SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The quantitative analysis of metallic cations in the seeds of Xanthium spinosum L. and Xanthium italicum Moretti was performed. The differences for the two species reflect the different presence of some organic compounds having a ligand character.
Explore the source record for details and available documents.
To assess the pattern of cross-sensitivity between 4 members of the Compositae family, namely Parthenium hysterophorus L., Xanthium strumarium L., Helanthus annuus L. and Chrysanthemum coronarium L., 63 patients clinically diagnosed to have airborne contact dermatitis, and 51 controls having well-defined patterns of contact dermatitis caused by agents other than plants, were patch tested with measured amounts of standardized aqueous extracts of these plants. Positive reactions were obtained in 62 patients and 13 controls with Parthenium hysterophorus, in 47 patients and 9 controls with Xanthium strumarium, in 7 patients and 2 controls with Helianthus annuus, and in 13 of the 57 patients and one out of 28 controls tested with Chrysanthemum coronarium. 2 patients were allergic to all 4 of the plants; 14 patients to 3 plants, namely Parthenium, Xanthium and Chrysanthemum in 9 cases and Parthenium, Xanthium and Helianthus in 5 cases; 32 patients to 2 plants, namely Parthenium and Xanthium in 30 cases, and Parthenium and Chrysanthemum, and Xanthium and Chrysanthemum in 1 case each; 15 patients were allergic to 1 plant only, that being Parthenium. All the 47 patients allergic to Xanthium, 13 patients allergic to Chrysanthemum and 7 patients allergic to Helianthus were positive with some other plant as well. There was 1 patient who was allergic to Xanthium and Chrysanthemum but not to Parthenium. The titre of contact hypersensitivity (TCH) determined in the patients allergic to Parthenium, Xanthium and Helianthus showed values that varied widely with each plant in different patients, and there was no parallelism between the TCH with various plants.(ABSTRACT TRUNCATED AT 250 WORDS)
Steady-state bioavailability of sustained-release theophylline (SRT); Theo-Dur, Uni-Dur and Xanthium were compared in 10 healthy males with theophylline clearance ranged from 0.3 - 0.8 ml/min/kg. Each of 400-mg SRT was administered once daily before breakfast for 7 consecutive days, one-week washout period in a crossover fashion. Serial blood samples were collected over 24 hours on days 6 and 7. Serum theophylline concentrations were determined by fluorescence polarized immunoassay. We found that the oral bloavailability relative to Franol (%F [90% CI]) of Theo-Dur, Uni-Dur and Xanthium were 97 (93-106), 85 (79-96) and 77 (72-87), respectively. Average bioequivalence revealed that the Css(min) (microg/ml) of Uni-Dur (5.07) was higher than Theo-Dur (4.29), and Xanthiume (4.18), while the Css(max) and Css(av) (microg/ml) of Theo-Dur (11.02, 7.87) were statistically higher than Uni-Dur (8.51, 6.91) and Xanthium (7.65, 6.27). The extent of absorption assessed by AUCss(0.24) of Theo-Dur was significantly greater than Uni-Dur and Xanthium. However, fluctuation index (% FI) of Theo-Dur (232) was twofold higher than Uni-Dur (137) and Xanthium (113). The median Tss(max) of Uni-Dur was 12 hours which was significantly longer than Xanthium (7 hours) and Theo-Dur (8 hours). There were no statistically significant differences between Uni-Dur and Xanthium regarding bioavailability, Css(max), Css(av) as well as % FI. Moreover, 400 mg OD of Uni-Dur and Xanthium are suitable for subjects with a theophylline clearance of 0.3-0.55 ml/min/kg while 400 mg OD Theo-Dur can be used in subjects with slower clearance rates of 0.3-0.39 ml/min/kg. Subjects with rapid theophylline clearance rates of 0.65-0.8 ml/min/kg required a higher dose of theophylline and twice-daily dosing was more appropriate.
