Transglycosylation of neohesperidin dihydrochalcone by Bacillus stearothermophilus maltogenic amylase

Neohesperidin dihydrochalcone (NHDC), a sweet compound derived from citrus fruits, was modified to a series of its oligosaccharides by transglycosylation activity of Bacillus stearothermophilus maltogenic amylase (BSMA). Maltotriose as a donor was reacted with NHDC as an acceptor to glycosylate for the purpose of increasing the solubility of NHDC. Maltosyl-NHDC was a major transglycosylation product among the several transfer products by TLC analysis. The structure of the major transglycosylation product was determined to be maltosyl-alpha-(1,6)-neohesperidin dihydrochalcone by MALDI-TOF/MS and (1)H and (13)C NMR. Maltosyl-NHDC was 700 times more soluble in water and 7 times less sweet than NHDC.     

Improved water solubility of neohesperidin dihydrochalcone in sweetener blends

Significant technological advantages in terms of sweetness synergy and hence cost-saving can be obtained if neohesperidin dihydrochalcone (NHDC) is used in sweetener blends with other intense or bulk sweeteners. The combination of NHDC with sodium saccharin or sodium cyclamate is an excellent method to improve the water solubility at room temperature of NHDC. In the case of NHDC-sodium saccharin, two different methods for blend preparation, a simple mixture and a cosolubilized mixture, can be used, with similar results obtained for solubility and solution stability properties. To improve temporally the water solubility of NHDC in combination with sodium cyclamate, it is absolutely necessary to prepare cosolubilized blends.     

Selective responses of three Ginkgo biloba leaf-derived constituents on human intestinal bacteria

The selective responses of Ginkgo biloba leaf-derived materials against six intestinal bacteria was examined using an impregnated paper disk method and compared with that of bilobalide, ginkgolides A and B, kaempferol, and quercetin. The components of G. biloba leaves were characterized as kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside), kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside, and quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) by spectroscopic analysis. The growth responses varied with each bacterial strain tested. At 2 mg/disk, kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) and quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) revealed potent inhibition against Clostridium perfringens, and kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside showed a clear inhibitory effect on Escherichia coli. At 0.5 mg/disk, quercetin 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) showed a strong activity against C. perfringens, but weak activity was exhibited by kaempferol 3-O-alpha-(6' "-p-coumaroylglucosyl-beta-1,4-rhamnoside) against C. perfringens and kaempferol 3-O-(2' '-O-beta-D-glucopyranosyl)-alpha-L-rhamnopyranoside against E. coli. No inhibition was observed from treatments conducted with bilobalide, ginkgolides A and B, kaempferol, or quercetin. Furthermore, these isolated compounds did not inhibit Bifidobacterium bifidum, B. longum, B. adolescentis, or Lactobacillus acidophilus.     

Selective growth inhibitor toward human intestinal bacteria derived from Pulsatilla cernua root

Among 21 medicinal plants, the growth-inhibiting activity of Pulsatilla cernua root-derived materials toward human intestinal bacteria was examined by using an impregnated paper disk method. The biologically active components of P. cernua roots were characterized as 4-hydroxy-3-methoxycinnamic acid and 3,4-dihydroxycinnamic acid by spectroscopic analysis. The activity was compared with that of six commercially available cinnamic acid derivatives trans-cinnamaldehyde, trans-cinnamic acid, cinnamyl alcohol, 2-methoxycinnamic acid, 3-methoxycinnamic acid, and 4-methoxycinnamic acid. The growth responses varied with each bacterial strain tested. Two isolated compounds revealed a potent inhibition against Clostridium perfringens, and moderate to weak activity against Escherichia coli was exhibited by 4-hydroxy-3-methoxycinnamic acid. Weak or no inhibitory activity was obtained against the bifidobacteria or Lactobacillus acidophilus. The inhibitory effect was much more pronounced in C. perfringens and E. coli as compared to B. adolescentis, B. bifidum, B. fragilis, B. longum, or L. acidophilus. Cinnamaldehyde exhibited a strong growth-inhibiting activity, but no inhibition was observed from treatments with trans-cinnamic acid, cinnamyl alcohol, 2-methoxycinnamic acid, 3-methoxycinnamic acid, and 4-methoxycinnamic acid. These results may be an indication of at least one of the pharmacological actions of P. cernua root.     

