Intraspecies chemical variability of the essential oil of Ledum palustre
The compositions of the essential oils of marsh tea,Ledum palustre L., from the southern regions of Tomsk, Transbaikalia and Amur province, and also from the southern part of the island of Sakhalin have been analyzed in detail. The results obtained indicate the sharply pronounced intraspecies chemical variability of this plant. In addition to the chemotype of march tea with myrcene as a macrocomponent which is widely distributed in the European part of the USSR, another three chemotypes with the macrocomponents limonene, sabinen, and p-cymene have been revealed.
Diurnal Effects on Chinese Wild Ledum palustre L. Essential Oil Yields and Composition
This study was conducted to evaluate the diurnal effect on essential oil yield and composition of Ledum palustre L. grown in northern Inner Mongolia, China. Essential oil content and composition were determined and compared as a function of different harvesting times viz. 7:00 AM, 11:00 AM, 3:00 PM, 7:00 PM, and 11:00 PM within a day. The essential oil obtained by hydrodistillation was investigated by gas chromatography-mass spectrometry (GC-MS). The yield of essential oil was varied from 1.21% to 1.62%; the maximum oil yield was obtained at 3:00 PM and the minimum at 7:00 PM. Similar to oil yield, qualitative difference in essential oil composition of L. palustre was observed. For the best essential oil yields, L. palustre should be harvested during 11:00 AM to 3:00 PM.
Coumarins of Artemisia dracunculoides and 3′,6-dimethoxy-4′,5,7-trihydroxyflavone in A. arctica
Abstract Six coumarins were isolated from Artemisia dracunculoides Pursh. Two of these are new, 7,8-methylenedioxy-6-methoxycoumarin and the γ,γ-dimethylallyl ether of scopoletin. The four others were scopoletin, scoparone, daphnetin methylene ether and daphnetin 7-methyl ether. Artemisia arctica Less. ssp. saxicola (Rydb.) Hulten yielded 3′,6-dimethoxy-4′,5,7-trihydroxyflavone.