A plant genus of the family ASCLEPIADACEAE. This is the true milkweed; APOCYNUM & EUPHORBIA hirta are rarely called milkweed. Asclepias asthmatica has been changed to TYLOPHORA.
Saturated derivatives of the steroid pregnane. The 5-beta series includes PROGESTERONE and related hormones; the 5-alpha series includes forms generally excreted in the urine.
The dogbane family of the order Gentianales. Members of the family have milky, often poisonous juice, smooth-margined leaves, and flowers in clusters. Asclepiadacea (formerly the milkweed family) has been included since 1999 and before 1810.
Any compound that contains a constituent sugar, in which the hydroxyl group attached to the first carbon is substituted by an alcoholic, phenolic, or other group. They are named specifically for the sugar contained, such as glucoside (glucose), pentoside (pentose), fructoside (fructose), etc. Upon hydrolysis, a sugar and nonsugar component (aglycone) are formed. (From Dorland, 28th ed; From Miall's Dictionary of Chemistry, 5th ed)

Metschnikowia vanudenii sp. nov. and Metschnikowia lachancei sp. nov., from flowers and associated insects in North America. (1/23)

Two new species of the ascosporic yeast genus Metschnikowia were isolated from nectaries and associated muscoid flies of flowers from the common milkweed (Asclepias syriaca) in North America, and are described as Metschnikowia vanudenii [type strain=PYCC 4650(T)=CBS 9134(T)=NRRL Y-27243(T)=UWO(PS) 86A4.1(T)] and Metschnikowia lachancei [type strain=PYCC 4605(T)=CBS 9131(T)=NRRL Y-27242(T)=UWO(PS) 7ASB2.3(T)]. As with the previously described Metschnikowia gruessii, M. vanudenii has vegetative cells with an 'aeroplane' or cross-like configuration, produces ovoid chlamydospores and forms ellipsoidopedunculate asci with two acicular ascospores. Metschnikowia lachancei is distinguished from other Metschnikowia species by formation of club-shaped asci with 1-2 thick clavate ascospores. The phylogenetic positions of the proposed new species within Metschnikowia were determined from sequence analysis of the D1/D2 domain of 26S rDNA. The new species show low nuclear DNA relatedness with neighbouring taxa.  (+info)

Flavonoids in the leaves of Asclepias incarnata L. (2/23)

Seven flavonoid compounds: quercelin 3-O-beta-galactopyranoside, 3-O-beta-glucopyranoside, 3-O-arabinoside, 3-O-beta-glucopyranosyl (1-->2)-beta-galactopyranoside, 3-O-beta-xylopyranosyl (1-->2)-beta-galactopyranoside, 3-O-alpha-rhamnopyranosyl (1-->2)-beta-galactopyranoside and kaempferol 3-beta-glucopyranoside were isolated and identified from the leaves of Asclepias incarnata, L. (Asclepiadaceae).  (+info)

Steroidal glycosides from the roots of Asclepias curassavica. (3/23)

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 spectroscopic and chemical methods.  (+info)

Phylogenetic escalation and decline of plant defense strategies. (4/23)


New cardenolide and acylated lignan glycosides from the aerial parts of Asclepias curassavica. (5/23)

Three new cardenolide glycosides and six new acylated lignan glycosides were obtained along with nineteen known compounds from the aerial parts of Asclepias curassavica L. (Asclepiadaceae). The structure of each compound was determined based on interpretations of NMR and MS measurements and chemical evidence.  (+info)

Acylated-oxypregnane glycosides from the roots of Asclepias syriaca. (6/23)

Twenty new pregnane glycosides were obtained from the roots of Asclepias syriaca L. (Asclepiadaceae). These glycosides were confirmed to contain ikemagenin, 12-O-nicotinoyllineolon, 5alpha,6-dihydroikemagenin, and 12-O-tigloylisolineolon, as their aglycones, using both spectroscopic and chemical methods.  (+info)

Biochemical analysis of a papain-like protease isolated from the latex of Asclepias curassavica L. (7/23)

Most of the species belonging to Asclepiadaceae family usually secrete an endogenous milk-like fluid in a network of laticifer cells in which sub-cellular organelles intensively synthesize proteins and secondary metabolites. A new papain-like endopeptidase (asclepain c-II) has been isolated and characterized from the latex extracted from petioles of Asclepias curassavica L. (Asclepiadaceae). Asclepain c-II was the minor proteolytic component in the latex, but showed higher specific activity than asclepain c-I, the main active fraction previously studied. Both enzymes displayed quite distinct biochemical characteristics, confirming that they are different enzymes. Crude extract was purified by cation exchange chromatography (FPLC). Two active fractions, homogeneous by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and mass spectrometry, were isolated. Asclepain c-II displayed a molecular mass of 23,590 Da, a pI higher than 9.3, maximum proteolytic activity at pH 9.4-10.2, and showed poor thermostability. The activity of asclepain c-II is inhibited by cysteine proteases inhibitors like E-64, but not by any other protease inhibitors such as 1,10-phenantroline, phenylmethanesulfonyl fluoride, and pepstatine. The Nterminal sequence (LPSFVDWRQKGVVFPIRNQGQCGSCWTFSA) showed a high similarity with those of other plant cysteine proteinases. When assayed on N-alpha-CBZ-amino acid-p-nitrophenyl esters, the enzyme exhibited higher preference for the glutamine derivative. Determinations of kinetic parameters were performed with N-alpha-CBZ-L-Gln-p-nitrophenyl ester as substrate: K(m)=0.1634 mM, k(cat)=121.48 s(-1), and k(cat)/K(m)=7.4 x 10(5) s(-1)/mM.  (+info)

