Red Wine High-Molecular-Weight Polyphenolic Complex Ameliorates High-Fat Diet-Induced Metabolic Dysregulation and Perturbation in Gut Microbiota in Mice.

Red wine polyphenolic complexes have attracted increasing attention as potential modulators of human metabolic disease risk. Our previous study discovered that red wine high-molecular-weight polymeric polyphenolic complexes (HPPCs) could inhibit key metabolic syndrome-associated enzymes and favorably modulate human gut microbiota (GM) in simulated colonic fermentation assay in vitro. In this work, the efficacy of HPPC supplementation (150 and 300 mg/kg/day, respectively) against high-fat diet (HFD)-induced metabolic disturbance in mice was investigated. HPPCs effectively attenuated HFD-induced obesity, insulin resistance, and lipid and glucose metabolic dysregulation and ameliorated inflammatory response and hepatic and colonic damage. It also improved the relative abundance of Bacteroidetes and Firmicutes, consistent with an anti-obesity phenotype. The favorable modulation of GM was further supported by improvement in the profile of fecal short-chain fatty acids. The higher dosage generally had a better performance in these effects than the low dosage. Moreover, serum metabolite profiling and pathway enrichment analysis revealed that HPPCs significantly modulated vitamin B metabolism-associated pathways and identified N-acetylneuraminic acid and 2-methylbutyroylcarnitine as potential biomarkers of the favorable effect on HFD-induced metabolic dysregulation. These findings highlight that dietary supplementation with red wine HPPCs is a promising strategy for the management of weight gain and metabolic dysregulation associated with HFD.

Advance toward isolation, extraction, metabolism and health benefits of kaempferol, a major dietary flavonoid with future perspectives.

As a major ubiquitous secondary metabolite, flavonoids are widely distributed in planta. Among flavonoids, kaempferol is a typical natural flavonol in diets and medicinal plants with myriad bioactivities, such as anti-inflammatory activity, anti-cancer activity, antioxidant activity, and anti-diabetic activity. However, the natural sources, absorption and metabolism as well as the bioactivities of kaempferol have not been reviewed comprehensively and systematically. This review highlights the latest research progress and the effect of kaempferol in the prevention and treatment of various chronic diseases, as well as its protective health effects, and provides a theoretical basis for future research to be used in nutraceuticals. Further, comparison of the different extraction and analytical methods are presented to highlight the most optimum for PG recovery and its detection in plasma and body fluids. Such review aims at improving the value-added applications of this unique dietary bioactive flavonoids at commercial scale and to provide a reference for its needed further development.

Bioactive compounds, health benefits, and industrial applications of Tartary buckwheat (Fagopyrum tataricum).

Tartary buckwheat belongs to the family Polygonaceae, which is a traditionally edible and medicinal plant. Due to its various bioactive compounds, the consumption of Tartary buckwheat is correlated to a wide range of health benefits, and increasing attention has been paid to its potential as a functional food. This review summarizes the main bioactive compounds and important bioactivities and health benefits of Tartary buckwheat, emphasizing its protective effects on metabolic diseases and relevant molecular mechanisms. Tartary buckwheat contains a wide range of bioactive compounds, such as flavonoids, phenolic acids, triterpenoids, phenylpropanoid glycosides, bioactive polysaccharides, and bioactive proteins and peptides, as well as D-chiro-inositol and its derivatives. Consumption of Tartary buckwheat and Tartary buckwheat-enriched products is linked to multiple health benefits, e.g., antioxidant, anti-inflammatory, antihyperlipidemic, anticancer, antidiabetic, antiobesity, antihypertensive, and hepatoprotective activities. Especially, clinical studies indicate that Tartary buckwheat exhibits remarkable antidiabetic activities. Various tartary buckwheat -based foods presenting major health benefits as fat and blood glucose-lowering agents have been commercialized. Additionally, to address the safety concerns, i.e., allergic reactions, heavy metal and mycotoxin contaminations, the quality control standards for Tartary buckwheat and its products should be drafted and completed in the future.

Current and potential trends in the bioactive properties and health benefits of Prunus mume Sieb. Et Zucc: a comprehensive review for value maximization.

