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Yonghong Liu - One of the best experts on this subject based on the ideXlab platform.

  • Diketopiperazine and enterotoxin analogues from the mangrove derived soil streptomyces sp scsio 41400 and their biological evaluation
    Natural Product Research, 2020
    Co-Authors: Yonghong Liu, Mengmeng Song, Yuhui Xie, Weihao Chen, Kai Zhao, Xiaolong Huang, Qingchao Liu
    Abstract:

    A new Diketopiperazine, cyclo-(d-8-acetoxyl-Pro-l-Leu) (1), together with eight known compounds (2-9) including three enterotoxins (2-4), four Diketopiperazines (5-8) and maltol (9), were isolated from the mangrove derived-soil Streptomyces sp. SCSIO 41400. The planar structures of all compounds were determined from analysis of NMR spectra, MS, optical rotation and comparing with literature data. The absolute configuration of compound 1 was assigned by electronic circular dichroism (ECD). The isolated compounds (1-9) were tested for their acetyl cholinesterase (AChE) and pancreatic lipase (PL) enzyme inhibitory activities. Among them, the new Diketopiperazine (1) displayed preferable PL enzyme inhibitory activity with IC50 value of 27.3 μg/mL, while compounds 2, 5 and 6 showed weak PL enzyme inhibitory activity. Further molecular docking simulation exhibited that compound 1 could be well bind with the catalytic pocket of the PL. Besides, compound 9 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with MIC value of 12.5 μg/mL, which was comparable to that of the positive control ampicillin with MIC value of 3.125 μg/mL.

  • structurally diverse Diketopiperazine alkaloids from the marine derived fungus aspergillus versicolor scsio 41016
    Organic chemistry frontiers, 2019
    Co-Authors: Xiaowei Luo, Chunmei Chen, Huaming Tao, Xiuping Lin, Bin Yang, Xuefeng Zhou, Yonghong Liu
    Abstract:

    Ten new Diketopiperazine alkaloids (DAs, 1–10) along with two known congeners (11–12) were characterized from the marine sponge-derived fungus Aspergillus versicolor SCSIO 41016. Their structures including absolute configurations were determined by spectroscopic analyses, quantum chemical calculations, and X-ray diffraction analysis. Pyranamides A–D (1–4) were obtained as rare 1-oxa-8,10-diazaspiro[5.5]undecane containing Diketopiperazine alkaloids, while secopyranamide C (5) was obtained as a tetrahydropyran-ring cleavage derivative. Plausible biosynthetic pathways of 1–12 were postulated. Compounds 7 and 12 exhibited weak cytotoxic activities against ACHN, OS-RC-2, and 786-O cells.

  • design and synthesis of novel soluble 2 5 Diketopiperazine derivatives as potential anticancer agents
    European Journal of Medicinal Chemistry, 2014
    Co-Authors: Shengrong Liao, Xiuping Lin, Bin Yang, Xuefeng Zhou, Xiaochu Qin, Junfeng Wang, Juan Liu, Xianwen Yang, Yonghong Liu
    Abstract:

    Non-protected 2,5-Diketopiperazine derivatives have poor solubility thus with negative impact on their bioavailability. In the present study, twenty-one novel soluble mono-protected, and three non-protected 2,5-Diketopiperazine derivatives were designed and synthesized. Their anticancer activity to ten cell lines were evaluated by using CCK8 assay, and the results showed that about half of the mono-protected derivatives had broad-spectrum anticancer activity. Among allyl-protected derivatives, compound 4m had strong activity to all the cell lines (IC50 = 0.5-4.5 mu M), especially to the cancer cell lines U937 (IC50 = 0.5 mu M) and K562 (IC50 = 0.9 mu M). Compound 4m could become a lead compound for further development for anticancer agents. (C) 2014 Elsevier Masson SAS. All rights reserved.

Thomas Hofmann - One of the best experts on this subject based on the ideXlab platform.

  • structures sensory activity and dose response functions of 2 5 Diketopiperazines in roasted cocoa nibs theobroma cacao
    Journal of Agricultural and Food Chemistry, 2005
    Co-Authors: Timo D. Stark, Thomas Hofmann
    Abstract:

    The taste compounds inducing the blood-like, metallic bitter taste sensation reported recently for a dichloromethane extract prepared from roasted cocoa nibs were identified as a series of 25 Diketopiperazines by means of HPLC degustation, LC−MS/MS, and independent synthesis. Among these 25 compounds, 13 cis-configured Diketopiperazines, namely, cyclo(l-IIe-l-Phe), cyclo(l-Val-l-Leu), cyclo(l-Pro-l-Pro), cyclo(l-IIe-l-Pro), cyclo(l-Val-l-Tyr), cyclo(l-Ala-l-Tyr), cyclo(l-Phe-l-Ser), cyclo(l-Ala-l-IIe), cyclo(l-Leu-l-Phe), cyclo(l-Pro-l-Val), cyclo(l-Pro-l-Thr), cyclo(l-Pro-l-Tyr), and cyclo(l-Val-l-Val) were identified for the first time in cocoa. In addition, the taste recognition thresholds for the metallic as well as the bitter taste of the Diketopiperazines were determined, and after quantitative analysis by using two diastereomeric Diketopiperazines as the internal standards, the sensory impact of the Diketopiperazines was evaluated on the basis of their dose-over-threshold (DoT) factors calculated a...

