The chemical composition of eight (seven shoot and one inflorescence) essential oils (EOs) of Rh. tomentosum H. plants growing in Eastern Lithuania is reported. The plant material was collected during different phases of vegetation (from April to October). The oils were obtained by hydrodistillation from air-dried aerial parts (leaves and inflorescences). In total, up to 70 compounds were identified by GC−MS and GC (flame-ionization detector, FID); they comprised 91.0 ± 4.7%–96.2 ± 3.1% of the oil content. Sesquiterpene hydrocarbons (54.1 ± 1.5%–76.1 ± 4.5%) were found to be the main fraction. The major compounds were palustrol (24.6 ± 2.6%–33.5 ± 4.4%) and ledol (18.0 ± 2.9%–29.0 ± 5.0%). Ascaridol isomers (7.0 ± 2.4%–14.0 ± 2.4% in three oils), myrcene (7.2 ± 0.3% and 10.1 ± 1.3%), lepalol (3.3 ± 0.3% and 7.9 ± 3.0%), and cyclocolorenone isomers (4.1 ± 2.5%) were determined as the third main constituents. The toxic activity of marsh rosemary inflorescence and shoot oils samples was evaluated using a brine shrimp (Artemia sp.) bioassay. LC50 average values (11.23–20.50 µg/mL) obtained after 24 h of exposure revealed that the oils were notably toxic. The oil obtained from shoots gathered in September during the seed-ripening stage and containing appreciable amounts of palustrol (26.0 ± 2.5%), ledol (21.5 ± 4.0%), and ascaridol (7.0 ± 2.4%) showed the highest toxic activity. Radical scavenging activity of Rh. tomentosum EOs depended on the plant vegetation stage. The highest activities were obtained for EOs isolated from young shoots collected in June (48.19 ± 0.1 and 19.89 ± 0.3 mmol/L TROLOX (6-hydroxy-2,5,7,8-tetra-methylchromane-2-carboxylic acid) equivalent obtained by, respectively, ABTS•+ (2,2′-amino-bis(ethylbenzothiazoline-6-sulfonic acid) diammonium salt) and DPPH•(2,2-diphenyl-1-picrylhydrazyl) assays). Agar disc diffusion assay against pathogenic yeast Candida parapsilosis revealed the potential antifungal activity of EOs. An alternative investigation of antifungal activity employed mediated amperometry at yeast Saccharomyces cerevisiae-modified electrodes. The subjection of yeast cells to vapors of EO resulted in a three to four-fold increase of electrode responses due to the disruption of yeast cell membranes.

中文翻译：

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毛杜鹃 H. 精油的毒性、自由基清除和抗真菌活性

Rh 八种（七枝一花）精油 (EOs) 的化学成分。报道了生长在立陶宛东部的 tomentosum H. 植物。在植被的不同阶段（从四月到十月）收集植物材料。这些油是从风干的地上部分（叶子和花序）通过水蒸馏获得的。GC-MS 和 GC（火焰离子化检测器，FID）总共鉴定了多达 70 种化合物；它们占油含量的 91.0 ± 4.7%–96.2 ± 3.1%。发现倍半萜烃 (54.1 ± 1.5%–76.1 ± 4.5%) 是主要组分。主要化合物是palustrol (24.6 ± 2.6%–33.5 ± 4.4%) 和ledol (18.0 ± 2.9%–29.0 ± 5.0%)。蛔虫异构体（7.0 ± 2.4%–14.0 ± 2.4% 在三种油中）、月桂烯（7.2 ± 0.3% 和 10.1 ± 1.3%）、来帕洛尔（3.3 ± 0.3% 和 7.9 ± 3.0%）、和环色酮异构体 (4.1 ± 2.5%) 被确定为第三主要成分。沼泽迷迭香花序和芽油样品的毒性活性使用盐水虾 (Artemia sp.) 生物测定法进行评估。暴露 24 小时后获得的 LC50 平均值 (11.23–20.50 µg/mL) 表明这些油具有明显的毒性。从 9 月种子成熟阶段采集的枝条中提取的油中含有可观数量的 palustrol (26.0 ± 2.5%)、ledol (21.5 ± 4.0%) 和蛔虫醇 (7.0 ± 2.4%)，显示出最高的毒性活性。Rh 的自由基清除活性。tomentosum EOs 取决于植物植被阶段。从 6 月份收集的幼枝中分离的 EO 获得了最高的活性（48.19 ± 0.1 和 19.89 ± 0.3 mmol/L TROLOX (6-hydroxy-2,5,7, 8-四甲基色满-2-羧酸)等价物分别由ABTS•+(2,2'-氨基-双(乙基苯并噻唑啉-6-磺酸)二铵盐)和DPPH•(2,2-二苯基- 1-苦基肼）测定）。针对致病性酵母近平滑念珠菌的琼脂盘扩散试验揭示了 EO 的潜在抗真菌活性。另一种抗真菌活性的研究在酵母酿酒酵母修饰的电极上采用介导的电流分析法。由于酵母细胞膜的破坏，酵母细胞受到 EO 蒸汽的影响导致电极响应增加三到四倍。针对致病性酵母近平滑念珠菌的琼脂盘扩散试验揭示了 EO 的潜在抗真菌活性。另一种抗真菌活性的研究在酵母酿酒酵母修饰的电极上采用介导的电流分析法。由于酵母细胞膜的破坏，酵母细胞受到 EO 蒸汽的影响导致电极响应增加三到四倍。针对致病性酵母近平滑念珠菌的琼脂盘扩散试验揭示了 EO 的潜在抗真菌活性。另一种抗真菌活性的研究在酵母酿酒酵母修饰的电极上采用介导的电流分析法。由于酵母细胞膜的破坏，酵母细胞受到 EO 蒸汽的影响导致电极响应增加三到四倍。