Prunus mume Sieb. Et Zucc (P. mume) is an acidic fruit native to China (named Chinese Mei or greengage plum). It is currently cultivated in several Asian countries, including Japan ("Ume"), Korea (Maesil), and Vietnam (Mai or Mo). Due to its myriad nutritional and functional properties, it is accepted in different countries, and its characteristics account for its commercialization. In this review, we summarize the information on the bioactive compounds from the fruit of P. mume and their structure-activity relationships (SAR); the pulp has the highest enrichment of bioactive chemicals. The nutritional properties of P. mume and the numerous uses of its by-products make it a potential functional food. P. mume extracts exhibit antioxidant, anticancer, antimicrobial, and anti-hyperuricaemic properties, cardiovascular protective effects, and hormone regulatory properties in various in vitro and in vivo assays. SAR shows that the water solubility, molecular weight, and chemical conformation of P. mume extracts are closely related to their biological activity. However, further studies are needed to evaluate the fruit's potential nutritional and functional therapeutic mechanisms. The industrial process of large-scale production of P. mume and its extracts as functional foods or nutraceuticals needs to be further optimized.

Therapeutic effects and mechanisms of Zhen-Wu-Bu-Qi Decoction on dextran sulfate sodium-induced chronic colitis in mice assessed by multi-omics approaches.

BACKGROUND: Zhen-Wu-Bu-Qi Decoction (ZWBQD), a traditional Chinese medicine formula comprising Poria, Radix Paeoniae Alba, Rhizoma Atractylodis Macrocephalae, Rhizoma Zingiberis Recens, Radix Codonopsis and Rhizoma Coptidis, is used for treating ulcerative colitis (UC). In a previous study, we have reported ZWBQD mitigates the severity of dextran sulfate sodium (DSS)-induced colitis in mice. HYPOTHESIS: In this study, we aimed to understand the systemic actions and underlying mechanisms of ZWBQD on experimental colitis in mice. METHODS: We used multi-omics techniques and immunoblotting approach to study the pharmacological actions and mechanisms of ZWBQD in DSS-induced chronic colitic mice. RESULTS: We showed that ZWBQD exhibited potent anti-inflammatory properties and significantly protected DSS-induced colitic mice against colon injury by regulating the PI3K-AKT, MAPK signaling pathway and NF-κB signaling pathways. We also revealed that ZWBQD significantly ameliorated gut microbiota dysbiosis and abnormalities of tryptophan catabolites induced by DSS. CONCLUSIONS: We demonstrated that the therapeutic effects of ZWBQD on experimental colitis are mediated by regulating multiple signaling pathways and modulation of gut microbiota. Our study employed an integrative strategy to elucidate novel mechanisms of ZWBQD, which provides new insights into the development of Chinese herbal medicine-based therapeutics for UC.

Multi-Mechanistic Antidiabetic Potential of Astaxanthin: An Update on Preclinical and Clinical Evidence.

Diabetes mellitus (DM) is a cluster of physiological dysfunctions typified by persistent hyperglycemia. Diet plays a paramount role in human health, and regular consumption of a fruit- and vegetable-rich diet can delay or prevent DM and its associated complications. The promising effect of fruits and vegetables could be partly attributed to their antioxidant constituents, including carotenoids. Carotenoids are natural antioxidants that occur in many vegetables, fruits, microalgae, and other natural sources. Astaxanthin is a xanthophyll carotenoid predominantly present in microalgae and some red-colored marine organisms. It is currently marketed as a health supplement and is well-known for its antioxidant capacity. Accumulating evidence indicates that astaxanthin exerts its beneficial effects against DM by acting on various molecular targets and signaling pathways in multiple organs/tissues. Astaxanthin can lower blood glucose levels by preserving ß-cell function, improving insulin resistance (IR), and increasing insulin secretion. This manuscript summarizes the connection between glucose homeostasis, oxidative stress, and DM. This is followed by a review of recent studies on astaxanthin's pharmacological effects against IR, microvascular (diabetic retinopathy, diabetic nephropathy, and neurological damage), and macrovascular DM complications emphasizing the cellular and molecular mechanisms involved. A few lines of clinical evidence supporting its antidiabetic potential are also highlighted.

Tricoumaroylspermidine from rose exhibits inhibitory activity against ethanol-induced apoptosis in HepG2 cells.

