Diabetes diminishes a typical metabolite of litchi pericarp oligomeric procyanidins (LPOPC) in urine mediated by imbalanced gut microbiota.

Animal studies and clinical trials have shown that dietary polyphenols and polyphenol-rich foods can reduce the risk of type 2 diabetes (T2D) and its complications, but how diabetes regulates the metabolism of polyphenol has not been fully elucidated. This study investigated the effects of diabetes on litchi pericarp oligomeric procyanidin (LPOPC) dynamic metabolism and its major static metabolites in urine. First, a high-fat and streptozotocin (STZ)-induced diabetic Sprague Dawley (SD) rat model was established. In the diabetic rat model, elevated fasting blood glucose, severely impaired glucose tolerance test, and increased reactive oxygen species (ROS) levels in serum and the liver were observed. Subsequently, 200 mg per kg body weight of LPOPC was administrated to control and diabetic SD rats, and the gastrointestinal tract was collected at 0.5 h, 1 h, 3 h, and 6 h. The results showed that the retention time of LPOPC was not changed in our diabetic rat model. However, the gut microbiota were significantly altered, with elevated Proteobacteria and Verrucomicrobia abundance in diabetic rats and decreased short chain fatty acid (SCFA)-producing bacteria. Interestingly, after one dose of 300 mg per kg body weight LPOPC, the total antioxidant capacity of urine in diabetic rats significantly decreased. We then tested the static metabolites of LPOPC, demonstrating that epicatechin had not changed in urine in diabetic rats, but that shikimic acid was significantly reduced in urine in diabetic rats. The changes in shikimic acid may be due to the alteration of gut microbiota and elevated ROS levels in serum.

Fabrication and characterization of whey protein isolates- lotus seedpod proanthocyanin conjugate: Its potential application in oxidizable emulsions.

Emulsified ω-3 polyunsaturated fatty acid have expanding application in different food matrix with improved water solubility while still prone to oxidation. Lotus seedpod proanthocyanidin (LSPC) was grafted to whey protein isolate (WPI) to create nature-derived antioxidant emulsifiers. 1HNMR, SDS-PAGE and multiple spectrometry showed that the structure of protein was changed after grafting. DPPH and FRAP measurements showed that WPI-LSPC conjugate (90.53 ± 1.48% of DPPH scavenging, 691.85 ± 4.54 µg/mL for FRAP assay) possessed a much better antioxidant ability than WPI (17.06 ± 3.34% of DPPH scavenging, 10.43 ± 0.26 µg/mL for FRAP assay). Ultrasonic emulsification and DSC experiments showed that WPI-LSPC conjugate were more effective at forming and stabilizing the flaxseed oil emulsions than pure WPI, with higher thermostability. Likewise, low levels of primary and secondary oxidation products were formed for the conjugate than the pure protein in O/W systems after storage, again suggesting WPI-LSPC could be used as fine antioxidant emulsifiers in oxidizing delivery systems.

Flavonoid compounds and antibacterial mechanisms of different parts of white guava (Psidium guajava L. cv. Pearl).

The flavonoid compositions, extracted from leaves, peel and flesh of white guava (Psidium guajava L. cv. Pearl), were identified and quantified by UPLC-ESI-QTOF-MS, HPLC-ESI-MS/MS and HPLC. The main components of three extracts all were quercetin-glycosides, but the proportion and content of quercetin-hexoside and quercetin-pentoside in each extract were different. Based on the measurements of MIC, MBC value and time killing curve, it emerged that 3 flavonoid extracts of white guava had good antibacterial effects on four pathogenic bacteria. White guava leaves flavonoids (WGLF) concentrations of 5.00 mg/mL and 0.625 mg/mL could change the micro-morphology of Escherichia coli and Staphylococcus aureus. It suggested that the antibacterial mechanism of WGLF on gram-positive and gram-negative bacteria was to destroy the structure and function of the cell membrane. It is indicated that the flavonoid extracts from white guava is a potential natural antimicrobial agent.

Potential TSPO Ligand and Photooxidation Quencher Isorenieratene from Arctic Ocean Rhodococcus sp. B7740.

