Discovering the secrets of holly: can Polish plants be a substitute for yerba mate?
Natural chemical compounds play a key role in improving the health of both humans and animals. One source rich in bioactive substances is the Paraguayan holly (Ilex paraguariensis), known as yerba mate. The plant is rich in substances such as polyphenols, saponins and alkaloids, which have therapeutic potential in the treatment of many diseases, including liver disorders, arthritis, obesity and hypertension. This is important because these diseases have already reached the scale of a societal problem, with obesity in particular and the resulting hypercholesterolaemia causing numerous deaths worldwide. It is therefore reasonable to look for ways to address such a problem that are readily available and easy to apply.
The properties of yerba mate are widely researched and the decoction from the leaves of this plant is a popular drink in many South American countries such as Argentina, Paraguay, Uruguay and Brazil. It is also slowly starting to become popular in Europe as well. Unfortunately, holly is a species of the subtropical climate zone and its cultivation in Poland is economically unviable. Therefore, a team of scientists organised by dr inż. Anna Zwyrzykowska Wodzińska from the Division of Pig and Horse Breeding at Wrocław University of Life Sciences, and including dr inż. Jakub Szperlik from the Tissue Cultures Laboratory of the Botanical Garden at the Faculty of Biological Sciences, decided to check whether other species of holly available in Poland, such as holly (Ilex aquifolium), Ilex × meserveae and Ilex perneyi, have fatty acid contents and profiles similar to those known for their subtropical counterpart. The results of their study were published in the journal Molecules.
The study was carried out using gas chromatography coupled to mass spectrometry (GC-MS). This allows both the quantification of the compounds analysed and their qualitative analysis, i.e. the identification of individual fatty acids. Using this method, 27 different fatty acids were identified in the holly samples. The most important component in all samples was α-linolenic acid, which belongs to the omega-3 fatty acid group.
It has long been known that fatty acids play diverse and important roles in plant metabolism. Fatty acids, both free and as part of more complex lipids, have three main functions in plants. Firstly, as in animals and humans, they are a metabolic fuel, both in the sense of energy source and energy storage. Secondly, they are a major component of all cell membranes and are responsible for both their proper fluidity and the proper anchorage of proteins associated with lipid bilayers. Thirdly, they act as regulators of gene expression. Fatty acids are broadly divided into saturated and unsaturated fatty acids, and their ratio plays a key role in maintaining cell membrane fluidity. This is also important because appropriate selective breeding aimed at obtaining plants with an appropriate fatty acid profile is able to lead to varieties resistant to both frost and heat, which is particularly valuable in the context of ongoing climate change.
Fats are an integral part of the diet of both humans and animals, providing essential energy and playing a significant role in the proper functioning of any organism. As an additive to animal feed, fatty acids have many functions, including: increasing animal productivity, improving feed utilisation, influencing animal condition, but also increasing the nutritional value of the feed. Due to the multifaceted function of fatty acids in plants, selecting holly varieties with a specific profile can be useful. Firstly, the specific profile of fatty acids in holly leaves can be used to select the most weather-resistant varieties. Potentially, selected varieties can be planted under harsh environmental conditions and used as a source of other important secondary metabolites, such as polyphenols, as well as saponins, which are known to have health-promoting properties. In addition, the same fatty acid can be used in various ways in the food and pharmaceutical industries. For example, selected chemotypes can be planted and used as potential sources of fatty acids. Some of them can be used on organic farms as natural fungicides, as chemicals are prohibited for this purpose and plant extracts are allowed. This is important in sustainable development strategies such as farm-to-table and the European Green Deal. Animals have a high capacity to convert fatty acids supplied with food into the structures of their tissues. Recently, the impact of feeding fatty acid supplements to animals has attracted more attention in terms of improving digestibility, productivity and metabolism. This increases both food production and the welfare of the animals themselves.
Scientific interest in non-Paraguayan holly as a functional food or medicinal plant can be considered recent compared to other plant products. Published work has shown that varieties of Ilex sp. can be divided into four groups based on their fatty acid profile and the evidence seems to point to the genus Ilex as a plant with a variety of compounds that can be used for human health and animal production. Further scientific research is needed to better understand the mechanisms of action of the compounds obtained from Ilex sp. and to confirm their positive health effects. The published results are the first such analysis in this field and open up new directions for holly research.
Link to publication in the journal Molecules.
Text: dr inż. Jakub Szperlik
Date of publication: 27.01.2025
Added by: E.K.
