Isoflavone Content in Subterranean Clover Germplasm from Sardinia

Area of Science:

• Plant biochemistry
• Agricultural science
• Nutraceutical science

Background:

• Subterranean clover (Trifolium subterraneum) is a key pasture legume with significant genetic diversity in Sardinia.
• Legumes, including clovers, produce bioactive flavonoids like isoflavones, which are natural phytoestrogens with health benefits.
• Current sources for isoflavones in medical and nutraceutical applications include red clover (Trifolium pratense) and soybean (Glycine max).

Purpose of the Study:

• To evaluate the flavonoid and isoflavone content in Sardinian subterranean clover genotypes.
• To compare the isoflavone profile of subterranean clover with red clover ecotypes.
• To assess the potential of subterranean clover as an alternative source of isoflavones for exploitation.

Main Methods:

• Cultivation of 14 subterranean clover genotypes and 2 red clover ecotypes ex-situ.
• Analysis of flavonoid content and composition using High-Performance Liquid Chromatography (HPLC) and Liquid Chromatography/Electrospray Ionization-Mass Spectrometry (LC/ESI-MS).
• Tentative identification of 20 compounds, including isoflavones and flavonols, primarily as glucosides or glucosyl malonates.

Main Results:

• Subterranean clover extracts were rich in derivatives of genistein, biochanin A, and formononetin.
• Subterranean clover exhibited higher total isoflavone content and lower total flavonol concentration compared to red clover.
• Isoflavone concentrations in subterranean clover surpassed reported levels in soybean and red clover.

Conclusions:

• Subterranean clover genotypes from Sardinia possess significant potential as a novel source of isoflavones.
• The high genotypic variation within subterranean clover allows for selection of varieties with enhanced isoflavone content.
• This species could serve as a valuable alternative for nutraceutical and pharmaceutical applications.