Due to its special aromatic structure, isorenieratene is thought to be an active natural antioxidant and photo/UV damage inhibitor. In this work, isorenieratene that was extracted from Rhodococcus sp. B7740 isolated from the Arctic Ocean, showed excellent scavenging ability of both singlet oxygen and hydroxyl radical in the UVB-induced auto-oxidation process using the EPR method. Within an ARPE-19 cell model damaged by UVB radiation, isorenieratene showed fine protective effects (1.13 ± 0.03 fold) compared with macular xanthophylls (MXs) through upregulating of tspo. The molecular docking was firstly performed to investigate the interaction of isorenieratene with TSPO as a special ligand. Results showed isorenieratene might form a better binding conformation (S-score -8.5438) than MXs and indicate that isorenieratene not only can function as a direct antioxidant but also activate tspo in ARPE-19 cells. Thus, isorenieratene might ease the UV-related damages including age-related macular degeneration (AMD).

Oligomer Procyanidins from Lotus Seedpod Regulate Lipid Homeostasis Partially by Modifying Fat Emulsification and Digestion.

Dietary polyphenols have shown hypolipidemic effects by reducing triglyceride absorption. The mechanisms may involve modifying fat emulsion during digestion in the gastrointestinal tract and suppressing lipase during hydrolysis in the small intestine. In an in vivo study, lotus seedpod oligomeric procyanidin (LSOPC) decreased total serum triglyceride and total cholesterol and elevated the high-density lipoprotein level in the hyperlipidemic rat model. In addition, LSOPC suppressed de novo lipogenesis-related gene expressions. In an in vitro study, the LSOPC-enriched emulsion decreased the mean droplet size from 0.36 to 0.33 µm and increased the viscosity of the emulsion. Moreover, the LSOPC-enriched emulsion improved the antioxidant properties. A digestion model was developed and showed that the particle size of the LSOPC-enriched emulsion increased in the oral cavity. However, an increase and then a significant drop of the particle size was measured in the stomach and small intestine. The free fatty acid release rate was decreased in the LSOPC-enriched emulsion partly ascribed to the inhibition of lipase by LSOPC.

Interaction between carboxymethyl pachyman and lotus seedpod oligomeric procyanidins with superior synergistic antibacterial activity.

The inhibitory effect of carboxymethyl pachyman (CMP) mixed with lotus seedpod oligomeric procyanidins (LSPC) in certain ratios against E. coli 10899 was determined. Added low concentration of LSPC could improve the antibacterial activity of CMP, and a significant synergistic effect could be observed between them, especially when the concentration of CMP was below its critical concentration (1.35 mg/mL). Then, the interaction between CMP and LSPC was characterized after mixing; the changes in spectral characteristics, thermal properties, crystallinity pattern, molecular weight, chain morphology and microrheological behaviour explained the influence of interaction on the structure of CMP and LSPC. The smaller molecular size, electrostatic interaction and stronger hydrophobic interaction might play important roles in improving the antibacterial activity of mixture. The dissociation constant (Kd) was determined to be 0.102±0.0008 mg/mL using MicroScale Thermophoresis (MST), and the micromorphology was observed by SEM. Therefore, this mixture might be an effective natural bacteriostat.

Characterization of MK8(H2) from Rhodococcus sp. B7740 and Its Potential Antiglycation Capacity Measurements.

Menaquinone (MK) has an important role in human metabolism as an essential vitamin (VK2), which is mainly produced through the fermentation of microorganisms. MK8(H2) was identified to be the main menaquinone from Rhodococcus sp. B7740, a bacterium isolated from the arctic ocean. In this work, MK8(H2) (purity: 99.75%) was collected through a convenient and economic extraction process followed by high-speed countercurrent chromatography (HSCCC) purification. Additionally, high-resolution mass spectrometry (HRMS) was performed for further identification and the hydrogenation position of MK8(H2) (terminal unit) was determined using nuclear magnetic resonance (NMR) for the first time. MK8(H2) showed a superior antioxidant effect and antiglycation capacity compared with ubiquinone Q10 and MK4. High-performance liquid chromatography⁻mass spectrometer (HPLC-MS/MS) and molecular docking showed the fine interaction between MK8(H2) with methylglyoxal (MGO) and bull serum albumin (BSA), respectively. These properties make MK8(H2) a promising natural active ingredient with future food and medicine applications.

(-)-Epigallocatechin-3-gallate (EGCG) inhibits starch digestion and improves glucose homeostasis through direct or indirect activation of PXR/CAR-mediated phase II metabolism in diabetic mice.

