Tiantian Zhang

Protective Effects of DHA-PC against Vancomycin-Induced Nephrotoxicity through the Inhibition of Oxidative Stress and Apoptosis in BALB/c Mice

The clinical use of glycopeptide antibiotic vancomycin is usually accompanied by nephrotoxicity, limiting its application and therapeutic efficiency. The aim of this study was to investigate the protection of DHA-enriched phosphatidylcholine (DHA-PC) against nephrotoxicity using a model of vancomycin-induced male BALB/c mice with renal injury by measuring death curves, histological changes, and renal function indexes. The addition of DHA in DHA and DHA-PC groups were 300 mg/kg per day on the basis of human intake level in our study. Results indicated that DHA-PC could dramatically extend the survival time of mice, while traditional DHA and PC had no significant effects. Moreover, oral administration of DHA-PC exhibited better effects on reducing vancomycin-induced increases of blood urea nitrogen, creatinine, cystatin C, and kidney injury molecule-1 levels than traditional DHA and PC. DHA-PC significantly delayed the development of vancomycin-induced renal injury, including tubular necrosis, hyaline casts, and tubular degeneration. A further mechanistic study revealed that the protective effect of DHA-PC on vancomycin-mediated toxicity might be attributed to its ability to inhibit oxidative stress and inactivate mitogen-activated protein kinase (MAPK) signaling pathways, which was associated with upregulation of Bcl-2 and downregulation of caspase-9, caspase-3, cytochrome-c, p38, and JNK. These findings suggest that DHA-PC may be acted as the dietary supplements or functional foods against vancomycin-induced nephrotoxicity.

Effects of Astaxanthin and Docosahexaenoic-Acid-Acylated Astaxanthin on Alzheimer’s Disease in APP/PS1 Double-Transgenic Mice

Alzheimers disease (AD) is a progressive neurodegenerative disorder with the characteristics of senile plaques, neuroinflammation, neurofibrillary tangles, and destruction of synapse structure stability. Previous studies have verified the protective effects of astaxanthin (AST). However, whether synthesized docosahexaenoic-acid-acylated AST diesters (AST-DHA) could delay AD pathogenesis remains unclear. In the present study, APP/PSEN1 (APP/PS1) double-transgenic mice were administrated with AST and AST-DHA for 2 months. The results of radial 8-arm maze and Morris water maze tests showed that AST-DHA exerted more significant effects than AST in enhancing learning and memory levels of APP/PS1 mice. Further mechanical studies suggested that AST-DHA was superior to AST in regulating the parameters of oxidative stress, reducing tau hyperphosphorylation, suppressing neuroinflammation, and regulating inflammasome expression and activation in APP/PS1 mice. The findings suggested that AST-DHA attenuated cognitive disorders by reducing pathological features in APP/PS1 mice, suggesting that AST-DHA might be a potential therapeutic agent for AD.

The Protective Effect of Antarctic Krill Oil on Cognitive Function by Inhibiting Oxidative Stress in the Brain of Senescence-Accelerated Prone Mouse Strain 8 (SAMP8) Mice: Protective effect of Antarctic Krill oil…

Alzheimers disease (AD) is a common neurodegenerative disorder, and oxidative stress plays a vital role in its progression. Antarctic krill oil (AKO) is rich in polyunsaturated fatty acids, which has various biological activities, such as improving insulin sensitivity, alleviating inflammation and ameliorating oxidative stress. In this study, the protective effect of AKO against AD were investigated in senescence-accelerated prone mouse strain 8 (SAMP8) mice. Results showed that treatment with AKO could effectively ameliorate learning and memory deficits and ease the anxiety in SAMP8 mice by Morris water maze, Barnes maze test and open-field test. Further analysis indicated that AKO might reduce β-amyloid (Aβ) accumulation in hippocampus through decreasing the contents of malondialdehyde (MDA) and 7,8-dihydro-8-oxoguanine (8-oxo-G), increasing the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in the brain of SAMP8 mice.nnnPRACTICAL APPLICATIONnThe results of Morris water maze, Barnes maze test and open-field test indicated that Antarctic krill oil (AKO) improved the cognitive function and anxiety of SAMP8 mice. AKO reduced the Aβ42 level in hippocampus of SAMP8 mice. AKO ameliorated oxidative stress in brain rather than in serum and liver of SAMP8 mice.

