Australian native mint shows potential as beneficial phenol source

Extracts of Australian native mint show strong antioxidant capacities and could be a source of beneficial phenolic compounds, say researchers.

The new study, published in Food Chemistry, noted that while Australian native mint (Mentha australis R. Br) has been traditionally used by indigenous people for natural remedies, its bioactive components have never been investigated. 

Led by Kitty Tang from the University of New South Wales, Australia, the team tested the antioxidant capacity and phenolic composition of the native mint for the first time – identifying nine phenolic acids and flavonoids.

“Aqueous methanolic extract of the mint exhibited comparable antioxidant capacity to the common spearmint,” wrote Tang and her colleagues – who concluded that Australian native mints contain a number of phenolic components “known for their beneficial biological functions.” 

As such, the team suggested that the health benefits arising from the consumption of the native herb is worth further investigation.

A traditional remedy

The team noted that Australian native mint has a long history of traditional use by the indigenous people of Australia.

“The indigenous people have an extensive knowledge of native plants uses as food and as well as their treatment of various illnesses and diseases,” said the authors. “This knowledge, accumulated through observations, has been passed down from generation to generation by word of mouth, and as a result much of this evidence is anecdotal.”

Tang and her colleagues noted that decoctions of native mint plants have been traditionally used to treat colds and coughs, “while inhaling the crushed mint relieved headaches.”

However, there has yet been any scientific evidence on the chemical composition and bioactivities of the native plant.

New study

The composition of phenolic compounds were investigated by high performance liquid chromatography (HPLC) and high resolution liquid chromatography mass spectrometry (LC-HRMS). After this the team used tandem mass spectrometry (LC–MS/MS) and nuclear magnetic resonance (NMR) analysis to confirm the presence of specific phenolic compounds.

“Once identified, the quantification of the components was carried out by HPLC coupled with a photodiode array detector (HPLC-PDA),” Tang and her colleagues said.

The major compounds identified through the analysis were rosmarinic acid, neoponcirin, narirutin, chlorogenic acid and biochanin A.

Minor compounds identified included caffeic acid, apigenin, hesperetin and naringenin, said the team.

“Neoponcirin and biochanin A were identified for the first time in the Mentha genus,” the authors confirmed.

Source: Food Chemistry

Volume 192, Pages 698–705, doi: 10.1016/j.foodchem.2015.07.032

“Identification and quantification of phenolics in Australian native mint (Mentha australis R. Br.)”

Authors: Kitty S.C. Tang, et al