As a major component of green tea, (-)-epigallocatechin-3-gallate (EGCG) has attracted interest from scientists owing to its potential to combat a variety of human diseases including abnormal glucose metabolism in obesity and diabetes. This study aims to (1) evaluate the molecular mechanism of EGCG in starch digestion before EGCG absorption; (2) investigate the link between PXR/CAR-mediated phase II metabolism and glucose homeostasis after EGCG is transported to small intestine and liver. EGCG suppressed starch hydrolysis both in vitro and in vivo. Molecular simulation results demonstrated that EGCG could bind to the active site of α-amylase and α-glucosidase, acting as an inhibitor. In addition, the anti-diabetic action of EGCG was investigated in high fat diet and STZ-induced type 2 diabetes. EGCG improved glucose homeostasis and inhibited the process of gluconeogenesis (PEPCK and G-6-Pase) and lipogenesis (SREBP-1C, FAS and ACC1) in the liver. Meanwhile, EGCG treatment activated PXR/CAR, accompanied by upgrading PXR/CAR-mediated phase II drug metabolism enzyme expression in small intestine and liver, involving SULT1A1, UGT1A1 and SULT2B1b. Dietary polyphenol EGCG could serve as a promising PXR/CAR activator and therapeutic intervention in diabetes.

Attenuated mTOR Signaling and Enhanced Glucose Homeostasis by Dietary Supplementation with Lotus Seedpod Oligomeric Procyanidins in Streptozotocin (STZ)-Induced Diabetic Mice.

This study investigated the protective role of lotus seedpod oligomeric procyanidins (LSOPC) and synbiotics (Bifidobacterium Bb-12 and xylo-oligosaccharide) against high fat and streptozotocin (STZ)-induced diabetes. Administration of LSOPC or synbiotics had no effect on blood glucose in normal mice. Treatments with LSOPC for 12 weeks markedly reduced blood glucose, FFA, endotoxin, and GHbA1c and improved glucose homeostasis, lipid metabolism, and insulin levels. In addition, administration of LSOPC significantly reversed the increase of mTOR and p66Shc in liver, skeletal muscle, and white adipose tissue (WAT). LSOPC significantly increased glucose uptake and glycolysis in liver, skeletal muscle, and WAT while improving heat generation in brown adipose tissue (BAT) and inhibiting gluconeogenesis and lipogenesis in liver. Furthermore, synbiotics strengthened the improving effect of LSOPC. These findings demonstrated that LSOPC and synbiotics may regulate glucose disposal in peripheral target tissues through the p66Shc-mTOR signaling pathway.

Separation and Identification of Anthocyanins Extracted from Blueberry Wine Lees and Pigment Binding Properties toward ß-Glucosidase.

Anthocyanins were isolated from blueberry wine lees using Sephadex LH-20 column chromatography and semipreparative high-performance liquid chromatography (semipreparative HPLC) and then identified by HPLC-DAD-ESI-MS/MS. Our results show that malvidin-3-hexose (Mv-3-hex) and malvidin-3-(6'acetyl)-hexose (Mv-3-ace-hex) are the major components in the anthocyanin extracts of blueberry wine lees (>90%). The binding characteristics of Mv-3-hex and Mv-3-ace-hex with ß-glucosidase were investigated by fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular docking. Spectroscopic analysis revealed that ß-glucosidase fluorescence quenched by Mv-3-hex and Mv-3-ace-hex follows a static mode. Binding of Mv-3-hex and Mv-3-ace-hex to ß-glucosidase mainly depends on electrostatic force. The result from CD spectra shows that adaptive structure rearrangement and increase of ß-sheet structure occur only in the presence of Mv-3-ace-hex. A molecular docking study suggests that Mv-3-ace-hex has stronger binding with ß-glucosidase than Mv-3-hex.

Characterization and preparation of oligomeric procyanidins from Litchi chinensis pericarp.

