Rhus
Toxicodendron
Laccase
Chalcones
Semialactone, isofouquierone peroxide and fouquierone, three new dammarane triterpenes from Rhus javanica. (1/36)
Three new dammarane triterpenes and semialactic acid were isolated from the stem bark of Rhus javanica. The structures of these triterpenes, named semialactone, isofouquierone peroxide and fouquierone, were elucidated by 2D-NMR analysis (HMQC, 1H-1H COSY and HMBC), and the 13C-NMR data of semialatic acid is revised. (+info)Effects of herbivory on the reproductive effort of 4 prairie perennials. (2/36)
BACKGROUND: Herbivory can affect every aspect of a plant's life. Damaged individuals may show decreased survivorship and reproductive output. Additionally, specific plant species (legumes) and tissues (flowers) are often selectively targeted by herbivores, like deer. These types of herbivory influence a plant's growth and abundance. The objective of this study was to identify the effects of leaf and meristem removal (simulated herbivory within an exclosure) on fruit and flower production in four species (Rhus glabra, Rosa arkansana, Lathyrus venosus, and Phlox pilosa) which are known targets of deer herbivory. RESULTS: Lathyrus never flowered or went to seed, so we were unable to detect any treatment effects. Leaf removal did not affect flower number in the other three species. However, Phlox, Rosa, and Rhus all showed significant negative correlations between seed mass and leaf removal. Meristem removal had a more negative effect than leaf removal on flower number in Phlox and on both flower number and seed mass in Rosa. CONCLUSIONS: Meristem removal caused a greater response than defoliation alone in both Phlox and Rosa, which suggests that meristem loss has a greater effect on reproduction. The combination of leaf and meristem removal as well as recruitment limitation by deer, which selectively browse for these species, is likely to be one factor contributing to their low abundance in prairies. (+info)Genetic variation and evidence of hybridization in the genus Rhus (Anacardiaceae). (3/36)
Rhus michauxii, a rare plant species endemic to the southeastern United States, was previously known only from central North Carolina and one site in Georgia. An additional site, which is now believed to represent the largest known concentration of R. michauxii, was recently discovered at Ft. Pickett near Blackstone, Virginia. Morphological characteristics in several of the Ft. Pickett Rhus populations appear to be intermediate between R. michauxii and the widespread R. glabra, a closely related congener that co-occurs at Ft. Pickett. Although morphological evidence of hybridization between R. michauxii and R. glabra in North Carolina has been provided previously, genetic marker data are lacking. In the present study we examined levels of allozyme variation at 11 polymorphic loci within and among seven populations of R. michauxii, one population of R. glabra, and four putative hybrid populations at Ft. Pickett. Overall, R. michauxii had typical levels of within-population genetic variation when compared to other species with similar life-history characteristics. In contrast, the proportion of genetic variation among populations (G(ST)) was considerably lower than expected. Finally, R. michauxii and R. glabra appear to have a fixed allelic difference at the Idh2 locus. This enabled us to confirm hybridization in all four of the putative hybrid populations and one of the R. michauxii populations. (+info)Identification of Rhus verniciflua Stokes compounds that exhibit free radical scavenging and anti-apoptotic properties. (4/36)
Rhus verniciflua Stokes (RVS) is a widely used herbal plant with various biological properties. Our previous study using cultured neuronal cells showed that an ethanol extract of RVS had strong antioxidant properties. In this study, we characterized the antioxidant activity of the RVS ethanol extract and identified the active compounds responsible for this activity. From the RVS ethanol extract, we derived three water-eluted fractions and another three fractions eluted by organic solvents, and determined that the water-eluted fractions are what protect against reactive oxygen species (ROS) generated by iron and enzymes. Water-eluted fraction F(2) was the most efficient antioxidant. Moreover, DNA fragmentation and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining experiments revealed that F(2) also protects against thymocyte apoptosis mediated by hydroxyl radicals. Finally, EI-MS, (1)H-NMR, and (13)C-NMR spectra signals confirmed that the fraction contained flavonoid derivatives, including fustin, quercetin, butein, and sulfuretin. These results suggest that the flavonoid derivatives in F(2) are the compounds in the RVS ethanol extract that act as antioxidants. (+info)Alkaline transition of phytocyanins: a comparison of stellacyanin and umecyanin. (5/36)
The effect of pH on Cu(I) and Cu(II) forms of the isolated soluble domain of the stellacyanin from Rhus vernicifera (SCu), the Japanese lacquer tree, has been studied by electronic and NMR spectroscopy and using direct electrochemical measurements. A pK(a) value of 10.1-10.4 is observed for the alkaline transition in this oxidized phytocyanin and results in a slightly altered active-site structure, as indicated by changes in the visible and paramagnetic (1)H NMR spectra. Electrochemical studies show that the pK(a) value for this transition in SCu(I) (reduced SCu) is 11.0. These results are compared with those recently obtained for other phytocyanins, and in particular umecyanin. In all cases, the alkaline transition is caused by the deprotonation of the surface lysine residue adjacent to the axial ligand. This lysine residue is completely conserved in known phytocyanin sequences. Also highlighted in these studies are the remarkable active-site similarities between stellacyanin and umecyanin. (+info)Ethanol-eluted extract of Rhus verniciflua stokes inhibits cell growth and induces apoptosis in human lymphoma cells. (6/36)
