Effect of phenolic acids and phenolics from plant cell walls on rumenlike fermentation in consecutive batch culture

Information on the interaction between mixed populations in the rumen and plant phenolics is required to fully elucidate the limitations of phenolic compounds on forage digestibility. The objective of this study was to examine the degradation of Italian ryegrass (Lolium multiflorum L.) hay incubated with mixed ruminal populations in consecutive batch culture (CBC) with or without phenolic acids or phenolic compounds extracted from plant cell walls. Each CBC consisted of a series of 10 cultures (3 replicates per culture) inoculated (10%, vol/vol) in sequence at 48-h intervals with microbial suspension from the previous set of cultures. All cultures were grown on a semidefined medium containing Italian ryegrass hay, and each CBC was initiated with an inoculum from the rumen. Rumenlike fermentation characteristics were maintained in control CBCs by repeated inoculum transfer. Treatment CBCs were transferred as described above, but cultures 5, 6, and 7 were incubated in the presence of trans-p-coumaric, cis-p-coumaric, or trans-ferulic acid or phenolics extracted from the cell walls of maize stem or barley straw. Mean apparent dry matter disappearance in control CBC cultures was 495 mg per g of hay, whereas the presence of phenolics reduced the initial dry matter disappearance by 6.3 to 25.6%. trans-p-Coumaric acid and, to a lesser extent, the phenolics from cell walls of maize stem were the most inhibitory compounds for dry matter disappearance and for the production of volatile fatty acids; trans-p-coumaric acid altered the molar ratio of acetate/propionate/butyrate. The CBC further showed variations in the ability of the rumen microbial population to adapt to phenolic compounds.     

Effect of phenolic acids and phenolics from plant cell walls on rumenlike fermentation in consecutive batch culture.

Information on the interaction between mixed populations in the rumen and plant phenolics is required to fully elucidate the limitations of phenolic compounds on forage digestibility. The objective of this study was to examine the degradation of Italian ryegrass (Lolium multiflorum L.) hay incubated with mixed ruminal populations in consecutive batch culture (CBC) with or without phenolic acids or phenolic compounds extracted from plant cell walls. Each CBC consisted of a series of 10 cultures (3 replicates per culture) inoculated (10%, vol/vol) in sequence at 48-h intervals with microbial suspension from the previous set of cultures. All cultures were grown on a semidefined medium containing Italian ryegrass hay, and each CBC was initiated with an inoculum from the rumen. Rumenlike fermentation characteristics were maintained in control CBCs by repeated inoculum transfer. Treatment CBCs were transferred as described above, but cultures 5, 6, and 7 were incubated in the presence of trans-p-coumaric, cis-p-coumaric, or trans-ferulic acid or phenolics extracted from the cell walls of maize stem or barley straw. Mean apparent dry matter disappearance in control CBC cultures was 495 mg per g of hay, whereas the presence of phenolics reduced the initial dry matter disappearance by 6.3 to 25.6%. trans-p-Coumaric acid and, to a lesser extent, the phenolics from cell walls of maize stem were the most inhibitory compounds for dry matter disappearance and for the production of volatile fatty acids; trans-p-coumaric acid altered the molar ratio of acetate/propionate/butyrate. The CBC further showed variations in the ability of the rumen microbial population to adapt to phenolic compounds.     

Biochemical characteristics and antioxidant activity of crude and purified sulfated polysaccharides from Gracilaria fisheri

Sulfated polysaccharides (SPs) from Gracilaria fisheri of Thailand, which were extracted in low-temperature (25 °C) water showed the highest content of phenolic compounds compared with those extracted at high temperature (55 °C). Crude SP antioxidant activity was evaluated by measuring the DPPH free radical scavenging effect which is directly related to the level of phenolic compounds. The sulfate content, total sugar, and SPs yield were also directly related to the extraction temperature. All extracts contained galactose as a major monosaccharide. High antioxidant activity of crude SP, positively correlated with the phenolic compound contents (R² = 0.996) contributed by the existence of sulfate groups and phenolic compounds. In purified SP, F1 fraction exhibited strong radical scavenging ability, but it was not significantly different compared to crude SP extracted at 25 °C. This indicated that the appropriate density and distribution of sulfate groups in the SP extract showed the best antioxidant activity.     

