Occurrence of stilbene oligomers in Cyperus rhizomes

Investigation of the chemical constituents of Rhizoma Cyperi (Cyperus rotundus Linneus) resulted in the isolation of novel enantiomeric and meso-stilbene trimers [i.e., (+)- and (−)-(E)-cyperusphenol A (1, 2 respectively) and (E)-mesocyperusphenol A (3)], a trimer bearing a novel hexacyclic ring system [cyperusphenol B (5)], as well as known stilbenoids (cyperusphenols C (4) and D (6), scirpusins A (7) and B (8), and piceid (9)) and luteolin. HPLC was used for the optical resolution of 1 and 2 as well as for the identification of cooccurrence of enantiomers of 7. The structures of the isolates were established by spectroscopic analyses, including a detailed NMR spectroscopic investigation. The isolates were evaluated in terms of their antiproliferative activity employing the Jurkat cell line (human T-cell leukemia cells), while the IC₅₀ potencies of a racemate of 1 and 2, 3, 5, and 6 were estimated as 27.4, 40.5, 26.4, and 26.3 μM, respectively. The suppression of cell growth by 6 was due to the induction of apoptosis, which was characterized by nuclear changes and PARP-1 cleavage determined by western blotting. We also evaluated the free radical scavenging activity of the isolates.     

Pharmacokinetics of cycloalliin, an organosulfur compound found in garlic and onion, in rats

Cycloalliin, an organosulfur compound found in garlic and onion, has been reported to exert several biological activities and also to remain stable during storage and processing. In this study, we investigated the pharmacokinetics of cycloalliin in rats after intravenous or oral administration. Cycloalliin and its metabolite, (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid, in plasma, urine, feces, and organs was determined by a validated liquid chromatography-mass spectrometry method. When administered intravenously at 50 mg/kg, cycloalliin was rapidly eliminated from blood and excreted into urine, and its total recovery in urine was 97.8% +/- 1.3% in 48 h. After oral administration, cycloalliin appeared rapidly in plasma, with a tmax of 0.47 +/- 0.03 h at 25 mg/kg and 0.67 +/- 0.14 h at 50 mg/kg. Orally administered cycloalliin was distributed in heart, lung, liver, spleen, and especially kidney. The Cmax and AUC0-inf values of cycloalliin at 50 mg/kg were approximately 5 times those at 25 mg/kg. When administered orally at 50 mg/kg, cycloalliin was excreted into urine (17.6% +/- 4.2%) but not feces. However, the total fecal excretion of (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid was 67.3% +/- 5.9% (value corrected for cycloalliin equivalents). In addition, no (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid was detected in plasma (<0.1 microg/mL), and negligible amounts (1.0% +/- 0.3%) were excreted into urine. In in vitro experiments, cycloalliin was reduced to (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid during anaerobic incubation with cecal contents of rats. These data indicated that the low bioavailability (3.73% and 9.65% at 25 and 50 mg/kg, respectively) of cycloalliin was due mainly to reduction to (3R,5S)-5-methyl-1,4-thiazane-3-carboxylic acid by the intestinal flora and also poor absorption in the upper gastrointestinal tract. These findings are helpful for understanding the biological effects of cycloalliin.     

Plant regeneration by somatic embryogenesis from mature seeds of <Emphasis Type="Italic">Magnolia obovata</Emphasis>

We attempted to develop a method for the regeneration of plantlets from mature seeds of medically important Magnolia obovata via the induction of somatic embryogenesis in vitro. We initially cultured halves of mature seeds on either Murashige and Skoog (MS) medium or B₅ medium that contained 0, 1, 5 or 10 μM gibberellic acid (GA₃) for 1 month and then transferred the half-seeds to half-strength MS basal medium or B₅ basal medium for further culture in the absence of GA₃. Proembryogenic masses (PEMs) were observed 1 month after the transfer of the halved mature seeds to the medium without GA₃. The frequency of formation of PEMs was higher (28%) after initial culture in MS basal medium plus 1 μM GA₃ than in other tested media (0 or 4%). Somatic embryos that had been developed from PEMs were cultured on half-strength MS basal medium or B₅ basal medium for completion of maturation and then transferred to fresh aliquots of the same medium for initiation of germination. The frequency of germination, with the formation of normal primary leaves and roots, was above 80%. We transferred the somatic embryo-derived plantlets to soil for acclimatization and the plantlets continued to thrive.     