Hepatocyte apoptosis is involved in the pathogenesis of alcohol-associated liver disease (ALD) and anti-apoptotic agents/extracts are thereby of great importance in the prevention/treatment of ALD. In this study, the protective effects of 10 edible flowers against ethanol-induced cell death were investigated in HepG2 cells, with rose (Rosa rugosa) showing the strongest activity. Therefore, rose was chosen for further separation and purification of bioactive fractions. A special fraction, SLs, was found to significantly increase the viability of EtOH-treated cells and attenuated EtOH-induced apoptosis partially via the activation of the AMPK/SIRT1 signaling pathway. Chromatographic analysis identified a series of hydroxycinnamic acid amides, kaempferol glycosides, and quercetin glycosides in this fraction, while the following intracellular uptake and cytotoxicity studies revealed that N1,N5,N10-(E)-tri-p-coumaroylspermidine (a hydroxycinnamic acid amide) in this fraction exhibited remarkable hepatoprotective activity with similar effective dosage to sulforaphane. Hence, our results highlighted the anti-alcohol and hepatoprotective benefits of consuming rose.

Oral administration of EGCG solution equivalent to daily achievable dosages of regular tea drinkers effectively suppresses miR483-3p induced metastasis of hepatocellular carcinoma cells in mice.

The effect of non-cytotoxic doses of epigallocatechin-3-gallate (EGCG) on the metastatic capability of human hepatocellular carcinoma (HCC) cells was investigated in vitro and in vivo. miR483-3p, a microRNA whose expression correlates inversely with survival and positively with disease progression in HCC patients, was found to promote HCC cell migration and invasion in vitro as well as lung metastasis in nude mice established by the tail-vein injection of HCC cells. The induction of reactive oxygen species (ROS) and downregulation of antioxidant defense factors Nrf2 and SOD2 appeared to be an important underlying mechanism and treatment with a non-cytotoxic dose of EGCG effectively reversed the miR483-3p-induced enhancement of HCC cell migration and invasion in vitro. Moreover, administration through drinking water at doses (0.1% and 0.5% EGCG solution, respectively) equivalent to the intake of regular to heavy tea drinkers could also significantly inhibit lung metastasis of HCC cells based on the estimation from the USDA Database for the Flavonoid Content of Selected Foods and FDA guidelines for the conversion of animal dose to human equivalent dose. EGCG also significantly counteracted the miR483-3p-induced alteration in the expression of epithelial-mesenchymal transition (EMT) markers, E-cadherin and vimentin, and downregulated the endogenous expression of miR483-3p in HCC cells through an epigenetic mechanism that led to the hypermethylation of the miR483-3p promoter region. The data from our study illustrate that miR483-3p promotes HCC metastasis likely through the induction of oxidative stress and uncover a novel role of EGCG for protection against miR483-3p-mediated HCC metastasis via the epigenetic modulation of miR483-3p expression. These findings therefore provide further evidence supporting that regular tea consumption may contribute to protection against miR-483-3p-induced ROS and the associated HCC progression.

Kinetic Study and Degradation Mechanism of Glycidyl Esters in both Palm Oil and Chemical Models during High-Temperature Heating.

A kinetic model for glycidyl ester (GE) formation in both palm oil and chemical models during high-temperature heating was built to investigate the formation and degradation mechanisms of GEs in refined palm oil. The results showed that the formation and degradation of GEs followed pseudo-first-order reactions, and the rate constants of reaction kinetics followed the Arrhenius equation. The estimated activation energy of the GE degradation reaction (12.87 kJ/mol) was significantly lower than that of the GE formation reaction (34.58 kJ/mol), suggesting that GE degradation occurred more readily than formation. The Fourier transform infrared (FTIR) band intensities of epoxy and ester carboxyl groups decreased over heating time, while no band assigned to the cyclic acyloxonium group was found. Furthermore, no 5,5-dimethyl-1-pyrroline N-oxide (DMPO)-cyclic acyloxonium radical adduct was detected by quadrupole time-of-flight mass spectrometry (Q-TOF-MS). The above findings indicated that GEs were decomposed, fatty acid was also liberated, and GE degradation did not involve a cyclic acyloxonium intermediate. GEs were primarily decomposed into monoacylglycerol via ring-opening reaction during heating followed by fatty acid and glycerol via hydrolysis reaction.

Fucoxanthin modulates cecal and fecal microbiota differently based on diet.