  • structures sensory activity and dose response functions of 2 5 Diketopiperazines in roasted cocoa nibs theobroma cacao
    Journal of Agricultural and Food Chemistry, 2005
    Co-Authors: Timo D. Stark, Thomas Hofmann
    Abstract:

    The taste compounds inducing the blood-like, metallic bitter taste sensation reported recently for a dichloromethane extract prepared from roasted cocoa nibs were identified as a series of 25 Diketopiperazines by means of HPLC degustation, LC-MS/MS, and independent synthesis. Among these 25 compounds, 13 cis-configured Diketopiperazines, namely, cyclo(L-IIe-L-Phe), cyclo(L-Val-L-Leu), cyclo(L-Pro-L-Pro), cyclo(L-IIe-L-Pro), cyclo(L-Val-L-Tyr), cyclo(L-Ala-L-Tyr), cyclo(L-Phe-L-Ser), cyclo(L-Ala-L-IIe), cyclo(L-Leu-L-Phe), cyclo(L-Pro-L-Val), cyclo(L-Pro-L-Thr), cyclo(L-Pro-L-Tyr), and cyclo(L-Val-L-Val) were identified for the first time in cocoa. In addition, the taste recognition thresholds for the metallic as well as the bitter taste of the Diketopiperazines were determined, and after quantitative analysis by using two diastereomeric Diketopiperazines as the internal standards, the sensory impact of the Diketopiperazines was evaluated on the basis of their dose-over-threshold (DoT) factors calculated as the ratio of the concentration and the threshold concentration of a compound. These data revealed DoT factors above 1.0 exclusively for cis-cyclo(L-Pro-L-Val), cis-cyclo(L-Val-L-Leu), cis-cyclo(L-Ala-L-Ile), cis-cyclo(L-Ala-L-Leu), and cis-cyclo(L-Ile-L-Pro), whereas all of the other Diketopiperazines were present below their individual bitter taste threshold concentrations and should therefore not contribute to the cocoa taste. Because the DoT factors do not consider the nonlinear relationship between the concentration and gustatory response of an individual compound, we, for the first time, report on the recording of dose/response functions describing the human bitter taste perception of Diketopiperazines more precisely.

Weimin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • indole Diketopiperazine alkaloids from the deep sea derived fungus aspergillus sp fs445
    Natural Product Research, 2021
    Co-Authors: Zhaoming Liu, Yuchan Chen, Hongxin Liu, Weimin Zhang
    Abstract:

    Twelve indole Diketopiperazine alkaloids (1‒12) including four new ones aspechinulins A‒D (1, 3, 5 and 12) were isolated from the deep-sea-derived fungus Aspergillus sp. FS445. Their structures were elucidated through spectroscopic analysis and the absolute configurations were determined by analyzing the experimental ECD data as well as the quantum chemical calculations. Compounds 1, 3 and 5 represented the first examples of indole Diketopiperazine derivatives constructing a C5 unit at 11-NH through an imide linkage. The NO production inhibitory activity of the isolated compounds was evaluated and compounds 2‒5, 7 and 9 exhibited potential inhibitory activities against NO production with the IC50 values in the range of 20 ∼ 90 µM.

Tianjiao Zhu - One of the best experts on this subject based on the ideXlab platform.

  • secondary metabolites from antarctic marine derived fungus penicillium crustosum hdn153086
    Natural Product Research, 2019
    Co-Authors: Congcong Liu, Zhenzhen Zhang, Yanyan Feng, Tianjiao Zhu
    Abstract:

    A new polyene compound (1) and a new Diketopiperazine (2), as well as three known compounds (3–5), were isolated from the Antarctic marine-derived fungus Penicillium crustosum HDN153086. The struct...

  • secondary metabolites of a deep sea derived fungus aspergillus versicolor cxctd 06 6a and their bioactivity
    Journal of Ocean University of China, 2014
    Co-Authors: Xianglan Kong, Tianjiao Zhu, Shengxin Cai, Yepeng Luan
    Abstract:

    In order to obtain novel secondary metabolites, a deep sea inhabiting fungus Aspergillus versicolor CXCTD-06-6a was investigated. One new Diketopiperazine brevianamide W (1a), as well as five known Diketopiperazine alkaloids, Diketopiperazine V (1b), brevianamide Q (2), brevianamide R (3), brevianamide K (4), and brevianamide E (5), were isolated from the EtOAc extract of the fermentation broth. Their structures were elucidated by spectroscopy techniques (NMR, MS). The six compounds exhibited moderate radical scavenging activity against DPPH with clearance ratio of 55.0% (1a and 1b), 53.7% (2), 46.2% (3), 61.4% (4) and 19.3% (5) at a concentration of 13.9 μmol L−1, respectively; while the positive control ascorbic acid showed a ratio of 70.3% at the concentration of 28.4 μmol L−1.

Jae Hak Sohn - One of the best experts on this subject based on the ideXlab platform.