The main purpose of this study is to characterize and prepare A-type oligomeric procyanidins from litchi pericarp (Litchi chinensis Baila). The variety of oligomeric procyanidins was characterized by LC-ESI-MS analysis. There were (+)-catechin, (-)-epicatechin, twelve dimers and six trimers of procyanidins were found in litchi pericarp extracts, and A-type procyanidins were much more abundant than B-type procyanidins. The main flavan-3-ol monomer and oligomeric procyanidins in litchi pericarp were (-)-epicatechin, A-type dimers (A1 and A2) and trimer (epicatechin-(4ß-8, 2ß-O-7)-epicatechin- (4ß-8)-epicatechin). Procyanidin A1 (epicatechin-(4ß-8, 2ß-O-7)-catechin) was identified by NMR in litchi pericarp for the first time. (-)-Epicatechin and oligomeric procyanidins were prepared by the combination of AB-8 column chromatography and Toyopearl HW-40S column chromatography. The results showed that each fraction predominantly owned a single compound and gave a high yield with (-)-epicatechin, A-type dimers (A1 and A2) and trimer, suggesting a useful method to obtain pure (-)-epicatechin and A-type oligomeric procyanidins.

Ameliorative effect of lotus seedpod proanthocyanidins on cognitive impairment and brain aging induced by D-galactose.

This study mainly investigated the ameliorative effect of lotus seedpod proanthocyanidins (LSPC) and the mechanism underlying such effect on cognitive impairment and brain aging induced by d-galactose. Aging mice induced by d-galactose (150 mg/kg, sc injection daily for 6 weeks) were chosen for the experiment. LSPCs (30, 60, and 90 mg/kg, ig) were provided after d-galactose injection. Learning and memory functions were detected by Y-maze and step-down avoidance tests. Then, some biochemical indexes related to cognitive ability and aging were measured. Histopathological feature and P53 protein expression in the hippocampus were observed. Results showed that the three different doses of LSPC could significantly ameliorate the learning and memory abilities impaired by d-galactose. LSPC significantly reduced the levels of malondialdehyde and nitric oxide (i.e. 90 mg/kg LSPC group vs. model group, P=0.008), reduced the content of ß-amyloid peptide 1-42 (i.e. 90 mg/kg LSPC group vs. model group, P=0.009), decreased the activities of acetylcholinesterase, monoamine oxidase B, total nitric oxide synthase (i.e. 90 mg/kg LSPC group vs. model group, P=0.006), and neuronal nitric oxide synthase and synchronously increased the activities of superoxide dismutase and glutathione peroxidase in the brain. Furthermore, LSPC could prevent neuron damage and could lessen the expression of P53 protein in the hippocampus. These findings demonstrated that LSPC effectively attenuated cognitive damage and improved parameters related to brain aging in senescent mice induced by d-galactose, and may be used to treat Alzheimer's disease.

Inhibition of Advanced Glycation Endproduct Formation by Lotus Seedpod Oligomeric Procyanidins through RAGE-MAPK Signaling and NF-κB Activation in High-Fat-Diet Rats.

This study investigated the protective properties of lotus seedpod oligomeric procyanidins (LSOPC) against nonalcoholic fatty liver disease (NAFLD) and its underlying mechanism. Sprague-Dawley (SD) male rats were fed a basic diet, a high-fat diet (HFD), or HFD plus 0.2 or 0.5% (w/w) LSOPC for 12 weeks. Administration of LSOPC markedly reduced serum and hepatic biochemical parameters and protein expression of advanced glycation endproducts (AGEs). Additionally, 0.5% (w/w) LSOPC treatment remarkably reversed the increasing tendency of receptor of advanced glycation endproduct (RAGE) to normal level. Furthermore, dietary LSOPC significantly decreased the protein levels of mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) and down-regulated genes involved in pro-inflammatory cytokines and adhesion molecules. Taken together, these findings demonstrate that LSOPC may protect obese rats with long-term HFD-induced NAFLD against RAGE-MAPK-NF-κB signaling suppression.

Lactobacillus casei-01 facilitates the ameliorative effects of proanthocyanidins extracted from lotus seedpod on learning and memory impairment in scopolamine-induced amnesia mice.

