Biochemical profile of Mentha L. plants of the VIR collection

Mint (Mentha L.) is a widely cultivated medicinal and aromatic crop. Its value is associated with the content of essential oils, carotenoids, polyphenols, organic acids, soluble sugars, and other bioactive components. Currently, there is growing interest in qualitatively and quantitatively increasing the content of health-beneficial compounds in mint leaves and inflorescences. The aim of our work was to conduct a comprehensive comparative analysis of the biochemical composition and antioxidant activity of 34 accessions of four species of the Mentha (M. suaveolens, M. longifolia, M. × piperita, M. spicata) of VIR Mentha collection, grown in the North-West Russia (St. Petersburg) in 2024-2025. The content of photosynthetic pigments, ascorbic acid, phenolic compounds, flavonoids, and antioxidant activity was determined spectrophotometrically. Significant interspecific and interannual variability in biochemical parameters was revealed. In the less favorable temperature regime of 2025, the chlorophyll content decreased by an average of 44%, and carotenoids by 30–50 % compared to 2024. Simultaneously, there increased the content of ascorbic acid (from 0.07±0.01 to 0.21±0.03 mg·g⁻¹) and phenolic compounds. The maximum content of phenolic compounds was noted in M. × piperita accessions (62.99 mg GA eq·g⁻¹ in 2025). M. suaveolens and M. longifolia accessions showed a tendency for increased flavonoid accumulation. The antioxidant activity of all species' accessions was consistently high (>83 %) with a low coefficient of variation (3.28–4.25 %). Principal component analysis differentiated the accessions into 6 statistically justified groups, indicating high intrageneric diversity. Promising genotypes were identified: M. × piperita and M. spicata accessions as sources of phenolic compounds and β-carotene. The results confirm the high adaptive potential of the studied species and the possibility of targeted selection of accessions with a specific biochemical profile for use in the pharmaceutical and food industries.