Aerial reproductive structures of vascular plants as a microhabitat for myxomycetes. (8/23)

This study explored the occurrence and distribution of myxomycete species on the aerial reproductive structures of vascular plants. Eight species of vascular plants representing five families were sampled. The doubled rope climbing method was used to collect bark and cones from the canopy of Pinus echinata. Bark and aerial seed pods were gathered from Cercis canadensis, follicles and stems from Asclepias syriaca, dried composite inflorescences and stems from Echinacea angustifolia, E. pallida, and E. paradoxa var. paradoxa, and capsules and stems from Yucca glauca and Y. smalliana. Reproductive structures and bark/stems for 202 host plants were separated and cultured in 541 moist chambers, resulting in 118 collections yielding 32 myxomycete species representing 11 genera, seven families and five orders. There was no significant difference in pH values of the reproductive structures and bark/stems of the host plants, however legume pods of C. canadensis (6.9 +/- 1.3) had higher pH than the bark (6.0 +/- 1.1) and had a different composition of myxomycete species. Myxomycete orders have optimal pH ranges. Nonmetric multidimensional scaling, multiresponse permutation procedure and indicator species analysis showed a significant difference in species richness of reproductive structures and bark/stems. The bark of trees had greater mean species richness of myxomycetes than the reproductive structures, but the reproductive structures of herbaceous plants had greater mean species richness of myxomycetes than the stems. A new term, herbicolous myxomycetes, is proposed for a group of myxomycetes frequently associated with herbaceous, perennial, grassland plants. An undescribed species of Arcyria occurred only on cones of P. echinata.  (+info)

"Asclepias" is a genus of plants in the dogbane family (Apocynaceae). It includes several species commonly known as milkweeds. These plants are native to North America and are known for their milky sap and clusters of pink, yellow, or white flowers. Some species of Asclepias are important host plants for the monarch butterfly, which lays its eggs on the leaves and uses the sap to fuel its migration.

Pregnanes are a class of steroid hormones and steroids that contain a pregnane nucleus, which is a steroid core with a carbon skeleton consisting of 21 carbons. This structure includes four fused rings, labeled A through D, and is derived from cholesterol.

Pregnanes are important precursors for the synthesis of various steroid hormones in the body, including progesterone, which plays a crucial role in maintaining pregnancy and regulating the menstrual cycle. Other examples of pregnanes include cortisol, a stress hormone produced by the adrenal gland, and aldosterone, a hormone that helps regulate electrolyte balance and blood pressure.

It's worth noting that pregnanes can also refer to synthetic compounds that contain this steroid nucleus and are used in various medical and research contexts.

Apocynaceae is a family of flowering plants that includes shrubs, trees, and vines. It's also known as the dogbane or milkweed family. The plants in this family have milky sap and contain toxic compounds, which can be harmful or even fatal to animals and humans if ingested. Some well-known members of Apocynaceae include the various species of milkweeds (Asclepias spp.), oleander (Nerium oleander), and periwinkle (Vinca spp.).

The family is characterized by having opposite leaves, flowers with five petals and five sepals, and a superior ovary. The fruits are usually paired follicles that contain numerous seeds with tufts of hair to aid in wind dispersal. Many species in this family have medicinal or toxic properties, and some have economic importance as ornamental plants, sources of fiber, or for their use in traditional medicine.

Glycosides are organic compounds that consist of a glycone (a sugar component) linked to a non-sugar component, known as an aglycone, via a glycosidic bond. They can be found in various plants, microorganisms, and some animals. Depending on the nature of the aglycone, glycosides can be classified into different types, such as anthraquinone glycosides, cardiac glycosides, and saponin glycosides.

These compounds have diverse biological activities and pharmacological effects. For instance:

* Cardiac glycosides, like digoxin and digitoxin, are used in the treatment of heart failure and certain cardiac arrhythmias due to their positive inotropic (contractility-enhancing) and negative chronotropic (heart rate-slowing) effects on the heart.
* Saponin glycosides have potent detergent properties and can cause hemolysis (rupture of red blood cells). They are used in various industries, including cosmetics and food processing, and have potential applications in drug delivery systems.
* Some glycosides, like amygdalin found in apricot kernels and bitter almonds, can release cyanide upon hydrolysis, making them potentially toxic.

It is important to note that while some glycosides have therapeutic uses, others can be harmful or even lethal if ingested or otherwise introduced into the body in large quantities.

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