Obesity is a major health concern worldwide and is considered to be associated with disruption of host-microbial homeostasis, especially microbiota composition in the gastrointestinal tract. Use of microbiota-directed foods or nutraceuticals therefore represents a promising approach for the control of obesity. Fucoxanthin, a marine carotenoid, has been proven to be one of the most effective anti-obesity natural products. However, its action mechanism is yet to be unraveled, especially with respect to its role in the modulation of gut microbiota composition. In the present study, profiles of microbiota in both the cecal and fecal samples from BALB/c mice given respectively the following treatments were examined: normal chow diet (NCD), NCD + fucoxanthin (NCDF), high-fat-diet (HFD), and HFD + fucoxanthin (HFDF). The results showed that fucoxanthin supplementation for 4 weeks significantly changed the composition of both cecal and fecal microbiota. In addition, a differential effect was observed between the supplementation to NCD and to HFD. The changes in the Firmicutes/Bacteroidetes ratio and the abundance of S24-7 and Akkermansia were identified to be among the major gut microbiota modulating events associated with the anti-obesity bioactivity of fucoxanthin. Hence, our results suggested that fucoxanthin could be a promising microbiota-targeted functional-food ingredient.

A comparison of mutagenic PhIP and beneficial 8-C-(E-phenylethenyl)quercetin and 6-C-(E-phenylethenyl)quercetin formation under microwave and conventional heating.

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is the most abundant mutagen/carcinogen produced in high temperature treated protein food. Quercetin has been shown to inhibit PhIP formation by trapping phenylacetaldehyde to form two human beneficial adducts 6-C-(E-phenylethenyl)quercetin (6-CEPQ) and 8-C-(E-phenylethenyl)quercetin (8-CEPQ). Here we studied the formation of PhIP as well as the phenylacetaldehyde-trapping ability of quercetin in microwave heating and conventional heating systems. LC-MS was applied for the comparison of PhIP formed in chemical models using microwave heating and conductive heating. Results showed that PhIP was produced time dependently under both heating conditions. Microwave heating produced a smaller amount of PhIP compared with conductive heating. Moreover, quercetin showed a more potent inhibitory effect on PhIP formation in microwave heating systems than in conductive heating models. The amount of 6-CEPQ and 8-CEPQ produced in chemical models and onion/beef soup using microwave heating was about 5 and 1.5 times more than using conductive heating, respectively. Our results demonstrate that microwave heating was a much safer and healthier thermal processing technology than conventional heating in terms of formation of less mutagenic PhIP and production of more human beneficial compounds 6-CEPQ and 8-CEPQ.

Screening and identification of inhibitors of advanced glycation endproduct formation from microalgal extracts.

The formation and accumulation of advanced glycation endproducts (AGEs) have been implicated in the pathogenesis of many chronic diseases, such as aging, Alzheimer's disease, diabetes and diabetic complications. The present study was aimed to investigate the inhibitory effects of the extracts from nine microalgae on the formation of AGEs by using in vitro models and identify key antiglycation constituents of the microalgae. A BSA-glucose model with simulated physiological conditions was used to evaluate the inhibitory effect on total AGE formation. A BSA-MGO model was used to study the inhibitory activity against the dicarbonyl-induced AGE formation. The results showed that the aqueous acetone extracts exhibited stronger antiglycation activity than the other extracts (ethyl acetate and dichloromethane) and that the marine microalgal extracts were generally more effective than the freshwater ones. Their inhibitory rates ranged from >60% to 90% when used at a concentration of 0.5 mg mL-1. HPLC-DAD and UPLC-Q-TOF-MSE analyses revealed that fucoxanthin was likely the principal component which contributed to the observed antiglycation activity. Further analysis established a highly significant positive correlation (R2 > 0.95) between the fucoxanthin content and the antiglycation activity of the aqueous acetone extracts. This is the first report on the antiglycation activity of fucoxanthin. The findings of the present study have not only identified a promising inhibitor of AGE formation, but have also identified a valuable natural source of this phytochemical which possesses great potential to be developed as functional food ingredients and pharmaceutical products to help reduce health risks associated with AGEs.

8-C-(E-phenylethenyl)quercetin from onion/beef soup induces autophagic cell death in colon cancer cells through ERK activation.

