Saving Europe’s medicinal plants from extinction

Traditional herbal remedies have survived from generation to generation through centuries. However today, many of the populations of medicinal plants are under threat of extinction due to environmental pressure and degradation.

Overexploitation of land in combination with climate change poses a never-before experienced threat to ecosystems and their inhabitants. Among the casualties are the plants that make up the rich biodiversity in the mountains of south-east Europe along the Balkan Peninsula.

At the heart of this region is Greece and the National and Kapodistrian University of Athens where Professor Nektarios Aligiannis and his team are working to reverse the plight of the unique flora found on the uplands of southern Europe, especially those used over the centuries in traditional medicine.

Prof. Aligiannis and his colleagues are working with funding from the EthnoHERBS project to preserve plant biodiversity in these mountain ecosystems. The issue is not just conservation. ‘The Balkan region is appreciated for its richness in indigenous medicinal plants and has a long tradition of using them for human health,’ explained Prof. Aligiannis.

Saving nature’s pharmacy

The team has a list of renowned medicinal plants that have been used for medicinal purposes over the centuries. These include Plantago, or plantain, used to calm inflammation, Hypericum, known as St John’s Wort, to treat depression, and Calendula, the daisy family for wound healing 

Traditionally, the sap was collected or plant parts dried and used as a poultice. Alternatively, plants were boiled and used as an antiseptic wash for affected areas. For solvents, natural products were used – water, olive oil, wine and wine vinegar.

The researchers’ aims are to systematically survey the plants in this region and link them to traditional knowledge and customs of the people by conducting ethnobotanical surveys. Then, using cutting-edge technologies in natural product chemistry, the team is exploiting the therapeutic potential of the plants.

Selected plants will be grown organically to ensure the conservation of biodiversity and the sustainability of the research. The most promising of these species will be cultivated to produce the required quantity of the final products.

Their plan makes use of the resources at the university as well as considerable expertise of several of the partners in the expanding field of cosmeceuticals (hybrid of cosmetics and pharmaceuticals). When they are not doing fieldwork in the mountains, they are conducting research in their lab (Lab of Pharmacognosy and Chemistry of Natural products, NKUA) and collaborating with the other 14 partnes of EthnoHERBS–for studying the biological activity behind the healing properties of the herbs.

From mountain to lab

There is a lot of lab work to be done. ‘All herbal extracts and compounds we separate will be subjected to a battery of tests for their biological activity. This includes antioxidant, antimicrobial, anti-inflammatory and anti-ageing properties. Also on the list of healing abilities are skin whitening and wound healing,’ Prof. Aligiannis told us.

Skin diseases can also be caused by a variety of microorganisms, and most of the current antibiotics available have considerable limitations in terms of antimicrobial spectrum as well as side-effects. Moreover, with the advent of ever-increasing resistant bacteria and fungal strains, there has been a corresponding rise in the universal demand for natural antimicrobial therapeutics.

For safety, the researchers are using computer models to predict possible toxicity or irritation. Additionally, the most promising products will be evaluated extensively for their biological activity and safety using cell-based assays. Potential ingredients are also to be tested on zebrafish for toxicity.

‘Clean’ technologies for ‘green’ extracts

Firmly in the 21st century, the researchers with EthnoHERBS have devised methods to extract and purify the active ingredients in an eco-friendly, non-toxic way.

Conventional extraction techniques are based on the correct choice of solvent and heat to increase the solubility of the desired compounds. Safety hazards associated with the use of organic solvents in industrial processing have led to pressure for the use of ‘clean’ technologies to produce ‘green’ extracts.

Microwave-assisted extraction provides efficient heat distribution to cut down on heat used and requires less solvent and time, saving energy and operational costs. Another new extraction technology the team has harnessed is pressurised liquid extraction that operates under constant pressure to provide consistent quality and herbal composition of the extract.

Plants used for traditional medicine contain a wide range of substances that can be used to treat chronic as well as acute infectious skin diseases. Research on wound healing agents and skin whitening is one of the developing areas in pharmacology, while effectiveness of natural products in wound care has now been recognised.

European researchers are also enlisting the aid of computer power to mitigate the high extinction risk for plants. ‘We are developing a model to predict the risk, where and when a species will become extinct,’ said Dr Spyros Theodoridis of the Senckenberg Research Institute and Natural History Museum in Germany.

‘Reasons for this continuing journey to extinction despite conservation efforts for many species are due to the high cost of technology for monitoring nowadays and lack of collaboration between conservation groups,’ outlined Dr Theodoridis, coordinator of the project BEEP.

Satellite and sequencing

‘Work is underway on the hills of the Balkan Peninsula to remedy this situation,’ noted Dr Theodoridis. The team is looking specifically at four widely used species of the herb Sideritis, known as ironwort.

‘We are using satellite data to show the shift in vegetation dynamics over the last four decades on the Balkan Peninsula mountains. Genetic change in the collections of mountain tea is being monitored in a total of 200 specimens in the Senckenberg Natural History Museum over the same time span,’ Dr Theodoridis explained. State-of-the-art technologies for high-throughput sequencing deal with a massive amount of genetic data. ‘Over a billion fragments are sequenced simultaneously,’ he added.

Enemies to this herb’s survival include ‘greening’ by trees that shade out ironwort. Rising temperatures allow the treeline to go farther up the mountain taking over the herb’s natural habitats. Furthermore, trees compete with ironwort for nutrients and the shade effect inhibits flowering and its reproductive capacity.

Made into tea, the dried plant is extremely sought after for its benefits that have been handed down through the generations. These include cough and mild stomach upset.

Moreover, the Committee on Herbal Medicinal Products considered laboratory studies that suggest that the plant has an anti-inflammatory and antimicrobial action as well as an effect in protecting the stomach and reducing contractions of gut muscles.

The team are close to finding a simple correlation between climate change and decrease in biodiversity. This will predict the rate at which the plant is travelling on its path to extinction.

Environmental organisations such as the European Environment Agency and the International Union for Conservation of Nature will be able to use this software to guide them in their efforts to ensure species do not die out before our eyes despite numerous monitoring initiatives.

The resulting computer model will enable institutions to showcase the plight of endangered species of medicinal plants to raise public awareness so work at grassroots level can increase. Dr Theodoridis pointed out: ‘Collecting a few plants for individual use is fine, but sometimes sacks are used to bring down many plants from the mountainside and this erodes populations. This is over-collection.’

Both teams think their models for conservation of traditional medicinal herbs can be applied on a wider basis. Prof. Aligiannis said: ‘Our model of conservation and exploitation could also be used for marine and animal products.’ Dr Theodoridis agreed: ‘I see our model being applied to many medicinal plants such as thyme and crocus under pressure from climate change and over-collection, contributing to the protection of Europe’s unique and invaluable medicinal ecosystem services.’

This article was originally published in Horizon, the EU Research and Innovation magazine by Susan Langthorp


General Information

EthnoHERBS and BEEP projects

Grant agreement ID: 823973 and 890201