Wild medicinal and aromatic plants (MAPs) have a high potential for domestification and growing in organic farming and further use in medicine, food and cosmetics. The Institute for Environmental Solutions (IES) in cooperation with agriculture experts and organic farming company SIA “Field and Forest”, as well as Latvian Institute of Organic Synthesis study the potential of 9 wild spring MAP species growing in organic farming.
The researchers together with partners from industry have selected the following MAPs for the study – cowslip (Primula veris), woodruff (Galium odoratum), mezereon (Daphne mezereum), coltsfoot (Tussilago farfara), pasqueflower (Pulsatilla pratensis), lily of the valley (Convallaria majalis), ground-ivy (Glechoma hederacea), greater celandine (Chelidonium majus) and lady’s mantle (Alchemilla spp).
IES spoke to leading researcher Dr Arta Kronberga, who showcased the latest conclusions and described further steps of the research.
IES: How the development of new growing technologies for 9 wild spring MAPs has been going?
Dr Arta Kronberga (A.K.): At the beginning of this research, we selected 9 medical and aromatic plant species to understand which ones are suitable for commercial cultivation. The MAPs suitability for the cultivation is determined by a variety of factors: genotype, quality of the chemical composition, agronomic aspects (how each species adjusts to cultivation conditions), economic benefits (is it economically beneficial to grow the particular MAPs in organic farming).
Our study is coming to an end. Last harvest is planned to be in Spring 2021. Then, the researchers form the Latvian Institute of Organic Synthesis (OSI) will do the final chemical composition analysis of the harvested MAP samples. After that we will be able to draw conclusions on which medical plant species are suitable for organic farming. We can already conclude that the results for each species will be different.
IES: How the chemical analysis of MAPs have evolved?
A.K.: OSI researchers have planned more than one campaign of MAPs chemical composition analysis during this research. The planned campaigns are the following:
- First chemical analysis campaign by OSI researchers was done on samples collected in wild.
- Next set of chemical analysis was done to assess the concentration of active compounds of the first MAPs species grown in experimental fields in Priekuļi municipality (Spring / Summer season 2019).
- Third chemical analysis campaign was done on MAPs samples gathered from experimental fields in 2020 vegetation season. Chemical composition analysis was carried out for different populations within each of the nine MAP species that were grown by using various organic farming methods. This allows us to understand how the methods, such as distance between plants or harvesting time, influence chemical composition of MAPs.
IES: What conclusions can you draw from the chemical composition analysis of these 9 MAPs?
A.K.: OSI researchers are still working on the chemical composition analysis. They do them in two steps:
- First step – to identify full chemical profile of each MAP sample to understand what kind of active substances they contain.
- Second step – to analyse the chemical composition of each MAP sample and to measure concentration of active compounds in each sample.
We already see differences in responsibility of different species to wild and organic farming conditions, as well as differences between evaluated populations within each specie. When evaluating the suitability of growing these plants in commercial organic farming, we also have to take into account other factors, such as agronomic, yield and economic factors.
Besides chemical analysis of active compounds, OSI researchers go one step further in this research. They have started to test plant extracts on cells to assess their biological activity. Additional task is evaluation of presence of toxic alkaloids with focus on such species as greater celandine and coltsfoot.
IES: How the testing of plant extracts on human skin cells are carried out?
A.K.: In the last research season, OSI researchers started their first tests on cells. They do not use all 9 MAPs in the tests. They use those plants that have shown interesting chemical compositions during the chemical analysis stage.
“In these tests, we use the ethnobotany research experience and expertise of IES about MAPs usage in medicine. We are testing whether the people historical knowledge about medicinal plants has a real background . For example, in ethnobotany expeditions researchers obtained information about use of MAP mezereon (Daphne mezereum) as a treatment for the dental pain. By using mezereon material, we can assess its effects on cells.”
IES: Regarding mezereon (Daphne mezereum), how the propagation by using plantlet rooting has evolved?
A.K.: These experiments are still in process because ligneous plant and shrub propagation by using this method require time. Propagation by using plantlet rooting method includes following steps – we take mezereon plant and cut it in pieces. Then, we test different environments and plant hormones that help to root the plant pieces. Propagation is done in controlled conditions where all necessary elements for plant development are provided. First results show that propagation by using plantlet rooting is more suitable than propagation with seeds – we already have propagated first roots and leaves.
Next step of this method will be plant adaptation. Plants that are grown in controlled conditions are not able directly to grow outside in the field. At its first stages these plants have had all the necessary growing conditions – temperature, light, humidity level, nutrients. Adaptation is necessary so mezereon plants could survive in natural conditions.
IES: Why the measurements of alkaloid level in MAPs are necessary?
A.K.: Medicinal and aromatic plants with high levels of alkaloids are poisonous for humans. There is an increasing global tendency to identify hazardous compounds or alkaloids in medical plants. If alkaloid concentrations in MAPs are too high, they are not suitable for further use in medicine, food and cosmetics. Therefore, they also are not suitable for commercial cultivation.
IES: Was special preparation of experimental fields for winter research season necessary?
A.K.: As we are growing wild medicinal and aromatic originated from Latvia, no special treatment before winter was done. These plants are used to climate conditions in Latvia. Before winter we counted each individual plant that grows in experimental fields in Priekuļi municipality. After the winter season we will repeat this process to understand how these plants have survived through the winter. Same processes were already done before and after previous winter season (2019/2020). Results showed that survival rate of MAPs is quite high, we expect similar results in Spring 2021.
IES: What is planned for next research season?
A.K.: We will focus on the result compilation of previous vegetation season and growing method assessment. Over the next research season, we are going to focus on the planning of the 2021 vegetation season, as it will be the last one in this research. It is planned that harvesting will start in April or May, when the first plants – coltsfoot (Tussilago farfara) will blossom.
After the harvesting, OSI researchers will conduct the chemical composition analysis. After analysis, we will be able to assess the concentration levels of active compounds in plants, draw conclusions and develop knowledge-based cultivation methods for commercial plant cultivation in organic farming.
The research is a part of the project “Innovative solutions for growing technologies and applications of spring medicinal and aromatic plants” (Nr. 126.96.36.199/18/A/043). It is supported by European Regional Development Fund, as a part of Measure 188.8.131.52 “Industry-Driven Research” of specific objective 1.1.1 “To increase the research and innovation capacity of scientific institutions of Latvia and their ability to attract external funding by investing in human resources and infrastructure”.
More about the project here.