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At least 145 records · Page 8Linked to original sources
PubMed2006

Hydrogen peroxide concentrations in leaves under natural conditions.

While H2O2 has been implicated in numerous plant environmental responses, normal levels and variabilities are poorly established, and estimates of leaf tissue concentrations span more than three orders of magnitude, even in a single species under similar conditions. Here, leaf tissue H2O2 contents under natural conditions are reported after determining (i) that H2O2 in extracts was stable with time, (ii) that H2O2 added to the extract was recovered quantitatively, and (iii) that the H2O2 calibration curve was unaffected (or quantifiably affected) by the extract. The broad applicability of the protocol and variability in leaf concentrations were demonstrated using tissue collected from several habitats in association with three, more extensive, experiments. The first involved nychthemeral studies of the mangrove, Rhizophora mangle L. Lowest H2O2 levels occurred in the early morning and near sunset, with higher levels both at midday and at night. Second, using five temperate species in Spring, concentrations were compared on a warm, sunny day and a cool, cloudy day. Higher concentrations were found on the warm day for Aesculus glabra Willd., Glechoma hederacea L., Plantago major L., and Viola soraria Willd., while there were no differences in Quercus macrocarpa Michx. Finally, the effects of elevated CO2 and ozone were examined in soybean, Glycine max L. Pioneer 93B15 under Free Air gas Concentration Enrichment (FACE) conditions. Both supplements led to elevated H2O2. Overall, mean leaf, midday, and mid-summer H2O2 concentrations ranged from 0.67 micromol (gFW)(-1) in mangrove to 3.6 micromol (gFW)(-1) in A. glabra Willd. Greatest within-species differences were only 2.5-fold in any of the studies.

Environment↗
PubMed2006

Optical properties of bud scales and protochlorophyll(ide) forms in leaf primordia of closed and opened buds.

The transmission spectra of bud scales of 14 woody species and the 77 K fluorescence emission spectra of the innermost leaf primordia of closed and opened buds of 37 woody species were studied. Pigment concentrations were determined in some species. Bud scales had low transmittance between 400 and 680 nm with a local minimum around 680 nm. Transmittance increased steeply above 680 nm and was > 80% in the 700-800 nm spectral region. Significant protochlorophyllide (Pchlide) accumulation was observed in leaf primordia of tightly packed, closed buds with relatively thick, dark bud scales. In common ash (Fraxinus excelsior L.) and Hungarian ash (Fraxinus angustifolia Vahl.), the innermost leaf primordia of the closed buds contained protochlorophyll (Pchl) and Pchlide (abbreviated as Pchl(ide)), but no chlorophyll. We observed Pchl(ide) forms with emission maxima at 633, 643 and 655 nm in these leaves. Complete transformation of Pchlide(655) (protochlorophyllide form with maximum emission at 655 nm) into Chlide(692) (chlorophyllide form with maximum emission at 692 nm) occurred after irradiation for 10 s. The innermost leaf primordia of the buds of four species (flowering ash (Fraxinus ornus L.), horse chestnut (Aesculus hippocastanum L.), tree of heaven (Ailanthus altissima P. Mill.) and common walnut (Juglans regia L.)) contained Pchl(ide)(633), Pchl(ide)(643) and Pchlide(655) as well as an emission band at 688 nm corresponding to a chlorophyll form. The Pchlide(655) was fully photoactive in these species. The outermost leaf primordia of these four species and the innermost leaf primordia of 28 other species contained all of the above described Pchl(ide) forms in various ratios but in small amounts. In addition, Chl forms were present and the main bands in the fluorescence emission spectra were at 690 or 740 nm, or both. The results indicate that Pchl(ide) accumulation occurs in leaf primordia in near darkness inside the tightly closed buds, where the bud scales and the external leaf primordia function as optical filters.

Color↗
PubMed2001

Cavitation fatigue. Embolism and refilling cycles can weaken the cavitation resistance of xylem.

Although cavitation and refilling cycles could be common in plants, it is unknown whether these cycles weaken the cavitation resistance of xylem. Stem or petiole segments were tested for cavitation resistance before and after a controlled cavitation-refilling cycle. Cavitation was induced by centrifugation, air drying of shoots, or soil drought. Except for droughted plants, material was not significantly water stressed prior to collection. Cavitation resistance was determined from "vulnerability curves" showing the percentage loss of conductivity versus xylem pressure. Two responses were observed. "Resilient" xylem (Acer negundo and Alnus incana stems) showed no change in cavitation resistance after a cavitation-refilling cycle. In contrast, "weakened" xylem (Populus angustifolia, P. tremuloides, Helianthus annuus stems, and Aesculus hippocastanum petioles) showed considerable reduction in cavitation resistance. Weakening was observed whether cavitation was induced by centrifugation, air dehydration, or soil drought. Observations from H. annuus showed that weakening was proportional to the embolism induced by stress. Air injection experiments indicated that the weakened response was a result of an increase in the leakiness of the vascular system to air seeding. The increased air permeability in weakened xylem could result from rupture or loosening of the cellulosic mesh of interconduit pit membranes during the water stress and cavitation treatment.

