The active compounds of medicinal plants vary in composition and content depending on environmental factors, such as light, temperature, and soil. According to the Korean Pharmacopoeia standards for herbal medicine, the sum of nodakenin, decursin, and decursinolangelate, which are the marker components of Korean Angelica, should be at least 6.0 g/100 g. However, the content of the components in Korean Angelica cultivated in South Korea often fall below 6.0 g/100 g, due to weather conditions and cultivation site characteristics. This study aimed to gather information about environmental factors that affect the root growth and the content of active compounds. In total, 18 cultivation sites in Pyeongchang, Jecheon, and Bonghwa regions in Korea were investigated for this study. Environmental factors, such as the monthly mean temperature, mean relative humidity, duration of sunshine, total precipitation, soil acidity, and the characteristics of soil nutrient, were investigated over the growing season from April to October 2017. As for the growth characteristics, the dry weight of roots of Korean Angelica was measured. The sum of the contents of the three active compounds was 5.3–7.0 g/100 g and the nodakenin content was 0.3–1.3 g/100 g in the cultivation sites. This study concludes that the root yields in the cultivation sites would be improved if weather conditions are maintained with similar levels as those in their natural habitats. Additionally, the environment that improves root growth did not increase the content of active compounds; however, when there was a lot of gravel or high temperatures during the growth period, the content of active compounds was relatively high.

In total, four new eudesmane-type sesquiterpene glycosides, askoseosides A–D (1–4), and 18 known compounds (5–22) were isolated from the flowers of Aster koraiensis via chromatographic techniques. Chemical structures of the isolated compounds were identified by spectroscopic/spectrometric methods, including NMR and HRESIMS, and the absolute configuration of the new compounds (1 and 2) was performed by electronic circular dichroism (ECD) studies. Further, the anticancer activities of the isolated compounds (1–22) were evaluated using the epidermal growth factor (EGF)-induced as well as the 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell transformation assay. Among the 22 compounds, compounds 4, 9, 11, 13–15, 17, 18, and 22 significantly inhibited both EGF- and TPA-induced colony growth. In particular, askoseoside D (4, EGF: 57.8%; TPA: 67.1%), apigenin (9, EGF: 88.6%; TPA: 80.2%), apigenin-7-O-β-d-glucuronopyranoside (14, EGF: 79.2%; TPA: 70.7%), and 1-(3′,4′-dihydroxycinnamoyl) cyclopentane-2,3-diol (22, EGF: 60.0%; TPA: 72.1%) showed higher potent activities.

Distillation time (DT) is a key parameter influencing yield and chemical composition, and its optimisation is crucial for production. This study is the first laboratory-scale investigation of the effect of distillation time (DT) on the leaf essential oils of Abies koreana, aiming to maximise oil yield and target bioactive components for cosmetic applications. Essential oils were obtained by hydrodistillation at 14 DTs (1, 3, 5, 10, 20, 40, 80, 120, 160, 200, 240, 280, 360, and 480 min), and the yields, chemical profiles, and fragrance characteristics were comparatively analysed. The control (exhaustive hydrodistillation: 20 h) yielded 2.82% and was dominated by D-limonene, bornyl acetate, and camphene. The contents of bioactive compounds associated with whitening and anti-wrinkle activities (α-pinene, D-limonene, borneol, and bornyl acetate) varied markedly with DT. The highest oil yield was obtained at 80 min (0.30 ± 0.01%), while the targeted components were achieved at 80–160 min. Heatmap-based multivariate analysis revealed distinct compositional differences between oils distilled at 80 min and 160 min, with DT shifting fragrance profiles from fresh, monoterpene-rich notes (linalyl acetate, camphor, and fenchol) to longer-lasting, sesquiterpene-dominated aromas (α-bisabolol and β-eudesmol). Therefore, distillation time significantly influenced A. koreana oil, with shorter distillation (80 min) maximising yield and longer distillation (80–160 min) enriching bioactive components for cosmetic applications.

Distillation is widely used for essential oils extraction, and distillation time (DT) influences the quality and quantity of oils. This study presents the effects of 14 DTs (1, 3, 5, 10, 20, 40, 80, 120, 160, 200, 240, 280, 360, and 480 min) on leaf oils from Thuja occidentalis L., aiming to maximise the yield and modulate chemical profiles. Also, a safety assessment of T. occidentalis oils obtained at different DTs was conducted based on thujone levels under International Fragrance Association (IFRA) guidelines. Oil yield varied with DT, reaching a maximum at 40–80 min (0.54 ± 0.04% and 0.59 ± 0.02%, respectively). Monoterpenes (sabinene, fenchone, and thujone) decreased with prolonged DT, whereas higher molecular weight compounds, including sesquiterpenes (caryophyllene) and diterpenes (hibaene and rimuene) increased. Principal component analysis (PCA) grouped samples into three stages, early (1–10 min), mid (20–80 min), and late (120–480 min), with clear compositional separation (PC1: 68.4%, PC2: 11.8%). As DT increased, the fragrance profile progressively shifted from monoterpene-rich characteristics in the early-stage oils to more persistent aromas associated with sesquiterpenes (caryophyllene, α-cadinol, and α-eudesmol) and diterpenes (hibaene and rimuene) in the late-stage oils. Safety assessment revealed that early-stage oils contained high thujone levels (67.19–71.88%), limiting their allowable use. In contrast, prolonged DTs (≥200 min) reduced thujone content, increasing permissible usage across multiple IFRA categories. Overall, DT significantly influences the oil yield, chemical composition, and regulatory applicability of T. occidentalis oils, with extended distillation enhancing formulation flexibility in cosmetic and fragrance applications.

The essential oil of Torreya nucifera, a coniferous tree native to East Asia, has notable bioactive properties with potential industrial applications. This study examined the effects of seasonal and regional factors on the yield and bioactive constituents of T. nucifera oils in South Korea. Leaf samples were collected in spring (March), summer (June), and autumn (September) of 2023–2024 from three ecologically distinct regions: Jeju Island, Jinju, and Hwasun. Oil yield was stable across seasons (0.9–1.6%) but varied significantly by region (p < 0.05), with Hwasun showing the highest yield. This stability across seasons may reflect the perennial evergreen nature of T. nucifera. Gas Chromatography-Mass Spectrometry (GC–MS) identified 32 volatile components, predominantly monoterpenes (83.7–90.4%) and sesquiterpenes (5.4–11.7%), with D-limonene and 3-carene as key chemical markers. Notably, 3-carene levels were significantly affected by region (p < 0.0001), with higher concentrations in Jeju oils, while D-limonene was influenced by season, region, and their interaction (p < 0.001), reaching peak levels in Hwasun during summer and autumn (up to 70%). Therefore, T. nucifera oil from Hwasun harvested in autumn can be optimised for commercial production by maximising oil yield and enhancing chemical markers.