Phytochemical and reproductive capacity of the Bulgarian endemic species Achillea thracica Velen

Authors: SEMERDJIEVA, IVANKA - Bulgarian Academy Of Sciences; YANKOVA-TSVETKOVA, ELINA - Bulgarian Academy Of Sciences; Cantrell, Charles; KACÁNIOVÁ, MIROSLAVA - Slovak University Of Agriculture; ZHELJAZKOV, VALTCHO - Oregon State University

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2025
Publication Date: 5/23/2025
Citation: Semerdjieva, I.B., Yankova-Tsvetkova, E., Cantrell, C.L., Kacániová, M., Zheljazkov, V.D. 2025. Phytochemical and reproductive capacity of the Bulgarian endemic species Achillea thracica Velen. Industrial Crops and Products. 232(2025):121187. https://doi.org/10.1016/j.indcrop.2025.121187.
DOI: https://doi.org/10.1016/j.indcrop.2025.121187

Interpretive Summary: Endemic taxa, with their limited distribution, represent some of the most distinctive and interesting components of any flora . The plant diversity of Bulgarian flora can be attributed to the country's varied climate, unique geographical location, and rich geological history. Despite its relatively small territory, the Bulgarian flora is rich in Bulgarian and Balkan endemic plants comprising 270 species. Most of the endemic species are threatened and have limited distribution. Endemic plants often possess unique biochemical pathways, producing novel biomolecules with potential applications in medicine, agriculture, and biotechnology. Achillea thracica, a member of the Asteraceae family, is a critically endangered species. Endemic species like A. thracica are often under-studied, yet they hold significant potential for the discovery of novel compounds. The goal of this study was to assess the reproductive capacity of A. thracica (pollen and seeds viability) and its reproductive structures, and to characterize the chemical profile and the antimicrobial activity of its essential oil (EO). The male and female generative spheres show that A. thracica reproduces via sexual reproduction. Furthermore, the normal progression of processes leading to pollen and seed formation is essential for fully realizing reproductive capacity. Despite the high fertility observed in the pollen of the target species, seed viability was found to be very low. Further, the female gametophyte of A. thracica is highly influenced by environmental conditions, which directly affect the quality of the seeds produced. Moreover, the lack of alternative reproductive mechanisms, such as apomixis, limits the plasticity of A. thracica populations, reducing their adaptability to environmental changes. Overall, the composition of A. thracica EO was notably different from that of other Achillea species within Sec. Filipendulinae. With its vigorous growth, unique essential oil (EO) composition, and strong antimicrobial activity, Achillea thracica demonstrates significant potential for cultivation and development as a high-value crop.

Technical Abstract: Achillea thracica Velen. Sec. Achillea s.l. [=Sect. Filipendulinae (DC.) Afan.] is a Bulgarian endemic species found in a single population within the country. Endemic species like A. thracica are often under-studied, yet they hold significant potential for the discovery of novel compounds. The goal of this study was to assess the reproductive capacity of A. thracica (pollen and seeds viability) and its reproductive structures, and to characterize the chemical profile and the antimicrobial activity of its essential oil (EO). The male and female generative spheres show that A. thracica reproduces via sexual reproduction. Furthermore, the normal progression of processes leading to pollen and seed formation is essential for fully realizing reproductive capacity. Despite the high fertility observed in the pollen of the target species, seed viability was found to be very low. Further, the female gametophyte of A. thracica is highly influenced by environmental conditions, which directly affect the quality of the seeds produced. Moreover, the lack of alternative reproductive mechanisms, such as apomixis, limits the plasticity of A. thracica populations, reducing their adaptability to environmental changes. Overall, the composition of A. thracica EO was notably different from that of other Achillea species within Sec. Filipendulinae. Santolina and yomogi alcohols and ß-eudesmol were the most abundant compounds found in the EO. The strongest antimicrobial activities of A. thracica EO in our study were found against Clostridium perfringens followed by Yersinia enterocolitica and Listeria monocytogenes. With its vigorous growth, unique essential oil (EO) composition, and strong antimicrobial activity, Achillea thracica demonstrates significant potential for cultivation and development as a high-value crop. Additionally, A. thracica EO serves as a promising natural source of ß-eudesmol, creating opportunities for diverse commercial applications.