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Ten new sucrose esters, physakengoses A-J (1 - 10), were isolated from the aerial parts of Physalis alkekengi var. franchetii under the guidance of ¹H NMR spectroscopy. Their structures were determined by spectroscopic analyses (HRESIMS, 1D and 2D NMR, and ESIMS) and chemical methods. These new compounds were tested for antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli. Among them, compounds 2 and 5-8 showed potent inhibitory effects against test strains with MIC values ranging from 3.5 to 14.9 μg/mL. These findings may indicate that the P. alkekengi var. franchetii has potential application as an ingredient in pharmaceuticals. [ABSTRACT FROM AUTHOR]

A rare labdane diterpene γ-lactam, 1, and two new labdane diterpenoids, 2 and 3, along with two known diterpenes, 4 and 5, were isolated from the roots of Amomum maximum. Their structures were established on the basis of spectroscopic data. All of the isolates were evaluated for their cytotoxic activities, and compound 3 was found to exhibit an inhibitory activity against MG-63 cell lines with an IC50 value of 3.3±0.8 mg/ml. [ABSTRACT FROM AUTHOR]

Peer-to-peer (P2P) networks have been emerging as one of the most promising approaches to improve the scalability of video-on-demand (VoD) service over Internet. Although a number of architectures and streaming protocols have been proposed in past years, there is few work to study the practical performance of P2P-based VoD service especially considering the real user behavior which actually has significant impact on the system scalability. Therefore, in this paper, we first characterize the user behavior by analyzing a large amount of real traces from a popular VoD system supported by the biggest television station in China, cctv.com. Then, we examine the practical scalability of P2P-based VoD service through extensive trace-driven simulation under a general system framework. The results show that P2P networks scale well in providing VoD service under real user behavior by saving a considerable percentage of server bandwidth. Moreover, it is observed that adopting hard cache at client side achieves much better system scalability than that with soft cache. We also identify the impact of various aspects of user behavior upon system scalability through detailed simulation. We believe that our study will shine insightful light on the understanding of practical scalability of P2P-based VoD service and be helpful to future system design and optimization. [ABSTRACT FROM AUTHOR]

Peer-to-peer (P2P) networks have been adopted for Internet live video-streaming service, and several practical systems have been deployed in past years due to the inherent scalability and ease of deployment. However, most of these systems are commercial and proprietary, and hence little research was done in the area of characterizing practical system performance properties. In this article, we mainly present our experience on a practical P2P-based live video-streaming system called GridMedia, which was employed to broadcast live the Chinese Spring Festival Gala show over the Internet. Benefiting from two sets of flush-crowd traces with about 15,239 and 224,453 concurrent users in a 300 kb/s streaming session in 2005 and 2006, we perform a trace study to understand the service capacity, quality of streaming service, connection heterogeneity, user geographic distribution, and request and online duration characteristics. Our observations shed light on those systems and further improvements in the arena of large-scale live video-streaming service over the Internet. [ABSTRACT FROM AUTHOR]

The fingerprints of Rhizoma coptidis (Huanglian) collected in different growing periods were established by high-performance liquid chromatography (HPLC), and the seasonal variations of six alkaloids, namely berberine, palmatine, jateorrhizine, coptisine, epiberberine and columbamine were assessed. In order to highlight the differences of their HPLC fingerprints, three chemometrics methods including Spearman's rank correlation, hierarchical clustering analysis (HCA) and principal component analysis were applied. The anti-inflammatory activity of R. coptidis collected in different developing stages was measured by NO inhibition assay. The relationship between HPLC fingerprints and anti-inflammatory activity named spectrum- effect relationship was investigated by partial least squares regression. The anti-inflammatory activity was positively correlated with the alkaloid contents. Berberine, palmatine, coptisine, jateorrhizine and epiberberine were the main anti-inflammatory components on the basis of the quantitative determination of the six alkaloids and spectrum–effect investigation. The collecting time of R. coptidis impacted the plant's alkaloid contents and its anti-inflammatory activity. [ABSTRACT FROM AUTHOR]

Three new 16-norphragmalin limonoids, chukvelutins A−C (1−3), were isolated from the stem bark of Chukrasia tabularisvar. velutina, which possess unprecedented skeletons, featured with a characteristic ketal moiety between the phragmalin skeleton and a biosynthetically extended isobutyryl group at C-15. Their structures were elucidated by extensive spectroscopic technologies. [ABSTRACT FROM AUTHOR]

γ-Glutamyltranspeptidase (GGT) plays critical roles in regulating various physiological/pathophysiological processes including the intracellular redox homeostasis. However, an effective fluorescent probe for dissecting the relationships between GGT and oxidative stress in vivo remains largely unexplored. Herein, we present a light-up fluorescent probe (DCDHF-Glu) with long wavelength emission (613 nm) for the highly sensitive and selective detection of GGT using dicyanomethylenedihydrofuran derivative as the fluorescent reporter and γ-glutamyl group as the enzyme-active trigger. DCDHF-Glu is competent to real-time image endogenous GGT in live cells and mice. In particular, DCDHF-Glu enables the direct real-time visualization of the upregulation of GGT under drug-induced oxidative stress in the HepG2 cells and the LO2 cells, as well as in vivo, vividly implying its excellent capacity in elucidation of GGT function in GGT-related biological events. [ABSTRACT FROM AUTHOR]

