Agro-ecological cultivation, phytochemical composition, and antioxidant potential of three Salvia L. species grown at two sites in the Khorezm and Samarkand regions of Uzbekistan for functional food development

Three Salvia species — S. sclarea, S. officinalis, and S. verticillata — were cultivated at two sites with contrasting soil and climatic conditions, Khiva district (Khorezm region) and Urgut district (Samarkand region), Uzbekistan, with the primary aim of identifying which species–site combination delivers the greatest phytochemical and antioxidant potential for functional food ingredient development. Field cultivation was carried out in randomised complete block design (RCBD, three blocks, three species, two sites), and aerial parts (leaves, stems, and inflorescences in approximately 3:2:1 dry weight ratio) were collected at full anthesis. Dried material was extracted with 80% methanol at room temperature (1:10 w/v, 150 rpm, 24 h). Total phenolic content (TPC) and total flavonoid content (TFC) were determined by Folin–Ciocalteu and aluminium chloride colorimetric methods, respectively. Antioxidant capacity was evaluated by DPPH and ABTS radical scavenging assays; all percentage inhibition values are reported at a fixed extract concentration of 200 μg/mL. IC₅₀ values were derived by nonlinear regression. Raw material yield (t/ha) and essential oil content (%) were recorded in parallel. Each assay was performed in analytical triplicate on one composite sample from each of three field blocks; the analytical measurements were treated as technical replicates. Because block-level values were not available for a block-adjusted factorial analysis, differences among species–site combinations are interpreted descriptively, and associations were explored by Pearson correlation and simple linear regression on the six group means. Across all parameters and species, material from the Urgut district site exceeded material from the Khiva district site. The highest values were recorded for S. sclarea from the Urgut district site: TPC 48.32 ± 2.31 mg GAE/g DW, TFC 15.87 ± 0.93 mg QE/g DW, DPPH inhibition 82.4 ± 1.72% (IC₅₀ = 48.7 ± 1.8 μg/mL), and ABTS inhibition 85.1 ± 1.42% (IC₅₀ = 44.1 ± 1.6 μg/mL). Across the six group means, TPC was closely associated with DPPH (r = 0.999) and ABTS inhibition (r = 0.998); these exploratory associations among group means do not establish causality or predictive performance. These results indicate that S. sclarea grown under conditions similar to those of the Urgut district site is a promising source of natural antioxidant ingredients; because only one site per region was studied in a single season, the findings should not be generalised to the regions as a whole. These findings are based on in vitro assays; in vivo validation remains necessary before specific health claims can be substantiated.