati
K
Hanhineva
School of Pharmacy, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland.
Marko
M
Lehtonen
The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK.
Gordon J
GJ
McDougall
The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK.|Norwegian Institute of Bioeconomy Research, Nord Holt, Postboks 2284, N-9269, Tromsø, Norway.
Derek
D
Stewart
Institute of Public Health and Clinical Nutrition, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland.|Department of Environmental and Biological Sciences, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland.
Reijo O
RO
Karjalainen
D002851:Chromatography, High Pressure Liquid; D005419:Flavonoids / Q000032:analysis / Q000378:metabolism; D031985:Fragaria / Q000737:chemistry* / Q000378:metabolism; D005638:Fruit / Q000737:chemistry / Q000378:metabolism; D044949:Kaempferols / Q000032:analysis / Q000378:metabolism; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry* / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry* / Q000378:metabolism
D005419:Flavonoids; D044949:Kaempferols; D010636:Phenols; D010936:Plant Extracts; C006552:kaempferol
Fragaria × ananassa; cultivars; leaves; non-targeted metabolite profiling; polyphenols