Phenotypic variability of phenolic compounds in Silybum marianum (L.) seeds

Introduction. For the first time, the content of phenolic compounds in the seeds of wild Silybum marianum L. collected in natural conditions of Dagestan along the latitudinal gradient in different years was assessed. Aim. Study of the accumulation of phenolic compounds in the seeds of spotted milk thistle collected in natural populations of Dagestan along the latitudinal gradient taking into account the altitude above sea level. Research methods. The seeds were collected from inflorescences in the ripening phase. The content of flavonoids and anthocyanins was determined in water-ethanol (70%) extracts by spectrophotometric method in 3-fold replication. Results. It was found that the content of flavonoids and anthocyanins in S. marianum seeds varies within 0.04–1.28% (in terms of rutin), and anthocyanins from 0.01 to 0.53% (in terms of 3-cyanidin glucoside) depending on the population, year of collection, and seed phenotype. Statistical analysis allowed us to estimate the inter-population differentiation in the content of flavonoids and anthocyanins. Conclusions. It was revealed that the accumulation of phenolic compounds is directly dependent on the year of research and the place of growth of milk thistle plants, while the dependence on the seed phenotype is insignificant. Suggestions for practical applications and directions for future research. The obtained results have significant theoretical value for studying the processes of accumulation of secondary metabolites, as well as practical importance in the development of highly productive samples.