Month: January 2021

Phthalocyanine–Peptide Conjugates: Receptor-Targeting Bifunctional Agents for Imaging and Photodynamic Therapy

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The synthesis of a series of new zinc phthalocyanine–peptide conjugates targeting the gastrin-releasing peptide (GRP) and integrin receptors is reported. Two alternative synthetic methods based on Sonogashira cross-coupling of an iodinated zinc phthalocyanine with acetylenic bombesin or arginine–glycine–aspartic acid (RGD) derivatives, either in solution or on solid phase, are presented. The water-soluble conjugates were screened for their photodynamic efficacy against several cancer cell lines expressing different levels of GRP and integrin receptors, and their intracellular localization was evaluated via confocal fluorescence microscopy. Variations in photocytotoxicity between the conjugates correlate to differences in hydrophobicity as well as receptor-mediated cell uptake. In the case of the phthalocyanine–bombesin conjugate, competition experiments confirm the involvement of the GRP receptor in both the phototherapeutic activity as well as intracellular localization. These findings warrant further in vivo studies to evaluate the potential of this conjugate as photosensitizer for photodynamic therapy (PDT) of cancers overexpressing the GRP receptor. (J. Med. Chem. 2013, 56, 4, 1520–1534.)

Synthesis and evaluation of novel dolastatin 10 derivatives for versatile conjugations

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Dolastatin 10 (1) is a highly potent cytotoxic microtubule inhibitor (cytotoxicity IC50 < 5.0 nM) and several of its analogs have recently been used as payloads in antibody drug conjugates. Herein, we describe the design and synthesis of a series of novel dolastatin 10 analogs useful as payloads for conjugated drugs. We explored analogs containing functional groups at the thiazole moiety at the C-terminal of dolastatin 10. The functional groups included amines, alcohols, and thiols, which are representative structures used in known conjugated drugs. These novel analogs showed excellent potency in a tumor cell proliferation assay, and thus this series of dolastatin 10 analogs is suitable as versatile payloads in conjugated drugs. Insights into the structure–activity relationships of the analogs are also discussed.(Bioorganic & Medicinal Chemistry. Volume 26, Issue 8, 1 May 2018, Pages 1643-1652.)

Potential protective effect of Trans-10-hydroxy-2-decenoic acid on the inflammation induced by Lipoteichoic acid

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Royal jelly (RJ) is known as a functional food for its diverse health-beneficial properties and complicated chemical compositions. Trans-10-hydroxy-2-decenoic acid (10-HDA) is the exclusive lipid component in RJ. In the present study, the in vitro anti-inflammatory effect of 10-HDA in LTA (Lipoteichoic acid from Staphylococcus aureus) induced RAW 264.7 macrophages are evaluated. The results showed that 10-HDA had potent, dose-dependent inhibitory effects on the release of major inflammatory mediators and NO. Several key inflammatory genes, including IL-1β, IL-6, MCP-1 and COX-2 have also been suppressed by 10-HDA. Furthermore, the effects of 10-HDA on LTA-induced pulmonary damage were also examined in mice. It was found that the administration of 10-HDA (100 mg/kg) can provide protective effects by attenuating lung histopathological changes and modulating the secretion of LTA-stimulated inflammatory cytokines in mice, such as IL-10, MCP-1 and TNF-α. Conclusively, the results reveal the potent anti-inflammatory properties of 10-HDA and provide biological information for the future application.(Journal of Functional Foods. Volume 45, June 2018, Pages 491-498.)

Properties of octenyl succinic anhydride (OSA) modified starches and their application in low fat mayonnaise

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Wheat starch (WS), corn starch (CS), waxy corn starch (WCS), potato starch (PS), sweet potato (SP), rice starch (RS) and kidney bean (KB) were modified using octenyl succinic anhydride (OSA) and evaluated for various properties. Degree of substitution (DS) showed significant increase with increase in amylose (AM) content. OSA modified starches showed higher paste viscosities compared to their native counterparts. OSA groups acted majorly on the surface and caused some superficial pores, but crystalline pattern was not significantly altered for all starches. OSA modified starches were used in preparing low fat mayonnaise by substituting 75% fat. OSA modified starches enhanced the emulsifying properties of mayonnaise. Mayonnaises prepared using OSA modified starches were evaluated for phase separation, brightness (L*), color index (dE), and rheological parameters (G′ and G″). Mayonnaises prepared using OSA modified starches showed higher G’ and exhibited gel like structure. Fat substituted (FS) mayonnaise was preferred over full fat (FF) mayonnaise by the consumers. No significant effect of fat substitution was observed on particle size and phase separation for all mayonnaise samples. (International Journal of Biological Macromolecules.,Volume 131, 15 June 2019, Pages 147-157.)