Background: The Lamiaceae family, one of the most important
herbaceous and shrub plant families, includes a wide variety of plants with
biological and medicinal uses. This study aimed to conduct a comparative analysis
of phenolic compounds content and biological activity of extracts from eight
species of Lamiaceae plants, cultivated in a temperate climate, and to
study the effect of the foliar salicylic acid application on these parameters.
Methods: Lamiaceae plants (Lavandula angustifolia,
Salvia officinalis, Hyssopus officinalis, Agastache
foeniculum, Thymus serpyllum, Mentha piperita,
Origanum vulgare, Monarda didyma) cultivated on field
experimental sites. Plants were sprayed with salicylic acid at a concentration of
1 mM. The untreated with salicylic acid plants were used as control.
Results: The highest contents of hydroxycinnamic acids and flavonoids in
control plants were observed in the Agastache foeniculum (6.4
0.6 mg g and 6.5 0.4 mg g respectively). The highest
content of phenolic compounds was found in Monarda didyma (13.8
0.7 mg g). Among the control plants, Agastache foeniculum,
Hyssopus officinalis, and Mentha piperita were
characterized by the highest antioxidant activity. All the studied extracts had
the ability to inhibit -amylase and -glucosidase. Significant
positive correlations were revealed between the antioxidant activity and the
contents of hydroxycinnamic acids, total phenolic compounds, and flavonoids. A
high degree of correlation was found between the -amylase inhibitory
activity and the content of hydroxycinnamic acids (r = 0.72, p 0.05), as well as between the -glucosidase inhibitory activity
and the content of flavonoids (r = 0.83, p 0.05) and
hydroxycinnamic acids (r = 0.81, p 0.05). The foliar
treatment with salicylic acid led to an increase in the contents of
hydroxycinnamic acids (in 6 species), flavonoids (in 2 species), total phenolic
compounds (in 7 species), antioxidant activity (in 5 species), as well as in
-amylase (in 4 species) and -glucosidase (in 5 species)
inhibitory activity compared to the control plants. Lavandula
angustifolia was the most susceptible to foliar treatment with salicylic acid.
In this plant species, a significant increase in all studied biochemical
parameters was noted. Conclusions: The results obtained on the
stimulating effects of salicylic acid can be used to increase the nutritional and
pharmacological value of plants of the Lamiaceae family cultivated in
temperate climates.