Rhus verniciflua Stokes (RVS) has been used as a traditional herbal medicine. Several earlier studies indicated that an ethanol extract of RVS has both anti-oxidant and anti-tumor properties, although the mechanism for the activity remains to be elucidated. In this report, we prepared a highly purified ethanol extract from RVS, named REEE-1 (Rhus ethanol eluted extract-1), and investigated the mechanism involved in its growthinhibitory effect on the human B and T lymphoma cell lines, BJAB and Jurkat, respectively. Results from tritium uptake proliferation assays showed that the proliferative capacities of both BJAB and Jurkat cells were strongly suppressed in the presence of REEE-1. This was further confirmed through trypan blue exclusion experiments that revealed a dose-dependent decrease in viable cell numbers after REEE-1 treatment. REEE-1-mediated suppression of cell growth was verified to be apoptotic, based on the increase in DNA fragmentation, low fluorescence intensity in nuclei after propidium iodide staining, and the appearance of DNA laddering. In particular, REEE-1 exerted its anti-oxidant activity through the inhibition of hydroxyl radical-mediated degradation by iron ion chelation rather than direct scavenging of hydroxyl radicals. Furthermore, REEE-1 was revealed to be a potential scavenger of superoxide anions. Collectively, our findings suggest that REEE-1 is a natural anti-oxidant that could be used as a cancer chemo-preventive and therapeutic agent. (+info)The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts. (7/36)
BACKGROUND: Butein (3,4,2',4'-tetrahydroxychalone), a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the growth of breast cancer cells, we investigated the ability of butein to inhibit the clonogenic growth of small numbers of breast cancer cells co-cultured with fibroblasts in vitro. METHODS: We first measured the clonogenic growth of small numbers of the UACC-812 human breast cancer cell line co-cultured on monolayers of serum-activated, human fibroblasts in the presence of butein (2 microg/mL) or various other modulators of fibroblast function (troglitazone-1 microg/mL; GW9662-1 microM; meloxican-1 microM; and 3,4 dehydroproline-10 microg/mL). In a subsequent experiment, we measured the dose-response effect on the clonogenic growth of UACC-812 breast cancer cells by pre-incubating the fibroblasts with varying concentrations of butein (10 microg/ml-1.25 microg/mL). Finally, we measured the clonogenic growth of primary breast cancer cells obtained from 5 clinical specimens with normal fibroblasts and with fibroblasts that had been pre-treated with a fixed dose of butein (2.5 microg/mL). RESULTS: Of the five modulators of fibroblast function that we tested, butein was by far the most potent inhibitor of clonogenic growth of UACC-812 breast cancer cells co-cultured with fibroblasts. Pre-treatment of fibroblasts with concentrations of butein as low as 2.5 microg/mL nearly abolished subsequent clonogenic growth of UACC-812 breast cancer cells co-cultured with the fibroblasts. A similar dose of butein had no effect on the clonogenic growth of breast cancer cells cultured in the absence of fibroblasts. Significantly, clonogenic growth of the primary breast cancer cells was also significantly reduced or abolished when the tumor cells were co-cultured with fibroblasts that had been pre-treated with a fixed dose of butein. CONCLUSION: We conclude that fibroblasts pre-treated with non-toxic doses of butein (a natural herbal compound) no longer support the clonogenic growth of small numbers of primary breast cancer cells seeded into co-cultures. These results suggest that interference with the interaction between fibroblasts and breast cancer cells by the natural herbal compound, butein, should be further investigated as a novel experimental approach for possibly suppressing the growth of micrometastases of breast cancer. (+info)Do xylem fibers affect vessel cavitation resistance? (8/36)
Possible mechanical and hydraulic costs to increased cavitation resistance were examined among six co-occurring species of chaparral shrubs in southern California. We measured cavitation resistance (xylem pressure at 50% loss of hydraulic conductivity), seasonal low pressure potential (P(min)), xylem conductive efficiency (specific conductivity), mechanical strength of stems (modulus of elasticity and modulus of rupture), and xylem density. At the cellular level, we measured vessel and fiber wall thickness and lumen diameter, transverse fiber wall and total lumen area, and estimated vessel implosion resistance using (t/b)(h)(2), where t is the thickness of adjoining vessel walls and b is the vessel lumen diameter. Increased cavitation resistance was correlated with increased mechanical strength (r(2) = 0.74 and 0.76 for modulus of elasticity and modulus of rupture, respectively), xylem density (r(2) = 0.88), and P(min) (r(2) = 0.96). In contrast, cavitation resistance and P(min) were not correlated with decreased specific conductivity, suggesting no tradeoff between these traits. At the cellular level, increased cavitation resistance was correlated with increased (t/b)(h)(2) (r(2) = 0.95), increased transverse fiber wall area (r(2) = 0.89), and decreased fiber lumen area (r(2) = 0.76). To our knowledge, the correlation between cavitation resistance and fiber wall area has not been shown previously and suggests a mechanical role for fibers in cavitation resistance. Fiber efficacy in prevention of vessel implosion, defined as inward bending or collapse of vessels, is discussed. (+info)"Rhus" is a genus of plants that includes several species commonly known as poison ivy, poison oak, and poison sumac. These plants contain an oil called urushiol, which can cause an allergic reaction in many people when they come into contact with the plant's leaves, stems, or roots. The reaction typically includes a red, itchy rash that can blister and ooze.
