Methanol extract of Xanthium strumarium L. possesses anti-inflammatory and anti-nociceptive activities.
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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. (+info)
Respiration and reproductive effort in Xanthium canadense.
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BACKGROUND AND AIMS: The proportion of resources devoted to reproduction in the plant is called the reproductive effort (RE), which is most commonly expressed as the proportion of reproductive biomass to total plant biomass production (RE(W)). Reproductive yield is the outcome of photosynthates allocated to reproductive structures minus subsequent respiratory consumption for construction and maintenance of reproductive structures. Thus, RE(W) can differ from RE in terms of photosynthates allocated to reproductive structures (RE(P)). * METHODS: Dry mass growth and respiration of vegetative and reproductive organs were measured in Xanthium canadense and the amount of photosynthates and its partitioning to dry mass growth and respiratory consumption were determined. Differences between RE(W) and RE(P) were analysed in terms of growth and maintenance respiration. * KEY RESULTS: The fraction of allocated photosynthates that was consumed by respiration was smaller in the reproductive organ than in the vegetative organs. Consequently, RE(P) was smaller than RE(W). The smaller respiratory consumption in the reproductive organ resulted from its shorter period of existence and a seasonal decline in temperature, as well as a slower rate of maintenance respiration, although the fraction of photosynthates consumed by growth respiration was larger than in the vegetative organs. * CONCLUSIONS: Reproductive effort in terms of photosynthates (RE(P)) was smaller than that in terms of biomass (RE(W)). This difference resulted from respiratory consumption for maintenance, which was far smaller in the reproductive organ than in vegetative organs. (+info)
Evidence for involvement of photosynthetic processes in the stomatal response to CO2.
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Stomatal conductance (gs) typically declines in response to increasing intercellular CO2 concentration (ci). However, the mechanisms underlying this response are not fully understood. Recent work suggests that stomatal responses to ci and red light (RL) are linked to photosynthetic electron transport. We investigated the role of photosynthetic electron transport in the stomatal response to ci in intact leaves of cocklebur (Xanthium strumarium) plants by examining the responses of gs and net CO2 assimilation rate to ci in light and darkness, in the presence and absence of the photosystem II inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and at 2% and 21% ambient oxygen. Our results indicate that (1) gs and assimilation rate decline concurrently and with similar spatial patterns in response to DCMU; (2) the response of gs to ci changes slope in concert with the transition from Rubisco- to electron transport-limited photosynthesis at various irradiances and oxygen concentrations; (3) the response of gs to ci is similar in darkness and in DCMU-treated leaves, whereas the response in light in non-DCMU-treated leaves is much larger and has a different shape; (4) the response of gs to ci is insensitive to oxygen in DCMU-treated leaves or in darkness; and (5) stomata respond normally to RL when ci is held constant, indicating the RL response does not require a reduction in ci by mesophyll photosynthesis. Together, these results suggest that part of the stomatal response to ci involves the balance between photosynthetic electron transport and carbon reduction either in the mesophyll or in guard cell chloroplasts. (+info)
Phenolic acids in Fructus Xanthii and determination of contents of total phenolic acids in different species and populations of Xanthium in China.
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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. (+info)
In folio respiratory fluxomics revealed by 13C isotopic labeling and H/D isotope effects highlight the noncyclic nature of the tricarboxylic acid "cycle" in illuminated leaves.
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