Results – Stage 1 – 2024

Step 1: Obtaining and characterizing extracts from different perennials

Executive summary of the activities performed

During this stage, optimized extracts in terms of total content of polyphenols, flavonoids, alkaloids and antioxidant capacity from the perennial plants Rheum rhabarbarum, Reynoutria sachalinensis and Sophora flavescens were obtained. The optimization of the extracts from the selected plants was achieved by using the extraction technique (ultrasonication) combined with the optimization of the extraction conditions obtained with the help of the experimental Central Composite Design (CCD), an approach less used for extracts from the these plants. Overall, the results obtained for the extracts from the selected plants showed significant variation of the amount of bioactive compounds and antioxidant capacity as a function of the type of plant used and of the extraction conditions, highlighting the importance of optimizing the extraction methods for each species. In order to determine the synergistic effect, mixtures of plant extracts were prepared and characterized. Taking into account the antioxidant capacity, the mixture consisting of extracts of R. sachalinensis – leaves and R. sachalinensis – stalks (1:2 ratio, v/v) showed synergistic effect.

Tests were also performed in order to determine the antifungal effects of the optimised extracts. The extracts of R. rhabarbarum showed an inhibitory effect on the growth of the phytopathogenic fungus Fusarium oxysporum f. sp. lycopersici 4287 for all the concentrations used, extracts of S. flavescens showed an inhibitory effect on the growth of the investigated phytopathogenic fungus at higher concentrations, while the extract of R. sachaliensis showed a small stimulating effect on its growth.

The optimal extraction methods for each plant selected within this project will be used, during the following stages of the project, in order to obtain extracts necessary to prepare microemulsions with different adjuvants (e.g.: rapeseed oil, pelecol, etc.) that will be tested as potential antifungals and insecticides for cucumber and plum crops. Thus, during this stage, the conditions for the application of extracts/microemulsions in the plum orchard were established in order to evaluate their effect on the cotton aphid (Aphis gossypii), the spider mite (Tetranychus urticae Koch) and the plum fruit moth (Grapholita funebrana). The prepared extracts/microemulsions will be tested on cucumber crops in order to evaluate their mildew.

In conclusion, the optimised extracts obtained might be used as natural insecticides and fungicides, reducing the application of chemicals and helping the development of a cleaner and more sustainable agriculture.

Results obtained

Three extraction methods:

  1. Optimized extraction method of total polyphenols from Sophora flavescens, R. rhabarbarum, Reynoutria sachalinensis, authors: Ocsana Opriş, Maria-Loredana Soran, Ildiko Lung, Adina Stegarescu, Svetlana Jalbă (registration number 1876 / 10.12.2024);
  2. Optimized extraction method for total flavonoids from Sophora flavescens, Reynoutria sachalinensis, authors: Ildiko Lung, Maria-Loredana Soran, Ocsana Opriş, Adina Stegarescu, Svetlana Jalbă (registration number 1877 / 10.12.2024);
  3. Extraction method in order to obtain extracts from Sophora flavescens, R. rhabarbarum, Reynoutria sachalinensis. with high antioxidant activity, authors: Maria-Loredana Soran, Ildiko Lung, Ocsana Opriş Adina Stegarescu (registration number 1878 / 10.12.2024).

Dissemination of results at international conferences:

  1. V. Todiraș, A. Gușan, M.-L. Soran, A. Stegarescu, Effectiveness of sofora and neem plant extracts in fightig pests in protected areas, International Scientific Conference “Genetics, Physiology and Plant Breeding” (VIIIth Edition), 7 – 8 octombrie 2024, Chişinău, Republic of Moldova – oral presentation.
  2. V. Todiraș, S. Jalbă, T. Erhan, I. Lung, O. Opriș, A. Stegarescu, M.-L. Soran, Preparation and characterization of Sophora flavescens extract as natural insecticide in greenhouse, International Conference on Agriculture and Biological Sciences (ICOABS-24), 3rd – 4th of December 2024, Amsterdam, The Netherlands.
  3. S. Jalbă, V. Todiraș, T. Erhan, I. Lung, O. Opriș, A. Stegarescu, Optimization of Reynoutria sachalinensis extracts for organic pests management, International Conference on Agriculture and Biological Sciences (ICOABS-24), 3rd – 4th of December 2024, Amsterdam, The Netherlands.