Swiss herbs in climate change: HPTLC fingerprints of thyme, sage and horehound from Zermatt and a controlled green house

Thymus vulgaris L., Salvia officinalis L. and Marrubium vulgare L. have been used traditionally in Switzerland for relieving symptoms in the upper respiratory tract. Ricola is a well-known producer of Swiss cough lozenges and herbal teas based on a traditional 13 herb mixture, which contains the aforementioned three herbs from the Lamiaceae family.

In order to assess the influence of climate change on the accumulation of secondary metabolites, a primary study which involved the cultivation of the seeds of Ricola varieties of thyme, sage and horehound compared to seedlings from a commercial nursery inside a climate controlled green house as well as outdoors at 450 m elevation, was carried out. In addition, the Ricola varieties were harvested from the Ricola herb garden in Zermatt, Blatten at 1740 m altitude. The morphologies of the plants were assessed until harvest. Dried plant samples were extracted with 50% MeOH (v/v) 1:20 15 min in an ultrasonic bath and a semiquantitative analysis using HPTLC fingerprints with Neu’s reagent for flavonoids/phenolic acids in 366 nm was carried out, as well as DPPH in white light to compare radical scavenging activity of the same zones.

The results show that the effect of elevated temperature averaging from 7 – 9°C on growth, morphology and metabolites is plant and accession specific. Sage and horehound exhibited more and larger zones and stronger radical scavenging activities, whereas thyme did not exhibit notable differences. The results are a first indication of how chemodiversity is influenced by elevated temperatures. Further agro-phytochemical studies over several harvest seasons are needed to assess consequences of climate change on herbs.

Publication History

Article published online:
16 November 2023