Learning and memory abilities are associated with alterations in gut function. The two-way proanthocyanidins-microbiota interaction in vivo enhances the physiological activities of proanthocyanidins and promotes the regulation of gut function. Proanthocyanidins extracted from lotus seedpod (LSPC) have shown the memory-enhancing ability. However, there has been no literature about whether Lactobacillus casei-01 (LC) enhances the ameliorative effects of LSPC on learning and memory abilities. In this study, learning and memory abilities of scopolamine-induced amnesia mice were evaluated by Y-maze test after 20-day administration of LC (10(9) cfu/kg body weight (BW)), LSPC (low dose was 60 mg/kg BW (L-LSPC) and high dose was 90 mg/kg BW (H-LSPC)), or LSPC and LC combinations (L-LSPC+LC and H-LSPC+LC). Alterations in antioxidant defense ability and oxidative damage of brain, serum and colon, and brain cholinergic system were investigated as the possible mechanisms. As a result, the error times of H-LSPC+LC group were reduced by 41.59% and 68.75% relative to those of H-LSPC and LC groups respectively. LSPC and LC combinations ameliorated scopolamine-induced memory impairment by improving total antioxidant capacity (TAOC) level, glutathione peroxidase (GSH-Px) and total superoxide dismutase (T-SOD) activities of brain, serum and colon, suppressing malondialdehyde (MDA) level of brain, serum and colon, and inhibiting brain acetylcholinesterase (AchE), myeloperoxidase, total nitric oxide synthase and neural nitric oxide synthase (nNOS) activities, and nNOS mRNA level. Moreover, LC facilitated the ameliorative effects of H-LSPC on GSH-Px activity of colon, TAOC level, GSH-Px activity and ratio of T-SOD to MDA of brain and serum, and the inhibitory effects of H-LSPC on serum MDA level, brain nNOS mRNA level and AchE activity. These results indicated that LC promoted the memory-enhancing effect of LSPC in scopolamine-induced amnesia mice.

A significant inhibitory effect on advanced glycation end product formation by catechin as the major metabolite of lotus seedpod oligomeric procyanidins.

Several lines of evidence suggested that B-type procyanidin oligomers from lotus seedpod (LSOPC) may effectively modulate the formation of advanced glycation end products (AGEs). In vivo, LSOPC is metabolized by intestinal flora to become various kinds of phenolic compounds that possess potent antioxidant activities. However, few reports of the absorption and metabolism of LSOPC have been revealed. In the present study, rats were orally administered with LSOPC at a dose of 300 mg/kg body weight. The metabolites of LSOPC in urine were elucidated by HPLC-MS/MS analysis 24 h post-administration. Eight major metabolites were significantly increased by the administration of 300 mg/kg of LSOPC (p < 0.01). The anti-glycative activity of LSOPC and its metabolites were investigated. The results showed that LSOPC and catechin had greater anti-glycative activities than other metabolites, which were positively correlated to their carbonyl scavenging activities and antioxidant capacities.

Oligomeric procyanidins of lotus seedpod inhibits the formation of advanced glycation end-products by scavenging reactive carbonyls.

It has been reported that oligomeric procyanidins of lotus seedpod (LSOPC) is effective in the alleviation of Alzheimer's disease and diabetes through its antioxidant and insulin-potentiating activities. This study investigated the anti-glycative activity of LSOPC in a bovine serum albumin (BSA)-glucose model. The level of glycation and conformational alterations were assessed by specific fluorescence, Congo red binding assay and circular dichroism. The results show that LSOPC has a significant anti-glycative activity in vitro and it can also effectively protect the secondary structure of BSA during glycation. LSOPC or catechin (a major constituent unit of LSOPC), were used to react with methylglyoxal. The structures of their carbonyl adducts were tentatively identified using HPLC-MS(2). Their capacity to scavenge methylglyoxal suggested carbonyl scavenging as a major mechanism of antiglycation. Therefore, LSOPC could be helpful to prevent AGEs-associated diseases, and with the potential to be used as functional food ingredients.

Absorption and urinary excretion of A-type procyanidin oligomers from Litchi chinensis pericarp in rats by selected ion monitoring liquid chromatography-mass spectrometry.

Intervention studies with A-type oligomeric procyanidins from litchi (Litchi chinensis) pericarp (LPOPC) suggested its protective effect against cardiovascular diseases. However, there is no consensus on the absorption and metabolism of LPOPC. It was demonstrated that the main components in LPOPC were (-)-epicatechin, A-type procyanidin dimers, trimers and tetramers. Rats were orally administered different levels of LPOPC (150 and 300 mg/kgbw), the procyanidins and their microbial metabolites in urine were identified by HPLC-MS/MS analysis 18 h post-administration. Data indicated that seven aromatic acid metabolites excreted were significantly increased by 300 mg/kgbw of LPOPC (P<0.01). However, only (-)-epicatechin and its methylated derivatives were detected in rat plasma 1h after 300 mg/kgbw of LPOPC administration. The total EC content absorbed in plasma was only 2.54 ± 0.53 µmol/L, indicating that the biological properties of LPOPC should be probably explained by its microbial degraded phenolic acids.