Growth-inhibiting effects of Coptis japonica root-derived isoquinoline alkaloids on human intestinal bacteria.

The growth-inhibiting activity of Coptis japonica (Makino) root-derived materials toward eight human intestinal bacteria was examined using an impregnated paper disk method and compared to that of four commercially available isoquinoline alkaloids [berberine sulfate (BS), berberine iodide (BI), palmatine chloride (PC), and palmatine sulfate(PS)], as well as that of Thea sinensis leaf-derived epigallocatechin gallate (EGCG). The biologically active constituents of the Coptis extract were characterized as the isoquinoline alkaloids berberine chloride (BC), palmatine iodide (PI), and coptisine chloride (CC) by spectral analysis. The growth responses varied with both chemical and bacterial strain used. In a test using 500 microg/disk, BC and PI produced a clear inhibitory effect against Bifidobacterium longum, Bifidobacterium bifidum, Clostridium perfringens, and Clostridium paraputrificum, whereas weak or no inhibition was observed in Bifidobacterium adolescentis, Lactobacillus acidophilus, Lactobacillus casei, and Escherichia coli. At 1000 microg/ disk, CC revealed weak or no growth inhibition toward all test bacteria, whereas EGCG exhibited weak growth inhibition against only C. perfringens and C. paraputrificum. Among various isoquinoline alkaloids, BC exhibited more potent inhibitory activity toward C. perfringens than BI and BS, whereas the inhibitory effect was more pronounced in PI compared to PC and PS. The Coptis root-derived materials did not promote growth of B. longum and C. perfringens.     

Selective growth-inhibiting effects of compounds identified in Tabebuia impetiginosa inner bark on human intestinal bacteria

The growth-inhibiting activity of anthraquinone-2-carboxylic acid and lapachol identified in the inner bark of taheebo, Tabebuia impetiginosa, toward 10 human intestinal bacteria was evaluated by using a paper disk diffusion bioassay and compared to those of seven lapachol congeners (1,4-naphthoquinone, naphthazarin, menadione, lawsone, plumbagin, juglone, and dichlone) as well as two commercially available antibiotics, chloramphenicol and tetracycline. Anthraquinone-2-carboxylic acid exhibited very strong growth inhibition of Clostridium paraputrificum at 1 microg/disk while 100 microg/disk of lapachol was needed for moderate growth inhibition of the same organism. These two isolates exhibited weak inhibition of Clostridium perfringens and Escherichia coli at 100 microg/disk while no adverse effects were observed on the growth of Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium infantis, Lactobacillus acidophilus, and Lactobacillus casei at 1000 microg/disk. Structure-activity relationships indicate that a methyl group in the C-2 position of 1,4-naphthoquinone derivatives might play an important role in antibacterial activity.     

Screening of intestinal microflora for effective probiotic bacteria

Increasing consumer awareness of health-promoting intestinal bacteria has fueled the addition of viable probiotic bacteria as functional ingredients in certain foods. However, to effectively market the enhanced attributes of these foods, the added probiotic bacteria need to have scientific credibility. The scientific rationale for using many of the strains of probiotic bacteria currently on the market is weak. Furthering the current understanding of what features a bacterium needs to have for effective probiotic functionality will enable the selection of strains with a more credible scientific rationale. To screen for effective strains, one must understand the microbial diversity in the intestines of healthy individuals. The advent of molecular tools has greatly enhanced our ability to accomplish this. These tools comprise genetic fingerprinting, specific probes, molecular speciation, and techniques for the in situ analysis of specific microbial groups in the intestine. This review will detail these scientific approaches and how their impact will improve criteria for selection of probiotic bacteria.     

