Mucic acid is a hexaric acid that can be biosynthesized by oxidation of D-galacturonic acid, which is the main constituent of pectin. The structure and properties of mucic acid are similar to that of glucaric acid, and can be widely applied in the preparation of important platform compounds, polymers and macromolecular materials. Pectin is a cheap and abundant renewable biomass resource, thus developing a process enabling production of mucic acid from pectin would be of important economic value and environmental significance. This review summarized the structure and hydrolysis of pectin, the catabolism and regulation of D-galacturonic acid in microorganisms, and the strategy for mucic acid production based on engineering of corresponding pathways. The future application of mucic acid are prospected, and future directions for the preparation of mucic acid by biological method are also proposed.
Hexuronic Acids/metabolism* ; Pectins/metabolism* ; Sugar Acids/metabolism*

Background: Pectin is a pharmaceutically relevant excipient that can be upcycled from selected Philippine fruit peel wastes. Method optimization of pectin extraction leads to maximizing yields from limited resources, while also reducing environmental wastes, and providing local alternative sources. Objectives: This study aimed to optimize the method of extracting pectin from selected Philippine fruit peel wastes using the Box-Behnken design, by varying the acid extraction solvent, treatment time, and working temperature. Methodology: The three-level (-1, 0, 1) Box-Behnken design (15 set-ups) was used to optimize the pectin extraction in each of the fruit peel samples (C. maxima; A. heterophyllus; ripe and unripe M. indica; D. zibethinus; and H. undatus). The three experimental factors were the type of 3N acid used as extracting solvent (HNO₃, H₂SO₄, and HCl); duration of treatment in minutes (60, 90, and 120); and temperature of treatment in C 60, 75, and 90). The %yield was computed in each set-up, and the projected yields were generated using multiple linear regression. The pectin samples obtained from the optimized conditions were subjected to the physicochemical characterization, with apple pectin as the standard. Degree of esterification (DE), equivalent weight (EW), methoxy content (MC), alkalinity of ash (AA), and anhydrouronic acid content (AUA) were performed. Results: Maximum yields were extracted from C. maxima (28.96%), A. heterophyllus (20.12%), ripe M. indica (26.23%), and unripe M. indica (25.89%), using 3N H₂SO₄, for a treatment duration of 60 minutes, at a working temperature of 90 C, and H. undatus (25.03%) at 60 C, for a treatment duration of 120 minutes. Conclusion Optimum conditions were identified to extract pectin in each of the fruit peel samples. The 3N H₂SO₄ produced the highest pectin yields in all of the set-ups, while the treatment time and working temperature vary per fruit peel sample. Pectin extract from C. maxima, A. heterophyllus, and M. indica was comparable to the standard.
Pectins

Pectin methylesterase (PME) is an important pectinase that hydrolyzes methyl esters in pectin to release methanol and reduce the degree of methylation of pectin. At present, it has broad application prospects in food processing, tea beverage, paper making and other production processes. With the in-depth study of PME, the crystal structures with different sources have been reported. Analysis of these resolved crystal structures reveals that PME belongs to the right-hand parallel β-helix structure, and its catalytic residues are two aspartic acids and a glutamine, which play the role of general acid-base, nucleophile and stable intermediate, in the catalytic process. At the same time, the substrate specificity is analyzed to understand the recognition mechanism of the substrate and active sites. This paper systematically reviews these related aspects.
Carboxylic Ester Hydrolases ; chemistry ; metabolism ; Catalytic Domain ; Crystallography ; Pectins ; metabolism ; Protein Structure, Tertiary ; Substrate Specificity

OBJECTIVETo evaluate the efficacy of pectin, a kind of soluble dietary fiber, in diarrhea predominant irritable bowel syndrome(IBS-D).

METHODSA total of 87 patients with IBS-D were selected in the Jinling Hospital between July 2011 and December 2013. Using a randomized, controlled trial, the efficacy of pectin for IBS-D was prospectively evaluated. Subjects were randomly assigned to receive 24 g pectin powder/d (n=46) or a placebo (n=41). Before and after 6 weeks of treatment, colonic microflora was examined by real-time PCR and compared between groups. Changes in stool frequency and form (Bristol stool scale), composite score of symptoms (Likert scale) and QOL scores (IBS-QOL questionnaire) were also monitored. Peripheral blood sample from patients with IBS-D was obtained to estimate the cytokines level, which was compared with that obtained from a group of age- and sex-matched healthy volunteers (n=20).

RESULTSThose patients randomized to pectin experienced a greater reduction in composite symptom scores and Bristol stool scale scores, as well as significant improvement in QOL scores (P<0.05). The pectin acted as prebiotics and significantly enhanced faecal bifidobacteria and decreased total Clostridium sp (P<0.05). At baseline, patients with IBS-D demonstrated an abnormal IL-10/IL-12 ratio, which was normalized by pectin feeding alone (P<0.01). Placebo did not exert these effects on the aforementioned parameters after treatment. No significant adverse effects were reported during the study.