Freeze-dried recombinant bacteria for on-site detection of phenolic compounds by color change

We herein report the development of a recombinant bacterial biosensor for the rapid and easy detection of phenolic compounds in the field. A plasmid was designed to encode a beta-galactosidase reporter gene under the control of capR, an activator involved in phenolic compound degradation. The construct was transformed into Escherichia coli, and transformed cells were stored after being freeze-dried in the presence of sucrose. For detection of phenolic compounds, the cells were rehydrated, and used instantly, without any growth step. In the presence of 0.1 microM-10mM phenol, we observed a red color from hydrolysis of chlorophenol red beta-D-galactopyranoside (CPRG) or an indigo color from hydrolysis of X-galactopyranoside (X-gal). Other phenolic compounds could be detected by this system, including catechol, 2-methylphenol, 2-chlorophenol, 3-methylphenol, 2-nitrophenol, and 4-chlorophenol. These results suggest that this novel bacteria biosensor may be useful for easy, on-site detection of phenolic compounds without the need for unwieldy equipment or sample pretreatment. Indeed, biosensor systems involving beta-galactosidase-expressing freeze-dried recombinant bacteria could prove useful for the in situ detection of many more compounds in the future.     

Vanillin production from simple phenols by wine-associated lactic acid bacteria

AIMS: The ability of lactic acid bacteria (LAB) to metabolize certain phenolic precursors to vanillin was investigated. METHODS AND RESULTS: Gas chromatography-mass spectrometry (GC-MS) or HPLC was used to evaluate the biosynthesis of vanillin from simple phenolic precursors. LAB were not able to form vanillin from eugenol, isoeugenol or vanillic acid. However Oenococcus oeni or Lactobacillus sp. could convert ferulic acid to vanillin, but in low yield. Only Lactobacillus sp. or Pediococcus sp. strains were able to produce significant quantities of 4-vinylguaiacol from ferulic acid. Moreover, LAB reduced vanillin to the corresponding vanillyl alcohol. CONCLUSIONS: The transformation of phenolic compounds tested by LAB could not explain the concentrations of vanillin observed during LAB growth in contact with wood. SIGNIFICANCE AND IMPACT OF THE STUDY: Important details of the role of LAB in the conversion of phenolic compounds to vanillin have been elucidated. These findings contribute to the understanding of malolactic fermentation in the production of aroma compounds.     

Correlations between Accumulation of Dianthramides, Dianthalexin and Unknown Compounds, and Partial Resistance to Fusarium oxysporum f. sp. dianthi in Eleven Carnation Cultivars

The accumulation of dianthramides, dianthalexin and other phenolic compounds in carnation cells at different times before and after inoculation of plants with Fusarium oxysporum f. sp. dianthi, and the development of wilt symptoms were compared for eleven carnation cultivars. Untreated and water-treated controls contained only a little acetone-extractable phenolics. Upon inoculation with F. oxysporum f. sp dianthi, all cultivars accumulated the same range of phenolic compounds, including several dianthramides and dianthalexin, but in different proportions. The total amount of accumulated phenolic compounds per fresh material weight of the extracted stem segments could not be related to the disease resistance level of the different cultivars. However, the accumulation of dianthramides and dianthalexin in the cultivars was positively correlated to resistance, while the accumulation of two other, as yet unidentified, compounds was inversely related to resistance.     

Cause analysis of the effects of acid-catalyzed steam-exploded corn stover prehydrolyzate on ethanol fermentation by Pichia stipitis CBS 5776

The prehydrolyzate obtained from acid-catalyzed steam-exploded corn stover (ASC) mainly contains xylose and a number of inhibitory compounds that inhibit ethanol fermentation by Pichia stipitis. In this study, the effects of the ASC prehydrolyzate, specifically those of the carbohydrate-degradation products, lignin-degradation products (which were extracted from ASC prehydrolyzate using ethyl acetate), and six major phenolic compounds (added to pure-sugar media individually or in combination), on ethanol fermentation were investigated. Results indicate that the effects of the carbohydrate-degradation products were negligible (10 h delayed) compared with those of pure-sugar fermentation, whereas the effects of the lignin-degradation products were significant (52 h delayed). Meanwhile, the inhibitory effects of the major phenolic compounds were not caused by certain types of inhibitors, but were due to the synergistic effects of various inhibitors.     