Fermentation of plant cell wall derived polysaccharides and their corresponding oligosaccharides by intestinal bacteria

New types of nondigestible oligosaccharides were produced from plant cell wall polysaccharides, and the fermentation of these oligosaccharides and their parental polysaccharides by relevant individual intestinal species of bacteria was studied. Oligosaccharides were produced from soy arabinogalactan, sugar beet arabinan, wheat flour arabinoxylan, polygalacturonan, and rhamnogalacturonan fraction from apple. All of the tested substrates were fermented to some extent by one or more of the individual species of bacteria tested. Bacteroides spp. are able to utilize plant cell wall derived oligosaccharides besides their reported activity toward plant polysaccharides. Bifidobacterium spp. are also able to utilize the rather complex plant cell wall derived oligosaccharides in addition to the bifidogenic fructooligosaccharides. Clostridium spp., Klebsiella spp., and Escherichia coli fermented some of the selected substrates in vitro. These studies do not allow prediction of the fermentation in vivo but give valuable information on the fermentative capability of the tested intestinal strains.     

In vitro fermentation of alternansucrase raffinose-derived oligosaccharides by human gut bacteria

In this work, in vitro fermentation of alternansucrase raffinose-derived oligosaccharides, previously fractionated according to their degree of polymerization (DP; from DP4 to DP10), was carried out using small-scale pH-controlled batch cultures at 37 °C under anaerobic conditions with human feces. Bifidogenic activity of oligosaccharides with DP4-6 similar to that of lactulose was observed; however, in general, a significant growth of lactic acid bacteria Bacteroides , Atopobium cluster, and Clostridium histolyticum group was not shown during incubation. Acetic acid was the main short chain fatty acid (SCFA) produced during the fermentation process; the highest levels of this acid were shown by alternansucrase raffinose acceptor pentasaccharides at 10 h (63.11 mM) and heptasaccharides at 24 h (54.71 mM). No significant differences between the gas volume produced by the mixture of raffinose-based oligosaccharides (DP5-DP10) and inulin after 24 h of incubation were detected, whereas lower gas volume was generated by DP4 oligosaccharides. These findings indicate that novel raffinose-derived oligosaccharides (DP4-DP10) could be a new source of prebiotic carbohydrates.     

Absorption of anthocyanins from blueberry extracts by caco-2 human intestinal cell monolayers

Recent studies have shown that dietary polyphenols may contribute to the prevention of cardiovascular disease and cancer. Anthocyanins from different plant sources including blueberries have been shown to possess potential anticancer activities. One of the key factors needed to correctly relate the in vitro study results to human disease outcomes is information about bioavailability. The objectives of the current study were to evaluate the absorption of blueberry anthocyanin extracts using Caco-2 human intestinal cell monolayers and investigate the effects of different aglycones, sugar moieties, and chemical structure on bioavailability of different types of anthocyanins. The results of this study showed that anthocyanins from blueberries could be transported through the Caco-2 cell monolayers although the transport/absorption efficiency was relatively low compared to other aglycone polyphenols. The transport efficiency of anthocyanins averaged approximately 3-4% [less than 1% in delphinidin glucoside (Dp-glc)]. No significant difference in transport/absorption efficiency was observed among three blueberry cultivars. The observed trends among different anthocyanins generally agreed well with some published in vivo results. Dp-glc showed the lowest transport/absorption efficiency, and malvidin glucoside (Mv-glc) showed the highest transport/absorption efficiency. Our result indicates that more free hydroxyl groups and less OCH(3) groups can decrease the bioavailability of anthocyanins. In addition, cyanindin glucoside (Cy-glc) showed significantly higher transport efficiency than cyanidin galactoside (Cy-gal), and peonidin glucoside (Pn-glc) showed significantly higher transport efficiency than peonidin galactoside (Pn-gal), indicating that glucose-based anthocyanins have higher bioavailability than galactose-based anthocyanins.     