Increasing antioxidant activity of procyanidin extracts from the pericarp of Litchi chinensis processing waste by two probiotic bacteria bioconversions.

Litchi chinensis pericarp from litchi processing waste is an important plant source of A-type procyanidins, which were considered a natural dietary supplement because of their high biological activity in vivo. Litchi pericarp oligomeric procyanidins (LPOPCs) did not selectively modify the growth of Streptococcus thermophilus and Lactobacillus casei -01 at concentrations of 0.25 and 0.5 mg/mL, and it was demonstrated that the two strains could transform procyanidins during their log period of growth by two different pathways. S. thermophilus was able to metabolize procyanidin A2 to its isomer, and L. casei could decompose flavan-3-ols into 3,4-hydroxyphenylacetic acid, 4-hydroxyphenylpropionic acid, m-coumaric acid, and p-coumaric acid. The total antioxidant capability (T-AOC) of LPOPCs before and after microbial incubation was estimated, and the results suggested that probiotic bacteria bioconversion is a feasible and efficient method to convert litchi pericarp procyanidins to a more effective antioxidant agent.

Characterization of oligomeric procyanidins and identification of quercetin glucuronide from lotus ( Nelumbo nucifera Gaertn.) seedpod.

Procyanidins are a class of polyphenols in the plant kingdom. Lotus ( Nelumbo nucifera Gaertn.) seedpods, the inedible part of lotus and a byproduct during the production of lotus seeds, were found to be a new source rich in procyanidins. Detailed information about oligomeric procyanidins in lotus seedpods remains unknown. In this study, lotus seedpods were extracted using 60% aqueous methanol and characterized with phloroglucinolysis and liquid chromatography (mass spectrometry with an electrospray ionization source). The results indicate that the oligomeric and polymeric fraction had a mean degree of polymerization of 3.2 and 15.4, respectively, and consisted of (+)-catechin (m/z 289), gallocatechin or epigallocatechin (m/z 305), quercetin glycoside (m/z 463), quercetin glucuronide (m/z 477), procyanidin dimers (m/z 577.1), proanthocyanidin dimer gallate (m/z 593.3), prodelphinidin dimers (m/z 609.1), procyanidin trimers (m/z 865.1), etc. Quercetin glucuronide was further purified using flash chromatography and identified as quercetin-3-O-ß-glucuronide by determining its exact mass using ion-trap time-of-flight mass spectrometry and ¹H and ¹³C nuclear magnetic resonance, ¹H-detected heteronuclear single-quantum coherence, and ¹H-detected heteronuclear multiple-bond correlation analyses.

Memory impairment in cognitively impaired aged rats associated with decreased hippocampal CREB phosphorylation: reversal by procyanidins extracted from the lotus seedpod.

The major purpose of this study was to determine the effects of procyanidins extracted from the lotus seedpod on cAMP-response element-binding protein phosphorylation in hippocampus and cerebral cortex in cognitively impaired aged rats. Based on Morris water maze, aged unimpaired and aged impaired rats were chosen from aged rats. Comparing with young and aged unimpaired animals, aged impaired rats exhibited significant reduction in hippocampal but not cortical cAMP-response element-binding phosphorylation states as well as brain-derived neurotrophic factor messenger RNA and protein expressions, which were accompanied by decreased phosphorylation states of hippocampal extracellular signal-related kinase (42/44) and calcium calmodulin kinase IV. Lotus seedpod supplementation (50 and 100 mg/kg body weight intragastric administration) for 7 weeks significantly reversed all these declines happened in hippocampus except calcium calmodulin kinase IV phosphorylation levels. These results suggested that lotus seedpod might enhance cAMP-response element-binding-dependent transcription through the activation of extracellular signal-related kinase signalling pathway, which might contribute to its ameliorative effects on cognitive deficits in aged impaired animals.