• DOI:10.3390/molecules23071664
• Published online 2018 Jul 9

Dorota Kregiel, Ewelina Pawlikowska, and Hubert Antolak^*

Abstract

Nettles (genus Urtica, family Urticaceae) are of considerable interest as preservatives in foods for both human and animal consumption. They have also been used for centuries in traditional medicine. This paper reviews the properties of nettles that make them suitable for wider applications in the food and pharmaceutical industries. Nettles contain a significant number of biologically-active compounds. For example, the leaves are rich sources of terpenoids, carotenoids and fatty acids, as well as of various essential amino acids, chlorophyll, vitamins, tannins, carbohydrates, sterols, polysaccharides, isolectins and minerals. Extracts from the aerial parts of nettles are rich sources of polyphenols, while the roots contain oleanol acid, sterols and steryl glycosides. Due to the variety of phytochemicals and their proportions they contain, nettles show noticeable activity against both Gram-positive and Gram-negative bacteria. These properties make nettles suitable for a range of possible applications, including functional food, dietary supplements and pharmacological formulations. Despite these benefits, the nettle is still an underestimated plant source. This paper provides a unique overview of the latest research on nettle plants focusing on the possibilities for transforming a common weed into a commercial plant with a wide range of applications. Special attention is paid to the antimicrobial activity of the active compounds in nettles and to possible uses of these valuable plants in food and feed formulations.

Keywords: Urtica spp., bioactive compounds, antioxidant activity, antimicrobial activity, traditional medicine, food industry, animal breeding

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1. Habitats of Urtica spp. Plants

The genus Urtica belongs to the family Urticaceae in the major group Angiosperms (flowering plants). There are 46 species of flowering plant of the genus Urtica [1] (Table 1). The most prominent members of the genus are the stinging nettle Urtica dioica L. and the small nettle U. urens L., which are native to Europe, Africa, Asia and North America. Plants belonging to the genus Urtica are herbaceous perennials and can grow up to 2 m tall. Serrated leaves are attached in pairs opposite each other to the stem. The soft leaves and the rest of the plant are coated in hairs, some of which sting. The serrated, hairy leaves and sting are generally recognized characteristics of this plant [2]. However, the European variety U. galeopsifolia does not have stinging hairs [3]. The underground roots by which the plant spreads are noticeably yellow. Small flowers, each with four greenish-white petals, sit in dense clusters on elongated inflorescences towards the top of the stem.

Reference:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6100552/