微生物降解阿特拉津的研究进展

除草剂阿特拉津长期使用所造成环境污染问题的日益加重,受污染土壤、水体的生物降解、生态修复等诸多问题也受到人们的广泛关注,本文综述了降解阿特拉津的微生物类群、阿特拉津降解酶以及微生物对阿特拉津的作用方式和降解途径,并对其应用前景进行了展望。     

Degradation of Sevin by soil microorganisms

Microorganisms capable of transforming the pesticide 1-naphthyl N-methyl-carbamate (Sevin) were isolated from soil. Three isolates were able to accelerate the hydrolysis of Sevin to 1-naphthol. Several unidentified intermediates were separated by thin-layer chromatography and also by following the decomposition of Sevin-methyl-¹⁴C. Since 1-naphthol is a biological as well as a chemical decomposition product of Sevin, its transformation by the isolated microbes was also studied. A fungus, identified as Fusarium solani, altered 1-naphthol rapidly. Whereas one strain of bacterium degraded the hydrolysis product gradually, another strain accumulated it under certain conditions. Mixed cultures of the investigated microbes were more effective in transforming Sevin than pure cultures, and this phenomenon was also observed with 1-naphthol as substrate with the exception of one bacterial strain.     

Tracing faecal pollution by coprostanol and intestinal bacteria in an ice-covered finnish lake loaded with both industrial and domestic sewage

The relationships existing between coprostanol (5β-cholestan-3β-ol), faecal indicator bacteria and various physico-chemical tracer and bacterial stress factors in an ice-covered Finnish lake were investigated. Field observations show that coprostanol lies below the theoretical mixing line, indicating a net removal, primarily by settling together with suspended sediments. Faecal indicator bacteria, however, are differently transported and are removed by various environmental factors e.g. industrial wastes. Thus, only faecal streptococci show a regional covariance to coprostanol. Principal component analyses reveal a strong correlation between coprostanol and faecal streptococci in water but not with coliforms and sulfite reducing sporing anaerobs. However, in sediments also coliforms are correlated significantly with coprostanol and faecal streptococci. Therefore it might be necessary to estimate the quality of those waters polluted by both industrial and faecal wastes by means of coprostanol, a principal sterol in sewage of man and higher animals, which is thus well suited as a chemical marker of faecal pollution.     

Degradation of ochratoxin a by Brevibacterium species

The ability to degrade ochratoxin A was studied in different bacteria with a well-known capacity to transform aromatic compounds. Strains belonging to Rhodococcus, Pseudomonas, and Brevibacterium genera were grown in liquid synthetic culture medium containing ochratoxin A. Brevibacterium spp. strains showed 100% degradation of ochratoxin A. Ochratoxin α was detected and identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) as a degradation product in the cell-free supernatants. The degradation of ochratoxin A is of public concern for food and environmental safety, because it could contribute to the development of new biological ochratoxin A detoxification systems in foodstuffs. In this study, the degradation of ochratoxin A by bacteria belonging to the food chain was demonstrated for the first time.     

Liquid chromatographic determination of naringin and neohesperidin as a detector of grapefruit juice in orange juice

Naringin/neohesperidin ratios can be used to differentiate orange juice which may contain added grapefruit juice from orange juice which may include juices from other naringin-containing cultivars. The naringin/neohesperidin ratios in juice vary from 14 to 83 in grapefruit (C. grandis) and from 1.3 to 2.5 in sour orange (C. aurantium) cultivars; the ratio is always less than 1 for the K-Early tangelo. Concentrations of both naringin and neohesperidin can be determined in orange juice by using a single liquid chromatographic isocratic reverse-phase system with a C-18 column. The detection limit for both compounds is 1 ppm with a linear working range to 500 ppm. Concentration relative standard deviations range from 0.47 to 1.06% for naringin and from 0.4 to 1.27% for neohesperidin. Naringin and neohesperidin recoveries ranged from 93 to 102% at concentrations of 5 and 50 ppm. Naringin values from blind duplicate samples of orange/grapefruit juice blends could be duplicated to +/- 3%.     