Acibenzolar-S-methyl-Induced Systemic Resistance against Anthracnose and Powdery Mildew Diseases on Cucumber Plants without Accumulation of Phytoalexins

In a study to elucidate the possible involvement of phytoalexins in acibenzolar-S-methyl (ASM)-induced systemic resistance in cucumber plants ( Cucumis sativus L.), the phenolic compounds were extracted from ASM-treated and inoculated plants and compared with those from Milsana^®-treated plants previously reported to accumulate phytoalexins in cucumber. The glycoside-linked phenolic compounds from cucumber leaves were tested for their antifungal activity to the growth of pathogens which were most effective against the cucumber anthracnose fungus Colletotrichum orbiculare , followed by the scab fungus Cladosporium cucumerinum but ineffective against the Corynespora leaf spot fungus Corynespora cassiicola . Nevertheless, the accumulations of active compounds appeared to increase with the growth stages of cucumber plants irrespective of ASM treatment. In ASM-pretreated cucumber plants either inoculated with anthracnose or the powdery mildew fungus, there was no increase in phytoalexin-like phenolics.     

忍冬属植物花药药隔的特化结构及其生物学意义

花药药隔的特化结构通常具有重要的生物学意义。目前,有关药隔特化出贮存酚类物质的异细胞群的研究报道甚少,该特化结构有何生物学意义则未见报道。本研究运用半薄切片技术、冰冻切片技术、组织化学和细胞化学等方法对忍冬属Lonicera植物特化药隔异细胞群的主要内含物进行定性分析,实验证明忍冬属特化药隔异细胞群内含丰富的酚类物质。另外通过对忍冬属华南忍冬L.confusa药隔薄壁组织的发育及其与药隔维管束的关系分析,推测忍冬属特化药隔可能一方面对发育中的花药维管束起保护作用,另一方面又可作为酚类物质的临时贮存场所。同时研究发现忍冬属植物特化药隔异细胞群的形成及其分布特点可能具有重要的系统学意义。     

Phenolic compounds and antioxidants from Eucalyptus camaldulensis as affected by some extraction conditions,a preparative optimization for GC-MS analysis

Abstract

Four organic solvents along with water were applied for the conventional extraction of Eucalyptus camaldulensis (Myrtaceae), phenolic contents and antioxidant activities were investigated through variable protocols and correlation coefficients were considered, the phenolic composition was also characterized by Gas chromatography-mass spectrometry (GC-MS). Using solvents with dissimilar polarities affected the phenolic yields extracted from E. camaldulensis and their related antioxidant activities varied significantly among the four investigated plant organs. The leaf extract of acetone 70% contained the highest amount of phenolic compounds (46.56?mg/g dry weight); while the bud-water boiled extract maintained the maximum value of tannins (45.68?mg/g dry weight). Correlation coefficients indicated that phenolic compounds were mostly accountable for the phosphomolybednum antioxidant potentials (0.520), followed by tannins (0.460). Also, both the reducing power activities and hydrogen peroxide scavenging of E. camaldulensis extracts positively correlated with tannins, but at different significance degrees. However, the GC-MS analysis revealed that most of the detected phenolic constituents were more abundant in the plant seed. So, the existence of some other compounds such as organic acids, along with phenolics, may have increased the antioxidant potentials of leaf and bud. Undeniably, the optimization of extraction conditions could stimulate the antioxidant capabilities of the plant extracts of E. camaldulensis.     

加工因素对橄榄叶提取物抗氧化活性的影响

研究在橄榄叶加工过程中,加工因素对橄榄叶提取物中抗氧化活性的影响,这些因素包括:(1)干燥方式(微波炉干燥,烘箱干燥,低温冷冻干燥和熏蒸及烘箱结合干燥);(2)提取方式(超声波提取和搅拌式提取);(3)提取溶剂的酸度(pH 4、7、10).实验将总多酚含量和清除自由基活性作为衡量提取物抗氧化有效成分和活性的指标.研究结果表明,通过低温冷冻干燥、调节pH至4和采用超声波提取的方式,橄榄叶提取物中的抗氧化有效成分最多.本研究对橄榄叶等天然植物中抗氧化成分提取工艺的制定具有参考价值.     

