Conformational Preferences and Antiproliferative Activity of Peptidomimetics Containing Methyl 1'-Aminoferrocene-1-carboxylate and Turn-Forming Homo- and Heterochiral Pro-Ala Motifs

Jackfruit Leaf Protein Hydrolysates Obtained by Enzymatic Hydrolysis of Leaf Protein Concentrate with Pepsin and Pancreatin: Molecular Weight, Cytotoxicity, Antiproliferative Activity, and Oxidative Stress

Jackfruit leaf protein hydrolysates obtained from the enzymatic hydrolysis of leaf protein concentrate with gastrointestinal enzymes have shown good techno-functional properties and high antioxidant capacity. However, molecular weight, antiproliferative activity, cytotoxicity and the ability to reduce reactive oxygen species (ROS) are still unknown. Therefore, this study aimed to evaluate the effect of jackfruit leaf protein hydrolysates obtained by enzymatic hydrolysis with pepsin and pancreatin at different hydrolysis times (30-240 min) on molecular weights, cytotoxicity, antiproliferation of cancer cells, and the reduction of reactive oxygen species in H2O2-induced HaCaT cells. The electrophoretic profile indicated that H-Pep contains peptides with molecular weights between 25 - 20 kDa. Meanwhile, H-Pan is composed of molecular weight products between 25 - 20 kDa and < 20 kDa. H-Pan and H-Pep (125-500 µg/mL) did not show significant cytotoxicity on HaCaT (human keratinocytes) and J774A.1 (murine macrophage cells). Antiproliferative activity was achieved in human cervical, ovarian, and liver cancer cells. H-Pan-240 min (1000 µg/mL) reduced the cell viability of cervical cancer cells by 23% while H-Pan-60 min significantly reduced cell viability of ovarian and liver cancer cells by 14.5 (500 µg/mL) and 17% (1000 µg/mL), respectively (P < 0.05). The protective effect against oxidative stress on H2O2-stressed HaCaT cells was obtained with H-Pep-60 min, which reduced 25% of ROS at 250 µg/mL (P < 0.05). The findings demonstrate the safe use of green biomass as a source of plant protein hydrolysates.

Recent Advances in the Field of Amino Acid-Conjugated Aminoferrocenes-A Personal Perspective

The development of turn-based inhibitors of protein-protein interactions has attracted considerable attention in medicinal chemistry. Our group has synthesized a series of peptides derived from an amino-functionalized ferrocene to investigate their potential to mimic protein turn structures. Detailed DFT and spectroscopic studies (IR, NMR, CD) have shown that, for peptides, the backbone chirality and bulkiness of the amino acid side chains determine the hydrogen-bond pattern, allowing tuning of the size of the preferred hydrogen-bonded ring in turn-folded structures. However, their biological potential is more dependent on their lipophilicity. In addition, our pioneering work on the chiroptical properties of aminoferrocene-containing peptides enables the correlation of their geometry with the sign of the CD signal in the absorption region of the ferrocene chromophore. These studies have opened up the possibility of using aminoferrocene and its derivatives as chirooptical probes for the determination of various chirality elements, such as the central chirality of amino acids and the helicity of peptide sequences.

Novel ferrocene imide derivatives: synthesis, conformational analysis and X-ray structure

The synthesis and structural characterization of the ferrocene imide derivatives Fc−CO−NH−CO−Me (4), Fc−CO−NH−CO−Fc (7) and Fc−CO−NH−CO−Fn−CO−NH−CO−Fc (8) have been reported. The mononuclear, dinuclear and trinuclear ferrocene imides were prepared by the reaction of ferrocenecarboxamide (3), with acetyl chloride, ferrocenecarbonyl chloride (2) and ferrocene-1,1’-(dicarbonyl chloride) (6), respectively. IR spectroscopic analysis revealed the absence of intramolecular hydrogen bonds in solutions of imides 4, 7 and 8. The crystal packing of N-acetylferrocenecarboxamide (4) is characterized by N−H⋯O hydrogen bonds forming centrosymmetric dimers, while the molecules of its homologue N-methylferrocenecarboxamide (5) are self-assembled by intermolecular N−H⋯O bonds into infinite chains. A detailed conformational analysis (DFT study) suggests the cis-trans configuration of ferrocene imide derivative 7 in solution. The effect of different substituents attached to bridged imide nitrogen on conformational properties of bis-ferrocenyl imides was further investigated and results compared to the existing experimental data.