Stability of Enzyme-Modified Flavonoid C- and O-Glycosides from Common Buckwheat Sprout Extracts during In Vitro Digestion and Colonic Fermentation.

Common buckwheat sprout (CBS) contains more flavone C-glycosides (FCGs) and flavonol O-glycosides (FOGs) than does common buckwheat seed. Both flavonoids in CBS are well known for providing benefits to human health. However, they are relatively less bioaccessible and more directly degradable to aglycone during digestion than are multiglycosylated flavonoids. To overcome such limitations, the water solubility and digestion stability of FCGs and FOGs were enhanced by transglycosylation using cyclodextrin glycosyltransferase. Gastric conditions had little effect on the stability of FCGs and FOGs and their enzyme-modified compounds. In contrast, under intestinal conditions, transglycosylated FCGs lost a glucose moiety and reverted to their parent compounds before transglycosylation. Under colonic fermentation using human fecal samples, the different profiles and concentrations of short-chain fatty acids were suggested to be mainly due to the presence of transglycosylated FCGs and FOGs. These findings indicate that the process of transglycosylation changes the bioaccessibility of flavonoids in CBS.

Rose Petal Extract (Rosa gallica) Exerts Skin Whitening and Anti-Skin Wrinkle Effects.

We sought to investigate the effect of extracts from Rosa gallica petals (RPE) on skin whitening and anti-wrinkle activity. Tyrosinase activity was attenuated by RPE treatment, concomitant with the reduction of melanin accumulation in human B16F10 melanoma. Treatment of the facial skin of volunteers in a clinical trial with an RPE-containing formulation enhanced skin brightness (L* value) significantly. The underlying mechanism responsible was determined to be associated with mitogen-activated protein kinase (MAPK) activation. In addition, RPE exhibited anti-wrinkle formation activity of human dermal fibroblasts by suppressing matrix metalloproteinase (MMP)-1 level. In vivo study, RPE also inhibited solar ultraviolet-stimulated MMP-1 level by c-Jun regulation. Overall, our findings indicate that RPE evokes skin whitening and anti-wrinkle formation activity by regulating intracellular signaling, supporting its utility as an ingredient for skin whitening and anti-wrinkle cosmetic products.

pH-adjusted solvent extraction and reversed-phase HPLC quantification of isoflavones from soybean (Glycine max (L.) Merr.).

Soybeans, Glycine max (L.) Merr., are among the most important food crops worldwide. Isoflavones are major bioactive phytochemicals in soybeans, and have a variety of health benefits, including antioxidative, antiatherosclerotic, antiinflammatory, and weak estrogen-like effects. The isoflavone content and composition of soybeans vary according to the cultivar and the extraction solvent conditions. Therefore, we investigated the effects of three different solvent pHs (1.0, 5.5, and 10.0) on the isoflavone, total phenolic, and total flavonoid contents and antioxidant capacities of eight soybean cultivars developed in Korea. Twelve isoflavones in soybeans were efficiently separated and identified on a reversed-phase high-performance liquid chromatography (HPLC) system. The percentage distribution of isoflavones measured by HPLC in the eight soybean cultivars at various extraction pHs decreased as follows: malonyl isoflavones (67.2% to 81.3%) > isoflavone glucosides (16.2% to 29.0%; as nonacylated form) > acetyl isoflavones (1.6% to 5.9%). The highest contents of isoflavone glucosides, malonyl derivatives, and acetyl derivatives were extracted at solvent pHs of 10.0, 1.0, and 5.5, respectively. The solvent extraction at pH 1.0 yielded a lower total isoflavone content than those at pHs 5.5 and 10.0. However, the highest total phenolic and flavonoid contents were extracted from soybeans at pH 1.0. Soybeans extracted at pH 10.0 displayed the highest antioxidant capacities in the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical assay. Taken together, these results suggest that proper solvent pH adjustment is needed to maximize the extraction of targeted forms of isoflavones from soybeans. PRACTICAL APPLICATION: Soybeans contain a variety of bioactive compounds, including isoflavones, which function as antioxidants and weak phytoestrogens. Chemical and instrumental analyses can facilitate the selection of soybean cultivars with high amounts of isoflavones for soybean breeding and isoflavone-enriched product development. Proper solvent pH adjustment allows for the efficient extraction of high amounts of targeted isoflavone subgroups (acetyl and malonyl forms) from soybeans for functional food products.

Enrichment of Polyglucosylated Isoflavones from Soybean Isoflavone Aglycones Using Optimized Amylosucrase Transglycosylation.