SCOPE: Quercetin, a flavonoid, widely distributed in edible fruits and vegetables, was reported to effectively inhibit 2-amino-1-methyl-6-phenylimidazo[4, 5-b]pyridine (PhIP) formation in a food model (roast beef patties) with itself being converted into a novel compound 8-C-(E-phenylethenyl)quercetin (8-CEPQ). Here we investigated whether 8-CEPQ could be formed in a real food system, and tested its anticancer activity in human colon cancer cell lines. METHODS AND RESULTS: LC-MS was applied for the determination of 8-CEPQ formation in onion/beef soup. Anticancer activity of 8-CEPQ was evaluated by using cell viability assay and flow cytometry. Results showed that 8-CEPQ suppressed proliferation and caused G2 phase arrest in colon cancer cells. Based on immunofluorescent staining assay, western blot assay, and RNA knockdown data, we found that 8-CEPQ did not cause apoptotic cell death. Instead, it induced autophagic cell death. Moreover, treatment with 8-CEPQ induced phosphorylation of extracellular signal-regulated kinase (ERK). Inhibition of ERK phosphorylation by the mitogen-activated protein kinase kinase (MEK)/ERK inhibitor U0126 attenuated 8-CEPQ-induced autophagy and reversed 8-CEPQ-mediated cell growth inhibition. CONCLUSION: Our results demonstrate that 8-CEPQ, a novel quercetin derivative, could be formed in onion/beef soup. 8-CEPQ inhibited colon cancer cell growth by inducing autophagic cell death through ERK activation.

Preclinical predictors of anticancer drug efficacy: critical assessment with emphasis on whether nanomolar potency should be required of candidate agents.

In the current paradigm of anticancer drug development, candidate compounds are evaluated by testing their in vitro potency against molecular targets relevant to carcinogenesis, their effect on cultured cancer cells, and their ability to inhibit cancer growth in animal models. We discuss the key assumptions inherent in these approaches. In recent years, great emphasis has been placed on selecting for development compounds with nanomolar in vitro potency, expecting that they will be efficacious and safer based on the assumption that they can be used at lower doses ("the nanomolar rule"). However, this rule ignores critical parameters affecting efficacy and toxicity such as physiochemical and absorption, distribution, metabolism and excretion properties, off-target effects, and multitargeting activities. Thus, uncritical application of the nanomolar rule may reject efficacious compounds or select ineffective or toxic compounds. We present examples of efficacious chemotherapeutic (alkylating agents, hormonal agents, antimetabolites, thalidomide, and valproic acid) and chemopreventive (aspirin and sulindac) agents having millimolar potency and compounds with nanomolar potency (cyclooxygenase-2 inhibitors) that, nevertheless, failed or proved to be unsafe. The effect of candidate drugs on animal models of cancer is a better predictor of human drug efficacy; particularly useful are tumor xenografts. Given the cost of failure at clinical stages, it is imperative to keep in mind the limitations of the nanomolar rule and use relevant in vivo models early in drug discovery to prioritize candidates. Although in vivo models will continue having a major role in cancer drug development, more robust approaches that combine high predictive ability with simplicity and low cost should be developed.

Steroidal saponins and ecdysterone from Asparagus filicinus and their cytotoxic activities.

Two new spirostanoides, filiasparosides E (1) and F (2), one new furostanoside, filiasparoside G (3), and one new ecdysterone, stachysterone A-20, 22-acetonide (4), together with six known steroidal saponins, asparagusin A (5), filiasparoside A (6), filiasparoside B (7), aspafilioside A (8), aspafilioside B (9), and filiasparoside C (10) were isolated from the roots of Asparagus filicinus Buch.-Ham. Their structures were elucidated on the basis of spectroscopic and chemical evidence. Compounds 1-10 were investigated for their cytotoxicities against human breast adenocarcinoma MDA-MB-231 cell line and compounds 8-10 exhibited cytotoxic activities with IC(50) values ranging from 3.4 to 6.6microM.

Tyrosinase inhibitory constituents from the roots of Morus nigra: a structure-activity relationship study.