CONCLUSIONSPectin acts as a prebiotic in specifically stimulating gut bifidobacteria in IBS-D patients and is effective in alleviating clinical symptoms, balancing colonic microflora and relieving systemic inflammation. In view of its ability to re-establish a healthy gut ecosystem, pectin has the potential of being a therapeutic agent in IBS-D.

Bifidobacterium ; Diarrhea ; Feces ; Humans ; Irritable Bowel Syndrome ; Pectins ; Treatment Outcome

We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8+ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.
Acute-Phase Proteins/metabolism ; Adaptor Proteins, Vesicular Transport/metabolism ; Animals ; Antigens, CD14/metabolism ; Bone Marrow Cells/cytology/drug effects ; CD8-Positive T-Lymphocytes/*immunology ; Carrier Proteins/metabolism ; Cell Differentiation/drug effects ; Cell Nucleus/drug effects/metabolism ; Cell Proliferation/drug effects ; Cytokines/biosynthesis ; Dendritic Cells/cytology/drug effects/enzymology/*immunology ; Enzyme Activation/drug effects ; Lymphocyte Activation/*drug effects ; Membrane Glycoproteins/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Mitogen-Activated Protein Kinases/metabolism ; Myeloid Differentiation Factor 88/metabolism ; NF-kappa B/metabolism ; Neoplasms/immunology/*pathology ; Pectins/*pharmacology ; Phenotype ; Protein Transport/drug effects ; Receptors, Chemokine/metabolism ; Signal Transduction/drug effects ; T-Lymphocytes, Cytotoxic/cytology/drug effects ; Toll-Like Receptor 4/*agonists/metabolism

OBJECTIVETo study the effects of oxaliplatin combined with low-molecular-weight citrus pectin (LCP) on cell proliferation and apoptosis in human colon carcinoma cell line HT29 in vitro.

METHODSEffects of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cells proliferation were determined by MTT. Coefficient of drug interaction (CDI) was calculated. Influence of oxaliplatin alone and oxaliplatin combined with LCP on HT29 cell apoptosis was determined by fluorescence activated cell sorting (FACS). Protein expression change of procaspase-3, 8, 9, PARP was examined by Western blotting.

RESULTSBoth oxaliplatin alone and oxaliplatin combined with LCP could suppress HT29 cell proliferation in both dose- and time-dependent manner. The inhibitory effect of oxaliplatin combined with LCP on HT29 cell proliferation was more significant (P<0.01) with a CDI less than 1. FACS analysis showed that oxaliplatin alone and combination therapy could increase the apoptosis proportion of HT29 cells. After the drug treatment for 6, 24, and 48 hours, the apoptosis rate of oxaliplatin alone group was (9.76±0.47)%, (20.45±0.74)%, (28.70±3.29)%, and apoptotic rate of the combination group was (20.63±0.69)%, (34.35±1.02)%, (49.47±3.04)%, respectively, which was significantly higher as compared to oxaliplatin alone (P<0.01). Both oxaliplatin alone and combination therapy down-regulated expressions of procaspase-3, 9, and PARP protein. Procaspase-3, 9, PARP protein expression in combination group decreased more significantly, while procaspase-8 expression was not significantly different between the two groups.

CONCLUSIONLCP can enhance the ability of oxaliplatin to inhibit cell proliferation and induce apoptosis, which may be associated with the activation of mitochondrial apoptosis pathway.

Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Colonic Neoplasms ; pathology ; HT29 Cells ; Humans ; Organoplatinum Compounds ; pharmacology ; Pectins ; pharmacology

The purpose of this study was to examine the anti-oxidative activity of pectin and other polysaccharides in order to develop a cosmeceutical base having anti-oxidative effects towards retinyl palmitate (RP). The anti-oxidative stabilizing effects of pectin and other polysaccharides on RP were evaluated by DPPH assay and then the stabilizing effect of pectin on RP was examined as a function of time. Among the polysaccharides we examined, pectin exhibited a considerably higher anti-oxidative activity, with an approximately 5-fold greater DPPH radical scavenging effect compared to other polysaccharides. The DPPH radical scavenging effect of pectin increased gradually with increasing concentrations of pectin. At two different RP concentrations, 0.01 and 0.1% in ethanol, addition of pectin improved the stability of RP in a concentration dependent manner. The stabilizing effect of pectin on RP was more effective for the lower concentration of RP (0.01%, v/v). Further, degradation of RP was reduced following the addition of pectin as measured over 8 hours. From the results obtained, it can be suggested that pectin may be a promising ingredient for cosmeceutical bases designed to stabilize RP or other pharmacological agents subject to degradation by oxidation.
Ethanol ; Pectins ; Polysaccharides ; Vitamin A

