Publications by authors named "Qing Yong Li"

Background: Camptothecin (CPT), a pentacyclic alkaloid with antitumor properties, is derived from the Camptotheca acuminata. Topotecan and irinotecan (CPT derivatives) were first approved by the Food and Drug Administration for cancer treatment over 25 years ago and remain key anticancer drugs today. However, their use is often limited by clinical toxicity.

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Structurally, FL118 is a camptothecin analogue and possesses exceptional antitumor efficacy against human cancer through a novel mechanism of action (MOA). In this report, we have synthesized and characterized 24 FL118 Position 7-substituted and 24 FL118 Position 9-substituted derivatives. The top compounds were further characterized for their MOA in colorectal cancer (CRC) models using CRC patient-derived xenograft (PDX) models and pancreatic cancer PDX models to evaluate their antitumor activities.

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Background And Objectives: Sepsis is a life-threatening organ dysfunction syndrome arising from uncontrolled inflammatory responses. Liver injury is a crucial factor for the prognosis of sepsis. Camptothecins (CPTs) have been reported to suppress the inflammatory response induced by sepsis.

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In recent years, streptococcal diseases have severely threatened the development of tilapia aquaculture, but effective prevention and control methods have not yet been established. To understand the immune responses of vaccinated Nile tilapia (Oreochromis niloticus), digital gene expression (DGE) technology was applied in this study to detect the gene expression profile of the Nile tilapia (O. niloticus) liver in response to ScpB (Streptococcal C5a peptidase from group B Streptococcus, ScpB) vaccination and a Streptococcus agalactiae-challenge.

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In an effort to decrease the toxicity of camptothecin (CPT) and improve selectivity for hepatoma and colon cancer cells, bile acid groups were introduced into the CPT 20 or 10 positions, resulting in the preparation of sixteen novel CPT-bile acid analogues. The compounds in which a bile acid group was introduced at the 20-hydroxyl group of CPT showed better cytotoxic selectivity for human hepatoma and colon cancer cells than for human breast cancer cells. Fluorescence microscopy analysis demonstrated that one compound (E2) entered human hepatoma cells more effectively than it did human breast cancer cells.

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A new coumarin, edgeworic acid (1), was isolated from the flower buds of Edgeworthia chrysantha, together with the five known coumarins umbelliferone (2), 5,7-dimethoxycoumarin (3), daphnoretin (4), edgeworoside C (5), and edgeworoside A (6). Their structures were established on the basis of spectral data, particularly by the use of 1D NMR and several 2D shift-correlated NMR pulse sequences (1H-1H COSY, HSQC and HMBC), in combination with acetylation reactions.

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A new, simple, sensitive and specific reversed-phase high performance liquid chromatographic (HPLC) method using tandem mass spectrometry detection was initially developed and validated for the analysis of 10-(2-pyrazolyl-ethoxy)-(20S)-camptothecin (CPT13) in rat plasma. Pretreatment of the sample obtained from plasma involved a single protein precipitation step with using acetonitrile containing 0.1% formic acid.

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The mismatched CYP2C9 * 3 DNA was detected by a exciplex fluorescent-probe system. The exciplex fluorescent-probe model system comprises of two 12-mer oligonucleotides fluorescent-probes, complementary to neighbouring sites of a 24 (47) -mer DNA target and plasmid target, each equipped with moieties able to form an exciplex on correct, contiguous hybridization. Very similar results were obtained between the 24-mer target and the 47-mer target when WT and MT systems were detected by the exciplex fluorescent-probe.

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A series of 10-position substituted nitrogenous heterocyclic aromatic group derivatives of SN-38 were prepared. Most of these compounds possessed lower cytotoxicities than CPT. Compound 13 revealed potent cytotoxicity similar to CPT, and compounds 17, 18, and 19 showed similar cytotoxic activity to topotecan.

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The present research was to develop the exciplex-based fluorescence detection of DNA. A SNP-containing region of cytochrome P450 2C9 DNA systems was evaluated to define some of the structural and associated requirement of this new class of exciplex-formed probe, and a 24-base target was selected which contains single-nucleotide polymorphisms (SNP) in genes coding for cytochrome P450. The two probes were all 12-base to give coverage of a 24-base target region to ensure specificity within the human genome.

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10-(2-pyrazolyl-ethoxy)-(20S)-camptothecin (CPT13) is a novel semi-synthetic analogue of camptothecin, our previous report had shown that it possessed higher in vitro cytoxicity activity towards human colon cancer HCT8 cell line than topotecan. In this study, the anti-proliferative effect of CPT13 on HCT8 cell line in vitro was analyzed. In order to further explore the underlying mechanism of cell growth inhibition of CPT13 towards HCT8 cell line, the cell cycle distribution, apoptosis proportion, the nuclei morphological changes and caspase-8 and caspase-3 activities were measured.

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The review provides a detailed discussion of recent advances in the medicinal chemistry of camptothecin, a potent antitumor agent that targets topoisomerase I. Thousands of CPT derivatives have been synthesized. Two of them, Topotecan and Irinotecan, are commercially approved for use in clinic as antitumor agents while more are still in clinic trials.

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Aim: To find new anticancer drug based on the structure of 10-hydroxy camptothecin.

Methods: Six camptothecin glycosides (7-12) were synthesized by phase transfer catalysis. The structures of all compounds synthesized were determined by 1H NMR, IR and MS.

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Aim: To find new anticancer drug based on the structure of 10-hydroxy camptothecin.

Methods: Seven camptothecin derivatives (3 -9) were synthesized and the antitumor activities of these derivatives were evaluated.

Results: Structures of seven new compounds were determined by 1HNMR, IR, MS.

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In an effort to improve the water solubility of camptothecin, 16 water soluble 10-substituted quaternary ammonium salt derivatives of camptothecin were prepared. Their antitumor activity was evaluated on cancer cells in vitro. All of these salts possess lower cytotoxicities than CPT in comparison.

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