Morphogenesis of galls induced by Baccharopelma dracunculifoliae (Hemiptera: Psyllidae) on Baccharis dracunculifolia (Asteraceae) leaves.
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The commonest insect gall on Baccharis dracunculifolia (Asteraceae) leaves is induced by Baccharopelma dracunculifoliae (Hemiptera, Psyllidae). The gall-inducing insect attacks young leaves in both the unfolded and the fully expanded stages. Four developmental phases were observed in this type of gall: 1) A folding phase, during which the leaf lamina folded upward alongside the midrib and the edges of the upper portion of the leaf approached each other, forming a longitudinal slit. A single chamber was formed on the adaxial surface of the leaf; 2) A swelling phase, in which the folded leaf tissues thickened and the edges of the leaf drew closer together, narrowing the slit. In this phase the gall matured, turning succulent, fusiform and pale green. The single nymphal chamber was lined with white wax and was able to house from one to several nymphs; 3) A dehiscence phase, characterized by the opening of the slit to release inducers; and 4) A senescence phase, when the gall turned dark and dry. The dermal system of the mature gall was composed of a single-layered epidermis. The mesophyll was swollen, and the swelling was due mainly to hyperplasia of the parenchyma. The vascular tissues along the midrib vein were conspicuous and the perivascular fibers resembled parenchymal cells. The hypertrophied secretory cavities contained low lipophylic content. This gall does not form nutritive tissue, but salivary sheaths left by the inducers were observed near the parenchyma, vascular bundles and secretory cavities. This study complements our current knowledge of gall biology and sheds further light on the plasticity of plant tissues stimulated by biotic factors. (+info)
Studies on the constituents of the leaves of Baccharis dracunculifolia (Asteraceae) and their cytotoxic activity.
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A new sesquiterpene, named baccharisketone (1), and a new monoterpene, p-methoxythymol acetate (2), were isolated from the leaves of Baccharis dracunculifolia along with seventeen known compounds (3-19). The structures of the new compounds were determined by spectroscopic means. The growth inhibitory activity of the isolated compounds against leukemia cells (L 1210) was tested and three terpene phenols (4, 6, 17) and five sesquiterpene alcohols (8, 10, 11, 13, 16) were found to exhibit strong cytotoxic activity. (+info)
Clerodane diterpenoids and flavonoids with NGF-potentiating activity from the aerial parts of Baccharis gaudichaudiana.
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A new clerodane diterpene, 15-hydroxy-16-acetoxy-ent-clerod-3-en-18-oic acid (1), together with three known clerodane diterpenes (2-4) and three known flavones (5-7), were isolated from the aerial parts of Baccharis gaudichaudiana. Their structures were elucidated on the basis of spectroscopic analysis. Compounds 2, 3, and 5 showed enhancing activity of nerve growth factor (NGF)-induced neurite outgrowth in PC 12D cells. (+info)
Screening the phytoremediation potential of desert broom (Baccharis sarothroides Gray) growing on mine tailings in Arizona, USA.
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The metal concentrations in a copper mine tailings and desert broom (Baccharis sarothroides Gray) plants were investigated. The metal concentrations in plants, soil cover, and tailings were determined using ICP-OES. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in tailings was 526.4, 207.4, 89.1, 84.5, 51.7, 49.6, 39.7, and 35.6mgkg(-1), respectively. The concentration of all elements in soil cover was 10-15% higher than that of the tailings, except for molybdenum. The concentration of copper, lead, molybdenum, chromium, zinc, arsenic, nickel, and cobalt in roots was 818.3, 151.9, 73.9, 57.1, 40.1, 44.6, 96.8, and 26.7mgkg(-1) and 1214.1, 107.3, 105.8, 105.5, 55.2, 36.9, 30.9, and 10.9mgkg(-1) for shoots, respectively. Considering the translocation factor, enrichment coefficient, and the accumulation factor, desert broom could be a potential hyperaccumulator of Cu, Pb, Cr, Zn, As, and Ni. (+info)
Antimicrobial activity of three baccharis species used in the traditional medicine of Northern Chile.
