Hydrodistillation time-dependent variations in the volatile oil characteristics of fresh and dried Salvia species

Salvia species are valued for their medicinal and aromatic properties, which largely arise from their volatile oils (VOs). The content and chemical composition of VOs depend on factors such as harvest time, post-harvest processing, and extraction conditions. This study investigated the effects of hydrodistillation (HD) duration and leaf state (fresh vs. dried) on the content and chemical composition of VOs from Salvia officinalis and Salvia fruticosa. Leaves were distilled for 1-5 h, and VOs were analyzed using GC/FID-MS. In S. officinalis, VO content increased with HD time (0.37-0.64% in fresh leaves; 1.48-2.00% in dried leaves). In dried leaves, most of the recoverable VO was obtained within 3 h, with only limited additional increases thereafter, indicating diminishing returns beyond ~ 3 h under the applied conditions. In S. fruticosa, VO content increased in fresh leaves from 0.42% to 0.50% and in dried leaves during the first three hours (1.2-1.52%), although fresh leaves provided a higher VO content relative to the original fresh weight. GC/FID-MS identified 41 and 32 compounds in fresh and dried S. officinalis, and 49 and 48 in S. fruticosa. α-Thujone was the predominant component in both species, showing its highest relative abundance at 1 h and decreasing with prolonged HD; a similar pattern was observed for 1,8-cineole, consistent with time-dependent shifts in the volatile profile. α-Pinene was higher in dried S. fruticosa (6.62-9.28%) than fresh (4.62-7.45%). Oxygenated monoterpenes were the most abundant chemical group, while sesquiterpenes and diterpenoids increased with extended HD. These findings highlight species-specific extraction dynamics and underscore the importance of selecting HD duration according to the intended balance between VO content and compositional profile.