Plants of Xanthium strumarium L. and Lycopersicon esculentum Mill. cv ;Rheinlands Ruhm' were grown in solution culture, and control and steam-girdled intact plants were stressed. Detached roots of both species were stressed to different extents in two ways: (a) either in warm air or, (b) in the osmoticum Aquacide III. The roots of both species produced and accumulated progressively more abscisic acid (ABA), the greater the stress inflicted by either method. ABA-glucose ester levels in Xanthium roots were not affected by water stress and were too low to be the source of the stress-induced ABA. The fact that ABA accumulated in detached roots and in roots of girdled plants proves that ABA was synthesized in the roots and not merely transported from the shoots.Maximum ABA accumulation in detached roots occurred after 60 to 70% loss of fresh weight. In Xanthium roots, ABA levels continued to increase for at least 11 hours, and no catabolism was apparent when stressed roots were immersed in water, although the roots did stop accumulating ABA. When osmotically stressed, Xanthium roots reached a maximum ABA level after 2 hours, but ABA continued to rise in the medium.Under optimal stress conditions, endogenous ABA levels increased 100 times over their prestress values in detached roots of Xanthium, and 15 times in Lycopersicon under nonoptimal stress, when endogenous ABA was expressed as concentrations based on tissue water content. These are much greater relative increases than observed in the leaves (15 times in Xanthium, 3 times in Lycopersicon), although the roots contain substantially less ABA than the leaves in all circumstances. The results suggest that the endogenous level of ABA in roots could rise appreciably prior to leaf wilt, and could modify the plant's water economy before the leaves become stressed.
RESEARCH ON THE BIOSYNTHESIS OF ABSCISIC ACID (ABA) HAS FOCUSED PRIMARILY ON TWO PATHWAYS: (a) the direct pathway from farnesyl pyrophosphate, and (b) the indirect pathway involving a carotenoid precursor. We have investigated which biosynthetic pathway is operating in turgid and stressed Xanthium leaves, and in stressed Xanthium roots using long-term incubations in (18)O(2). It was found that in stressed leaves three atoms of (18)O from (18)O(2) are incorporated into the ABA molecule, and that the amount of (18)O incorporated increases with time. One (18)O atom is incorporated rapidly into the carboxyl group of ABA, whereas the other two atoms are very slowly incorporated into the ring oxygens. The fourth oxygen atom in the carboxyl group of ABA is derived from water. ABA from stressed roots of Xanthium incubated in (18)O(2) shows a labeling pattern similar to that of ABA in stressed leaves, but with incorporation of more (18)O into the tertiary hydroxyl group at C-1' after 6 and 12 hours than found in ABA from stressed leaves. It is proposed that the precursors to stress-induced ABA are xanthophylls, and that a xanthophyll lacking an oxygen function at C-6 (carotenoid numbering scheme) plays a crucial role in ABA biosynthesis in Xanthium roots. In turgid Xanthium leaves, (18)O is incorporated into ABA to a much lesser extent than it is in stressed leaves, whereas exogenously applied (14)C-ABA is completely catabolized within 48 hours. This suggests that ABA in turgid leaves is either (a) made via a biosynthetic pathway which is different from the one in stressed leaves, or (b) has a half-life on the order of days as compared with a half-life of 15.5 hours in water-stressed Xanthium leaves. Phaseic acid showed a labeling pattern similar to that of ABA, but with an additional (18)O incorporated during 8'-hydroxylation of ABA to phaseic acid.
From previous work (Zeevaart 1980 Plant Physiol 66: 672-678) Xanthium leaves are known to contain a high level of alkali-hydrolyzable conjugated abscisic acid. This abscisic acid conjugate has been isolated and identified by mass spectrometry, nuclear magnetic resonance, and chemical and enzymic degradation techniques, as the glucosyl ester of abscisic acid, beta-d-glucopyranosyl abscisate. The glucosyl ester of abscisic acid was the only abscisic acid conjugate found in Xanthium leaves. It was also isolated from spinach leaves.An insignificant amount of the glucosyl ester of abscisic acid partitioned into diethyl ether, whereas 12% partitioned into ethyl acetate. Consequently, removal of abscisic acid by partitioning with ethyl acetate will result in considerable losses of the glucosyl ester of abscisic acid from the aqueous phase. Diethyl ether is, therefore, recommended for separation of abscisic acid and the glucosyl ester of abscisic acid by solvent partitioning.A method for quantitation of the glucosyl ester of abscisic acid as the tetraacetate derivative by gas-liquid chromatography with an electron capture detector was developed. The level of beta-d-glycopyranosyl abscisate in Xanthium leaves increased from 3.6 nanomoles per gram fresh weight in turgid leaves to 22.9 nanomoles in leaves from plants subjected to seven wilting-recovery cycles. beta-d-glycopyranosyl abscisate in Xanthium leaves may be a stable end product of abscisic acid metabolism.