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The antimicrobial activities of aqueous ethanol and chloroform extracts of three Baccharis species currently used in Northern Chile folk medicine for the treatment of several infectious and inflammatory disorders were tested against Gram-positive and negative bacteria and fungal spp. using the agar-disc diffusion assay. The results indicated that the activity was more pronounced against Gram-positive than against Gram-negative bacteria and yeast. No significant differences on the antibacterial activity were observed in the aqueous ethanol versus chloroform extracts. None of the plant extracts evaluated exhibited any activity against ten fungi tested. (+info)
Baccharis pteronioides toxicity in livestock and hamsters.
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Baccharis pteronioides DC has been intermittently associated with livestock poisoning in the southwestern United States. In 2004, nearly 100 cows were reported poisoned by B. pteronioides in southern New Mexico. Initial field studies and postmortem examinations found drought conditions, evidence of B. pteronioides consumption, and a reported mortality of nearly 40%. Because postmortem materials were unsuitable for further examination, plant samples were collected for feeding trials and chemical evaluation. Forty-eight Syrian hamsters (8 weeks old) were randomly divided into 4 groups and dosed with 0, 50, 100, and 200 mg of B. pteronioides for 10 days. After dosing, the hamsters were necropsied; sera were analyzed biochemically; and tissues were collected and evaluated histologically. The hamsters treated with 200 mg and several of the 100-mg animals developed anorexia and diarrhea. These animals developed multiple hemorrhagic infarcts in the liver and kidney, with severe hemorrhagic enteritis. Histologically, the higher-dosed animals had severe necrotizing vasculitis with vascular thrombosis of hepatic and renal vessels. Many glomerular capillaries contained fibrin thrombi. The superficial intestinal and colonic mucosa was necrotic, with extensive hemorrhage and proliferation of luminal bacteria. Lower-dosed animals had mild hepatocellular swelling, with proliferation of intestinal and gastric bacteria and yeast. The findings indicate that at high doses, B. pteronioides is toxic to hamsters and produces lesions that are very similar to bacterial endotoxin-produced vasculitis and infarction. Research to purify and identify the toxin, the toxic dose, and mechanism of toxicity are ongoing. (+info)
Antihypertensive effects of flavonoids isolated from brazilian green propolis in spontaneously hypertensive rats.
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Propolis, a honeybee product, has become popular as a food and alternative medicine. Its constituents have been shown to exert pharmacological effects, such as anticancer, antimicrobial, and anti-inflammatory effects. The present study was performed to investigate whether Brazilian green propolis exerts antihypertensive effects in spontaneously hypertensive rats (SHR) and which constituents are involved in its effects. Brazilian green propolis was extracted with ethanol and subjected to LH-20 column chromatography eluted with ethanol. The ethanol-eluted fractions at 10 mg/kg were administered orally to SHR for 14 d. Significant decreases in blood pressure were observed in fractions 6 and 7. The active constituents were purified and identified to be four flavonoids: dihydrokaempferide and isosakuranetin in fraction 6 and betuletol and kaempferide in fraction 7. These flavonoids at 10 mg/kg were administered orally to SHR for 28 d, and as a result, isosakuranetin, dihydrokaempferide and betuletol produced significant decrease in blood pressure, especially marked were the effects observed in the group that received isosakuranetin. Brazilian green propolis, fractions 6 and 7, and the 4 active constituents relaxed isolated SHR aorta in a concentration-dependent manner. Therefore, these finding suggest that the vasodilating action may be partly involved in the mechanism of antihypertensive effect. Hence, the ethanol extract of Brazilian green propolis and its main constituents may be useful for prevention of hypertension. (+info)
Inhibition of cyclooxygenase activity by standardized hydroalcoholic extracts of four Asteraceae species from the Argentine Puna.
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