Degradation of certain aromatic compounds by rhizobia

The ability of 22 strains of Rhizobium to degrade catechol, protocatechuic acid, p-hydroxybenzoic acid and salicylic acid all at 1 mm concentration was examined. In the presence of 4.8 mm Na-glutamate, all rhizobia tested degraded catechol (99–100%), p-hvdroxybenzoic acid (79–99%), protocatechuic acid (81 97%) and salicylic acid (20–83%).The concentration of Na glutamate in the medium affected the degradation of the phenolic compounds at 1 mm concentration. Increased glutamate favoured degradation of p-hydroxybenzoic and salicylic acids but had little effect on catechol. Degradation of protocatechuic acid was inhibited by increased glutamate concentration.Rhizobium phaseoli 405 grown with 8.0 mM Na-glutamate, directly cleaved catechol and protocatechuic acid. p-Hydroxybenzoic acid was converted to protocatechuic acid before ring cleavage. Salicylic acid was converted to gentisic acid before further oxidation. O₂ uptake experiments showed that R. phaseoli 405 grown with p-hydroxybenzoic acid was adapted to this compound and protocatechuic acid. A lag of 30 min was required for catechol and salicylic acid.     

In vitro fermentation by human gut bacteria of proteolytically digested caseinomacropeptide nonenzymatically glycosylated with prebiotic carbohydrates

The in vitro fermentation selectivity of hydrolyzed caseinomacropeptide (CMP) glycosylated, via Maillard reaction (MR), with lactulose, galacto-oligosaccharides from lactose (GOSLa), and galacto-oligosaccharides from lactulose (GOSLu) was evaluated, using pH-controlled small-scale batch cultures at 37 °C under anaerobic conditions with human feces. After 10 and 24 h of fermentation, neoglyconjugates exerted a bifidogenic activity, similar to those of the corresponding prebiotic carbohydrates. No significant differences were found in Bacteroides , Lactobacillus - Enterococcus , Clostridium histolyticum subgroup, Atopobium and Clostridium coccoides - Eubacterium rectale populations. Concentrations of lactic acid and short-chain fatty acids (SCFA) produced during the fermentation of prebiotic carbohydrates were similar to those produced for their respective neoglycoconjugates at both fermentation times. These findings, joined with the functional properties attributed to CMP, could open up new applications of MR products involving prebiotics as novel multiple-functional ingredients with potential beneficial effects on human health.     

Degradation of pentachlorophenol by potato polyphenol oxidase

In this study, polyphenol oxidase (PPO) was extracted from commercial potatoes. Degradation of pentachlorophenol by potato PPO was investigated. The experimental results show that potato PPO is more active in weak acid than in basic condition and that the optimum pH for the reaction is 5.0. The degradation of pentachlorophenol by potato PPO reaches a maximum at 298 K. After reaction for 1 h, the removal of both pentachlorophenol and total organic carbon is >70% with 6.0 units/mL potato PPO at pH 5.0 and 298 K. Pentachlorophenol can be degraded through dechlorination and ring-opening by potato PPO. The work demonstrates that pentachlorophenol can be effectively eliminated by crude potato PPO.     

Digestive Stability, micellarization, and uptake of beta-carotene isomers by Caco-2 human intestinal cells

While isomeric profiles of carotenoids found in food often differ from those in body fluids and tissues, insights about the basis for these differences remain limited. We investigated the digestive stability, relative efficiency of micellarization, and cellular accumulation of trans and cis isomers of beta-carotene (BC) using an in vitro digestion procedure coupled with human intestinal (Caco-2) cells. A meal containing applesauce, corn oil, and either water-soluble beadlets (WSB) or Dunaliella salina (DS) as a BC source was subjected to simulated gastric and small intestinal digestion. BC isomers were stable during digestion, and the efficiency of micellarization of cis-BC isomers exceeded that of all-trans-BC isomers. The cellular profile of carotenoids generally reflected that in micelles generated during digestion, and intracellular isomerization was minimal. These data suggest that cis isomers of BC are preferentially micellarized during digestion and transferred across the brush-border surface of the enterocyte from mixed micelles with similar efficiency as all-trans-BC at the concentrations of the carotenoids utilized in this study.