OBJECTIVE: To study the chemical constituents of Fructus Xanthii and to determine the contents of total phenolic acids (TPA) in fruits of Xanthium from different populations for evaluating the quality of them. METHODS: Components in Fructus Xanthii were isolated and purified by various column chromatographies and the contents of TPA were determined by ultraviolet spectrophotometry with chlorogenic acid (CHA) as reference substance. RESULTS: Six caffeoylquinic acids along with caffeic acid and ferulic acid were isolated from Fructus Xanthii. The contents of TPA of the samples collected from 29 populations in China varied from 0.31% to 1.44%. Among the samples originated from two species and 1 variety of Xanthium, the contents of TPA in X. sibiricum var. subinerme samples with an average of 0.36% were relatively lower than those in other 2 species. While the content of TPA in Sample 3 collected from Shanghai was 1.44% and the highest among all the samples, and that in Sample 12 from Xinjian of Jiangxi Province was 0.38% and the lowest among the X. sibiricum samples. CONCLUSION: 5-O-caffeoylquinic acid, 1,4-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid were isolated from Xanthium plant for the first time. The difference of contents of TPA in samples from different species and different populations in China was relatively significant. Fructus Xanthii in Shanghai and Sanming of Fujian Province were considered high quality if contents of TPA were used as reference for quality evaluating.
OBJECTIVE: To gain a clear idea on the resources and pharmacognostic identification of medicinal plant Xanthium in China. METHOD: Identification of botanical origin, analysis of fruit shapes and properties, microscopic characteristics, TLC and UV. RESULT: Identification criteria have been worked out for Xanthium and its confused species. CONCLUSION: The resources of medicinal plant Xanthium may be appropriately expanded.
Recently, French Association for Ragweed Study (AFEDA) founders published, in French, a book "Ambrosia, ragweed, biological pollutants". This association was founded in 1982. The authors referred to Bonaparte Herbarium set up in the Université Claude-Bernard Lyon 1. This herbarium is ranking second in France and seventh in the world. There were three aims for this work: to set up, for this herbarium, a complete list of different species of Ambrosia, Franseria and their pollen grains and to study with them Xanthium whose pollen grains look like Ambrosia, to establish a chronological order for Ambrosia that were collected in Europe and in some countries of the New World, to compare some pollen grains of Ambrosia and Xanthium (scanning electronic microscope). Good state plants in spite of about a century of conservation could be selected. They were photographied and some pollens so. The consultation of this herbarium brought a better morphological knowledge of different species of Ambrosia, Franseria and Xanthium, (plants and pollen grains). The authors were able to broadcast this knowledge to scientists and interested public through their book.
The germination of seeds of Xanthium pensylvanicum Wallr. occurs in 2 phases, an initial passive phase of water uptake followed by an active phase of growth. These 2 phases have been separated experimentally, and shown to occur similarly in isolated cotyledons and embryonic axes. Measurements of the physical thrust generated by the entire seed and its separate components of cotyledon and axis reveal that non-dormant Xanthium seeds develop more than twice the thrust of dormant seeds, and that this difference develops principally in the second phase of enlargement of the axis. Measurement of the forces required for piercing the testa of these seeds establishes that whereas the thrust developed by non-dormant seed is adequate to cause testa rupture, that developed by dormant seeds is not. It is concluded that the dormancy of Xanthium involves an inadequacy in the embryo for rupture of the testa.