The phytochemical profiles of Morus nigra roots and twigs were compared by HPLC with those of the old and young twigs of Morus alba which are known to contain oxyresveratrol and mulberroside A as major components. It was found that M. nigra root extract contains some unknown natural products with potential tyrosinase inhibitory activity. The extract (95% ethanol) of the roots of M. nigra was further investigated in this study. One new compound, 5'-geranyl-5,7,2',4'-tetrahydroxyflavone, and twenty-eight known phenolic compounds were isolated. Their structures were identified by mass spectrometry and NMR spectroscopy. Nine compounds, 5'-geranyl-5,7,2',4'-tetrahydroxyflavone, steppogenin-7-O-beta-D-glucoside, 2,4,2',4'-tetrahydroxychalcone, moracin N, kuwanon H, mulberrofuran G, morachalcone A, oxyresveratrol-3'-O-beta-D-glucopyranoside and oxyresveratrol-2-O-beta-D-glucopyranoside, showed better tyrosinase inhibitory activities than kojic acid. It was noteworthy that the IC(50) values of 2,4,2',4'-tetrahydroxychalcone and morachalcone A were 757-fold and 328-fold lower than that of kojic acid, respectively, suggesting a great potential for their development as effective natural tyrosinase inhibitors.

Direct trapping of acrylamide as a key mechanism for niacin's inhibitory activity in carcinogenic acrylamide formation.

The inhibitory mechanism of niacin, which was found in our previous study to effectively reduce acrylamide (AA) formation in both chemical models and fried potato strips, was investigated in the present study. Maillard chemical models containing the amino acid asparagine and glucose with or without niacin were closely examined by liquid chromatography/tandem mass spectrometry. Comparison of the chemical profiles revealed two additional peaks in models where niacin was present together with the AA precursors, which thus suggests the formation of compounds from reactions between niacin and other chemical species in the model systems. The predicted molecular weights of these two analytes were consistent with adducts formed between niacin and asparagine or AA, respectively. The niacin-acrylamide adduct was also detected in fried potato strips pretreated with niacin. In addition, the niacin-acrylamide adduct was subsequently purified and characterized by NMR spectroscopy as 1-propanamide-3-carboxy pyridinium, a novel compound that has never been reported previously. Furthermore, incubation of niacin with AA in simulated physiological conditions showed that niacin was capable of significantly reducing the level of AA. Findings from this study suggest that niacin not only has the potential to remove AA from food products during heat treatment by directly trapping it but also is a potential agent to scavenge AA in human body.

Effects of fruit extracts on the formation of acrylamide in model reactions and fried potato crisps.

Natural products extracted from plants and fruits have attracted increasing attention for the development of effective inhibitors against the formation of acrylamide during food processing. In this study, six fruit extracts (apple, blueberry, mangosteen, longan, dragon fruit with white flesh, and dragon fruit with red flesh) were compared for their activities against acrylamide formation in chemical models containing equal molar quantities of glucose and asparagine in distilled water (160 degrees C for 30 min). Apple extract demonstrated potent inhibition on acrylamide formation. Blueberry, mangosteen, and longan extracts did not have significant impact, whereas dragon fruit extracts enhanced acrylamide formation. Column chromatography guided by chemical model analysis showed that the proanthocyanidin-rich subfraction played a key role in mediating the inhibitory activity. The inhibitory activity was finally corroborated in fried potato crisps. The present study identified some natural products that might have important applications in the food industry to inhibit acrylamide formation.

Chemical components and tyrosinase inhibitors from the twigs of Artocarpus heterophyllus.

An HPLC method was developed and validated to compare the chemical profiles and tyrosinase inhibitors in the woods, twigs, roots, and leaves of Artocarpus heterophyllus . Five active tyrosinase inhibitors including dihydromorin, steppogenin, norartocarpetin, artocarpanone, and artocarpesin were used as marker compounds in this HPLC method. It was discovered that the chemical profiles of A. heterophyllus twigs and woods are quite different. Systematic chromatographic methods were further applied to purify the chemicals in the twigs of A. heterophyllus. Four new phenolic compounds, including one isoprenylated 2-arylbenzofuran derivative, artoheterophyllin A (1), and three isoprenylated flavonoids, artoheterophyllin B (2), artoheterophyllin C (3), and artoheterophyllin D (4), together with 16 known compounds, were isolated from the ethanol extract of the twigs of A. heterophyllus. The structures of compounds 1-4 were elucidated by spectroscopic analysis. However, the four new compounds did not show significant inhibitory activities against mushroom tyrosinase compared to kojic acid. It was found that similar compounds, such as norartocarpetin and artocarpesin in the twigs and woods of A. heterophyllus, contributed to their tyrosinase inhibitory activity.

Trapping effects of green and black tea extracts on peroxidation-derived carbonyl substances of seal blubber oil.

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.