Two isocoumarins from Pleurospermum angelicoides.
(49/112)
Two new isocoumarins, angelicoins A and B, were isolated from the roots of Pleurospermum angelicoides, and their structures were established by spectral means. (+info)
Basiliolides, a class of tetracyclic C19 dilactones from Thapsia garganica, release Ca(2+) from the endoplasmic reticulum and regulate the activity of the transcription factors nuclear factor of activated T cells, nuclear factor-kappaB, and activator protein 1 in T lymphocytes.
(50/112)
Calcium concentration within the endoplasmic reticulum (ER) plays an essential role in cell physiology. We have investigated the effects of basiliolides, a novel class of C19 dilactones isolated from Thapsia garganica, on Ca(2+) mobilization in T cells. Basiliolide A1 induced a rapid mobilization of intracellular Ca(2+) in the leukemia T-cell line Jurkat. First, a rapid calcium peak was observed and inhibited by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester. This initial calcium mobilization was followed by a sustained elevation, mediated by the entry of extracellular calcium through store-operated calcium release-activated Ca(2+) (CRAC) channels and sensitive to inhibition by EGTA, and by the CRAC channel inhibitor N-{4-[3,5-bis(trifluoromethyl)-1H-pyrazol-1-yl]phenyl}-4-methyl-1,2,3-thiadiazole -5-carboxamide (BTP-2). Basiliolide A1 mobilized Ca(2+) from ER stores, but in contrast to thapsigargin, it did not induce apoptosis. Basiliolide A1 induced nuclear factor of activated T cells 1 dephosphorylation and activation that was inhibited by BTP-2 and cyclosporine A. In addition, we found that basiliolide A1 alone did not mediate IkappaBalpha degradation or RelA phosphorylation (ser536), but it synergized with phorbol 12-myristate 13-acetate to induce a complete degradation of the nuclear factor-kappaB inhibitory protein and to activate the c-Jun NH(2)-terminal kinase. Moreover, basiliolide A1 regulated both interleukin-2 and tumor necrosis factor-alpha gene expression at the transcriptional level. In basiliolide B, oxidation of one of the two geminal methyls to a carboxymethyl group retained most of the activity of basiliolide A1. In contrast, basiliolide C, where the 15-carbon is oxidized to an acetoxymethine, was much less active. These findings qualify these compounds as new probes to investigate intracellular calcium homeostasis. (+info)
Insect folivory in Didymopanax vinosum (Apiaceae) in a vegetation mosaic of Brazilian cerrado.
(51/112)
Susceptibility of Didymopanax vinosum (Apiaceae) to insect herbivores was investigated in three sites of a cerrado mosaic--composed of campo cerrado (a grassland with scattered trees and shrubs), cerradao (a tall woodland) and cerrado sensu stricto (intermediate between the two)--situated in Cerrado Pe-de-Gigante, Santa Rita do Passa Quatro, SP, Brazil. We also examined the relationship of folivory with the composition and abundance of the insect herbivore fauna, and with several nutritional and defensive plant characteristics (water, nitrogen, cellulose, lignin, tannin leaf contents, and leaf toughness). We collected insects associated with D. vinosum every month, and we measured leaf damage every three months. In general, the annual folivory differed among sites. It reached the highest rates in site 1 and site 3: 7.33 and 8.5 percent, respectively. Only 1.32 percent of annual folivory was observed in site 2. These levels resulted from the higher abundance, in sites 1 and 3, of the thrips Liothrips didymopanacis (Phlaeothripidae), the most abundant herbivore sampled, responsible for more than 90 percent of the observed damage. However, no significant relationship was found between insect activity and the chemical and physical composition of the leaves. Our findings suggest that, at least in this species, other chemical compounds or variables related to plant apparency and resource availability to herbivores (e.g. plant architecture) might play a more decisive role in the spatial variation of folivory than the nutritional and defensive traits that were analyzed. (+info)
Simultaneous determination of urinary metabolites of methoxypsoralens in human and Umbelliferae medicines by high-performance liquid chromatography.
(52/112)
A high-performance liquid chromatography method has been developed for the determination of coumarins and furocoumarins (psoralens). Nine coumarins and furocoumarins are separated simultaneously on a Hypersil C(8) (25 cm x 4.6-mm i.d.) column with a gradient of methanol and acetonitrile aqueous solution as mobile phase at 1.0 mL/min with two-channel UV-vis absorbance detection. The limits of detection are 0.366, 0.219, 0.317, 0.440, 0.536, 0.300, 0.531, 0.531, 0.237, and 0.280 ng/mL for coumarin, 7-hydroxycoumarin, 7-methoxycoumarin, citropten (5,7-dimethoxycoumarin), 7-ethoxy-4-methylcoumarin, psoralen, xanthotoxin (8-methoxypsoralen), bergapten (5-methoxypsoralen), isopimpinellin (5,8-dimethoxypsoralen), and imperatorin (9-isopenteneoxypsoralen), respectively. Human urine is analyzed 1-6 days after ingestion of the oral Chinese medicines. This lead to the conclusion that the concentration of coumarins and furocoumarins is higher than that of the control urine. The coumarins and furocoumarins are detected at 312 and 249 nm, respectively. (+info)
Seed dormancy and germination of the European Chaerophyllum temulum (Apiaceae), a member of a trans-Atlantic genus.