Isoflavones in soybeans are well-known phytoestrogens. Soy isoflavones present in conjugated forms are converted to aglycone forms during processing and storage. Isoflavone aglycones (IFAs) of soybeans in human diets have poor solubility in water, resulting in low bioavailability and bioactivity. Enzyme-mediated glycosylation is an efficient and environmentally friendly way to modify the physicochemical properties of soy IFAs. In this study, we determined the optimal reaction conditions for Deinococcus geothermalis amylosucrase-mediated α-1,4 glycosylation of IFA-rich soybean extract to improve the bioaccessibility of IFAs. The conversion yields of soy IFAs were in decreasing order as follows: genistein > daidzein > glycitein. An enzyme quantity of 5 U and donor:acceptor ratios of 1000:1 (glycitein) and 400:1 (daidzein and genistein) resulted in high conversion yield (average 95.7%). These optimal reaction conditions for transglycosylation can be used to obtain transglycosylated IFA-rich functional ingredients from soybeans.

Optimizing the ultrasound-assisted deep eutectic solvent extraction of flavonoids in common buckwheat sprouts.

In this study, deep eutectic solvents (DESs) coupled with ultrasound-assisted extraction (UAE) were evaluated and optimized for the extraction of major flavonoids from common buckwheat sprouts. Initially, 18 different choline chloride (CC)-based DESs were evaluated as potential extraction solvents, and 80% CCTG (CC-based DES composed of triethylene glycol and 20 vol% water) extracted significantly higher (p < 0.05) amounts of flavonoids than other DESs studied. The extraction efficiency of 80% CCTG was even higher (p < 0.05) than that of methanol for the extraction of vitexin and quercetin-3-O-robinobioside. Procedure using 80% CCTG and UAE were optimized; an extraction temperature of 56 °C and extraction time of 40 min were considered optimal. The optimized extraction procedure was reliable and efficient for the extraction of major flavonoids from common buckwheat sprouts. In addition, flavonoids could be efficiently recovered from DES extracts with high recovery yields (>97%) by using a C18 solid-phase extraction.

Dispersive liquid-liquid microextraction with in situ derivatization coupled with gas chromatography and mass spectrometry for the determination of 4-methylimidazole in red ginseng products containing caramel colors.

A rapid analytical method was developed for the determination of 4-methylimidazole from red ginseng products containing caramel colors by using dispersive liquid-liquid microextraction with in situ derivatization followed by gas chromatography with mass spectrometry. Chloroform and acetonitrile were selected as the extraction and dispersive solvents, and based on the extraction efficiency, their optimum volumes were 200 and 100 µL, respectively. The optimum volumes of the derivatizing agent (isobutyl chloroformate) and catalyst (pyridine), pH, and concentration of NaCl in the sample solution were determined to be 25 and 100 µL, pH 7.6, and 0% w/v, respectively. Validation of the optimized method showed good linearity (R2  > 0.999), accuracy (≥89.86%), intra- (≤6.70%) and interday (≤4.17%) repeatability, limit of detection (0.96 µg/L), and limit of quantification (5.79 µg/L). The validated method was applied to quantify 4-methylimidazole in red ginseng juices and concentrates, 4-methylimidazole was only found in red ginseng juices containing caramel colorant (42.91-2863.4 µg/L) and detected in red ginseng concentrates containing >1% caramel colorant.

Welsh onion extract inhibits PCSK9 expression contributing to the maintenance of the LDLR level under lipid depletion conditions of HepG2 cells.

Statins mediate the transactivation of PCSK9, which in turn limits their cholesterol-lowering effects via LDL receptor (LDLR) degradation. The objective of the present study was to investigate the mechanism of action by which Welsh onion (Allium fistulosum L. [family Amaryllidaceae]) extract (WOE) regulates LDLR and PCSK9. HepG2 cells were cultured under lipid depletion conditions using a medium supplemented with delipidated serum (DLPS). WOE (50, 100, 200, and 400 µg ml-1) significantly attenuated the DLPS-mediated increases in LDLR, PCSK9, and SREBP2 gene expression. While WOE treatment maintained the DLPS-mediated increases in LDLR protein expression, it dose-dependently and significantly attenuated the DLPS-mediated increases in the protein content of PCSK9. The suppression of PCSK9 was associated with the WOE-mediated reductions in SREBP2, but not HNF1α. WOE also dose-dependently reduced PCSK9 protein expression that was otherwise markedly induced by concomitant statin treatment. WOE-mediated PCSK9 inhibition contributed to LDLR lysosomal degradation suppression, and subsequent LDLR protein stabilization. HPLC analysis indicated that WOE contains kaempferol, quercetin, ferulic acid, and p-coumaric acid. Kaempferol and p-coumaric acid contributed to the maintenance of LDLR expression by inhibiting PCSK9 in lipid depleted HepG2 cells. Altogether, these findings suggest that WOE inhibits PCSK9 transcription and protein expression via the reduction of SREBP2, and decreased PCSK9 further contributes to LDLR degradation prevention and LDLR protein stabilization under conditions of lipoprotein deficiency. The PCSK9 inhibition-mediated mechanism of WOE was likely attributed to the action of kaempferol and p-coumaric acid present in WOE.