Metabolism of phenolic compounds in <Emphasis Type="Italic">Vitis riparia</Emphasis> seeds during stratification and during germination under optimal and low temperature stress conditions

We studied the alterations in phenolic compounds in grape seeds during their stratification and germination under optimal conditions (+25 °C) and at low temperature (+10 °C). Biological materials in the study were seeds of Vitis riparia. Phenolic compounds were extracted from defatted seeds using 80 % methanol or 80 % acetone. The content of total phenolics was determined with the Folin-Ciocalteau reagent, while the content of tannins was determined by vanillin assay and the protein (BSA) precipitation method. The RP-HPLC method was used to determine phenolic compounds (phenolic acids, catechins) in the extracts. High amounts of tannins, catechins, gallic acid and lesser amounts of p-coumaric acid were found in the seeds. The content of total phenolics in acetone extracts was higher than that obtained using methanol. The amounts of phenolic acids and tannins found in V. riparia seeds after stratification were much lower. It may confirm a possible role of these compounds in dormancy of V. riparia seeds. After 72 h of low temperature treatment, inhibition of grape root growth and biochemical changes in seeds were detected. The chilling stimulated increased accumulation of some phenolic compounds (free gallic acid and catechins) in the seeds. These substances can protect plants against some abiotic stressors.     

COMPOUNDS FROM THE STIGMAS OF TEN SPECIES

Extracts of the intact stigmatic surface of 10 species from different families contained little or no free sugar. The principal components of the extracts consisted of phenolic (anthocyanins, flavonoids, cinnamic acids) and lipid compounds. The phenolic compounds occurred as glycosides or esters. Phenolic compounds could inhibit insects and diseases, stimulate or inhibit pollen germination, or provide specificity to the pollen selection-germination process of the stigma by interacting with growth-regulators or related compounds.     

Phenolic acids in groundnut seed exudates

Summary Seed exudates were collected aseptically and extracted for phenolic acids. Paper chromatographic analysis revealed the presence of eleven phenolic compounds.Department of Botany, S.V. University, Tirupati-517502, Andhra Pradesh, India.     

Free phenols in maize pith and their relationship with resistance to Sesamia nonagrioides (Lepidoptera: Noctuidae) attack

The stem borer Sesamia nonagrioides (Lefèbvre) is the most important insect pest of maize, Zea mays L., in northwestern Spain. Among the metabolites present in maize, phenolic compounds could play an important role in resistance. The objective of this work was to determine whether a relationship between phenols and the amount of resistance exists. Amounts of free phenolic compounds in the pith of 13 inbred maize lines that differ in resistance were measured. The phenolic compounds identified were p-coumaric acid, cafeic acid, ferulic acid, vanillic acid, syringic acid, chorogenic acid, sinapic acid, p-hydroxybenzoic acid, and vanillin. The amount of free p-coumaric acid was correlated with the resistance level. Higher quantities of p-coumaric in the pith could contribute to general resistance to stem borer attack. Jointly with ferulic acid, p-coumaric could provide resistance mechanisms through cell wall fortification and lignification. The other compounds showed no or an unclear relationship with resistance. The vanillic acid showed a decreased tendency after silking, when maize is most attractive for S. nonagrioides, suggesting this acid could act as a chemoattractant for S. nonagrioides larvae or adults. Future studies that focus on these phenolic compounds could be useful in understanding S. nonagrioides resistance.     

