Biodegradation of furan aldehydes in lignocellulose hydrolysates / 生物工程学报

Lignocellulose is the most abundant renewable organic carbon resource on earth. However, due to its complex structure, it must undergo a series of pretreatment processes before it can be efficiently utilized by microorganisms. The pretreatment process inevitably generates typical inhibitors such as furan aldehydes that seriously hinder the growth of microorganisms and the subsequent fermentation process. It is an important research field for bio-refining to recognize and clarify the furan aldehydes metabolic pathway of microorganisms and further develop microbial strains with strong tolerance and transformation ability towards these inhibitors. This article reviews the sources of furan aldehyde inhibitors, the inhibition mechanism of furan aldehydes on microorganisms, the furan aldehydes degradation pathways in microorganisms, and particularly focuses on the research progress of using biotechnological strategies to degrade furan aldehyde inhibitors. The main technical methods include traditional adaptive evolution engineering and metabolic engineering, and the emerging microbial co-cultivation systems as well as functional materials assisted microorganisms to remove furan aldehydes.

The crucial role of metabolic regulation in differential hepatotoxicity induced by furanoids in Dioscorea bulbifera / 中国天然药物

Diterpenoid lactones (DLs), a group of furan-containing compounds found in Dioscorea bulbifera L. (DB), have been reported to be associated with hepatotoxicity. Different hepatotoxicities of these DLs have been observed in vitro, but reasonable explanations for the differential hepatotoxicity have not been provided. Herein, the present study aimed to confirm the potential factors that contribute to varied hepatotoxicity of four representative DLs (diosbulbins A, B, C, F). In vitro toxic effects were evaluated in various cell models and the interactions between DLs and CYP3A4 at the atomic level were simulated by molecular docking. Results showed that DLs exhibited varied cytotoxicities, and that CYP3A4 played a modulatory role in this process. Moreover, structural variation may cause different affinities between DLs and CYP3A4, which was positively correlated with the observation of cytotoxicity. In addition, analysis of the glutathione (GSH) conjugates indicated that reactive intermediates were formed by metabolic oxidation that occurred on the furan moiety of DLs, whereas, GSH consumption analysis reflected the consistency between the reactive metabolites and the hepatotoxicity. Collectively, our findings illustrated that the metabolic regulation played a crucial role in generating the varied hepatotoxicity of DLs.

A new quinone and a new phenolic glycoside from Thymus quinquecostatus / 中草药

Objective: To study the chemical components of Thymus quinquecostatus in order to find new compounds. Methods: The constituents were separated by column chromatographic methods of silica gel, AB-8 resin, Sephadex LH-20 and ODS column. The structures were elucidated by MS and NMR analyses. Results: Two compounds were isolated and identified as 6-hydroxy-11-methyl-12-hydroxymethyl naphtho [2,3-β] furan-1,4-dione (1) and 2-hydroxy-4-isopropyl-5-methylbenzene-O-β-D- glucopyranoside (2). Conclusion: Compounds 1 and 2 are new compounds, named quinquequinone A and quinqueside A, respectively.

Determination of furans in tea by headspace-gas chromatographic mass spectrometry / 预防医学

Objective@#To establish a method for the determination of furans in tea by headspace-gas chromatographic mass spectrometry. @*Methods@#The 20% sodium chloride solution and isotope internal standards were added to the crushed and weighed tea sample. Furan, 2-methylfuran, 3-methylfuran, 2,5-dimethylfuran were separated by HP-PLOT Q capillary column and then determined by gas chromatography mass spectrometry with electron impact ionization mode.@*Results@# In the range of 5-400 ng, good linear relationships were observed in the four furan compounds, with the correlation coefficients ranging from 0.999 2 to 0.999 6. The detection limits ranged from 0.2 to 1.9 μg/kg, the quantification limit ranged from 0.4 to 3.1 μg/kg. The recovery rates of furans ranged from 95.4% to 128.2% when spiked at 5.0, 20.0 and 100.0 μg/kg, and the relative standard deviations ranged from 0.8% to 11.3%. Eighty-one tea samples were determined, the concentration of four furan compounds was highest in black tea, followed by dark tea, oolong tea, green tea and scented tea. @*Conclusion@# Headspace-gas chromatography-mass spectrometry can reduce the matrix interference of tea, and meet the requirements in the linear range, recovery and precision, which is suitable for simultaneous determination of four furan compounds in tea.