Comparison of Anti-Inflammatory Effects of Flavonoid-Rich Common and Tartary Buckwheat Sprout Extracts in Lipopolysaccharide-Stimulated RAW 264.7 and Peritoneal Macrophages.

Buckwheat sprouts have been widely consumed all around world due to their great abundance of bioactive compounds. In this study, the anti-inflammatory effects of flavonoid-rich common buckwheat sprout (CBS) and tartary buckwheat sprout (TBS) extracts were evaluated in lipopolysaccharide- (LPS-) stimulated RAW 264.7 murine macrophages and primary peritoneal macrophages from male BALB/c mice. Based on the reversed-phase HPLC analysis, the major flavonoids in CBS were determined to be C-glycosylflavones (orientin, isoorientin, vitexin, and isovitexin), quercetin-3-O-robinobioside, and rutin, whereas TBS contained only high amounts of rutin. The TBS extract exhibited higher inhibitory activity as assessed by the production of proinflammatory mediators such as nitric oxide and cytokines including tumor necrosis factor-α, interleukin- (IL-) 6, and IL-12 in LPS-stimulated RAW 264.7 macrophages than CBS extract. In addition, TBS extract suppressed nuclear factor-kappa B activation by preventing inhibitor kappa B-alpha degradation and mitogen-activated protein kinase phosphorylation in LPS-stimulated RAW 264.7 macrophages. Moreover, the TBS extract markedly reduced LPS-induced cytokine production in peritoneal macrophages. Taken together, these findings suggest that TBS extract can be a potential source of anti-inflammatory agents that may influence macrophage-mediated inflammatory disorders.

Rhus verniciflua Stokes Extract and Its Flavonoids Protect PC-12 Cells against H2O2-Induced Cytotoxicity.

Rhus verniciflua Stokes (RVS), an herbal medicine found in East Asia, was extracted and further fractionated to investigate its antioxidant capacity and neuroprotective effects. The RVS ethyl acetate (EtOAc) fraction had the highest level of total phenolics and antioxidant capacity among all solvent fractions tested. Pretreatment of PC-12 cells with the EtOAc fraction effectively attenuated H2O2-induced oxidative damage. Furthermore, the EtOAc fraction significantly attenuated caspase-3 activity, resulting in inhibition of H2O2-induced apoptosis. We identified and quantified fustin, sulfuretin, and butein in the EtOAc fraction using accurate mass quadrupole time-of-flight mass spectrometry and reversed-phase high-performance liquid chromatography. The intracellular antioxidant capacity and superoxide dismutase (SOD) activity were significantly increased in PC-12 cells treated with the EtOAc fraction and with individual flavonoids. When cells were pretreated with the EtOAc fraction or individual flavonoids and then co-incubated with diethyldithiocarbamic acid (an inhibitor of SOD activity), cell viability against H2O2-induced oxidative stress was attenuated. These results suggest that the RVS EtOAc fraction and its flavonoid constituents protect PC-12 cells against H2O2-induced neurotoxicity through their antioxidant properties.

Estimated daily intake of phenolics and antioxidants from green tea consumption in the Korean diet.

To estimate daily intake of total phenolics and flavonoids from green tea and the contribution of green tea to the antioxidant intake from the Korean diet, 24 commercial brands of green tea were selected and analyzed. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 and 2011 indicate that the green tea consumption in these 2 years was 2.8 g/tea drinker/day and 2.9 g/tea drinker/day, respectively. Based on data derived from direct measurements of green tea phenolics and the dataset of the 2008 KNHANES, we estimated the daily per tea drinker phenolics intake to be 172 mg gallic acid equivalents (GAE), the total flavonoids to be 43 mg catechin equivalents (CE) and the total antioxidants to be 267 mg vitamin C equivalents (VCE; 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay) and 401 mg VCE (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay). In 2011, we estimated the daily per tea drinker total phenolics intake to be 246 mg GAE, the total flavonoids to be 60 mg CE and the antioxidants to be 448 mg VCE (DPPH assay) and 630 mg VCE (ABTS assay). The daily intake of total phenolics, total flavonoids and antioxidants from green tea consumption increased from 2008 to 2011.