In some contexts, "rhus" may also refer to homeopathic remedies made from these plants. However, it is important to note that the use of such remedies is not supported by scientific evidence and can be dangerous. It is always best to consult with a healthcare provider for medical advice regarding allergic reactions or other health concerns.
"Toxicodendron" is a genus of flowering plants in the family Anacardiaceae, also known as the cashew family. This genus includes several species that are well-known for causing allergic reactions in humans, particularly through contact with their sap or urushiol-containing parts of the plant. The most common and notorious species in this genus is Toxicodendron radicans, also known as poison ivy, poison oak, and poison sumac. These plants can cause an itchy, blistering rash upon contact with the skin, which is a type of allergic reaction called contact dermatitis. The severity of the reaction can vary from person to person, depending on their sensitivity to urushiol and the amount of exposure they have had to the plant.
Laccase is an enzyme (specifically, a type of oxidoreductase) that is widely distributed in plants, fungi, and bacteria. It catalyzes the oxidation of various phenolic compounds, including polyphenols, methoxy-substituted phenols, aromatic amines, and some inorganic ions, while reducing molecular oxygen to water. This enzyme plays a crucial role in lignin degradation, as well as in the detoxification of xenobiotic compounds and in the synthesis of various pigments and polymers. The medical relevance of laccase is linked to its potential applications in bioremediation, biofuel production, and biotechnology.
Ascorbate oxidase is an enzyme that catalyzes the oxidation of ascorbic acid (vitamin C) to dehydroascorbic acid in the presence of oxygen. This reaction also results in the production of water and hydrogen peroxide as byproducts. Ascorbate oxidase plays a significant role in regulating the levels of ascorbic acid in plants, where it is primarily found. It belongs to the family of copper-containing oxidoreductases. The enzyme's active site contains two copper ions that facilitate the electron transfer during the catalytic process. Ascorbate oxidase is not considered essential for human health since humans do not produce ascorbic acid and must obtain it through dietary sources.
Chalcones are a class of compounds that have a chemical structure consisting of two aromatic rings connected by a three-carbon α,β-unsaturated carbonyl system. The name "chalcone" is derived from the Greek word "chalcos," meaning copper, due to the yellow color that many chalcones exhibit.
Chalcones are synthesized through a reaction known as the Claisen-Schmidt condensation between an aldehyde and a ketone. They are important intermediates in the biosynthesis of flavonoids, which are a large group of plant pigments that have various biological activities, such as antioxidant, anti-inflammatory, and anticancer properties.
Chalcones themselves have been studied for their potential medicinal properties, including their ability to inhibit the growth of cancer cells, bacteria, and fungi. However, more research is needed to fully understand their mechanisms of action and safety profiles before they can be developed into drugs.
'Toxic plants' refer to those species of plants that contain toxic substances capable of causing harmful effects or adverse health reactions in humans and animals when ingested, touched, or inhaled. These toxins can cause a range of symptoms from mild irritation to serious conditions such as organ failure, paralysis, or even death depending on the plant, the amount consumed, and the individual's sensitivity to the toxin.
Toxic plants may contain various types of toxins, including alkaloids, glycosides, proteins, resinous substances, and essential oils. Some common examples of toxic plants include poison ivy, poison oak, nightshade, hemlock, oleander, castor bean, and foxglove. It is important to note that some parts of a plant may be toxic while others are not, and the toxicity can also vary depending on the stage of growth or environmental conditions.
If you suspect exposure to a toxic plant, it is essential to seek medical attention immediately and, if possible, bring a sample of the plant for identification.
I'm sorry for any confusion, but "Plant Bark" is not a term with a specific medical definition. In general, the bark refers to the outermost covering of a tree or other plant, which serves as protection and provides a barrier against external threats. It is composed of layers including the inner bark (phloem), which transports nutrients throughout the plant, and the outer bark (periderm), which is made up of dead cells that form a protective layer.
While some plants or plant parts do have medicinal properties and are used in various forms of traditional or alternative medicine, "Plant Bark" by itself does not have any specific medical connotations. If you're referring to a specific type of plant bark with potential medicinal uses, please provide more details so I can give a more accurate response.