Intraoperative acridine orange photodynamic therapy and cribriform electron-beam irradiation for canine intranasal tumors: A pilot study

Untreated canine intranasal tumors carry a poor prognosis. We retrospectively evaluated the efficacy of marginal tumor resection in combination with intraoperative acridine orange (AO) photodynamic therapy (PDT) and 1 fraction of 5 Gy megavoltage irradiation for canine intranasal malignant tumors. When cribriform plate invasion or turbinate destruction around the cribriform plate was present, an additional fraction of 20 Gy was delivered with an electron beam during surgery. The study included 6 dogs, 2 of which were classified as stage I, 1 as stage II, and 3 as stage IV. The median local disease-free survival time and overall survival after the treatment were 8.5 and 13 months, respectively. Recurrence was noted in 2 of the 6 dogs after 4 and 7 months. Adverse events were mild (subcutaneous emphysema in 1 case, and rhinitis in 3 cases). Combination AO therapy may increase the tumor control time of dogs with marginally resectable intranasal malignant tumors.     

RAPD Polymorphism of the White-Flowered Gourd (Lagenaria siceraria (Molina) Standl. Landraces and its Wild Relatives in Kenya

The present study was performed to investigate genetic diversity of Kenyan landraces of the white-flowered gourd (Lagenaria siceraria), which exhibits tremendous morphological variation. RAPD analyses were performed on 53 landraces of the cultivated species L. siceraria and 42 accessions of three wild species (40 L. sphaerica, 1 L. abyssinica, and 1 L. breviflora). A total of 432 polymorphic bands were detected using 54 primers. The four species were clearly differentiated from one another. Intra-specific variations were investigated with L. siceraria and its wild relative L. sphaerica. Landraces of the cultivated species collected from different ethnic communities or regions were differentiated. Morphological variations were not associated with RAPD variations. Bitter landraces collected in Maasai communities showed two specific RAPD bands. In the wild species, accessions collected from the eastern and western sides of the Great Rift Valley were genetically differentiated from each other. In both species, genetic and geographical distance matrices computed among all pairs of accessions were significantly correlated, implying that the observed geographical variation can be explained by the 'Isolation by distance model'. Progeny plants derived from a common mother in L. siceraria showed a low level of segregation in RAPD pattern, suggesting that collected landraces are cultivated, maintaining their inherent traits although they are monoecious and insect-pollinated, whereas the wild relative L. sphaerica showed a higher level of segregation. The morphological diversity observed among landraces of L. siceraria is the result of human selection and their genetic identities are maintained by inbreeding probably resulting from frequent self-pollination.     

Very long baseline interferometric observations made with an orbiting radio telescope

An orbiting spacecraft and ground observatories have been used to obtain interferometric observations of cosmic radio sources. The Tracking and Data Relay Satellite System (TDRSS) was used as the orbiting observatory in conjunction with two 64- meter radio telescopes at ground observatories, one in Australia and one in Japan. The quasars 1730-130 (NRAO 530), 1510-089, and 1741-038 were observed at a frequency of 2.3 gigahertz, and a maximum projected baseline of 1.4 earth diameters was achieved. All quasar observations for which valid data were acquired resulted in detected fringes. Many of the techniques proposed for a dedicated very long baseline interferometry observatory in space were used successfully in this experiment.     