Flavonoid analysis of buckwheat sprouts.

It is known that common buckwheat sprouts contain several flavonoids, including orientin, isoorientin, vitexin, isovitexin, rutin, and quercetrin, whereas tartary buckwheat sprouts contain only rutin. In this study, we evaluated flavonoids present in buckwheat sprouts and identified a previously unreported flavonoid. Simultaneous detection by HPLC was used to separate rutin and a compound that was not separated in previous studies. We used a novel HPLC elution gradient method to successfully separate rutin and the previously unidentified compound, for which we performed structural analysis. The identification of six flavonoids by HPLC was confirmed using HPLC-ESI-MS/MS analysis. The newly identified compound, [M+H](+) =611.17, was identified by NMR as the rutin epimer quercetin-3-O-robinobioside. Unlike common buckwheat sprout, tartary buckwheat sprout contained rutin as a main flavonoid, whereas other flavonoids appeared only in trace amounts or were not detected. Quercetin-3-O-robinobioside was not detected in tartary buckwheat sprout.

Polyphenol-rich blackcurrant extract prevents inflammation in diet-induced obese mice.

Obesity is closely associated with chronic, low-grade inflammation. We investigated if polyphenol-rich blackcurrant extract (BCE) can prevent inflammation in vivo. Male C57BL/6J mice were fed a modified AIN-93M control diet containing high fat/high cholesterol (16% fat, 0.25% cholesterol by weight) or the control diet supplemented with 0.1% BCE (wt/wt) for 12 weeks. In BCE-fed mice, the percentage of body weight and adipocyte size of the epididymal fat were significantly lower than those of control mice. There were fewer crown-like structures (CLS) with concomitant decreases in F4/80, cluster of differentiation 68 and inhibitor of nuclear factor κB kinase ε (IKKε) mRNA in the epididymal adipose of BCE-fed mice. F4/80 and IKKε mRNA levels were positively correlated with CLS number. In the skeletal muscle of mice fed with BCE, mRNA expression of genes involved in energy expenditure and mitochondrial biogenesis, including PPARα, PPARδ, UCP-2, UCP-3 and mitochondrial transcription factor A, were significantly increased. When splenocytes from BCE-fed mice were stimulated by lipopolysaccharides, tumor necrosis factor α and interleukin-1ß mRNA were significantly lower than control splenocytes. Together, the results suggest that BCE supplementation decreases obesity-induced inflammation in adipose tissue and splenocytes, at least in part, by modulating energy metabolism in skeletal muscle.

Effect of cinnamon water extract on monocyte-to-macrophage differentiation and scavenger receptor activity.

BACKGROUND: Water soluble cinnamon extract has been shown to increase insulin sensitivity and modulate macrophage activation, a desirable trait for the management of obesity or atherosclerosis. Our present study investigated whether cinnamon water extract (CWE) may influence the differentiation of monocytes into macrophages and the activity of macrophage scavenger receptors, commonly observed in atherosclerotic lesions. METHODS: We investigated the effect of CWE on the expression of various surface markers and the uptake of acetylated low density lipoprotein (LDL) in phorbol-12-myristate-13-acetate (PMA)-stimulated THP-1 cells. The protein levels of PMA or macrophage-colony stimulating factor (M-CSF)-stimulated type 1 macrophage scavenger receptor (SRA) were analyzed. Finally, the role of extracellar signal-related kinase (ERK) 1/2 in SRA synthesis and the effect of CWE on PMA-stimulated ERK1/2 were determined. RESULTS: CWE inhibited the differentiation of monocyte by decreasing the expression of CD11b, CD36 and SRA and the uptake of acetyl LDL. CWE suppressed the upregulation of SRA by M-CSF and modulated ERK1/2 activity, which was required for PMA-induced SRA synthesis. CONCLUSIONS: Our results demonstrate that CWE was able to interfere with monocyte differentiation and macrophage scavenger activity, indicating its potential in preventing the development of atherosclerotic lesions.

Flavonoids from the grains of C1/R-S transgenic rice, the transgenic Oryza sativa spp. japonica, and their radical scavenging activities.