A cycloheximide-sensitive increase in the activity of phenylalanine ammonia-lyase (EC 4.3.1.5) occurs in Xanthium leaf disks exposed to light. Radioactive ammonia-lyase has been isolated by means of sucrose density gradient centrifugation and starch gel electrophoresis from disks fed l-isoleucine-U-(14)C or l-arginine-U-(14)C. The incorporation of radioactive amino acids into phenylalanine ammonia-lyase together with the inhibitory effects of cycloheximide indicate that the observed increase in enzyme activity involves the induction of lyase synthesis.The light-dependent synthesis of the ammonia-lyase is completely inhibited by 50 mum 3-(4-chlorophenyl)-1,1-dimethylurea (CMU) indicating that photosynthesis is involved. Only a trace quantity of some photosynthetic product must be needed because half light saturation occurs at very low intensity (ca. 30 ft-c). Exogenous carbohydrate is also required for continuing enzyme synthesis over a 72 hr period. But carbohydrate does not replace the photosynthetic requirement in darkness. Enzyme formed in light disappears rapidly from disks placed in the dark. The decay of ammonia-lyase activity follows first order kinetics. The half-life of the lyase ranged from 6 to 15 hr in leaf material used. Cyoloheximide inhibits the decay of lyase activity. Thus the maintenance of turnover in Xanthium leaf disks requires de novo synthesis of protein. That turnover, i.e., degradation as well as synthesis of lyase protein occurs is suggested by the apparent loss of radioactive ammonia-lyase from leaf disks placed in darkness. Light-induced synthesis coupled with rapid turnover can produce a diurnal fluctuation of ammonia-lyase activity in Xanthium leaf disks. Alternating periods of enzyme synthesis and degradation were observed in disks exposed to 24 hr cycles of light and dark. The average level of enzyme activity maintained in the tissue was directly related to the length of the light period. Induction of lyase synthesis was also observed in excised leaves and to a lesser extent in leaves of whole plants.
As an attempt to identify bioactive natural products with anti-inflammatory activity, we evaluated the effects of the methanol extract of the semen of Xanthium strumarium L. (MEXS) on lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-alpha) production in RAW 264.7 cells. Our data indicate that MEXS is a potent inhibitor of NO, PGE2 and TNF-alpha production. Consistent with these findings, the expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein and iNOS, COX-2 and TNF-alpha mRNA were down-regulated in a concentration-dependent manner. Furthermore, MEXS inhibited nuclear factor kappa B (NF-kappaB) DNA binding activity and the translocation of NF-kappaB to the nucleus by blocking the degradation of inhibitor of kappa B-alpha (IkappaB-alpha). We further evaluated the anti-inflammatory and anti-nociceptive activities of MEXS in vivo. MEXS (100, 200 mg/kg/d, p.o.) reduced acute paw edema induced by carrageenin in rats, and showed analgesic activities in an acetic acid-induced abdominal constriction test and a hot plate test in mice. Thus, our study suggests that the inhibitions of iNOS, COX-2 expression, and TNF-alpha release by the methanol extract of the semen of Xanthium strumarium L. are achieved by blocking NF-kappaB activation, and that this is also responsible for its anti-inflammatory effects.
The allergenic components present in whole pollen extract of Xanthium strumarium were isolated by sequential ammonium sulphate precipitation, DEAE Sephadex A50 chromatography and gel filtration. The techniques of RAST inhibition and skin test were utilized to check the allergenicity of fractionated proteins revealing the presence of Xan Ib and Xan VIa as the important allergenic components. Xan Ib was found to be devoid of carbohydrate and had a molecular weight of 103,000 daltons. Xan VIa was a glycoprotein of molecular weight 17,000 daltons. The carbohydrate moiety of Xan VIa was found to be associated with allergenicity. The characteristic pattern of whole pollen extract on CIE and TLIEF showed 36 and 21 protein bands, respectively. The use of FPLC in isolation of partially purified allergens from Xanthium is discussed.
The active turnover of chlorogenic acid (3-caffeoylquinic acid(3)), a major phenolic component of Xanthium leaves and potato tuber disks, has been demonstrated in these tissues. Pulse-labelling experiments with radioactive l-phenylalanine and trans-cinnamic acid as well as direct feeding experiments with chlorogenic acid-(14)C labelled in the caffeoyl moiety have been employed in the turnover studies. The rate of turnover is calculated to be on the order of 50 to 100 mmumoles per hour per gram fresh weight of tissue.In Xanthium leaves chlorogenic acid is in part converted to an isochlorogenic acid identified by silica gel chromatography as 3,5-dicaffeoylquinic acid. Radioactivity of the caffeoyl moiety of chlorogenic acid is also incorporated into lignin-like insoluble polymers in the leaf. Turnover of chlorogenic acid in tuber tissue is largely accounted for by the incorporation of the caffeoyl moiety into insoluble polymers in the tissue.The significance of chlorogenic acid turnover is discussed in relation to the perception of the photoperiodic stimulus by leaves and to the possible role of chlorogenic acid in lignin synthesis.
