Two new 9,10-secocycloartane triterpenoidal saponins, named huangqiyenins E (1) and F (2) were isolated from the leaves of Astragalus membranaceus Bunge. Enzymatic hydrolysis of 1 and 2 afforded the aglycones huangqiyegenins III (3) and IV (4), resp. Further alkaline hydrolysis of 3 provided trideacetylhuangqiyegenin III (5). Their structures were established by detailed spectroscopic analysis as (3S,5R,6S,10R,12b,16b,24E)-26-(b-d-glucopyranosyloxy

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Liriodendron tulipifera L., is a wide-spread, fast-growing pioneering tree species native to eastern North America. Commonly known as yellow-poplar, tulip tree, or tulip-poplar, the species is valued, both ecologically and economically. It is perhaps the most commonly used utility hardwood in the USA, and is planted widely for reforestation and, in varietal forms, as an ornamental. Although most seedlings used for reforestation today derive from collections in natural populations, two known seed orchards, established from plus-tree selections, i.e. superior phenotypes, in the 1960's and 1970's have been used for local and regional planting needs in Tennessee and South Carolina. However, very little is known about the population genetics of yellow-poplar nor the genetic composition of the existing seed orchards. In this study, 194 grafted yellow-poplar trees from a Clemson, SC orchard and a Knoxville, TN orchard were genetically characterized with 15 simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs). Of the 15 EST-SSR markers, 14 had a polymorphic information content (PIC) of at least 0.5. There was no significant difference between the Clemson and Knoxville orchards in average effective number of alleles (5.93 vs 3.95), observed and expected heterozygosity (Ho: 0.64 vs 0.58; He: 0.74 vs 0.70), Nei's expected heterozygosity (0.74 vs 0.58), or Shannon's Information index (1.84 vs 1.51). The larger Clemson orchard exhibited a significantly greater number of observed alleles than the Knoxville orchard (15.3 vs7.4). Overall, substantial genetic diversity is captured in the Clemson and Knoxville orchards.

The roots of Eleutherococcus senticosus (Rupr. & Maxim.) Maxim., a well-known medicinal plant from Eastern Asia, are used worldwide for their known beneficial medicinal properties. Recently, the leaves have been used as an alternative to the roots. The present study was aimed at exploring the leaf essential oil as a potential source of compounds for mosquito management. Gas chromatography/mass spectrometry analysis of the leaf essential oil revealed 87 compounds, constituting 95.2% of the oil. α-Bisabolol (26.46%), β-caryophyllene (7.45%), germacrene D (6.87%), β-bisabolene (4.95%), and α-humulene (3.50%) were five of the major constituents. The essential oil was subjected to biting deterrence and repellent activity against mosquito Aedes aegypti. The biting deterrence of the oil produced a proportion not biting (PNB) value of 0.62 at 10 µg/cm2 as compared with 0.86 of control DEET (N,N-diethyl-3-methylbenzamide) at a standard dose of 25 nmol/cm2. Among individually selected compounds present in the oil (α-bisabolol, β-caryophyllene, α-humulene, and caryophyllene oxide), only α-bisabolol produced a PNB value of 0.80, equivalent to DEET at 25 nmol/cm2, whereas the others were not repellent. The artificial mixture (AMES-1) of these four selected compounds produced a relatively high PNB value of 0.80. The repellent activity measured by minimum effective dosage (MED) for α-bisabolol and α-humulene produced MED values of 0.094 and 0.104 mg/cm2, respectively, as compared with 0.023 mg/cm2 of DEET. The leaf essential oil, the artificial mixture (AMES-1), and other binary and tertiary combinations of major compounds showed no repellent activity. In addition, morpho-anatomical features of the leaf are provided for correct identification of the species.