Antioxidative activities of caffeoyl-proline dipeptides

The antioxidant peptides from walnut protein hydrolysates and their protective activity against alcoholic injury

In this study, walnut protein was hydrolyzed, separated by ultrafiltration, purified by RP-HPLC, identified by LC-MS/MS, and screened by molecular docking to finally obtain three novel antioxidant peptides HGEPGQQQR (1189.584 Da), VAPFPEVFGK (1089.586 Da) and HNVADPQR (949.473 Da). These three peptides exhibited excellent cellular antioxidant activity (CAA) with EC50 values of 0.0120 mg mL-1, 0.0068 mg mL-1, and 0.0069 mg mL-1, respectively, which were superior to that of the positive control GSH (EC50: 0.0122 mg mL-1). In the ethanol injury model, three antioxidant peptides enhanced the survival of cells treated with ethanol from 47.36% to 62.69%, 57.06% and 71.64%, respectively. Molecular docking results showed that the three antioxidant peptides could effectively bind to Keap1, CYP2E1 and TLR4 proteins. These results suggested that walnut-derived antioxidant peptides could be potential antioxidants and hepatoprotective agents for application in functional foods.

Caffeoyl-Pro-His amide relieve DNCB-Induced Atopic Dermatitis-Like phenotypes in BALB/c mice

The main factors involved in the pathogenesis of atopic dermatitis (AD) are skin barrier abnormality, allergy/immunology, and pruritus. Considering how oxidative stress influences these factors, antioxidant agents may be effective candidates in the treatment of AD. To evaluate the effect of Caffeoyl–Pro–His amide (CA-PH), an antioxidant agent, on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like phenotypes in BALB/c mice. Topical sensitization and challenge by DNCB were performed on the dorsal skin of BALB/c mice to induce AD-like cutaneous lesions, phenotypes, and immunologic response. CA-PH was applied topically for 2 weeks to assess its effects on DNCB-induced AD-like phenotypes. As a result, CA-PH relieved DNCB-induced AD-like phenotypes quantified by dermatitis severity score, scratching duration, and trans-epidermal water loss. Histopathological analysis showed that CA-PH decreased epidermal thickening, the number of mast cells, and eosinophil infiltration in dermis. Immunohistochemical staining revealed that CA-PH recovered skin barrier-related proteins: filaggrin, involucrin, and loricrin. As for the immunologic aspects, CA-PH treatment lowered mRNA or protein levels of interleukin (IL)-4, IL-6, IL-17a, IL-1b, IL-31, and IL-33 levels and thymic stromal lymphopoietin (TSLP) levels in cutaneous tissue, reducing the DNCB-induced serum IgE level elevation. In conclusion, topical CA-PH may be a therapeutic option for the treatment of AD.

An efficient one-pot synthesis of polyphenolic amino acids and evaluation of their radical-scavenging activity

A simple and efficient procedure for the synthesis of N-acyl 4-hydroxy, 4-hydroxy-3-methoxy and 3,4-dihydroxy phenylglycine amides by a strategy based on the multicomponent Ugi reaction is proposed. Hydroxybenzaldehyde derivatives were reacted with 4-methoxybenzylamine, cyclohexyl isocyanide and benzoic acid or 2-naphthylacetic acid to give Ugi adducts that were treated with trifluoroacetic acid yielding N-acyl hydroxyphenylglycine amides in good yields. The same procedure using as acid component protocatechuic acid or hydrocaffeic acid gave N-catechoyl 3,4-dihydroxyphenylglycine amides. The use of N-benzyloxycarbonylglycine as acid component allowed the preparation of a 3,4-dihydroxyphenylglycyl dipeptide derivative. Radical-scavenging activity studies of the polyphenolic amino acid derivatives showed a sharp increase in activity with the increase in number of hydroxyl or catechol groups present. Cyclic voltammetry experiments established a correlation between oxidation peak potentials and the radical-scavenging activity.

Caffeic acid derivatives, analogs and applications: a patent review (2009-2013)

INTRODUCTION

Caffeic acid (CA) is broadly distributed in several species of the plant kingdom and is widely consumed in human diet. CA and derivatives have been extensively studied in the past years, which unveiled a broad spectrum of biological activities and potential therapeutic applications. As a result, there has been an upsurge in the development of new chemical entities based on the CA scaffold.

AREAS COVERED

The scope of this review is to revisit the therapeutic potential of CA and derivatives. It provides an overview of patented processes and applications thereof between 2009 and 2013.

EXPERT OPINION

The phenylpropanoid framework is currently considered a valid structure for drug discovery programs. Actually, CA has been widely used as a template for the development of new chemical entities with potential therapeutic interest in human diseases associated with oxidative stress. Additionally, the applicability of CA derivatives expands to the realms of cosmetic industry due to its stabilizing properties. The synthesis of esters, amides and hybrids with currently marketed drugs is a trending strategy for the development of derivatives with therapeutic application. It is our opinion that the innovative artwork currently being developed involving this chemical scaffold will yield new and effective therapeutic agents in a foreseeable future.

Antioxidant activity of caffeoyl-prolyl-histidine amide and its effects on PDGF-induced proliferation of vascular smooth muscle cells

Caffeic acid (CA) is one of the antioxidants found in plants, which protects vascular cells against vascular injuries from oxidative stress. In our previous study, caffeoyl-prolyl-histidine amide (CA-L-Pro-L-His-NH2; CA-PH; a CA derivative) was synthesized, which exhibited a strong antioxidant activity with sufficient stability. In this study, we investigated the role of CA-PH in vascular smooth muscle cells (VSMCs) and confirmed the enhanced antioxidant activity of CA-PH compared with that of CA. In in vitro tube assays, CA-PH showed a higher free-radical-scavenging activity and lipid-peroxidation-inhibition activity than those of CA. In VSMCs, CA-PH significantly reduced hydrogen peroxide-induced ROS generation and increased the expression of heme oxygenase-1. Moreover, CA-PH effectively inhibited the platelet-derived growth factor-induced cellular proliferation of VSMCs, which was confirmed by a decrease in the expression of the proliferating cell nuclear antigen and the phosphorylation of Akt.

In vitro antioxidant activities of polysaccharides extracted from Moso Bamboo-Leaf

The objective of this study was to evaluate in vitro antioxidant capacities of polysaccharides extracted from Moso Bamboo-Leaf (BLP). The molecular weight of the polysaccharides were obtained by SEC-LLS and their molecular masses were 13.4×10(4)Da, 2.8×10(4)Da and 1.9×10(4)Da, respectively. Available data obtained with in vitro models suggested WB1 (precipitated by 30% ethanol) showed significant inhibitory effects on superoxide radical, hydroxyl radical, DPPH radical and ferrous metal-chelating capacities. These results clearly establish the possibility that polysaccharides extracted from Moso Bamboo-Leaf could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress.