- Discovery of a Membrane-Active, Ring-Modified Histidine Containing Ultrashort Amphiphilic Peptide That Exhibits Potent Inhibition of Cryptococcus neoformans
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The new structural classes of ultrashort peptides that exhibit potent microbicidal action have potential as future drugs. Herein, we report that C-2 arylated histidines containing tripeptides His(2-Ar)-Trp-His(2-Ar) exhibit potent antifungal activity against Cryptococcus neoformans with high selectivity. The most potent peptide 12f [His(2-biphenyl)-Trp-His(2-biphenyl)] displayed high in vitro activity against C. neoformans (IC50 = 0.35 μg/mL, MIC = MFC = 0.63 μg/mL) with a selectivity index of >28 and 2 times higher potency compared to amphotericin B. Peptide 12f exhibited proteolytic stability, with no apparent hemolytic activity. The mechanism of action study of 12f by confocal laser scanning microscopy and electron microscopy indicates nuclear fragmentation and membrane disruption of C. neoformans cells. Combinations of 12f with fluconazole and amphotericin B at subinhibitory concentration were synergistic against C. neoformans. This study suggests that 12f is a new structural class of amphiphilic peptide with rapid fungicidal activity caused by C. neoformans.
- Sharma, Krishna K.,Maurya, Indresh Kumar,Khan, Shabana I.,Jacob, Melissa R.,Kumar, Vinod,Tikoo, Kulbhushan,Jain, Rahul
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p. 6607 - 6621
(2017/08/17)
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- Synthetically modified l-histidine-rich peptidomimetics exhibit potent activity against Cryptococcus neoformans
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We describe the synthesis and antimicrobial evaluation of structurally new peptidomimetics, rich in synthetically modified l-histidine. Two series of tripeptidomimetics were synthesized by varying lipophilicity at the C-2 position of l-histidine and at the N- and C-terminus. The data indicates that peptides (5f, 6f, 9f and 10f) possessing highly lipophilic adamantan-1-yl group displayed strong inhibition of Cryptococcus neoformans. Peptide 6f is the most potent of all with IC50 and MFC values of 0.60 and 0.63 μg/mL, respectively, compared to the commercial drug amphotericin B (IC50 = 0.69 and MFC = 1.25 μg/mL). The selectivity of these peptides to microbial pathogen was examined by a tryptophan fluorescence quenching study and transmission electron microscopy. These studies indicate that the peptides plausibly interact with the mimic membrane of pathogen by direct insertion, and results in disruption of membrane of pathogen.
- Mahindra, Amit,Bagra, Nitin,Wangoo, Nishima,Jain, Rohan,Khan, Shabana I.,Jacob, Melissa R.,Jain, Rahul
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p. 3150 - 3154
(2015/02/19)
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- Synthesis and antimicrobial activities of His(2-aryl)-Arg and Trp-His(2-aryl) classes of dipeptidomimetics
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In this communication, we report the design, synthesis and in vitro antimicrobial activity of ultra short peptidomimetics. Besides producing promising antibacterial activities against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA), the dipeptidomimetics exhibited high antifungal activity against C. neoformans with IC50 values in the range of 0.16-19 μg mL-1. The most potent analogs exhibited 4-fold higher activity than the currently used drug amphotericin B, with no apparent cytotoxicity in a panel of mammalian cell lines. This journal is the Partner Organisations 2014.
- Mahindra, Amit,Sharma, Krishna K.,Rathore, Dinesh,Khan, Shabana. I.,Jacob, Melissa R.,Jain, Rahul
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p. 671 - 676
(2014/05/06)
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