Risk Assessment of Furan Exposure in the Norwegian Population

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has on request of The Norwegian Food Safety Authority performed a risk assessment of furan intake in the Norwegian population based on the most recent national food consumption surveys. National occurrence data of furan concentrations in food were preferentially used in the risk assessment. When national data were lacking, VKM has used occurrence data of furan from other countries. The assessment has been performed by the VKM Panel on Food Additives, Flavourings, Processing Aids, Materials in Contact with Food and Cosmetics and the VKM Panel on Contaminants. Furan is a volatile and lipophilic compound formed in a variety of heat-treated commercial foods and contributes to the sensory properties of the product. The substance has been found in a number of foods such as coffee, canned and jarred foods including baby food containing meat and various vegetables. High concentrations of furan have been found in coffee and the presence of furan in jarred baby food and infant formulae has received much attention since such products may be the sole diet for many infants. The occurrence of furan in a variety of foods suggests that there are multiple routes of furan formation rather than a single mechanism. The Norwegian Food Safety Authority has in 2008 and 2009 collected data on furan concentrations in different food products sold on the Norwegian market (Norwegian Food Safety Authority, 2008). In 2011, the Norwegian Food Safety Authority also decided to analyse commercial porridges for infants and children sold on the Norwegian market, to see if furan could be detected in such products. The calculated furan exposures from food and beverages are based on data from the nationally representative food consumption surveys; Spedkost, Småbarnskost, Ungkost and Norkost. The consumption for each relevant food or food category in the dietary surveys were multiplied with the corresponding mean furan concentrations and totalled for each individual. The liver is the main target organ for furan toxicity both in mice and rats, but the rat is the most sensitive species. A dose-dependent increase in hepatocellular adenomas and carcinomas was observed in mice and rats, and an increase in the incidence of cholangiocarcinomas was observed in rat liver. Cholangiocarcinomas in male and female rats were the most sensitive toxicological end point observed in rodents. On the basis of the available data, VKM considers that rat cholangiocarcinomas may be relevant for assessing human risk from furan. Available in vivo data with furan indicate that a reactive metabolite, most likely cis-2-butene1,4-dial (BDA), is formed and that this metabolite can react with DNA and induce mutations. To VKM’s knowledge, no in vivo studies on genotoxicity of BDA have been performed, but BDA was found to be genotoxic in several in vitro tests. VKM therefore considers that a genotoxic mechanism in furan-induced carcinogenesis cannot be excluded and the substance was assessed as a genotoxic carcinogen. VKM used the Margin of Exposure (MOE) approach in this risk assessment. The suitability of different studies on cholangiocarcinomas for dose-response modelling was considered. The 9-month interim evaluation of a 2-year study from NTP (1993) was chosen because it demonstrates a dose-response relationship. From this study, a point of departure of 0.02 mg/kg bw/day was chosen, based on a benchmark dose lower bound (BMDL10) of 0.14 mg furan/kg bw/day and a correction factor of 7 for shorter than full life-time (2 years) study duration. For 6-, 12- and 24-month-old children, the main source of furan exposure is jarred baby food. For 4-, 9- and 13-year-old children, the major food source to the furan exposure is breakfast cereals. In adults, the major contribution to the furan exposure is coffee. The highest furan exposure was calculated for 12-month-old infants and ranged from 0.62-1.51 µg/kg bw/day. In adults the furan exposure ranged from 0.27-0.82 µg/kg bw/day. For mean exposure among infants, children and adolescents, the MOE-values ranged from 29 in 12-month-infants to 2000 in the 13-year-old adolescents. Among high consumers in these groups, the MOE-values ranged from 13 to 400. In adults, the corresponding MOE-values ranged from 59 to 74 for mean furan exposure and from 24 to 26 for high exposure. It should be noted that this risk assessment of furan contains notable uncertainties and limitations. The use of the 9-month interim study in rats including a correction factor of 7 to derive a point of departure, instead of a full life-time study (2-year) study, likely overestimates the hazard of furan. A possible over-diagnosis of the cholangiocarcinomas, due to the similarities in histopathology between cholangiofibrosis and cholangiocarcinomas in rats, may overestimate the hazard. There are also limitations in assessing food consumption and furan content in foods, leading to uncertainties in estimation of furan exposure. VKM considers that the current exposure to furan in all age groups, particularly among infants and children, is of health concern.

