Green synthesis of nanoparticles which have eco-friendly favourable solvent systems and environmentally reducing agents is of excessive importance. In this paper, we aimed to develop environmentally friendly, rapid and simple producer for the synthesis gold nanoparticles (Au-NPs) using aqueous extract of sumac as reducing agents for gold ions as well capping agent for the bioformed Au-NPs. The bio-synthesized Au-NPs were characterized by the UV-visible spectroscopy, FTIR, TEM, and zeta-potential measurements. The surface plasmon resonance band centred at 520 nm for Au-NPs was characterized by UV-visible spectrophotometer. The probable bio-molecules are polyphenols may responsible for reduction of gold ions were recognized through FT-IR. The TEM result shows the bioformed Au-NPs are spherical in shapes with the mean size of 20.83 ±4.4 nm. The capping of anionic bio-molecules on the surface of Au-NPs was confirmed by zeta potential assessment (-25.3 mV) and is responsible for the electrostatic stability. In vitro antioxidant activity studies showed that DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2, 2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid) activities increased in a dose dependent manner. The bio-synthesized nanoparticles can potentially useful in pharmaceutical and biomedical applications.

Peptides from natural sources such as milk are shown to have a wide spectrum of biological activities. In this study, three peptides with antioxidant capacity were identified from camel milk protein hydrolysate. Pepsin and pancreatin were used for hydrolysis of milk proteins. Ultrafiltration and reverse-phase high-performance liquid chromatography were used for the concentration and purification of the hydrolysate, respectively. Sequences of the three peptides, which were determined by matrix-assisted laser desorption/ionization time-of-flight spectrophotometry, were LEEQQQTEDEQQDQL [molecular weight (MW): 1860.85 Da, LL-15], YLEELHRLNAGY (MW: 1477.63 Da, YY-11), and RGLHPVPQ (MW: 903.04 Da, RQ-8). The 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate the cytotoxicity of these chemically synthesized peptides against HepG2 cells. In vitro analysis showed antioxidant properties and radical scavenging activities of these peptides on 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)+, O, and OH free radicals. HepG2 cells were treated with YY-11 peptide for 48 hours, and the expression of superoxide dismutase and catalase genes was examined using real-time polymerase chain reaction. The results revealed a significant increase in the expression of superoxide dismutase and catalase genes in treated HepG2 cells.

A peptide from ostrich (Struthio camelus) egg white protein hydrolysate (OEWPH) was purified, characterized, and its antioxidant and enzyme inhibitory properties were evaluated. The OEWPH was prepared using pepsin and pancreatin, and then fractionated using reversed-phase high performance liquid chromatography. The antioxidant activity of the WG-9 peptide was investigated based on its scavenging capacity for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,20-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), superoxide (O), hydroxyl (OH), and lipid peroxidation inhibition. The angiotensin-converting enzyme (ACE) inhibitory activity and kinetic parameters of the peptide were determined using N-[3-(2-Furyl)acryloyl]-L-phenylalanyl-glycyl-glycine (FAPGG) as a substrate. Tandem mass spectrometry analysis of the purified peptide revealed a sequence of WESLSRLLG (MW: 1060 Da; WG-9). This peptide inhibited linoleic acid oxidation and acted as a DPPH (IC = 15 ± 0.4 μg/mL), ABTS (IC = 130 ± 4.5 μg/mL), superoxide (IC = 160 ± 6.4 μg/mL), and hydroxyl (IC = 150 ± 6.7 μg/mL) radical scavenger. The ACE-inhibitory activity and kinetic parameters of the WG-9 peptide were determined, showing an ACE inhibitory activity with IC of 46.7 ± 1.4 μg/mL. The parameters of peptide/ACE interactions were investigated by molecule docking. Furthermore, viability assays showed that the identified peptide had no cytotoxicity against an HFLF-PI-5 cell line. In conclusion, the WG-9 peptide showed potent antioxidant and ACE-inhibitory activity.

Cerium oxide nanoparticle (CeO‐NP) was synthesized using Origanum majorana L. leaf extract and characterized using particle size analyzer, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD) and Fourier transform infrared (FTIR). The antioxidant properties and cytotoxic effects of CeO‐NP in human breast carcinoma cells (MDA‐MB‐231 cell line) and human umbilical vein endothelial cells (HUVEC) as normal cells were evaluated. To determine the probable molecular mechanism of action of CeO‐NP on cellular redox and anti‐inflammatory potential, the expressions of antioxidant‐related genes catalase (CAT), superoxide dismutase (SOD) in HUVEC cell line were also analyzed. The results indicated that spherically shaped nanoparticles with a size of 10–70 nm bound to functional phenolic and flavonoids from O. majorana L. leaf extract. The green synthesized CeO‐NP showed antioxidant activity by free radical scavenging activity against DPPH and ABTS free radicals. The antioxidant activity was significantly (p < 0.001) lower than that of Butylated hydroxyanisole (BHA) as a reference antioxidant. The obtained results elucidated that CeO‐NP possessed cytotoxicity. The cytotoxic effects of CeO‐NP were higher against MDA‐MB‐231 cancer cells compared to HUVEC normal cells. In addition, this NP was capable to enhance the expression of CAT and SOD as main antioxidant‐related genes. Consequently, the higher cytotoxic effects of CeO‐NP against breast cancer compared to normal cells indicated the potential use of this NP as anti‐cancer agent. However, more research on its cytotoxicity against other cancer cells and mechanisms in which this NP exert its anti‐cancer properties should be performed.

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