(53/112)
BACKGROUND AND AIMS: The European Chaerophyllum temulum and two North American Chaerophyllum species have a trans-Atlantic disjunct distribution. This work aimed to resolve requirements for dormancy break and germination of C. temulum seeds and to compare dormancy traits with those of the two North American congeners. METHODS: Phenology of germination and embryo growth was studied by regularly exhuming seeds sown in natural conditions. Temperature requirements for embryo growth, breaking of dormancy and germination were determined by incubating seeds under controlled laboratory conditions. Additionally the effect of GA(3) on germination was tested to determine the specific dormancy type. KEY RESULTS: In natural conditions, embryo growth starts in early winter. Seedlings emerge in late winter shortly after the embryos reached the critical ratio for embryo length to seed length (E : S) of approx. 0.95. Growth of the embryo only occurs during a prolonged incubation period at 5 degrees C. After stratification at 5 degrees C, which breaks physiological and morphological dormancy, seeds can germinate at a wide range of temperatures. GA(3) did not substitute for cold stratification in seeds placed at 23 degrees C. CONCLUSIONS: Chaerophyllum temulum has deep complex morphophysiological dormancy. This dormancy type differs considerably from that of the two North American congeners. (+info)
Lignans and coumarins from the roots of Anthriscus sylvestris and their increase of caspase-3 activity in HL-60 cells.
(54/112)
A new lignan, sylvestrin (1), was isolated from the MeOH-soluble fraction of the roots of Anthriscus sylvestris HOFFM. (Umbelliferae), along with six lignans (2-7), three coumarins (8-10), and a polyacetylene (11). The structure of sylvestrin was determined to be 2-(3',4',5'-trimethoxybenzylidene)-3-(3'',4''-methylendioxybenzyl)-gamma-butyrola ctone (1) by spectroscopic means, including 2D-NMR. The eleven compounds were assessed for their abilities to activate a caspase-3 in human promyeloid leukemic HL-60 cells. The intracellular caspase-3 activity of (-)-deoxypodophyllotoxin (3), angeloyl podophyllotoxin (5), deoxypicropodophyllin (6), picropodophyllotoxin (7), and falcarindiol (11) increased approximately 4.6, 3.6, 3.7, 3.9, and 3.9-fold, at 0.001, 1, 1, 1, and 20 microM, respectively, over that of the untreated control. In addition, compounds 3, 5, 6, and 7 showed apoptosis-inducing activities that were measured by DNA fragmentation in HL-60 cells. (+info)
A new chromone, 11-hydroxy-sec-O-glucosylhamaudol from Ostericum koreanum.
(55/112)
From the ethyl acetate fraction of the roots of Ostericum koreanum, a new chromone, 11-hydroxy-sec-O-glucosylhamaudol (1) along with the known compounds: four chromones, three coumarins, six phenolic compounds, and three quinic acids were isolated. These compounds were assessed for antioxidant activities in the DPPH radical and superoxide anion radical scavenging assay systems. Among isolates, 4-(2-hydroxy-vinyl)-benzene-1,2-diol (12) showed the most potent DPPH radical scavenging activity (IC(50)=4.80+/-0.62 mug/ml) and superoxide anion radical scavenging activity (IC(50)=11.05+/-0.83 microg/ml) in the xanthine/xanthine oxidase system. The antioxidant activities of 12 were comparable to those of quercetin and luteolin. (+info)
The naturally occurring flavolignan, deoxypodophyllotoxin, inhibits lipopolysaccharide-induced iNOS expression through the NF-kappaB activation in RAW264.7 macrophage cells.
(56/112)
Deoxypodophyllotoxin (DPT), a naturally occurring flavolignan with anti-inflammatory activity, was isolated from Anthriscus sylvestris HOFFM., and we examined its effects on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated, murine macrophage-like RAW264.7 cells. Western blot analysis performed with specific anti-iNOS antibodies showed that a decrease in nitric oxide (NO) was accompanied by a decrease in the iNOS protein level. To clarify the mechanistic basis for DPT's ability to inhibit iNOS induction, we examined the effect of DPT on nuclear factor (NF)-kappaB transcriptional activity and DNA binding activity. DPT potently suppressed both reporter gene activity and DNA binding activity. These findings suggest that DPT in RAW264.7 cells abolished LPS-induced iNOS expression by inhibiting the transcription factor, NF-kappaB. (+info)