Simultaneous Determination of Furan and Vinyl Acetate in Vapor Phase of Mainstream Cigarette Smoke by GC-MS

ABSTRACT A simple and sensitive method for simultaneous determination of furan and vinyl acetate (VA) in vapor phase of mainstream cigarette smoke with cold trap and gas chromatography-mass spectrometry (GC-MS) was developed. A Cambridge filter pad (CFP) was placed in front of the impingers of smoking machine to remove the particle phase from cigarette smoke. Furan and VA in vapor phase of mainstream cigarette smoke were collected in two impingers connected in series by filled with methanol at -78°C. The solutions were added with deuterium-labeled furan-d4 and VA-d6 as internal standards and analyzed by GC-MS. The results showed that the calibration curves for furan and VA were linear (r2 > 0.9995) over the studied concentration range. The intra- and inter-day precision values for furan and VA were <7.07% and <9.62%, respectively. The extraction recoveries of furan and VA were in the range of 94.5-97.7% and 92.3-94.9%, respectively. Moreover, the limits of detection for furan and VA were 0.028 µg mL-1 and 1.3 ng mL-1, respectively. The validated method has been successfully applied to determine the emissions of furan and VA in the vapor phase of mainstream cigarette smoke under International Organization for Standardization (ISO) and Canadian Intense (CI) smoking regimen.

Two new annonaceous acetogenins from seeds of Annona squamosa / 中草药

Objective: To study the chemical constituents from the seeds of Annona squamosa. Methods: Modern methods such as silica gel column and preparation liquid phase were used to isolate and purify the components of annonaceous acetogenins from the seeds of A. squamosa. The structures of the compounds were identified by their physico-chemical properties, UV, NMR and mass spectrometry data. Results: Ten adjacent bistetrahydrofuran annonaceous acetogenins were isolated from CO2 supercritical extract of the seeds from A. squamosa. They were 3-((13R)-13-((2R,2'R,5R,5'R)-5'-((1S)-1,5-dihydroxynonyl) octahydro-[2,2'-bifuran]-5-yl)-13-hydroxytridecyl)-5-methylfuran-2 (5H)-one (1), 3-((2R,9R)-2,9-dihydroxy-9-((2R,2'R,5R,5'R)-5'-((S)-1-hydroxypentadecyl) octahydro-[2,2'-bifuran]-5-yl) nonyl)-5-methylfuran-2 (5H)-one (2), 6-hydroxy-desacetyl-uvaricin (3), 6-hydroxy-4-deoxy-squamotacin (4), bullanin (5), 10-hydroxy-asimicin (6), folianin A (7), annosquacin I (8), annosquacin C (9), and squamocin I (10). Conclusion: Compounds 1 and 2 are two new compounds named as 28-hydroxy-squamocin L (1) and 4-hydroxy-squamocin Y (2), respectively. Compounds 3-7 are isolated from A. squamosa for the first time.