Leucine aminopeptidase (LAP) is a kind of proteolytic enzymes and associated closely with pathogenesis of cancer and liver injury. Accurate detection of LAP activity with high sensitivity and selectivity is imperative to detect its distribution and dynamic changes for understanding LAP’s function and early diagnosing the disease states. However, fluorescent detection of LAP in living systems is challenging. To date, rarely fluorescent probes have been reported for imaging LAP in vivo. In this study, a novel probe (TMN-Leu) was developed by conjugating a near-infrared dicyanoisophorone derivative fluorophore with LAP activatable L-leudne amide moiety for the first time. TMN-Leu featured large Stokes shift (198 nm), favorable water solubility, ultrasensitive sensitivity (detection limit of ~0.38 ng/mL), good specificity, excellent cell membrane permeability, low toxicity, and a prominent near-infrared emission (658 nm) in response to LAP. TMN-Leu has been successfully applied to track LAP of cancer cells and normal cells, monitor LAP changes in different disease models, and rapidly evaluate LAP inhibitor in cell-based assay. Notably, this probe firstly revealed that HCT116 cells with higher LAP activity were more invasive than LAP siRNA transfected HCT116 cells, suggesting that LAP might serve as an indicator reflecting the intrinsic invasion ability of cancer cells. Finally, TMN-Leu was also employed for in vivo real-time imaging LAP in living tumor-bearing nude mice with low background interference. All together, our probe possesses potential value as a promising tool for diagnostic application, cell-based screening inhibitors and in vivo real-time tracking enzymatic activity in preclinical applications. [ABSTRACT FROM AUTHOR]

Artemisians A--D (1--4), the first examples of [4 + 2] Diels--Alder type adducts presumably biosynthesized from a rare 1, 10-4, 5-diseco-guaianolide and a guaianolide diene, along with their possible precursor 5, were isolated from the traditional Chinese medicine Artemisia argyi. The structures of 1--4 were elucidated by extensive spectroscopic analyses and calculated electronic circular dichroism. Compound 2, with an IC50 value of 3.21 μM, exhibited significant antiproliferative activity via apoptosis induction and G2/M arrest in MDA-MB-468 cells. [ABSTRACT FROM AUTHOR]

Xylopiana A (1), a dimeric guaiane with an unprecedented pentacyclo[5.2.1.01,2.04,5'.05,4']decane-3,2'-dione core, and three biosynthetically related intermediates, compounds 2-4, were isolated from the leaves of Xylopia vielana. Their structures and absolute configurations were determined by a combination of spectroscopic data, X-ray crystallography, electronic circular dichroism calculations, and chemical conversion. The structure of known vielanin A was revised to be compound 3. Compound 4 exerted a 3.7-fold potentiation effect on doxorubicin susceptibility at the tested concentration of 10 μM. [ABSTRACT FROM AUTHOR]

The bulbs of Lilium brownii var. viridulum (LB) are commonly used as both traditional Chinese medicines and popular functional food for many centuries in China. Previous studies reported that the extract of lily bulbs exhibited anti-inflammatory activity both in vivo and in vitro, but its active components and associated molecular mechanisms remain elusive. In the present study, using bioassay-guided isolation method, two phenylpropenoid acylglycerols, 1-O-feruloyl-2-O-p-coumaroylglycerol (1) and 1,3-O-diferuloylglycerol (2), were obtained and identified from the chloroform fraction of LB. Both compounds 1 and 2 significantly decreased the production of nitrite oxide (NO) in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW264.7 cells in a dose-dependent manner with half maximal inhibitory concentration (IC50) values of 9.12 ± 0.72 μM and 12.01 ± 1.07 μM, respectively. They also inhibited the production of prostaglandin E2 (PGE2) and several other pro-inflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Furthermore, compounds 1 and 2 downregulated the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). They also inhibited the nuclear translocation of nuclear factor-κB (NF-κB) p65 subunit and suppressed mitogen-activated protein kinases (MAPKs) pathway. Taken these data together, compounds 1 and 2 exhibited anti-inflammatory activities through acting on the NF-κB and MAPKs pathway. This research provides the first evidence on the major bioactive constituents and related molecular mechanisms of LB as an anti-inflammatory agent. Our findings also advanced the understanding of LB as a traditional herbal medicine for the prevention and treatment of inflammation. [ABSTRACT FROM AUTHOR]

Rhodomyrtials A and B (1 and 2), two unprecedented triketone-sesquiterpene-triketone adducts, along with five biogenetically related intermediates, rhodomentone A (3) and tomentodiones A-D (4-7), were isolated from the leaves of Rhodomyrtus tomentosa. Their structures and absolute configurations were determined by a combination of NMR spectroscopy, chemical conversion, and X-ray diffraction analysis. Compounds 1 and 2 were biomimetically synthesized via 5 and 4, respectively, rather than 3, revealing their key ordering of biosynthetic events and confirming their structural assignments. Compound 7 exhibited potent metastatic inhibitory activity against DLD-1 cells by suppressing the activation of matrix metalloproteinase (MMP)-2 and MMP-9. [ABSTRACT FROM AUTHOR]

Spirotrichilins A (1) and B (2), two novel limonoids with an unprecedented spiro[cyclopenta[b]furan-2,1'-cyclopentan] ring system in A/B/C rings, were isolated from the fruits of trichilia connaroides. Their planar structures and absolute configurations were established based on 1D-, 2D-NMR data, electronic circular dichroism (ECD) exciton chirality method and time-dependent density functional theory (TDDFT)/ECD calculation. A benzilic acid-like rearrangement in ring A was proposed as the key step in the plausible biogenetic pathway of 1 and 2. [ABSTRACT FROM AUTHOR]

An unusual katsumadain dimer via a [2 2] cycloaddition, katsumadain C (1), and a unique chalcone-diarylheptanoid adduct via a Diels–Alder reaction, calyxin Y (2) with novel carbon frameworks, were isolated from the seeds of Alpinia katsumadai.Their structures and relative configurations were determined by spectroscopic evidence. [ABSTRACT FROM AUTHOR]