The transgenic rice cultivar of Oryza sativa spp. japonica cv. Hwa-Young, C1/R-S transgenic rice (C1/R-S rice), is a flavonoid-rich cultivar of rice. The grains of C1/R-S rice were extracted with aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH, and H2O, successively. Repeated silica gel, octadecyl silica gel (ODS), and Sephadex LH-20 column chromatographies for the EtOAc and n-BuOH fractions afforded four new flavonoids (compounds 2, 3, 7, and 8) along with four known flavonoids: (+)-3'-O-methyltaxifolin (1), brassicin (4), isorhamnetin-4'-O-ß-D-glucosyranoside (5), and 3'-O-methyltaxifolin-5-O-ß-D-glucopyranoside (6). The new flavonoids were identified as 3'-O-methyltaxifolin-7-O-ß-D-glucopyranoside (2), 3'-O-methyltaxifolin-4'-O-ß-D-glucopyranoside (3), isorhamnetin-7-O-ß-D-cellobioside (brassicin-4″-O-ß-D-glucopyranoside) (7), and brassicin-4'-O-ß-D-glucosyranoside (8) from the result of spectroscopic data including nuclear magnetic resonance spectrometry (NMR), mass spectrometry (MS), and infrared spectroscopy (IR). Also, quantitative analysis of major flavonoids (compounds 2, 3, and 8) in C1/R-S rice, O. sativa spp. japonica cv. Hwa-Young (HY), and a hybrid of two cultivar (C1/R-S rice/HY) extracts was performed using HPLC experiment. The isolated flavonoids were evaluated for their radical-scavenging effect on DPPH and ABTS radicals.

Protective effect of detoxified Rhus verniciflua stokes on human keratinocytes and dermal fibroblasts against oxidative stress and identification of the bioactive phenolics.

Oxidative stress due to the over-production of reactive oxygen species (ROS) is associated with human skin aging. This study was designed to identify the bioactive phenolics in detoxified Rhus verniciflua Stokes (DRVS) that may protect human skin against oxidative stress. Under oxidative stress caused by H2O2, the 40% (v/v) aqueous methanol extract of DRVS protected human keratinocytes in a dose-dependent manner. The expression of matrix metalloproteinase-1 (MMP-1) was also inhibited by the DRVS extract in human dermal fibroblasts-neonatal cells exposed to ultraviolet A. The major bioactive phenolics of DRVS were tentatively identified by LC/Q-TOF-ESI-MS/MS, and included gallic acid, 2-(ethoxymethoxy)-3-hydroxyphenol, fustin, a fustin isomer, tetragalloyl glucose, pentagalloyl glucose, fisetin, sulfuretin, a sulfuretin isomer, and butein. The results suggest that a DRVS extract may be effective in slowing skin aging through its antioxidative properties and by down-regulating MMP-1 expression. Further studies are needed to examine whether this effect would be mediated by the phenolics identified in this study.

Anthocyanins in the ripe fruits of Rubus coreanus Miquel and their protective effect on neuronal PC-12 cells.

Phenolics of the fresh ripe fruits of Rubus coreanus Miquel were extracted and separated into anthocyanin and the non-anthocyanin fractions, which were used for the evaluation for antioxidant capacity and neuroprotective effects. The anthocyanin fraction accounted for approximately 47-55% of the total antioxidant capacity of the whole extract and had significantly higher free radical-scavenging capacity than the non-anthocyanin fraction. Furthermore, the anthocyanins alleviated intracellular oxidative stress, as assayed by in vitro fluorescent measurements. The anthocyanins showed neuroprotective effects on PC-12 cells in vitro against oxidative stress in a dose-dependent manner. Triple quadrupole LC/MS and Q-TOF LC/MS analyses revealed four major anthocyanins; cyanidin 3-O-sambubioside, cyanidin 3-O-glucoside, cyanidin 3-O-xylosylrutinoside, and cyanidin 3-O-rutinoside in increasing order of amounts. These results demonstrated that anthocyanins are the major components and contributors to the antioxidant capacity of ripe R. coreanus Miquel fruits. Further studies are warranted to determine whether consumption of the fruits reduces oxidative stress in the brain and promotes health.

Chemical biology in stem cell research.