Insect antifeedants from tropical plants: structures of dumnin and dumsenin

Two novel A-seco limonoids, dumnin and dumsenin, were isolated from the methanolic extract of Croton jatrophoides by bioassay-guided fractionation, and the structures were determined by nuclear magnetic resonance, circular dichroism, and mass spectrometry experiments. These compounds showed potent antifeedant activity (PC(50) 相似文献   

Insect antifeedant activity of flavones and chromones against Spodoptera litura

The antifeedant polymethylated flavones 5-hydroxy-3,6,7,8,4'-heptamethoxyflavone, 5-hydroxy-3,6,7,8-tetramethoxyflavone, and 5,6-dihydroxy-3,7-dimethoxyflavone have been isolated from the cudweed, Gnaphalium affine D. Don (Compositae). These flavonoids and authentic analogues showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). In a previous paper, it was suggested that there was no substituent on the B-ring of the flavonoid for the beneficial antifeedant activity against the common cutworm. These flavonoids having a phenyl group as the B-ring and the chromone as elimination of the B-ring from the flavonoids were used to test the hypothesis of the previously described B-ring effect. The known fact is that Sculletaria baicarensis (Rutaceae) produced the 2-phenyl flavone. Test compounds and their methylated derivatives were prepared from this material for the structure-activity relationship (SAR) study of insect antifeedant activity. In spite of the 2-phenyl flavonoids, some tested compounds did not show any insect antifeedant activity against the common cutworm, although these inactive flavonoids were deficient in the 6-substituent group on the A-ring of the flavonoid. This 6-position-substituted derivative almost showed strong insect antifeedant activity against common cutworm. Moreover, the tested flavonoids having a hydroxyl group as a substituent on any of the positions tended to increase the activity. These results suggested the importance of the 6-position substitution on the flavonoid; however, hydrophilic substituents decreased the activity. Baicalein (5,6,7-trihydroxyflavone) derivatives did not show any activity despite having the 6-substituent derivative. Although the activity of some chromones increased the activity of the flavone, the bulky B-ring was a disadvantage for the antifeedant activity. It was suggested that the charge on C(3) and C(5) of the flavonoid was important for the biological activity. Additionally, an adequate hydrogen bonding property, which is different from lipophilicity, was an advantage for the activity on the basis of a QSAR analysis.     

Horizontal and vertical variations in photosynthetic capacity in a Pinus densiflora crown in relation to leaf nitrogen allocation and acclimation to irradiance

We measured horizontal and vertical gradients of light (rPPFD) along four first-order branches of a Pinus densiflora Sieb. & Zucc. crown, and compared variations in specific leaf area (SLA), needle nitrogen concentration (N), chlorophyll concentration (Chl) and photosynthetic capacity (i.e., maximum rate of carboxylation (V(cmax))) along the two axes. The horizontal gradient of rPPFD along first-order branches was similar in magnitude to the vertical gradient of rPPFD from the upper to the lower crown. None of the measured parameters (i.e., SLA, N, Chl and Vcmax) were strictly proportional to rPPFD, although they were more or less correlated with light when data obtained for all of the crown were pooled (r(2) = 0.31-0.80). The slope of rPPFD against N on an area basis (Narea) for a branch in the middle of the crown orientated northward was significantly greater than the slope for a similar branch orientated southward. Horizontal variations were unrelated to age effects because measurements were all on 1-year-old needles. We conclude that factors other than light (i.e., orientation) may influence N allocation within branches. There was considerably less variation in the relationship of Vcmax to Narea (r2 = 0.58) than in the relationship of Vcmax to rPPFD (r2 = 0.41). Fractional N distribution among components of the photosynthetic machinery was constant within the crown. Together with the relationships between rPPFD and N on a mass basis (r2 = 0.80) and SLA and Vcmax (r2 = 0.60), these findings suggest that most light acclimation in P. densiflora occurs through changes in needle morphology (e.g., SLA) during development.