Flowering is induced in Xanthium strumarium by a single dark period exceeding about 8.3 hours in length (the critical night). To study the mechanism which measures this dark period, plants were placed in growth chambers for about 2 days under constant light and temperature, given a phasing dark period terminated by an intervening light period (1 min to several hrs in duration), and finally a test dark period long enough normally to induce flowering. In some experiments, light interruptions during the test dark period were given to establish the time of maximum sensitivity.If the phasing dark period was less than 5 hours long, its termination by a light flash only broadened the subsequent time of maximum sensitivity to a light flash, but the critical night was delayed. In causing the delay, the end of the intervening light period was acting like the dusk signal which initiated time measurement at the beginning of the phasing dark period.If the phasing dark period was 6 hours or longer, time of maximum sensitivity during the subsequent test dark period was shifted by as much as 10 to 14 hours. In this case the light terminating the phasing dark period acted as a rephaser or a dawn signal.Following a 7.5-hour phasing dark period, intervening light periods of 1 minute to 5 hours did not shift the subsequent time of maximum sensitivity, but with intervening light periods longer than 5 hours, termination of the light acts clearly like a dusk signal. The clock appears to be suspended during intervening light periods longer than 5 to 15 hours. It is restarted by a dusk signal. There is an anomaly with intervening light periods of 10 to 13 hours, following which time of maximum sensitivity is actually less than the usual 8 hours after dusk.Ability of the clock in Xanthium to be rephased, suspended, restarted, or delayed, depending always upon conditions of the experiment, is characteristic of an oscillating timer and may confer upon this plant its ability to respond to a single inductive cycle. It is suggested that phytochrome may influence only the phase of the clock and not other aspects of flowering such as synthesis of flowering hormone.
The flowering of Xanthium pensylvanicum Wallr. was investigated using long dark periods. Attempts were made to ascertain evidence for the involvement of a flowering rhythm in Xanthium by use of variable-dark-length and light-interruption experiments.It was found that factors such as plant height (age), partial defoliation, and various pretreatments had little effect on the general nature of the flowering response. Maximum sensitivity to red light occurred at the eighth hour of 24-, 48-, and 72-hour dark periods. Temperature had little influence on this timing. The time of maximum sensitivity was delayed to the tenth hour by a pretreatment with 8 hours of darkness followed by 6 hours of light. These properties are similar to those of Pharbitis, which showed a clear rhythmic sensitivity to red light interruptions. The possible involvement of a rapidly damping rhythm of sensitivity to red light is discussed on the basis of this similarity. A distinct flowering rhythm similar to that of soybean and Chenopodium was not found. Although the results are inconclusive with respect to a rhythm, they do indicate similarities and differences to the responses of other short-day plants in which rhythms have been demonstrated.
A study was made of the effects of various durations, intensities and combinations of red and far-red light interruptions on the flowering responses of Xanthium pensylvanicum Wallr. A dual response to treatments of far-red light was observed. In short dark periods, far-red light alone did not greatly affect flowering but was able to overcome the inhibition of flowering caused by red light. In dark periods longer than 15 hours, far-red inhibited flowering and added to rather than overcame the inhibition by red light. The dark period length required for far-red inhibition remained the same whether far-red was given at the start or at the eighth hour of darkness.In 48-hour dark periods Xanthium showed 3 responses to additions of red and far-red light breaks: A) response to red light; B) response to far-red light; and C) response to red followed by far-red light. Red light given any time in the first 30 hours of darkness overcame the inhibitory effect of far-red light given at either the start or the eighth hour of darkness. Red light given later than the thirtieth hour did not overcome the far-red effect.Approximately the same energy of red light was required to overcome the inhibitory effect of far-red at the second hour of darkness as was required to produce maximum red light inhibition at the eighth hour. Although far-red light was most inhibitory when given early in a long dark period, approximately the same energy of far-red light was required to saturate the far-red response at the fourth, eighth and sixteenth hours.The results are discussed in relation to other reports of far-red inhibition of flowering in short-day plants.