Stem cells are offering a considerable range of prospects to the biomedical research including novel platforms for disease models and drug discovery tools to cell transplantation and regenerative therapies. However, there are several obstacles to overcome to bring these potentials into reality. First, robust methods to maintain stem cells in the pluripotent state should be established and factors that are required to direct stem cell fate into a particular lineage should be elucidated. Second, both allogeneic rejection following transplantation and limited cell availability issues must be circumvented. These challenges are being addressed, at least in part, through the identification of a group of chemicals (small molecules) that possess novel activities on stem cell biology. For example, small molecules can be used both in vitro and/or in vivo as tools to promote proliferation of stem cells (self-renewal), to direct stem cells to a lineage specific patterns (differentiation), or to reprogram somatic cells to a more undifferentiated state (de-differentiation or reprogramming). These molecules, in turn, have provided new insights into the signaling mechanisms that regulate stem cell biology, and may eventually lead to effective therapies in regenerative medicine. In this review, we will introduce recent findings with regards to small molecules and their impact on stem cell self-renewal and differentiation.

Imaging of Plasmodium liver stages to drive next-generation antimalarial drug discovery.

Most malaria drug development focuses on parasite stages detected in red blood cells, even though, to achieve eradication, next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4000 commercially available compounds with previously demonstrated blood-stage activity (median inhibitory concentration < 1 micromolar) and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. The orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 milligrams/kilogram) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open-source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms.

Neuroprotective effect of caffeoylquinic acids from Artemisia princeps Pampanini against oxidative stress-induced toxicity in PC-12 cells.

Phenolics in dry Artemisia princeps Pampanini, an herbal plant traditionally consumed as food ingredients in Korea was extracted, fractionated, and quantified as well as evaluated for its neuroprotection for PC-12 cells. Whole extract had 5,852 mg gallic acid equivalents/100 g of total phenolics and 6,274 mg and 9,698 mg vitamin C equivalents/100 g of antioxidant capacities assayed by DPPH and ABTS radicals, respectively. The fraction extracted with n-butanol had the highest levels of total phenolics and antioxidant capacity than the other fractions (n-hexane, chloroform, ethyl acetate, and water). Using a reversed-phase HPLC system, caffeoylquinic acid (CQA) and its derivatives such as 3-CQA, 4-CQA, 5-CQA, 1,5-diCQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA were isolated and quantified. The whole extract and its n-butanol fraction yielded 3,5-diCQA with the highest amount, which consisted of approximately 36.8% and 33.5%, respectively. The whole extract, the n-butanol fraction, and 3,5-diCQA showed neuroprotective effect on PC-12 cells under the insult of amyloid ß peptide in a dose-dependent manner. Treatments of the whole extract and the n-butanol fraction for PC-12 cells under oxidative stress increased approximately 1.6 and 2.4 times higher cell viability, compared with the control without treatments. For PC-12 cells treated with 3,5-diCQA, intracellular oxidative stress decreased by 51.3% and cell viability increased up to 2.8 times compared to the control with oxidative insult of amyloid ß peptide only. These results indicate that phenolics from A. princeps Pampanini alleviated the oxidative stress and enhanced the viability of PC-12 cells, suggesting that it may be applied as a dietary antineurodegenerative agent in functional foods.

Antineurodegenerative effect of phenolic extracts and caffeic acid derivatives in romaine lettuce on neuron-like PC-12 cells.

In recent decades, romaine lettuce has been one of the fastest growing vegetables with respect to its consumption and production. An understanding is needed of the effect of major phenolic phytochemicals from romaine lettuce on biological protection for neuron-like PC-12 cells. Phenolics in fresh romaine lettuce were extracted, and then its total phenolics and total antioxidant capacity were measured spectrophotometrically. Neuroprotective effects of phenolic extract of romaine lettuce and its pure caffeic acid derivatives (caffeic, chicoric, chlorogenic, and isochlorogenic acids) in PC-12 cells were evaluated using two different in vitro methods: lactate dehydrogenase release and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assays. Total phenolics and total antioxidant capacity of 100 g of fresh romaine lettuce averaged 22.7 mg of gallic acid equivalents and 31.0 mg of vitamin C equivalents, respectively. The phenolic extract of romaine lettuce protected PC-12 cells against oxidative stress caused by H(2)O(2) in a dose-dependent manner. Isochlorogenic acid, one of the phenolics in romaine lettuce, showed stronger neuroprotection than the other three caffeic acid derivatives also found in the lettuce. Although romaine lettuce had lower levels of phenolics and antioxidant capacity compared to other common vegetables, its contribution to total antioxidant capacity and antineurodegenerative effect in human diets would be higher because of higher amounts of its daily per capita consumption compared to other common vegetables.