Trapping Effects of Green and Black Tea Extracts on Peroxidation-Derived Carbonyl Substances of Seal Blubber Oil

School of Biological Sciences, The University of Hong Kong, Hong Kong, People's Republic of China.
Journal of Agricultural and Food Chemistry (Impact Factor: 3.11). 02/2009; 57(3):1065-9. DOI: 10.1021/jf802691k
Source: PubMed

ABSTRACT Green and black tea extracts were employed to stabilize seal blubber oil at 60 degrees C for 140 h. On the basis of the headspace SPME-GC-MS analysis, with the addition of green/black tea extracts, the contents of acetaldehyde, acrolein, malondialdehyde, and propanal, four major lipid peroxidation products, were reduced. The inhibition rates of acrolein formation by green tea and black tea extracts were 98.40 and 96.41% respectively, and were 99.17 and 98.16% for malondialdehyde, respectively, much higher than the inhibition of the formation of acetaldehyde and propanal. Because malondialdehyde and acrolein are reactive carbonyl species (RCS) and recent studies have suggested that phenolics can directly trap RCS, this study also investigated whether green tea polyphenols can trap acrolein or not. Acrolein was reduced by 90.30% in 3 h of incubation with (-)-epigallocatechin-3-gallate (EGCG). Subsequent LC-MS analysis revealed the formation of new adducts of equal molars of acrolein and EGCG. The reaction site for acrolein was elucidated to be the A ring of EGCG as evidenced by LC-MS/MS analysis and by testing of the acrolein-trapping capacities of the analogous individual A, B, and C rings of EGCG. Thus, EGCG's direct trapping of RCS may also contribute to the significant reduction of acrolein and other aldehydes in the peroxidation of seal blubber oil.

Download full-text


Available from: Qin Zhu, Jul 22, 2014
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the current study, the protective effects of phloretin were investigated in acrolein-challenged amino acid, protein, and cell models. It was found that the formation of FDP-lysine (a typical acrolein-lysine adduct) was strongly inhibited in the presence of phloretin and the remaining electrophilic site in FDP-lysine was also blocked by phloretin. Moreover, direct trapping of acrolein by phloretin was found to be responsible for inhibiting the incorporation of carbonyl groups into BSA and oligomerisation in RNase A. Subsequently, the reduction of LDH release in human neuroblastoma SH-SY5Y cells under acrolein challenge suggested the cytoprotective effects of phloretin. Such protection might be mediated through inhibiting the increased cellular protein carbonyl level as revealed by Western blotting analysis. The present study highlighted an apple phenolic compound, phloretin as a promising candidate in prevention or treatment of acrolein-associated human diseases.
    Food Chemistry 12/2012; 135(3):1762-8. DOI:10.1016/j.foodchem.2012.06.053 · 3.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Oxidative stress plays a major role in many disease pathologies, notably in the central nervous system (CNS). For instance, after initial spinal cord injury, the injury site tends to increase during a secondary chemical injury process based on oxidative stress from necrotic cells and the inflammatory response. Prevention of this secondary chemical injury would represent a major advance in the treatment of people with spinal cord injuries. Few therapeutics are useful in combating such stress in the CNS due to side effects, low efficacy, or half-life. Mesoporous silica nanoparticles show promise for delivering therapeutics based on the formation of a porous network during synthesis. Ideally, they increase the circulation time of loaded therapeutics to increase the half-life while reducing overall concentrations to avoid side effects. The current study explored the use of silica nanoparticles for therapeutic delivery of anti-oxidants, in particular, the neutralization of acrolein which can lead to extensive tissue damage due to its ability to generate more and more copies of itself when it interacts with normal tissue. Both an FDA-approved therapeutic, hydralazine, and natural product, epigallocatechin gallate, were explored as anti-oxidants for acrolein with nanoparticles for increased efficacy and stability in neuronal cell cultures. Not only were the nanoparticles explored in neuronal cells, but also in a co-cultured in vitro model with microglial cells to study potential immune responses to near-infrared (NIRF)-labeled nanoparticles and uptake. Studies included nanoparticle toxicity, uptake, and therapeutic response using fluorescence-based techniques with both dormant and activated immune microglia co-cultured with neuronal cells.
    Proc SPIE 03/2015; 9339. DOI:10.1117/12.2076048
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Acrolein, a very reactive aldehyde, is a culprit in the biochemical cascade after primary, mechanical spinal cord injury (SCI), which leads to the destruction of tissue initially unharmed, referred to as "secondary injury". Additionally, in models of multiple sclerosis (MS) and some clinical research, acrolein levels are significantly increased. Due to its ability to make more copies of itself in the presence of tissue via lipid peroxidation, researchers believe that acrolein plays a role in the increased destruction of the central nervous system in both SCI and MS. Hydralazine, an FDAapproved hypotensive drug, has been shown to scavenge acrolein, but its side effects and short half life at the appropriate dose for acrolein scavenging must be improved for beneficial clinical translation. Therefore, a nanomedical approach has been designed using silica nanoparticles as a porous delivery vehicle hydralazine. The silica particles are formed in a one-step method that incorporates poly(ethylene) glycol (PEG), a stealth molecule, directly onto the nanoparticles. As an additional avenue for study, a natural product in green tea, epigallocatechin gallate (EGCG), has been explored for its ability to react with acrolein, disabling its reactive capabilities. Upon demonstration of attenuating acrolein, EGCG's delivery may also be improved using the nanomedical approach. The current work exposes the potential of using silica nanoparticles as a delivery vehicle and EGCG's antioxidant capabilities in B35 neuroblastoma cells exposed to acrolein. We also measure nanotoxicity to individual rat neurons using high-throughput image scanning cytometry.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2014; DOI:10.1117/12.2040190 · 0.20 Impact Factor