Effects of phenolic monomers on growth of Acidothermus cellulolyticus

Previous studies on biological pretreatment of switchgrass by solid-state fermentation with Acidothermus cellulolyticus 11B have shown that inhibitory compounds prevent growth on untreated switchgrass. A. cellulolyticus was grown in liquid medium containing cellobiose with phenolic monomers added to determine if the phenolic compounds are one possible source of inhibition. Cinnamic acid derivatives (trans-p-coumaric, trans-ferulic, and hydrocinnamic acids), hydroxybenzoic acids (p-hydroxybenzoic, syringic, and vanillic acids), benzaldehydes (vanillin and p-hydroxybenzaldehyde), and condensed tannin monomers (catechin and epicatechin) were tested at levels up to 20 mM. All compounds exhibited a dose-response relationship and strongly inhibited growth at 20 mM. trans-p-Coumaric acid was found to be the strongest inhibitor of A. cellulolyticus growth, with a specific growth rate of 0.004 h(-1) at 1 mM (0.18 h(-1) without phenolic monomer). GC-MS and HPLC methods were used to confirm the presence of these phenolic compounds in switchgrass and measure the amounts extracted using different conditions. The amounts of phenolic compounds measured were found to be higher than the threshold for growth inhibition. Leaching with water at 55°C was inefficient at removing bound phenolics, whereas NaOH treatment improved efficiency. Phenolic compounds spiked into alkaline pretreated switchgrass were also found to inhibit growth of A. cellulolyticus in solid-state fermentation. However, addition of insoluble polyvinylpolypyrrolidone (PVPP) to switchgrass improved growth of A. cellulolyticus in liquid cultures, providing a possible approach for alleviating microbial inhibition due to phenolic compounds in lignocellulose.     

Isolation of anti-fungal phenolic compounds from petioles of two Hevea brasiliensis (rubber) genotypes and their effect on Phytophthora meadii

Phenolic compounds were present in greater amounts in non‐infected petioles of genotypes of Hevea brasiliensis that are resistant to Phytophthora leaf disease than in genotypes that are susceptible. Phenolic compounds extracted from petioles of either susceptible (PB86) or resistant (RRIC100) genotypes, before or after infection with Phytophthora meadii, had anti‐fungal properties. Artificially infected petioles of PB86 had phenolic acids, triterpenoids or flavonoids, whereas healthy petioles contained only triterpenoids or flavonoids. However, healthy or infected petioles of RRIC100 contained only trace amounts of the above compounds and of vanillin (3‐methoxy‐4‐hydroxybenzaldehyde). Vanillin and umbelliferone (7‐hydroxycoumarin) were shown to suppress zoospore germination of P. meadii on glass slides and to inhibit its growth in pea broth and V‐8 juice agar. Vanillin was slightly more active than umbelliferone. Resistance of RRIC100 to Phytophthora was suspected as being related to the polymerisation of phenolic compounds to form lignin, which may suppress further spread of the pathogen's mycelium into healthy tissues. Formation of lignin from phenolic aldehydes as a barrier to disease spread may be a critical factor in resistance.     

Phenolic Content in Male and Female Carica papaya: A Possible Physiological Marker for Sex Identification of Vegetative Seedlings

The phenolic composition was determined in the leaves, petioles and bark tissues of male and female plants of two papaya cultivars. The same kind of phenolics were isolated from the male and female plants. However, a marked difference was observed between the plant organs of different cultivars. The important free and bound phenolics extracted after acidic and alkaline hydrolysis were caffeic acid, gentisic acid, m-coumaric acid, p-coumaric acid, salicylic acid and quercetin. Four phenolic compounds were not identified. The amounts of free, acid-hydrolysable and alkali-hydrolysable phenolic compounds were considerably higher in male plants.     

The effect of different solvents and number of extraction steps on the polyphenol content and antioxidant capacity of basil leaves (Ocimum basilicum L.) extracts

The objectives of this study were to determine best conditions for the extraction of phenolic compounds from fresh, frozen and lyophilized basil leaves. The acetone mixtures with the highest addition of acetic acid extracted most of the phenolic compounds when fresh and freeze-dried material have been used. The three times procedure was more effective than once shaking procedure in most of the extracts obtained from fresh basil leaves – unlike the extracts derived from frozen material. Surprisingly, there were not any significant differences in the content of phenolics between the two used procedures in the case of lyophilized basil leaves used for extraction. Additionally, the positive correlation between the phenolic compounds content and antioxidant activity of the studied extracts has been noted. It is concluded that the acetone mixtures were more effective than the methanol ones for polyphenol extraction. The number of extraction steps in most of the cases was also a statistically significant factor affecting the yield of phenolic extraction as well as antioxidant potential of basil leaf extracts.