Acer↗
PubMed1999

[Bioactive saponins and glycosides. XIII. Horse chestnut. (3): Quantitative analysis of escins Ia, Ib, IIa, and IIb by means of high performance liquid chromatography].

As a part of our studies on the characterization of bioactive saponin constituents of horse chestnut trees, a quantitative method using high performance liquid chromatography (HPLC) has been developed for four principle saponin constituents, such as escins Ia, Ib, IIa, and IIb, isolated from the seeds of European horse chestnut trees (Aesculus hippocastanum L., Hippocastanaceae). As an application of this HPLC method, we examined the contents and compositions of these escins in the seeds of Japanese horse chestnut trees (A. turbinata BLUME) and in several commercial materials named as "beta-escin". Additionally, the distribution of escins in the Japanese horse chestnut trees was examined, and escins were found to be contained only in the seeds.

Chromatography, High Pressure Liquid↗
PubMed1999

Phytomedicine research in Germany.

In Germany since 1980, more than 300 clinical studies have been carried out with standardized phytopharmaceuticals, including Crataegus, Silybum, Ginkgo, Hypericum, Sabal, Urtica, Kava-Kava, Allium sativum, Valeriana, Aesculus, Echinacea, and Viscum drugs. These studies assessed the efficacy of phytopharmaceuticals for the treatment of moderate or moderately severe diseases and prevention. Several comparative clinical trials showed that these phytopharmaceuticals had full therapeutic equivalence with chemotherapeutics and had the simultaneous advantage of being devoid of any adverse effects. The mechanism of action of herbal drugs and their extract preparations, which differ in many respects from that of synthetic drugs or mono substances, can be characterized as a polyvalent action and interpreted as additive or, in some cases, potentiating. Currently, a rationale for the observed reversal effects and optimal effects with very low doses after a long-term application has not been developed, but is under investigation by systematic research at the molecular level.

Clinical Trials as Topic↗
PubMed1999

Herbal medications for common ailments in the elderly.

The popularity of herbal medicine is at an all time peak. This article provides an overview of systematic reviews of herbal treatments for conditions common in elderly individuals. According to this evidence, there is little doubt that Hypericum perforatum (St John's Wort) is well tolerated and effective for mild to moderate depression. Although widely used, Valeriana officinalis (valerian) has not been shown beyond reasonable doubt to be effective for insomnia. There is relatively compelling evidence that Ginkgo biloba (ginkgo) is effective in delaying the clinical course of dementias. It has been well documented that Aesculus hippocastanum (horse chestnut) seed extracts alleviate the subjective symptoms and reduce the objective signs of chronic venous insufficiency. Serenoa repens (saw palmetto) is effective in improving the symptoms of benign prostatic hyperplasia. Finally, yohimbine has been shown to be effective forerectile dysfunction. It is concluded that several plant-based medicines can be useful additions to our therapeutic repertoire for treating common conditions in the elderly. However, several uncertainties remain and, at present, prevent unreserved recommendations.

Aged↗
PubMed2001

Hemorrhoids and varicose veins: a review of treatment options.

Hemorrhoids and varicose veins are common conditions seen by general practitioners. Both conditions have several treatment modalities for the physician to choose from. Varicose veins are treated with mechanical compression stockings. There are several over-the-counter topical agents available for hemorrhoids. Conservative therapies for both conditions include diet, lifestyle changes, and hydrotherapy which require a high degree of patient compliance to be effective. When conservative hemorrhoid therapy is ineffective, many physicians may choose other non-surgical modalities: injection sclerotherapy, cryotherapy, manual dilation of the anus, infrared photocoagulation, bipolar diathermy, direct current electrocoagulation, or rubber band ligation. Injection sclerotherapy is the non-surgical treatment for primary varicose veins. Non-surgical modalities require physicians to be specially trained, own specialized equipment, and assume associated risks. If a non-surgical approach fails, the patient is often referred to a surgeon. The costly and uncomfortable nature of treatment options often lead a patient to postpone evaluation until aggressive intervention is necessary. Oral dietary supplementation is an attractive addition to the traditional treatment of hemorrhoids and varicose veins. The loss of vascular integrity is associated with the pathogenesis of both hemorrhoids and varicose veins. Several botanical extracts have been shown to improve microcirculation, capillary flow, and vascular tone, and to strengthen the connective tissue of the perivascular amorphous substrate. Oral supplementation with Aesculus hippocastanum, Ruscus aculeatus, Centella asiatica, Hamamelis virginiana, and bioflavonoids may prevent time-consuming, painful, and expensive complications of varicose veins and hemorrhoids.

