Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive ...

The goals of this study were to document the development of ozone-induced foliar injury, on a leaf-by-leaf basis, and to develop ozone exposure relationships for leaf cohorts and individual tall milkweeds (Asclepias exaltata L.) in Great Smoky Mountains National Park. Plants were classified as either ozone-sensitive or insensitive based on the amount of foliar injury. Sensitive plants developed...

Monitoring programs, where numbers of individuals are followed through time, are central to conservation. Although incomplete detection is expected with wildlife surveys, this topic is rarely considered with plants. However, if plants are missed in surveys, raw count data can lead to biased estimates of population abundance and vital rates. To illustrate, we had five independent observers surve...

Medicinal plants have remained the major sources of drugs; in fact many of the Currently available drugs were derived either directly or indirectly from them. The Approach to new drugs through natural products has proved to be the single most successful strategy for the discovery of new drugs. In the past decade, research has been focused on scientific evaluation of traditional drugs of plant o...

Medicinal plants are the local heritage with global importance playing a vital role in world health care system of developing countries. Calotropis procera (Asclepiadaceae), a giant milk weed, is known for its pharmacological importance for centuries. The coarse shrub is a very promising source of anticancerous, ascaricidal, schizonticidal, anti-microbial, anthelmintic, insecticidal, anti-infla...

A bioassay-guided fractionation of Juniperus procera berries yielded antiparasitic, nematicidal and antifouling constituents, including a wide range of known abietane, pimarane and labdane diterpenes. Among these, abieta-7,13-diene (1) demonstrated in vitro antimalarial activity against Plasmodium falciparum D6 and W2 strains (IC(50) = 1.9 and 2.0 microg/mL, respectively), while totarol (6), fe...

Phytochemical investigation of the above-ground biomass of Asclepias sullivantii L. (Asclepiadaceae) afforded six new pregnane glycosides, named sullivantosides A-F (1–6). The structures of 1–6 were elucidated through a variety of spectroscopic and spectrometric techniques (1D and 2D NMR; HRESIMS). To the best of our knowledge, this work represents the first phytochemical study of this species....

Twenty-six new acylated-oxypregnane glycosides were obtained along with three known cardenolide glycosides from the roots of Asclepias curassavica (Asclepiadaceae). The new compounds were confirmed to contain 12-O-benzoylsarcostin, 12-O-benzoyldeacylmetaplexigenin, kidjolanin, and 12-O-benzoyltayloron, and one new acylated-oxypregnane, 12-O-(E)-cinnamoyltayloron, as their aglycones, using both ...