Sabiperones A-F, new diterpenoids from Juniperus sabina. (33/40)

Six new diterpenoids, sabiperones A-F (1-6) have been isolated from the aerial part of Juniperus sabina. Their structures were elucidated by spectroscopic methods including 2D NMR techniques. Sabiperone F showed moderate cell growth inhibitory activities against five human cancer cell lines.  (+info)

Does day length affect winter bird distribution? Testing the role of an elusive variable. (34/40)

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Distillation time alters essential oil yield, composition, and antioxidant activity of male Juniperus scopulorum trees. (35/40)

The objective of this study was to evaluate the effect of 15 distillation times (DT), ranging from 1.25 to 960 min, on oil yield, essential oil profiles, and antioxidant capacity of male J. scopulorum trees. Essential oil yields were 0.07% at 1.25 min DT and reached a maximum of 1.48% at 840 min DT. The concentrations of alpha-thujene (1.76-2.75%), alpha-pinene (2.9-8.7%), sabinene (45-74.7%), myrcene (2.4-3.4%), and para-cymene (0.8-3.1%) were highest at the shortest DT (1.5 to 5 min) and decreased with increasing DT. Cis-sabinene hydrate (0.5-0.97%) and linalool plus trans-sabinene (0.56-1.6%) reached maximum levels at 40 min DT. Maximum concentrations of limonene (2.3-2.8%) and pregeijerene-B (0.06-1.4%) were obtained at 360-480 min DT, and 4-terpinenol (0.7-5.7%) at 480 min DT. Alpha-terpinene (0.16-2.9%), gamma-terpinene (0.3-4.9%) and terpinolene (0.3-1.4%) reached maximum at 720 min DT. The concentrations of delta-cadinene (0.06-1.65%), elemol (0-6.0%), and 8-alpha-acetoxyelemol (0-4.4%) reached maximum at 840 min DT. The yield of the essential oil constituents increased with increasing DT. Only linalool/transsabinene hydrate reached a maximum yield at 360 min DT. Maximum yields of the following constituents were obtained at 720 min DT: alpha-thujene, alpha-pinene, camphene, sabinene, myrcene, alpha-terpinene, para-cimene, limonene, gamma-terpinene, terpinolene, and 4-terpinenol. At 840 min DT, cis-sabinene hydrate, prejeijerene-B, gamma muurolene, delta-cadinene, reached maximum. At 960 min DT, maximum yields of beta-pinene, elemol, alphaeudesmol/betaeudesmol, 8-alpha-acetoxyelemol were reached. These changes were adequately modeled by either the Michaelis-Menten or the Power (Convex) nonlinear regression models. Oils from the 480 min DT showed higher antioxidant activity compared to samples collected at 40, 160, or 960 min DT. These results show the potential for obtaining essential oils with various compositions and antioxidant capacity from male J. scopulorum by varying DT. This study can be used as a reference paper for comparing results of reports where different lengths of the DT were used.  (+info)

Response of the soil microbial community to changes in precipitation in a semiarid ecosystem. (36/40)

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Colonization of abandoned land by Juniperus thurifera is mediated by the interaction of a diverse dispersal assemblage and environmental heterogeneity. (37/40)

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Climate control on tree growth at the upper and lower treelines: a case study in the qilian mountains, tibetan plateau. (38/40)

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Loss of Notch1 disrupts the barrier repair in the corneal epithelium. (39/40)

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Evidence of recovery of Juniperus virginiana trees from sulfur pollution after the Clean Air Act. (40/40)

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