Diagnosis, Differential↗
PubMed2003

[Fractal properties of the spatial pattern of rare and endangered plant populations in Houhe Nature Reserve in Hubei: Box-counting dimension].

The fractal properties of the spatial distribution pattern of 4 dominant plant populations and 7 rare and endangered plant populations were reflected through the box-counting dimensions. The results showed that the box-counting dimensions of 4 dominant populations ranged between 1.346 and 1.414, and occupied relatively larger ecological spaces in the community. Camellia cuspidata population occupied the largest ecological space because of its biggest box-counting dimensions. However, most of other populations occupied relatively smaller spaces due to their smaller values of the box-counting dimensions. The box-counting dimensions of 7 rare and endangered populations were smaller than 1 except Dipteronia sinensis population. The inflexion scales of 11 populations covered the range from 5 m to 12.5 m. According to the self-similarity of the fractal, the distribution pattern types under certain scales larger than the inflexion scale could be inferred as similar, and the results partly proved the ideas. The populations of Disopyros lotus, Pterostyrax psilophyllus, Davidia involucrata, Tetracentron sinense and Aesculus wilsonii were changed at the inflexion scale, and other 6 populations had the same distribution pattern types despite of the scale changed.

Conservation of Natural Resources↗
PubMedDate not supplied

Effects of proanthocyanidin on normal and reinnervated rat muscle.

Proanthocyanidin-A2, a catechic dimer extracted from the bark of Aesculus hippocastanum L., was tested on peripheral nerve regeneration. Reinnervation of EDL and soleus muscles following traumatic nerve damage was investigated in rats by using "in vivo" tension recording technique. Muscle contraction force (twitch and tetanus), the number of motor units and the time course of twitch (time to peak and half relaxation time), were observed. The results obtained do not show that the time course of EDL and soleus muscles reinnervation is different in Proanthocyanidin-A2-treated rats in comparison to control animals. On the contrary, results point out an increase in EDL and soleus muscle mass, both in denervated and in undenervated treated rats compared to corresponding controls. Moreover, consistently with this finding, an increase in their contraction force was found. These data show that Proanthocyanidin-A2 exerts a trophic effect on muscle.

Animals↗
PubMed1996

[Serious plant poisonings in Switzerland 1966-1994. Case analysis from the Swiss Toxicology Information Center].

AIM: To analyze the types, frequency and severity of plant poisonings in Switzerland over 29 years. METHODS: Retrospective analysis of severe poisonings with toxic plants reported to the Swiss Toxicological Information Center (STIC). Assessment of the causality, severity of symptoms and the types of plants involved. RESULTS: During the period under review the STIC registered 24 950 cases of contact with or ingestion of toxic plant material. In 99.4% of all cases the clinical course was either unknown, asymptomatic or associated with only minor symptoms (no hospitalization). Severe plant poisonings occurred in 152 cases. Detailed analysis was possible in 135 cases (23 children, 112 adults) including 5 lethal cases (all adults). The 24 plants involved produced the following severe symptoms: Atropa belladonna (42 cases): anticholinergic syndrome (42), acute psychosis (33), convulsions (2), coma (2). Heracleum mantegazzianum (18): severe photodermatitis (18). Datura stramonium (17): anticholinergic syndrome (17), psychosis (12), coma (2). Dieffenbachia (11): severe stomatitis (8), corneal lesions (3). Colchicum autumnala (10): diarrhea (10), liver necrosis (9), fatal multiorgan failure (2). Veratrum album (8): bradycardia ( < or = 40/min) (6), shock (5). Aconitum napellus (4): tachyarrhythmia (2), AV-block II/III (2). Aesculus hippocastanum (3): allergy (3), anaphylactic shock (2). Hyoscyamus niger (3): anticholinergic syndrome (3). Ricinus communis (3): diarrhea (3), toxic megacolon (1). Oenanthe crocata (2): convulsions (1), lethal coma (1). Taxus baccata (2): tachyarrhythmia (1), fatal asystole (1). Further single cases with severe poisonings were observed with Arum maculatum, Asarum europaeum, Chrysanthemum vulgare, Cyclamen persicum, Datura suaveolens, Glycyrrhiza glabra, Laburnum anagyroides, Lycopodium, Narcissus pseudonarcissus (lethal aspiration), Nerium oleander, Senecio vulgaris and Vicia faba. CONCLUSIONS: Potential and real intoxications with plant materials occurred in 7.2% of all cases registered at the STIC. However, among all plant cases only 0.6% were severe intoxications requiring hospitalization. Although severe plant intoxications are rare events, a small number of specific plants appear to be mainly responsible for continued serious plant poisoning in Switzerland. The present study has identified the plants with the highest toxicological risks and provides a data base for more rational prevention, diagnosis and treatment of plant poisoning cases in the future.

Adult↗