Chemical constituents from seed kernels of Entada phaseoloides / 中草药

Objective To study the chemical constituents from seed kernels of Entada phaseoloides. Methods The constituents were isolated and purified by silica gel and preparative HPLC column chromatographic methods, and their structures were identified by means of physicochemical properties and spectral analyses. Results Eight compounds were isolated from 70% ethanol extract of the seed kernels of E. phaseoloides, and identified as 4-methoxybenzyl-O-[α-L-arabinopyranosyl-(1→6)]-β-D-glucopyranoside (1), sinapyl-O-[β-D-apiofuranosyl-(1→2)]-O-β-D-glucopyranoside (2), 2-β-D-glucopyranosyloxy-5-hydroxy-phenylacetic acid (3), 2-β-D-glucopyranosyloxy-5-hydroxy-phenylacetic acid methyl ester (4), 5-O-β-D-glucopyranosyl-3-hydrobenzo [b] furan-2-one (5), dihydrophaseic acid-4'-O-β-D-glucopyranoside (6), corchoionoside C (7), and 1'S,4'S-4'-dihydroabscisic acid-4'-O-β-glucopyranoside (8). Conclusion Compound 1 is a new compound named phaseoloideside F, compound 5 is a new natural product, and compounds 2 and 4-8 are isolated from this plant for the first time.

Chemical constituents from Actinostemma lobatum (II) / 中草药

Objective: To investigate the chemical constituents from the whole plant of Actinostemma lobatum. Methods: The chemical constituents were isolated from the 75% alcohol extract of A. lobatum by silica column chromatography, C18, Sephadex LH-20 columns, and RP-HPLC. Their chemical structures were elucidated on the basis of physicochemical and spectral properties, 1H-NMR, and 13C-NMR. Results: Twelve compounds were isolated and identified as lobatoside B (1), tubeimoside II (2), tubeimoside V (3), gallic acid (4), methyl gallate (5), protocatechuic acid (6), protocatechuic acid methyl ester (7), 4-hydroxyacetophenone (8), p-hydroxybenzoic acid (9), p-hydroxybenzaldehyde (10), 5-(hydroxymethyl)-2-furaldehyde (11), and 1-[5-(hydroxymethyl) furan-2-yl] ethanone (12). Conclusion: Compounds 2 and 5-12 are isolated from the plants in Actinostemma Griff. for the first time.

A new furan-2-carboxylic acid from stem bark of Cassia alata / 中国中药杂志

A new furan-2-carboxylic acid, 5-[3-(hydroxymethyl)-4,5-dimethoxyphenyl]-3-methylfuran-2-carboxylic acid(1),has been isolated from the bark of Cassia alata by using various chromatographic techniques. It displayed cytotoxicity against NB4, A549, SHSY5Y, PC3 and MCF7 cell lines with IC₅₀ values of 2.5, 1.2, 2.2, 3.6 and 1.9 μmol•L⁻¹, respectively.

Lycopene Protects the Diabetic Rat Kidney Against Oxidative Stress-mediated Oxidative Damage Induced by Furan

Furan is a food and environmental contaminant and a potent carcinogen in animals. Lycopene is one dietary carotenoid found in fruits such as tomato, watermelon and grapefruit. The present study was designed to explore the protective effect of lycopene against furan-induced oxidative damage in streptozotocin (STZ)-induced diabetic rat kidney. At the end of the experimental period (28 days), we found that lycopene markedly decreased the malondialdehide (MDA) levels in the kidney, urea, uric acid and creatinine levels in the serum of furan-treated rats. The increase of histopathology in the kidney of furan-treated rats were effectively suppressed by lycopene. Furthermore, lycopene markedly restored superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities in the kidney of furan-treated rats. In conclusion, these results suggested that lycopene could protect the rat kidney against furan-induced injury by improving renal function, attenuating histopathologic changes, reducing MDA production and renewing the activities of antioxidant enzymes.

Assessment of the DNA Damage in Human Sperm and Lymphocytes Exposed to the Carcinogen Food Contaminant Furan with Comet Assay

ABSTRACTThe aim of this work was to assess the damage of DNA in human blood cell and spermin vitro under the influence of furan. These cells were administered 0-600 μM of furan at 37 and 32oC for 30 and 60 min, respectively. A significant increase in tail DNA%, tail length and moment indicating DNA damage was observed at increasing doses when compared to the controls. The treatment with 300 and 600 μM of furan showed a maximum increase of 86.74 ± 2.43 and 93.29 ± 8.68 compared to the control tail DNA% in lymphocytes. However, only 600 μM of furan showed a maximum increase of 94.71 ± 6.24 compared to the control tail DNA% in sperm. The results suggested that furan caused DNA damage in lymphocytes at increasing doses, but appeared to have not the same effect on human sperm at the low doses. Genotoxic activity had an impact on the risk assessment of furan formed on the food for human cells. Therefore, it would be important to further investigate these properties of furan as the food mutagen.