Synergistic effect of eicosapentaenoic acid-enriched phospholipids and sea cucumber saponin on orotic acid-induced non-alcoholic fatty liver disease in rats

Non-alcoholic fatty liver disease (NAFLD) is becoming an increasingly prevalent chronic liver disease all over the world. The present study was undertaken to explore the synergistic effects of sea cucumber saponins (SCS) and eicosapentaenoic acid-enriched phospholipids (EPA-PL) at ratios of 0.5u2009:u20090.5 and 1u2009:u20091 on NAFLD and demonstrate possible protective mechanisms. It was found that the combination of EPA-PL and SCS at half dose exhibited better effects than EPA-PL or SCS alone and the combination of EPA-PL and SCS at full dose in alleviating orotic acid (OA)-induced symptoms including growth parameters, serum parameters and liver function. Further evaluation of the mechanism illustrated that EPA-PL and SCS combination at the ratio of 0.5u2009:u20090.5 could markedly reduce the mRNA expressions of fatty acid synthase, acetyl-CoA carboxylase, glucose-6-phosphate dehydrogenase and malic enzyme genes and significantly increase expression of genes relevant to fatty acid β-oxidation including peroxisome proliferator-activated receptor and its target genes (CPT1, CPT2 and ACOX1), suggesting that the protection of the EPA-PL and SCS combination at the ratio of 0.5u2009:u20090.5 against OA-induced NAFLD might be mainly via lipogenesis inhibition and β-oxidation enhancement in the liver. The synergistic effects of EPA-PL and SCS make it possible to reduce the doses of EPA-PL or SCS to avoid side effects, which is of value for the development of dietary supplements or functional foods for preventing or treating NAFLD.

Antioxidant and anti-inflammatory effects of polyphenols extracted from Ilex latifolia Thunb

To promote the rational and effective application of Ilex latifolia Thunb., a Chinese bitter tea widely consumed as a health beverage, polyphenols were extracted from its leaves and their cellular antioxidant activity (CAA) and anti-inflammatory effect against mouse macrophage RAW 264.7 cells were analyzed. Results showed that the antioxidant capacity of polyphenols was high, and their CAA values in PBS wash and no PBS wash protocols were 6871.42 ± 85.56 and 25161.61 ± 583.55 μmol QE (quercetin equivalents)/100 g phenolic extracts, respectively. In addition, polyphenols from I. latifolia displayed strong inhibition on LPS-induced NO-production in RAW 264.7 cells. Polyphenol treatment inhibited the release of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) induced by LPS in a dose-dependent manner by ELISA and mRNA expression analysis. Western blot results showed that the anti-inflammatory activity of polyphenols from I. latifolia might be exerted through inhibiting the activation of MAPKs (ERK and JNK) and NF-κB to decrease NO, COX-2 and pro-inflammatory cytokines production. Thus, the polyphenol enriched extracts from I. latifolia are a good source of natural antioxidants with a beneficial effect against inflammation, and they may be applied as a food supplement and/or functional ingredient.

Comparative Study of Different Polar Groups of EPA‐Enriched Phospholipids on Ameliorating Memory Loss and Cognitive Deficiency in Aged SAMP8 Mice

SCOPEnRecent studies have shown that omega-3 PUFAs enriched phospholipids (n-3 PUFA-PLs) have beneficial effects on memory and cognition. However, most reports only attribute the benefit to docosahexaenoic acid (DHA) and pay little attention to eicosapentaenoic acid (EPA).nnnMETHODS AND RESULTSnWe investigate the effect of EPA-enriched phospholipids on cognitive deficiency in senescence-accelerated prone 8 (SAMP8) mouse. Ten-month-old SAMP8 mice are fed with 2% (w/w) EPA-enriched phosphatidylcholine/phosphatidyl ethanolamine (EPA-PC/PE; EPA:DHA = 46.8:3.01) or 2% EPA-enriched phosphatidylserine (EPA-PS; biosynthesized from EPA-PC/PE) for 8 weeks; we then test the behavioral performances in the Barnes maze test and Morris maze test; the changes of oxidative stress, apoptosis, neurotrophic factors, tau phosphorylation, and Aβ pathology are also measured. The results of behavior tests indicate that both EPA-PC/PE and EPA-PS significantly improve memory and cognitive deficiency. It is found that remarkable amelioration of oxidative stress and apoptosis occurs in both EPA-PC/PE and EPA-PS groups. EPA-PS shows more ameliorative effects than EPA-PC/PE on neurotrophic activity by decreasing hyper-phosphorylation of tau and depressing the generation and accumulation of β-amyloid peptide (Aβ).nnnCONCLUSIONnThese data suggest that EPA-PS exhibits better effects than EPA-PC/PE on ameliorating memory and cognitive function, which might be attributed to the phospholipid polar groups.

Saponins from Sea Cucumber and Their Biological Activities

Sea cucumbers, belonging to the phylum Echinodermata, have been valued for centuries as a nutritious and functional food with various bioactivities. Sea cucumbers can produce highly active substances, notably saponins, the main secondary metabolites, which are the basis of their chemical defense. The saponins are mostly triterpene glycosides with triterpenes or steroid in aglycone, which possess multiple biological properties including antitumor, hypolipidemic activity, improvement of nonalcoholic fatty liver, inhibition of fat accumulation, antihyperuricemia, promotion of bone marrow hematopoiesis, antihypertension, etc. Sea cucumber saponins have received attention due to their rich sources, low toxicity, high efficiency, and few side effects. This review summarizes current research on the structure and activities of sea cucumber saponins based on the physiological and pharmacological activities from source, experimental models, efficacy, and mechanisms, which may provide a valuable reference for the development of sea cucumber saponins.