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Preparation and antitumor evaluation of quercetin nanosuspensions with synergistic efficacy and regulating immunity. Int J Pharm 2020; 589:119830. [PMID: 32877732 DOI: 10.1016/j.ijpharm.2020.119830] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 02/07/2023]
Abstract
To study the effect of quercetin (QUR) on modulating immune effects, enhancing anti-tumor activity, and reducing drug related side effects, three QUR nanosuspensions (QUR-NPs) with different particle sizes were prepared by a microprecipitation-high pressure homogenization method using mPEG-DCA as a stabilizer. Dynamic light scattering was used to analyze the particle sizes of the three QUR-NPs. The results of stability tests showed that the three QUR-NPs had good storage and plasma stability. It was confirmed that plasma protein adsorption occurred for all three QUR-NPs. The results of DSC, DTG, XRPD, and Raman spectroscopy showed that there was no significant change in the crystal form of QUR for any of the three QUR-NPs compared with the commercial QUR. The in vitro dissolution rate of the three QUR-NPs was significantly faster than that of the micronized QUR, with the dissolution rate increasing as particle size decreased. All three QUR-NPs showed stronger in vitro inhibitory activity on MCF-7 cells than the pure QUR solution, with the largest NPs having the strongest inhibitory effect. The pharmacokinetic parameters in rats showed that the MRT and t1/2 of the QUR-NPs increased as particle size increased. QUR-NPs and the pure QUR solution showed obvious anti-tumor effects against murine hepatic carcinoma H22 model in vivo, although they were not as effective as cyclophosphamide (CTX). However, the anti-tumor effect of the large QUR-NPs combined with CTX was the strongest among all the tested groups. From the results of the thymus and spleen index, it was found that the QUR-NPs could not only regulate the immunity of tumor-bearing mice, but also alleviate the immunosuppression caused by CTX and protect normal tissues, all while enhancing the anti-tumor effect. The immunomodulatory effect of the QUR-NPs on tumor-bearing mice was significantly better than that of the pure QUR solution. Therefore, nanosuspensions can be used as a new drug delivery system for QUR to assist tumor therapy and regulate immunity.
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FitzGerald ES, Luz NF, Jamieson AM. Competitive Cell Death Interactions in Pulmonary Infection: Host Modulation Versus Pathogen Manipulation. Front Immunol 2020; 11:814. [PMID: 32508813 PMCID: PMC7248393 DOI: 10.3389/fimmu.2020.00814] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/08/2020] [Indexed: 12/12/2022] Open
Abstract
In the context of pulmonary infection, both hosts and pathogens have evolved a multitude of mechanisms to regulate the process of host cell death. The host aims to rapidly induce an inflammatory response at the site of infection, promote pathogen clearance, quickly resolve inflammation, and return to tissue homeostasis. The appropriate modulation of cell death in respiratory epithelial cells and pulmonary immune cells is central in the execution of all these processes. Cell death can be either inflammatory or anti-inflammatory depending on regulated cell death (RCD) modality triggered and the infection context. In addition, diverse bacterial pathogens have evolved many means to manipulate host cell death to increase bacterial survival and spread. The multitude of ways that hosts and bacteria engage in a molecular tug of war to modulate cell death dynamics during infection emphasizes its relevance in host responses and pathogen virulence at the host pathogen interface. This narrative review outlines several current lines of research characterizing bacterial pathogen manipulation of host cell death pathways in the lung. We postulate that understanding these interactions and the dynamics of intracellular and extracellular bacteria RCD manipulation, may lead to novel therapeutic approaches for the treatment of intractable respiratory infections.
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Affiliation(s)
| | | | - Amanda M. Jamieson
- Division of Biology and Medicine, Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, United States
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Mohotti S, Rajendran S, Muhammad T, Strömstedt AA, Adhikari A, Burman R, de Silva ED, Göransson U, Hettiarachchi CM, Gunasekera S. Screening for bioactive secondary metabolites in Sri Lankan medicinal plants by microfractionation and targeted isolation of antimicrobial flavonoids from Derris scandens. JOURNAL OF ETHNOPHARMACOLOGY 2020; 246:112158. [PMID: 31421182 DOI: 10.1016/j.jep.2019.112158] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 08/09/2019] [Accepted: 08/11/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Sri Lanka is known to have very diverse flora. Many of these species are used for plant-based remedies, which form the integral part of two Sri Lankan systems of traditional medicine, Ayurveda and Deshiya Chikitsa. Despite their widespread use, only a limited number of studies have probed into the scientific evidence for bioactivity of these medicinal plants. Such studies rarely progress to the identification of bioactive natural products. AIM OF THE STUDY The primary aim was to develop a bioactivity screening method and apply it to 50 Sri Lankan medicinal plants where antimicrobial properties could be relevant for its traditional use. The subsequent aim was the progression into defining and characterising potent isolates within targeted compound classes from such plants, i.e. Derris scandens and its antimicrobial flavonoids. MATERIAL AND METHODS The plant collection comprised 24 species of Fabaceae, 15 Rubiaceae, 7 Solanaceae and 4 Cucurbitaceae plants. These 50 species were collected based on their ethnopharmacological importance and use in Sri Lankan traditional medicine. Crude extracts from each species were initially subjected to radial disc diffusion and microdilution assays. Subsequently, aqueous extracts of all plants were microfractionated in deep well plates using reversed-phase HPLC. Fractions were tested for antibacterial and cytotoxic activities and masses of target bioactive compounds were identified using mass spectrometry. Bioactive compounds with the masses identified through microfractions were isolated from Derris scandens using reversed-phase HPLC. The isolated pure compounds were characterised using LC-MS and NMR. RESULTS Crude aqueous extracts from 19 species showed activity against Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) in the radial disc diffusion assay. Crude aqueous extracts from 34 plant species and organic extracts from 46 plant species were active against S. aureus (≤4 mg mL-1) in the microdilution assay. Microfractionation demonstrated antibacterial activity for 19 plants and cytotoxicity for 6 plants. Furthermore, target bioactive compounds and their molecular ions were identified during microfractionation. Dalpanitin and vicenin-3, two of the flavonoids isolated from Derris scandens gave MICs of 23 μg mL-1 against S. aureus. Dalpanitin also exhibited relevant MICs on Gram-negative bacteria (94 μg mL-1 against Escherichia coli and Pseudomonas aeruginosa). CONCLUSION The microfractionation protocol developed in this study enabled time-efficient screening of many plants species, using a small quantity of sample material. In addition, microfractionation served as a guiding tool for identifying individual antimicrobial compounds. Through this process, flavonoids were isolated from Derris scandens, out of which dalpanitin and vicenin-3 showed activity in the low micromolar range. The high hit rate for in vitro antibacterial properties from this ethnopharmacologically guided sample collection gives credence to Sri Lankan traditional herbal medicine as a source for drug discovery.
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Affiliation(s)
- Supun Mohotti
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden; Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Sanjeevan Rajendran
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden; Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Taj Muhammad
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden
| | - Adam A Strömstedt
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden
| | - Achyut Adhikari
- Central Department of Chemistry, Tribhuvan University, Kirtipur, Kathmandu, Nepal
| | - Robert Burman
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden
| | - E D de Silva
- Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Ulf Göransson
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden
| | - C M Hettiarachchi
- Department of Chemistry, Faculty of Science, University of Colombo, Thurston Rd, Colombo 03, Sri Lanka
| | - Sunithi Gunasekera
- Pharmacognosy, Department of Medicinal Chemistry, Uppsala University, Biomedical Centre, SE-751 23, Uppsala, Sweden.
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