Effect of furan coumarins from Angelica Dahuricae Radix on intestinal transport absorption of puerarin, paeoniflorin, and vincristine / 中草药

Objective: To investigate the influence of furan coumarins from Angelicae Dahuricae Radix on intestinal absorption of puerarin, paeoniflorin, and vincristine, and to explore the influence law of furan coumarins on the intestinal absorption of the drugs with different structures. Methods: The apparent permeability coefficient (Papp) of drugs across the Caco-2 cell monolayers as evaluated index and Caco-2 cell model was used to study the absorption effects of furan coumarins (imperatorin, isoimperatorin, bergapten, and oxypeucedanin) on the transport of puerarin, paeoniflorin, and vincristine across Caco-2 cell monolayers. Results: There are different effects of the four coumarins on puerarin, paeoniflorin, and vincristine. For imperatorin, isoimperatorin, and oxypeucedanin could improve the transport of puerarin on Caco-2 cell significantly (P < 0.05, 0.01), while bergapten has no effect on the transport of puerarin across Caco-2 cell monolayers. For imperatorin and bergapten have no effect on the transport of paeoniflorin: However isoimperatorin and oxypeucedanin could significantly inhibit the transport of paeoniflorin across Caco-2 cell monolayers (P < 0.05, 0.01). Iperatorin, isoimperatorin, and oxypeucedanin could improve the transport of vincristine across Caco-2 cell monolayers significantly (P < 0.05, 0.01), but bergapten could significantly restrain the transport of vincristine across Caco-2 cell monolayers (P < 0.05). Conclusion: Different furan coumarins have different effects on the intestinal transport of the same medicine. Although the structures all are the furan type, the influence shows the opposite effect on drug transport. The same furan coumarin combined with different drugs have the different influences on the intestinal transport of compatibility drugs.

Chemical constituents from Leonurus japonicus Injection / 中草药

Objective: To study the chemical constituents from Leonurus japonicus Injection. Methods: The constituents were purified by macroporus resin, silica gel, Sephadex LH-20, and recrystallization. The structures were identified by spectroscopic methods and spectroscopic analysis. Results: Fifteen compounds were isolated from L. japonicus Injection, including four amino acids and their derivatives such as N-isobutyl valine (1), valine (2), alanine (3), L-pyroglutamic acid methyl ester (4), nine alkaloids: stachydrine (5), choline (6), trigonelline (7), uracil (8), 5-methyluracil (9), 2', 3'-O-isopropylidene uridine (10), 3-hydroxypyridine (11), 5-hydroxyl-2-hydroxymethylpyridine (12), and 2-methyl-3-hydroxypyridine (13); and two furoic acids such as furan-2- carboxylic acid (14) and 5-hydroxymethyl-2-furancarboxyic acid (15). Conclusion: In addition to compounds 5 and 8, the others are isolated from the plants of Leonurus Linn. for the first time. Among them, compound 1 is a natural product. Its NMR data, undoubtedly assigned by 2D-NMR, have been reported for the first time.

Estudio teóricoppara evaluar la conductividad dl polifurano y el efecto de loss sustituyentes sobre la cadena polimérica / Theoretcal studyy to evaluate polyfuranelectrical conductivity and thee substituent effects on the polymeri cchain / Estud teorico paara avaliar a conductvidade do polifurano o e efeitoo dos substituintes sobre a cadeia polmmerica

Una serie de oligómeros de furano y furano sustituido fueron estudiados desde el punto de vista teórico con el objeto de conocer las propiedades electroconductoras de estos compuestos, y su respectiva extrapolación a polímeros, aprovechando la capacidad de la química computacional para proponer y diseñar nuevos materiales y sus posibles propiedades. Se relacionaron las propiedades electrónicas de estos oligómeros tales como la afinidad electrónica (AE), el potencial de ionización (PI), el band-gap (HOMOLUMO), y la relación de éstos con la conductividad; además, se demostró cómo cambia la longitud de los enlaces de los oligómeros al estar cargados; la longitud de los oligómeros de estudio fuer de dos, cuatro, seis y ocho anillos. En este estudio se realizaron cálculos a niveles AM1 y DFT/B3LYP/6-31G (d).

