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Maillard reaction products (MRPs), both crude and fractionated, were assessed for antioxidant potential using cell-free, in vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, Fenton reaction induced deoxyribose degradation and oxygen radical absorbance capacity-fluorescein (ORACFL) chemical assays. All MRPs displayed various affinities to scavenge free radicals generated in different reaction media and using different reactive oxygen species (ROS) substrates. High molecular weight MRPs consistently showed the greatest (P < 0.05) antioxidant potential in chemical assays. Repeating these tests in Caco-2 cells with both reactive oxygen and nitrogen (RNS) intracellular assays revealed that the low molecular weight components (LMW) were most effective at inhibiting oxidation and inflammation. In particular, a glucose-lysine (Glu-Lys) mixture heated for 60 min had marked intracellular antioxidant activity and nitric oxide (NO) and interleukin-8 (IL-8) inhibitory activities compared to other MRPs (P < 0.05). Further studies employing ultrafiltration, ethyl acetate extraction, and semipreparative high-performance liquid chromatography (HPLC) produced a bioactive fraction, termed F3, from heated Glu-Lys MRP. F3 inhibited NO, inducible nitric oxide synthetase (iNOS), and IL-8 in interferon γ (IFN-γ)- and phorbol ester (PMA)-induced Caco-2 cells. F3 modified several gene expressions involved in the NF-κB signaling pathway. Two components, namely, 5-hydroxymethyl-2-furfural (HMF) and 5-hydroxymethyl-2-furoic acid (HMFA), were identified in the F3 fraction, with an unidentified third component comprising a major portion of the bioactivity. The results show that MRP components have bioactive potential, especially in regard to suppressing oxidative stress and inflammation in IFN-γ- and PMA-induced Caco-2 cells.

Black garlic is a new garlic product produced through fermentation of fresh garlic and is very popular in Asia countries due to its health benefits. Its key aroma-active compounds were characterized by gas chromatography–olfactometry–mass spectrometry (GC-O-MS), gas chromatography–time-of-flight mass spectrometry (GC-TOFMS), and sensory evaluation. In total 52 aroma compounds were identified, and 15 of them with high flavor dilution (FD) factors based on aroma extract dilution analysis (AEDA) were selected and quantitated. Finally, 9 key aroma-active compounds, including acetic acid (sour), allyl methyl trisulfide (cooked garlic), Furaneol (caramel), diallyldisulfide (garlic), diallyltrisulfide (sulfur), (E,Z)-2,6-nonadien-1-ol (cucumber), 3-methylbutanoic acid (sweat), 5-heptyldihydro-2­(3H)-furanone (apricot), and diallyl sulfide (garlic), were determined through aroma recombination and omission experiment. In addition to the sulfur-containing compounds, heterocyclic compounds were the major aroma contributors in black garlic. Sensory evaluation revealed that the flavor profile of black garlic mainly consisted of sulfur, sour, sweet, fresh, sauce, gasoline, and roasted odors.

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Lactoferrin (LF) has been established as a potent anabolic factor for bone health both in vivo and in vitro. However, the molecular mechanisms underlying LF's action are still largely unknown. Here, we explore the signaling pathways that mediate LF's beneficial effect on osteoblast differentiation. In primary osteoblast and preosteoblast MC3T3-E1, LF promoted alkaline phosphatase (ALP) activity, osteocalcin (OCN) secretion, and mineralization. Along with this enhanced osteogenic differentiation, activation of p38 mitogen-activated protein kinase (MAPK) was detected in LF-treated MC3T3-E1 cells. Downregulating p38 with selective inhibitor SB203580 or p38a small interfering RNA (siRNA) attenuated the effect of LF on osteogenesis. Furthermore, knockdown of p38a significantly decreased LF-induced Runt-related transcription factor 2 (Runx2) phosphorylation. According to previous studies and our results, we speculated that LF-induced osteoblast proliferation and differentiation were two relatively separate processes controlled by extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 pathways, respectively. Besides p38 MAPK activation, protein kinase A (PKA) was also activated in MC3T3-E1 cells. PKA inhibitor H89 significantly inhibited LF-induced p38 activation, ALP activity, and OCN secretion, indicating that PKA possibly acted as an upstream kinase of p38. In order to further identify the role of LF's receptor lowdensity lipoprotein receptor-related protein 1 (LRP1), we constructed LRP1 stable-knockdown MC3T3-E1 cells. Neither LRP1 antagonist receptor associated protein (RAP), nor LRP1 knockdown approach could attenuate the LF-induced osteogenesis, implying that LF stimulated osteoblast differentiation via an LRP1-independent pathway. Taken together, the present work indicated that LF stimulated MC3T3-E1 preosteoblast differentiation mainly through LRP1-independent PKA and p38 signaling pathways. These results provided the first evidence of the signaling mechanisms of LF's effect on osteoblast differentiation.

Quercetin (Que) is a flavonoid widely distributed in vegetables and fruits and exhibits strong antioxidant activity, but the poor stability of Que limits its function and application. The present study developed a nanoparticle (NP) using bovine serum albumin (BSA) as a matrix to encapsulate Que. The stability of encapsulated Que by BSA NP was tracked in a simulated intestinal fluid (SIF). The antioxidant activity of encapsulated Que was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays. Furthermore, the stabilizing mechanism of Que by BSA NP was investigated, using scanning transmisson electron microscopy (STEM), dynamic light scattering (DLS), UV-vis, fluorescence spectrometry, and circular dichroism (CD). The results revealed that Que was effectively encapsulated by BSA and formed spherical NP (<10 nm). BSA NP not only promoted the stability of encapsulated Que but also kept the antioxidant activity of encapsulated Que. The driving forces for BSA-Que association were hydrophobic interaction and hydrogen bond, and the latter was involved in the mechanism of Que stabilization. This suggested that BSA NP could be a good carrier to deliver hydrophobic flavonols.

Fruits and vegetables waste byproducts could be utilized as a good source of cheap antioxidants for improving human health and reducing the risks of some chronic diseases. Results from examining industrial apple waste revealed that the total polyphenolic content in nonextractable polyphenols (NEPPs) reached 539.84 ± 8.90 mg as gallic acid equivalents/1 g of dry wt. in comparison to 77.26 ± 11.53 mg dry wt. of extractable polyphenols (EPPs). The antioxidant activities of NEPPs reported as percentage reduction in 2,2-Diphenyl-1-picrylhydrazyl and 2'.2'-azinobis(3-ethylbenzothiazline-6-sulfonic acid) diammonium salt were 89.76 ± 0.93% and 99.78 ± 0.38%, respectively. In addition, the antiproliferation study on human HeLa, HepG2, and HT-29 cancer cells showed that NEPPs at the concentration of 1 mg/mL had significant inhibitory effects against all tested cancer cells (46.2% to 95%), where EPP showed lower effect (3.9% to 22.2%). These results clearly indicated that NEPPs from industrial apple waste could be a good source of natural antioxidants with significant antiproliferation efficacy against human cancer cells.