The objective of this study was to estimate the contents of dietary insoluble and soluble fiber in school meal. Samples of the school meals were collected from May to June in 2008. Three elementary schools and three middle schools around Masan area were selected for analysis. Dietary soluble and insoluble fibers in the school meals were analyzed directly by the AOAC method. From the initial experiment phase, we used cellulose and pectin as a standard of dietary fiber, and average recovery rate of insoluble fiber and soluble fiber was calculated. The recovery rate was observed, the cellulose 109.7+/-11.7% (range 90~150%) and pectin 77.8+/-10.8% (range 64.7~96.7%), respectively. The amounts of insoluble fiber and soluble fiber were analyzed in the total of 66 dishes, which included 7 kinds of cooked rice (bab) made with some cereal products and vegetables, 19 kinds of soup (guk) made with meats or vegetables, 11 kinds of kimchi, 21 kinds of entrees or side dishes, and 8 special dishes. Conclusively the school meal, per serving size, would provide above 75% KDRI of total dietary fibers through mainly soups and special menu, with the exception to fruits. In addition, it might be expected that children could consume more soluble fiber from the meals with the special dishes than from the regular ones.
Cellulose ; Edible Grain ; Child ; Dietary Fiber ; Fruit ; Humans ; Meals ; Meat ; Nitroimidazoles ; Pectins ; Sulfonamides ; Vegetables

BACKGROUND/AIMS: The administration of liquid nutrients to patients is often accompanied by complications such as gastroesophageal reflux. To prevent gastroesophageal reflux, high-viscosity liquid meals are used widely, however, it still remains controversial whether high-viscosity liquid meals have any effect on the rate of gastric emptying. The present study was conducted with the aim of determining whether high-viscosity liquid meals had any effect on the rate of gastric emptying and mosapride might accelerate the rate of gastric emptying of high-viscosity liquid meals. METHODS: Six healthy male volunteers underwent 3 tests at intervals of > 1 week. After fasting for > 8 hours, each subject received one of three test meals (liquid meal only, high-viscosity liquid meal [liquid meal plus pectin] only, or high-viscosity liquid meal 30 minutes after intake of mosapride). A 13C-acetic acid breath test was performed, which monitored the rate of gastric emptying for 4 hours. Using the Oridion Research Software (beta version), breath test parameters were calculated. The study parameters were examined for all the 3 test conditions and compared using the Freidman test. RESULTS: Gastric emptying was significantly delayed following intake of a high-viscosity liquid meal alone as compared with a liquid meal alone; however, intake of mosapride prior to a high-viscosity liquid meal was associated with a significantly accelerated rate of gastric emptying as compared with a high-viscosity liquid meal alone. CONCLUSIONS: This study showed that high-viscosity liquid meals delayed gastric emptying: however, mosapride recovered the delayed rate of gastric emptying by high-viscosity liquid meals.
Benzamides ; Breath Tests ; Cross-Over Studies ; Fasting ; Gastric Emptying ; Gastroesophageal Reflux ; Humans ; Male ; Meals ; Morpholines ; Pectins

OBJECTIVETo evaluate the anti degenerative effect of pectin/polyvinyl alcohol composite (CoPP) hydrogel as artificial nucleus material in an animal model.

METHODSThirty-six New Zealand white rabbits were used to build animal models, the L₄₋₅ intervertebral discs were pierced with a Gauge#16 needle and polyvinyl alcohol (PVA) or CoPP implants were inserted into the holes. For comparative purposes, L₃₋₄ discs underwent sham treatment or control treatment in which the disc was pierced but no implant was inserted. All the discs were divided into four groups as follows: sham disc group, pierced disc group, PVA disc group and CoPP disc group. The discs were analyzed radiologically and histologically for degenerative changes at 1, 3 or 6 months after surgery.

RESULTSNone of the animals died from operative complications, such as paraplegia or infection before being killed. Macroscopically, none of the implants showed any signs of displacement at the time of harvest. The radiological analysis revealed that significantly less disc height loss was found with the PVA and CoPP replacement treatment than with the pierced treatment (P < 0.05). Changes in disc height after the replacement treatment were not significantly different from that after the sham treatment (P > 0.05). Histological degeneration of the replaced discs was delayed in comparison with that of the pierced discs (P < 0.05), but progressed with time, and PVA replacement showed faster disc degeneration than CoPP replacement.

CONCLUSIONSDegeneration of the anulus fibrosus after the CoPP prosthetic nucleus replacement treatment is delayed by preserving disc height and occupying the space of the nucleus pulposus, and it has great potential clinical application value.

Animals ; Female ; Implants, Experimental ; Intervertebral Disc ; pathology ; surgery ; Lumbar Vertebrae ; surgery ; Male ; Models, Animal ; Pectins ; therapeutic use ; Polyvinyl Alcohol ; therapeutic use ; Rabbits