DFT/B3LYP/6-31G (d) calculations were carried out on a series of molecules of furan and substituted furan to observe the type of variables that affect the conductivity of these molecules. In order to propose and design new molecules and its possible properties. The Ionization potential (IP), band-gap (HOMO-LUMO), electronic affinity (EA), was related with its conductivity. It was also shown how change the length of the olygomers bond when the number of the rings is changed from two to four, six and eight.

Uma serie de oligômeros de furano y furano substituido foram estudados teoricamente com a intenção de conhecer as propriedades electro-conductoras desses compostos e sua respectiva extrapolação a polímeros, aproveitando a capacidade da química computacional para propor e desenhar novos materiais e suas possíveis propriedades. Relacionaram-se as propriedades eletrônicas destes oligômeros, tais como a afinidade eletrônica (AE), o potencial de ionização (PI), o band-gap (HOMO-LUMO) e a relação destes com a condutividade, também se demostrou a mudança do comprimento das ligações dos oligômeros ao estar carregados, o comprimento dos oligômeros em estudo foram de dois, quatro, seis e oito anéis. Em este estudo realizaram-se cálculos a níveis AM1 e DFT/B3LYP/6-31G (d).

Bioactive dihydroxyfuranonaphthoquinones from the bark of Tabebuia incana A.H. Gentry (Bignoniaceae) and HPLC analysis of commercial pau d'arco and certified T.incana bark infusions

Tabebuia incana A.H. Gentry (Bignoniaceae) is a tree from the Brazilian Amazon having medicinal uses and is one several Tabebuia spp. known as pau d'arco or palo de arco in this region. Fractionation of the bark ethanolic extract afforded a mixture of 5 and 8-hydroxy-2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-diones (1 and 2, respectively) identified on the basis of nuclear magnetic resonance (NMR), infrared (IR) and mass (MS) spectra, whose in vitro antimalarial and antitumor activity have been shown previously. This is the first study on T. incana bark, and 2 are described in this species for the first time. Also, high performance liquid chromatography (HPLC) analysis of T. incana bark tea revealed the presence of the 1 + 2 mixture peak corresponding to a concentration in the range 10-6-10-5 M. The chromatograms of teas prepared from commercial pau d' arco and T. incana bark were also studied and the presence of the 1 + 2 peak has potential for quality control of commercial plant materials.

Tabebuia incana A.H. Gentry (Bignoniaceae) é uma árvore da Amazônia brasileira com usos medicinais. É uma de várias espécies de Tabebuia conhecidas como pau d'arco ou palo de arco nesta região. O fracionamento do extrato etanólico das cascas resultou no isolamento da mistura de 5 e 8-hidróxi-2-(1-hidroxietil)nafto[2,3-b]furano-4,9-dionas (1 e 2, respectivamente), identificadas com base em seus espectros de ressonância magnética nuclear (RMN), infravermelho (IV) e massa (EM), e cujas atividades antimalárica e antitumoral in vitro foram mostradas previamente. Este é o primeiro estudo das cascas de T. incana e a primeira vez que o composto 2 é descrito nesta espécie. Análises por cromatografia liquida de alto empenho (CLAE) do chá das cascas de T. incana revelaram a presença de um pico correspondente à mistura de 1 + 2, permitindo inferir uma concentração na faixa de 10-6-10-5 M desses componentes no chá. Os cromatogramas de chás (infusões) preparados a partir das cascas de pau d' arco commercial and T. incana certificada também foram estudados. A verficação da presença do pico das substâncias 1 + 2 nos cromatogramas tem potencial contribuição para o controle de qualidade de material vegetal comercial.